131mirafiori forum

Hi All,

I was reading in the thread listed below and Parrish states that the TC should be timed up on #4 and not #1, can someone explain why this is, I would have thought that it would not make any difference if the engine was timed with either #1 or #4 on the compression stroke, the crank at TDC and with the rotor arm pointing at the relevant terminal on the dizzy cap. Am I missing something here?

http://www.131mirafiori.com/smf/index.php?topic=4042.msg31705#msg31705

Regards

keith

Are you talking about ignition timing or camshaft timing? Parrish is correct about camshaft timing: With the crank and cam pulleys set to their correct timing marks, the rotor arm should point to number 4 cylinder. Get the ignition timing 180 degrees out and you'll get flames out of the carburettor(s) instead of in the cylinders. If you don't believe that I'll show you a badly burnt ITG air filter  :o ::) ;D

Fiat should have put the marks on the pulleys for first cilinder instead of the fourth. Would have been a lot easier. ;)

Hi Guys,

Both cam and ignition timing Theo,

Cam Timing...What position should the cam lobes be in when fitting a new belt to correctly time the cams?

Ignition Timing...On the standard engine with the cams and crank lined up with the relevant marks on the cam pulleys and the cam housings and with the crank lined up with TDC, is the distributor installed with the rotor arm pointing at 1 or 4 ???. Which cyclinder should be on the compression stroke? then the other would be on the exhaust stroke, or does it not matter. I ask this because I have read that a timing light should be attached to #4 lead.

Dare I say it but Haynes state that when fitting a timing belt, it should be set up on TDC with #1 on compression .. They also say the same when fitting a distributor and that the rotor should point to #1 and not #4. I know that people on here say that the manual should be put in the bin but surely there must be some truth in what they say, thats why I confused at being told that it should be set up on #4.

Mirafioriman, I dont understand what you mean by " Fiat should have put the marks on the pulleys for first cilinder instead of the fourth. Would have been a lot easier". Surely the cam marks are the same for setting both cyclinders, with the belt fitted then would it not be a case of just rotating the engine until #4 is on compression or #1 is on compression and then set the dizzy. What is the answer to my question under cam timing above, if I know the answer to that then my confusion should disappear.

Regards

keith

With the crank and cam wheel marks lined up to their marks, the rotor arm should be pointing to number 4 cylinder.
When setting up ignition timing, connect your timing light trigger to number 1 cylinder.

Hi Theo,

I was editing my post when you replied can you read my last post again especially relating to the cam timing. For instance if I were to line up the cams to the relevant marks and then rotated the pullys 360* then would the cam lobes return to the same position,  if not I think this is where I might be going wrong when fitting the belt. I havnt taken the cam covers off yet to see what happens everytime the pulley is rotated 360* I have just thought about it now following your comments. 

Is this what you mean by setting the cam timing to #4

Keith

You are confusing me now  :-\  The camshafts are turning at half the speed of the crankshaft, so when you say "rotate the pulleys 360 degrees" do you mean of the camshaft? which would be two revolutions of the crankshaft which would be a complete turn of the distributor (driven by the 'in block cam' or layshaft). If you rotate the crankshaft by 360 degrees, you'll only rotate the camshafts by 180 degrees so if you start with rotor arm at number 4 it will be at number 1. There are four strokes of intake, compression, combustion (power) and exhaust in a four-stroke engine and they occur during two crankshaft rotations per power cycle.

(http://upload.wikimedia.org/wikipedia/commons/d/dc/4StrokeEngine_Ortho_3D_Small.gif)

So if you are putting a new belt on the engine, line up the crankshaft pulley to its TDC mark, line up the two camshaft pulleys to their timing marks, line up the idler shaft pulley so the rivet is pointing to approximately 2:00 o'clock (so the distributor rotor arm is pointing to number 4)  and fit the belt. Then when the engine is started (hopefully!  ;)) connect your timing light to number 1 cylinder and set the timing to 10 degrees BTDC (set the idling as low as you can for this so the advance weights don't have any effect).

Hi Theo,

Thanks for the graphic,  

I think Ive got it, If I line up the crank to TDC and the cam pulleys to their marks should #1 valves be on the overlap whislt #4 is on compression.

As I said i havnt got access to take the cam covers off until the weekend but from what I can remember by looking at #1 is that the inlet cam lobe is about to open the valve and the exhaust lobe is just after closing. So in this position is #4 on compression? hence the rotor pointing to #4.

I thought that in this position that #1 valves were closed but I have realised that they are not closed but in the overlap position. I have been fitting the belt in this position which it would appear was actually correct relating to #4. But I thought I was setting up #1.

Is what I am saying now making sense.

Regards

keith

Yes, I think we're in agreement now  ;) ;D

You need to take the cam covers off to satisfy yourself but with all the marks lined up, number 1 cylinder is starting its four-stroke cycle, hence the reason for the marks being where they are  ;)  That means number 1 piston is at TDC having just finished the exhaust stroke and about to start the intake stroke so the exhaust valve has just closed and the inlet valve is about to open. At the point of number 1 starting its 4-stroke cycle, with a firing order of 1,3,4,2,  number 4 is half way though it's cycle; so it's finished the intake cycle (1) and also finished the compression cycle (2) and it's about to go into the power cycle (3) hence the rotor arm is at the point ready to fire number 4 spark plug. 

When it comes to using a timing light to time the ignition, you are not concerned about the position of the cams but only concerned with the position of the crankshaft (i.e. the pistons) and as there are two revolutions of the crank per engine cycle, you can connect the ignition light to either number 1 or number 4 cylinder. But I find it more logical and easier to connect to number 1 cylinder.

 

Thanks Theo,

Yeah I have got it now. I realise where I was going wrong in thinking that #1 valves were closed but in fact were overlapping and about to start its cycle.

You may recall from my previous posts in the Garage section, 2ltr cambelt query and valve clearance, I am having problems with the engine bottoming out at 80-85 mph. I have reset the valve clearances, I have replaced all the electrical components, all the jets in the carbs etc are as spec and clean, the float level is correct. I am now thinking that my problem may be to do with the advance in the distributor.

With the static advance set at 10*BTDC the full advance is only approx 25* including the static 10 at 3500 rpm. I am basing this on the distance between the 10* mark and the TDC mark (approx 12mm) and my full advance looks approx one and half times that again. I can try measure this accurately (got any tips) but is this in the ball park. Although I have read in the Guy Croft book that it should be in the region of 37*

Whats your opinion on this, could this be causing my speed problem. Is there an easy way to check that the advance springs are working ok? I have centrifugal advance.

keith

The standard 131 distributor has just centrifugal advance weights. The weights are controlled by two springs and I've seen a million (only slight exaggeration there  ;D) different types of springs. Unlike the 124 springs that are both the same, the 131 seems to have two different springs: one with slight tension and a tighter one with elongated 'loops' offering no resistance at all to start with.  I have experimented a lot with these springs and I can tell you that they make little noticeable difference.

I was always under the impression that static advance is 10 degrees and full advance is at 24 degrees so your measurements seem correct to me. It's important to have a very low idling speed when setting the static advance to make sure the weights are not advancing the ignition. If you can't get the idling slow enough (<500 rpm) then either disable the weights (cello-tape is good for this!) or set the 'idling' static advance to about 12 degrees. A lot of people now set the static advance to 5 degrees due to the low octane fuels but I found no problems running unleaded with 10 degrees advance. You can of course set up the static advance 'statically' but not so easy with electronic ignition.

I am certain that your limited top speed problem is nothing to do with ignition advance or with the ignition system at all. In fact from your description of the problem I'd say "it can't happen"!  :o ;D If you have no loss of power in lower speeds (which you claim you don't) and you are not running out of revs at 80mph (which you claim you don't) then I can't see why the engine is not pulling beyond 80mph. Are you sure it's not fitted with a lorry-type speed-limiter?  ;D ;D ;D

Now there's a point I forgot to look for a limitor, Ha.

Seriously I am getting really fed up trying to solve the problem, this engine was running superbly in the super and now its no better that the original moggy 1098cc engine, that used to do 70mph.

Something else I have thought about is the fuel return line, I have connected it and on reading guy croft book last night I came across this article. I have replaced the block mounted mechanical pump with an electrical pump fitted at the tank, based on what he says maybe the problem could lay here, under high rpm could some of the fuel be by passing the carb and returning to the tank?

keith

That would be equivalent to running out of fuel. So I think the engine would cough and splatter not just 'not-go-any-faster'.

Oh darn it

Easy way to set the ignition timing and get it right is to drive it down the road and advance ignition timing until it pinks and retard it until it doesn't, It will take few stops to get it right but will be spot on.
Re your power/speed problem are you sure the second choke is opening ?  I know I asked this before but as Thotos said it makes no sense !

Hi david,

I have opened the throttle at the carb with my hand and both chokes are opening fully (vertical) and I have wedged a piece of wood between the seat and the pedal and again both chokes are open (vertical). So that rules that out.

I find it hard to describe my problem exactly but I will try again, The engine idles ok at 900rpm it revs and sounds ok when standing still and will rev to 6000 rpm in 2nd, 3rd and 4th. From a standing start I can really give it some through the gears and appears to go ok but when I get to 80-85 then the car wont go any faster, when it is flat out I get a loud noise like a heavy drone coming from the engine. This happens if I drive it hard to 80 or just build up 80 slowly. Also when reving the engine hard it doesnt feel smooth.

As I said earlier the engine used to perform very well in my mirafiori. Its the same carb (34ADF) which was just cleaned and put back on. The idle mixture screw is 2 and a bit turns out from seated. As you can see in my previous posts, the carb has all the original spec jets etc. The float is set at 6mm. I fitted a new float jet.

Last week I replaced all the electrical components including the ignition module at the coil.

I thought it might have been fuel starvation due to the mechanical pump so I replaced it with a Facet electrical pump but made no difference.

Cam timing is ok, valve clearances done.

I have been trying to resolve this problem for approx 18 months and I am really getting p---ed off because it took me 9 years on and off to restore the car and after all that hard work I dont get to enjoy the car to its full potential. I rarely drive my cars over 70-80 mph but it is really annoying to know that I cant even if I wanted to.

I will try doing what you recommend regarding setting the timing and see what happens.

If you can think of any other possible causes (although we are running out of options) please let me know.

And theres me thinking that all an engine needs to run is compression, fuel and a spark. Hymmm

Thanks again

Keith
 

How about doing a plug cut to check under load mixture, or putting it on a Dyno for the same?  could the carb clean have the jets wrong way round?

The vibration is odd though.

I'm with Toad now. Get it on a decent rolling road and see what's actually going on under load. I'm still betting it's something simple.

Hi Guys,

The jets are 122 main and 130 secondary, i have checked this.

Vibration is probably a bit strong, from 3000 rpm upwards it just doesnt feel smooth.

Rolling road may be my next option I just wanted to check everything that I possibly can before going on a dyno.

when you say try a plug cut to check underload mixture do you mean drive the car at say 5000 -6000 rpm then put it in neutral and turn off the ignition and pull a plug to see what colour it is?

Something simple, that would be nice I only wish I could find it.

Regards

keith

Is that new or has it been reported before? Slight vibration I wouldn't worry about as the 2 litre twin-cams are not the smoothest of engines. I think we are missing a piece of the puzzle here  :-\  If the engine can rev to 6000rpm and sustain 6000rpm in 2nd and 3rd  gears then I don't see why it wouldn't do so in 4th gear (maybe not in 5th due to air resistance). 6000rpm in 4th should be over 100mph. If the engine cannot achieve 6000rpm in 4th (but does so in 3rd, 2nd and 1st) then it must be because it cannot overcome wind resistance so it must be down on power. But Keith claims it doesn't seem down on power in lower gears  :-\ But it can't be anything else! With the available information, I'd say the engine is down on power enough to make it unable to overcome wind resistance above 80mph but not enough to make the car seem slow in lower gears. So I'll agree with Roger and David and suggest that you get the car on a rolling road and when you see that you're getting 50 or 60bhp at the wheels you can start looking for the reason. Could be something as simple as the exhaust or more serious as engine wear.

what about the gearbox.... vibration, looses power only on higher gears..... the noise... Without wanting to joke, but this looks like a Dr. House case ;) You will get there

I am now coming back to my original suggestion with regards to the axle ratio but didn't you say this is a 131 unit ?  if so how did you rig it up ? have you got the original 131 set up with four trailing arms and panhard rod ? or have you modified it to use leaf spring as was original on the morris minor ?
I remember reading an article where there was a kit to convert ford escorts to four trailing arms and panhard rod as per 131's and if I recall correctly they said this setup puts 30% more power onto the road compared with a leaf spring setup but I think they were on about pulling from standstill as you get axle tramp with leaf springs.
What is your axle ratio or what 131 was it from ?  I was never keen on mk3 supers 10/35 as I thought they were to high geared and even if it was a 12/43 out of an automatic it would bottom out at 102mph with a 2000 t/c at the front so knowing what ratio it is would help but still doesn't explain 80mph.

Hi guys,

Dont get distracted by "vibration" i didnt say that what I said was that at full power there is a drone heard from the engine. The sound actually sums up whats happening and that is the engine struggling to go faster but is being prevented.
The noise has always been there but slipped my mind to mention it. Its not that drastic but there.

The engine will rev to 6000 in 4th but wont go over 80-85.

Theo you mention that it could be a wind resistance issue but as I said in my previous posts, the 131 is shaped like a brick but wind resistance didnt affect that, I could get 110 mph out of that without any problem.

Without regards to the lack of smoothness, well when in the 131 the engine was smooth right up to 110mph.

All the running gear is from the same car 1983 Y reg supermirafiori and as I said it worked perfect before, all I done was check them for leaks etc and drain and replace the oils etc.

The axle is located on new 7 leaf springs with two trailing arms. Adjustable spax dampers. Doesnt axle tramp only affect the car from a hard standing start? I dont get that anyway.

With regards to the gearbox, I have thought that the engine sounds like its over revving for the speed being achieved but it cant remember that being an issue when in the 131, but then again the sound proofing etc was far superior to the moggy.

I have met and spoken to many owners of moggies with 2ltr twinks fitted and none are experiencing the lack of speed problems that I have so the set up works, that may rule out the wind resistance theory.

I will remind you that the engine had a full balance, crank, flywheel, clutch, rods and crank pulley. The gearbox has had all new bearings. Compression is good.

The rolling road will have to wait til after xmas so meantime I was hoping to try and solve it through you guys.

There is a positive in all this and that is I have learned so much on here about the twin cam etc.

Please keep your theories coming, you could be the one to solve this amd make me very very happpy.

regards

keith

 ??? ??? I thought you said before that at 80mph the rev counter is showing 4000rpm! If the engine gets to 6000rpm in 4th but the car is only doing 80mph then it's a gearing issue or the clutch is slipping! 6000rpm in 4th gear with standard 131 gearbox, rear axle and wheel size, the car should be doing over 100mph.

Hi Theo,

Before all this started when I was doing 80 the rev counter was reading 4-4500 rpm. If I rev it hard the rpm can be 6000 at 80.

The wheels are not standard but 15" but as I said previously when checked against my sat nav the mph was only showing 4- 5 mph lower, so the wheels size arent affecting it.

I just been speaking to two rolling road garages in Lincs but the dont do cars with carbs, its all fuel injection and mapping work these days. Do you know of any place up this way.

keith

 ??? If at 80mph the rev counter is reading 4000-4500 and then you rev it hard and it goes up to 6000 but the speed stays at 80mph then the clutch is slipping! There's no other possible explanation for this!

Theo,

What is your RPM at 8o mph?



Keith

4000rpm in 5th.

You may be spot on with clutch slip although its not obvious. Is there a way to check if the clutch is slipping?

I have the cable adjusted so I can engage the gears smoothly,  if I slacken the cable off then it is a little harder to get into first gear and grinds and hard to select reverse gear.


Keith

If in any gear there's an increase in rpm without a corresponding increase in speed then the clutch is slipping. There could not be any other reason for this in a manual car. So if you are doing 80mph at 4000-4500rpm and you put your foot down and the engine rpm goes up to 6000rpm but you are still doing 80 mph then the clutch is slipping.

The clutch cable should be adjusted to give about 1 inch free play at the actuating arm or pedal. If that means you don't have smooth gear changes then most likely you haven't got enough clutch pedal travel.

Theo,

I have just been out to the car and the freeplay in the pedal is basically zilch. I think you have come up with the answer. I dont think I have enough clutch pedal travel and that is why I have to adjust the clutch tighter to be able to select gears. So if the cable is adjusted tightly then it wont be able to completely disengage.
Now that would explian the car struggling to achieve a higher speed and the drone because the engine is over revving in relation to the speed the car is doing.

I reused the fiat pedal box and servo unit but I guess the pedal is either the wrong shape (too near the floor) or the cable is too short or both.
I have a spare cable so I could weld a threaded rod to the end of the cable to extend the travel. But I think your right about the pedal travel, the pedal is most likely hitting the floor before full travel is achieved hence I have had to adjust the cable to suit.

Boy do I feel good right now.

Keith

Hi Keith !
If i was you i would put 13" tires on it and try again,if you have any!
 i used to have 132, 14" winter tires on my 131 special when i was in my younger age, i can remerber that it was struggling to make up to the toppspeed but always failed!

Also the speedometer showed wrong because the different ratio of the 14" winter tires,it felt ok at lower speeds but was struggling att higher!

What tires are you using with the 15"wheels?
Find a tire calculator and do the math..

Slipping clutch, even at high speed should not last very long time without slipping all the time..
Just my point of wiew,
Regards
Alf

So the reason for your problem is what I said right at the beginning ;) You've put the engine and gearbox in the wrong car  ;D ;D ;D ;D ;D

Thanks Alf,

I will keep what you say in mind but I think Theo has uncovered the problem in the clutch.

Keith

You did indeed,

but maybe if I fix the problem then it may forgive me. But as I said I could have been ruthless and sent it to the big scrap yard in the sky.

Gloating rights are all yours.

Keith

(http://rulingcatsanddogs.com/contents/submitted-pictures-only/Debi-L/Sadie-Russian-Blue-haired-cat-gloating.JPG)

 ;D Seriously though, no need for gloating; I'm glad to have been of help if I was  ;)
Changing the cable is not going to do it I'm afraid. You need to increase pedal travel or you can change the pedal pivot point (fulcrum) or you can extend the pedal above the pivot point so the point where the cable is attached to the pedal travels more (but that will give you a heavier clutch pedal).  Or you can shorten the clutch actuating arm (drill a new cable hole nearer the gearbox) but once again that will make the clutch heavier.

I was planning on cutting the pedal shaft itself and weld it back at a different angle so it wont hit the floor so soon. It wil bring the pedal higher so more travel, what do you think?

keith

That would work provided there's enough room for the other end of the pedal (where the cable connects) to travel the distance without hitting anything. But you don't want the clutch pedal to be higher than the brake pedal. I like the brake and clutch pedals to be at the same height as not only it looks better but makes it easier and quicker to move from one pedal to the other without hitting the side of the pedal. Can you not reposition the complete pedal box to allow for more clutch pedal travel?

Right I've got it clock the car with a friends car and see if the speedometer reading is roughly the same although you should be able to judge 80mph.
I did look at a morris minor years ago that had a 2000 t/c fitted and he was complaining about lack of performance but he had a right mix of parts in it ie a mk3 supermirafiori 2000 engine a 124 gearbox that was notchy and horrible and a rear axle from an 1800 morris marina and it was sluggish and the old gent who was 82 was well impressed with my 131 sport as I took him down the road and lit it up but he was going to come back so I could try and sort it out but I never saw him again ! maybe he popped his clogs ? hope it wasn't my driving  :(

There is not a lot of room in the footwell so moving the pedal box would probably be do-able but very difficult, as the servo is bolted through the pedal box aswell, and if I was to space it off the bulkhead then the servo piston might not be long enough to reach the brake pedal. I will explore the option of changing the angle of the pedal first.
I agree about the pedals being the same height but my installation may not allow that.

Tomorrow I will do some measureing and see what I can do to get more pedal travel.

keith

Hi David,

I have tried it with the sat nav and that was pretty close.

When building the car I was very conscious of keeping all the running gear the same, I was aware of the problems that mismatching parts can bring.

I really think that the lack of clutch pedal travel is the problem, it is now obvious that if I have no freeplay then the clutch cant be engageing fully hence the high rpm and reduced drive.

Keith

Theo,

in your post you say about changing the pivot point, extending the pedal above the pivot or shorten the clutch actuating arm.

Can you upload some basic hand sketches showing what you mean then I will have all the possible options whilst trying to work out the best option, just so I fully understand what you mean. It may also help me come up with another idea.

Keith

Can anybody tell me the relaxed length of the clutch return at the gearbox, mine doesnt have one fitted so I need to find a similar replacement.

regards

keith

Do you mean the return spring on the actuator arm? While I wouldn't say "you don't need one" (as you should really have one) my car's never had one and I also removed it from my previous Sport and never had problems. The 131 clutch pedal has a strong return spring on it.


Changing the pivot point won't be easy. You'll probably need to modify the complete pedal box for that so I wouldn't even try. I think your best bet is to extend the pedal at the top so the cable connects higher up and will have longer travel. But you might need to drill a new hole in the bulkhead for the cable to go through higher than before.

A clutch pedal is a first order lever where the fulcrum or pivot point is between the effort point and the load point.

(http://www.mechanicalaptitudetest.org/wp-content/uploads/2012/12/levers-example.png?9d7bd4)

In the clutch pedal, the effort point is the pad where you press with your foot and apply effort and the load point is where the cable is connected. If you increase the pedal at the top making the resistance arm longer, the tip of the extended pedal (where the cable is connected) will move a longer distance when the clutch is pressed.

The clutch actuating arm is a second order lever with the fulcrum or pivot point at one end.

(http://www.sciencelearn.org.nz/var/sciencelearn/storage/images/contexts/sporting-edge/sci-media/images/pivot-diagram-of-a-class-2-lever/14704-11-eng-NZ/Pivot-diagram-of-a-Class-2-lever_full_size_landscape.jpg)

The effort point is where the cable is connected and the load point is the clutch bearing. If you move the effort point nearer the load point, that is drill a new hole for the clutch cable nearer the gearbox, then for the same movement of the cable you'll get increased movement at the load point. Disadvantage of this is that more effort is required so the clutch will be heavier.

Depending on the amount of extra travel you need to get, you might have to use both the above options or just one of them.

Thanks Theo,

very informative, are you by any chance a physics teacher? The idea of drilling a new hole nearer to the gearbox sounds like the easiest option and hopefully I will get the extra travel I need. Even though I may end up with my left leg looking like Arnold shwartseniger right arm but if it works and my car runs as it should then I can live with that. I am not even bothered if the pedal gets so high that I knee myself in the chin when changing gear, on second thoughts that maybe going a bit too far.

Yes I was asking about the return spring fitted to the actuator arm, I measured the location and picked up one 150mm long to day and will make up a extension hook to achieve a pedal that is not too heavy.

Keith

The spring on the pedal returns the pedal to it's stop, it doesn't help with clutch cable return. The actuator arm spring pulls the cable back and the throwout bearing back from the pressure plate diaphragm fingers, reducing wear on the fingers and increasing throwout bearing life. It also allows easy assessment of clutch freeplay, without freeplay the throwout bearing wears out prematurely, it also pushes the crankshaft forward, causing wear to the crank thrust bearing.

There's no pedal stop on the 131. Not on any of mine anyway  :-\  But I agree with everything else you've said Mick which is why I said "you should really have one"  ;) ;D

I am goint to fit the spring, I am of the opinion that if the car designer put one there then there is a good reason for it, and Mick has just highlighted why it should be there.

Thanks Guys

keith

Both you and Mick are correct, of course  ;) which is why I said "you should really have one". What I was trying to say, was that fitting the missing spring would not solve your problem of slipping clutch.  The reason I don't have a spring is because the hook point on the gearbox is broken and I removed it from my previous Sport because it used to rattle and then preferred the lighter clutch action. Eventually I refitted it in my old Sport and replaced the pedal spring for a much lighter one  :D

I know thats what you were saying Theo, I do listen to you and I'd be a fool if I thought that a spring would fix my problem.
i have been trying a couple of things today, didnt get it finished because I had to remove the pedal box and move the servo so will finish it tomoz and hopefully I will get a good result.

Basically I what I have done is to cut and move the pin that that the cable eye fits to. Before I started the distance from the pin to the back plate of the pedal was 80mm, I have made a "L" shape and reduced the 80mm to 45mm. If need be I can raise the pedal for more travel.

This should give me a lot more pedal travel.  See pic below.

There is also more slack in the cable so the thrust bearing should release fully. Thats the theory anyway.

Regards

Keith

Hi All,

Theo, Your advice would be appreciated as this sort of thing sounds right up your street.

Got the pedal box back in and hooked up the clutch cable and because I moved the hook for the cable eye the cable is now too long. I have added spacers etc at the bulkhead and at the bell housing to get the pedal to work but I am having to take every bit of slack out of the cable and that is defeating the object.
So I need a shorter cable. I have a brand new one so if I can get an accurate way to determine what length I need then I can have it shortened but I am not too sure about which way to assertain the correct lentgh. I was thinking about doing the following but whats your opinion.

I was going to hook the cable eye to the pedal and set the pedal to the position I want it at, measure the lenght of the inner cable from the outer cable at the bulkhead to the pedal hook.

Set the actuator arm so that the release/thrust bearing is maybe 3-4mm clear of the pressure plate fingers, set the bulkhead adjustor to the centre of it adjustment travel, slide the cable through the actuator arm and measure the required length of the inner cable from outer cable at the bell housing to the required position on the actuator arm allowing for the locknuts etc to screw on and have the cable shortened to this length.

I havnt allowed for any alteration to the outer cable because I am not sure if that needs to be shortened because if I shorten that then it will make it a bit tighter to route the cable from the bulkhead to the mount in the gearbox bell housing. If I reduce the inner cable then do I need to shorten the outer cable.

Am I correct in what I am thinking or is it not as simple as that?

Regards

Keith

 

Hello Keith,

Your modification with the 'L' extension would not extend the pedal travel unless the pedal travel was restricted by the length of the cable, which I didn't think was the case. Your modification has extended the inner cable by 45mm so it's now too long. It'll make no difference to the pedal travel. In fact cable length is not important at all, you can have a cable a mile long and it could work fine as what's important is the difference between outer and inner cables. Since the outer cable is fixed at both ends, its length makes no difference at all as long as it's long enough to each between the two fixed points. As long as the outer cable reaches the two fixed points, it can have a lot of 'extra' length and in the RHD 131 it's long enough to go round the front of the engine. The inner cable needs to be longer than the outer cable by the amount of the two fixed points for the outer cable and the fixing points for the inner cable. In the 131 there are two ways to adjust this difference as the length of the outer cable is adjusted at the bulkhead end and the length of the inner cable is adjusted at the clutch actuator end. By extending the inner cable by 45mm you've made the inner cable too long and gone outside the adjustment available by the two adjustment points. So any 131 cable will do you as long as it fits, you don't need to change or modify the cable.

I think what you should do is first determine the amount of extra travel you need to get from the pedal. So what I think you should do is:

   1. Remove your 'L' modification and set the clutch up exactly a you had it before.
   2. Mark or measure the position of the actuator arm and mark the position of the cable adjusting nut. 
   3. Loosen the cable adjusting nut until you get some freeplay at the actuator arm. It should be about an inch but as long as you have some freeplay you should be OK with the release bearing clearing the pressure plate fingers.
   4. Measure the difference in position of the actuator arm to that in 2. above and the measurement is the amount of extra 'travel' you need.
   5. Once you know how much extra you need, you should be able to determine the best way to get the extra travel, either by drilling a new cable hole on the actuator arm, if you don't need much extra, or by modifying the pedal, or both!

If you have to modify the pedal, you need to extend the cable mounting point at the pedal upwards, not nearer the bulkhead. So instead of the 'L' you made, you need to make an 'I'  ;) So you need to extend the pedal upwards keeping the cable mounting point the same distance from the bulkhead. But it's likely that you'll have to drill a new hole on the bulkhead for the cable to go through, it all depends by how much you increase the pedal.

I hope all that makes sense.....  :-\

Hi Theo,

Yes what you are saying does make sense. I was of the opinion that if I moced the cable fixing point on the pedal towards the bulk head then the cable would travel more, I was aware that it would lengthen the inner cable thus allow the actuator arm to be pulled backwards by the spring and the release bearing would be free of the pressure plate, just didnt think of how I would adjust the excess cable. Hmmm

Unfortunately drilling the bulk head for the cable to go through higher up is difficult in my set up ( difficult not impossible ) so may have to hold fire on that for the mo.

Tomorrow I will put it back the way it was and check the measurement you recommend and see exactly what extra trave I need to achieve. I will come back to you then.

Thanks again.

keith

Theo,

To reset the cable hook point on the pedal back to vertical (80mm) from the bulkhead I need to remove the pedal box and with all the wiring etc in the way it is not an easy task, so before I do that I thought I would ask you this question first.

Whilst I have the box removed do you think that I should set the 80mm distance and then cut and weld the pedal shaft to give me some more travel. I was thinking of cutting through part of the pedal shaft from the rear towards the front and opening the cut up so that the gap is at the rear of the shaft say between 5 or 10 mm obviously I dont want the pedal to be too high and reweld it. Probably between the bottom of the pedal box and the return spring (see pic above). I think that this would be alot easier that drilling a new hole higher up the bulkhead..

Do you think I should do this at this point or put it back as you said, the way it was and measiure what travel is required.

Never realised how many cuts you can get working up behind a dash.

Regards

keith

As I mentioned in a previous post, my 131 does not have a clutch pedal return stop. If I lift up the pedal, it comes up a long way. Its rest position is determined by the return spring on the pedal. When the spring is in its rest (closed) position, the pedal stops but there's nothing physically stopping it from coming up further.  Assuming your pedal box is the same as mine, you don't need to cut and weld the pedal to increase its height and get more travel. So before you start cutting and welding the pedal, try lifting it up and if it can come up higher, then once you fit the actuator arm return spring and adjust the cable properly, the actuator spring will pull the pedal to the required height. If your pedal has a return stop and you don't mind the pedal being higher than the brake pedal, then maybe you can remove the stop and replace the pedal return spring for a shorter one. I wouldn't cut and weld the pedal at this point as it seems too drastic to me.

If you increase the height of the pedal at the point where the cable connect  by a small amount, say 10-15mm you probably won't need to drill a new bulkhead hole. The cable will be at a slight upwards angle but as the connecting point is 80mm away from the bulkhead you'll only have 5-6 degree upward turn on the cable and I don't think that's enough to chafe the cable.  You might even be able to bend the bulkhead at the cable hole to get a 5-6 degree upward angle for the cable and you'll have no chafing at all. So I still think that what you should do first is to determine how much extra travel you need.

Theo, a gentleman as always

Yep thats what I will do regarding slightly raising up the cable eye 10-15mm. i didnt realise that it would be such a small amount. i thought it may have been around 25mm or so which is why I was concerned about drilling a new hole higher up. Yes I should be able to slightly reshape the bulkhead to accommodate the new cable angle.

I dont have a pedal stop. When the cable is disconnected, my pedal return spring pulls the pedal to the floor, so that wont hold the pedal in any position other than on the floor so as you say all the pedal height is controlled by the actuator return spring, never realised that the actuator spring had to do so much work. It is working when the clutch is engaged and when its disengaged. Just aswell that the spring I have is quite robust but not too much to make a big difference to the strength of the pedal..

Keith

Hello Keith,

Thanks for the complement! (http://images.bravenet.com/common/images/smilies/12_smile.gif)


You may need 25mm or more, you won't know until you make the required measurements. If you're lucky to just need 10-15mm then the modification will be relatively simple but you may need 25mm or even a lot more!


 ??? Isn't that the wrong way? I thought the pedal return spring pulls the pedal up, not down  :-\

My pedal is pulled straight to the floor without the cable connected, see pic.

For a way forward I think it best if I set the clutch back to where it was ie cable eye hook to where it was 80mm from bulkhead and at the original height, I will do what ever adjustment is required to be able to operate the clutch but to do that the release bearing will be in contact with the pressure plate fingers as before ( hence the slipping ) and the bulkhead adjustor is fully turned clockwise.

I will do as you say and mark both the position of the actuator arm and the lock nut, I will then undo the lock nut and allow the return spring to pull the actuator arm backwards to allow the release bearing to clear the fingers by approx 15mm ( is that enough? ) then measure the difference.

When I get to that point, and  if you dont mind I will report my findings to you and then hopefully we will be in a better position to determine exactly what needs to be done to get the clutch working correctly.

I learnt a lesson many years ago, " measure twice cut once" so now I am going to ask twice and do once.

Regards

Keith

No picture unfortunately and I can't remember which way the pedal spring pulls  :-\  My 131 is not at home so I can't have a look to remind myself. But I think you're going about it the right way, try and find out how much extra travel you need before doing anything.

Theo, see the pic of the pedal that I put up 10 posts back.

Keith

Doh!  of course! :-\ 
Yes, that makes sense. The pedal spring is probably there to take up the slack in the cable. So if there's no pedal stop, what's stopping you from adjusting the cable correctly since you said you don't mind having a high clutch pedal?

To get the pedal up say level with the brake pedal then I need to use up all the adjustment available. The problem arises because the pedal hits the floor before I get enough clutch to be able to select gears smoothly. So I need to get the clutch to work before it hits the floor and becaues I have used all the adjustment to pull the cable tight the release bearing is in constant contact with the pressure plate fingers.

Does that make sense? I have attached a photo it may explain whats happening, The pedal is at that height to work but the cable is pulled so tight that the bearing in in contact with the fingers and I have no freeplay. You can see that the floor restricts the pedal movement. The wasnt a problem for the moggy pedals because they were floor mounted and pushed down into the floor.

The maroon car is mine and the other has been done by someone else

keith

Sorry Keith, I'm confused now  :-\  Since there's no stop on the clutch pedal, why does it not come up higher until the bearing is clear of the pressure plate springs? What's stopping the actuator from releasing fully and pulling the clutch pedal higher?

Welcome to the confused club.

As you said earlier the spring and the adjustment at the actuator arm is what keeps the pedal set at an acceptable height off the floor.

I can get the pedal higher but I would have to shorten the inner cable even further by adding spacers/packers at the bulkhead and or at the actuator arm but that will pull the actuator arm closer to the release bearing and thats no good. My problem is that i cannot achieve any acceptable free play in the pedal.

Thats why at the beginning I asked if my problem was to do with the cable lentgh or lack of pedal travel or both.

Keith

But now I don't understand why  ??? If you move the actuator arm towards the back of the car, the bearing moves away from the pressure plate and the pedal rises. Without a stop on the pedal, what's stopping the actuator arm from moving back far enough to fully release the clutch?

It must be the length of the cable. If I slacken off the cable to enable the actuator arm to move towards the back of the car then the pedal drops and i cant engage any gears.

The cable I am using is approx 1650mm long, its the one that was on my supermirafiori, it is in good condition so I reused it. I bought a new replacement as a spare and that is the same size. Is there only one size? but Theo you say that cables should go round the front of the engine but mine wouldnt, thats why I have had to route it the way I have.

I reused the fiat pedal box with the servo bolted to it through the bulhead, so that is identical to the fiat so far, the cable then runs above the master cyclinder to the end of the brake pipes, it than goes down next to the alternator and crosses under the sump and then the outer cable fits into the bell housing and the inner cable fits through the actuator arm

keith  

That's not right. When you slacken off the cable and the pedal drops, can you manually move the actuator arm further back and lift the pedal? If so, then I think you're right and the problem is cable length; either the inner cable is too long or the outer cable is too short. That's why both inner and outer cables are adjustable because it's the difference between the two that's important and not the overall cable length. Adjust the outer cable at the bulkhead so the outer cable is the longest it can be (maximum thread showing). Then adjust the cable at the actuator arm to get about 10mm freeplay and see where the pedal is. If it's lower than the brake pedal, you'll have to extend the outer cable. Probably the easiest way to do this is weld a big nut on the bulkhead engine-side where the cable goes through so effectively increasing the length of the outer cable.


Yes mine goes round the front of the engine but I've seen all kinds of ways of routing the clutch cable. I think mine is a 132 cable which is longer. But it doesn't really matter how long the cable is and which way it's routed, it's only the difference between inner and outer cable that's important.

Good morning Theo, another day, another brain storming session.

This morning I will re-instate the pedal hook but I will fit it a little higher, that can only help.

In reply to your last post, looking back at the problem I started with I think that the cable is too short, now whether its a problem with the inner or outer, well Im not sure.

Previously If I set the height ( block of wood underneath) of the pedal to say match the brake pedal then I had to pull the actuator arm forward to enable me to get the threaded cable end through the arm and get the lock nut on. When I removed the block of wood the pedal would drop approx half the distance to the floor. In this position I could not engage any gears so I would have to use both the adjustors to get the clutch to work but having to do this resulted in the release bearing being in constant contact with the pressure plate fingers, no freeplay.

As I said this morning I will put it back and set it up as you recommend and let you know my findings.

keith

Update..

Hi Theo

I put the clutch cable eye hook back to the original vertical position although I have raised it 10mm higher, thats the max I could go because the sleeve that slides through the bulkhead would interfere with the cable and cause chaffing.

I have taken a number of photos showing the different positions that I have tried the cable in regarding adjustment.

The pics are in groups of 3 showing the different positions of the pedal, the bulkhead adjuster and the actuator arm. In the first three groups the release bearing is in contact with the pressure plate

I have to do a number or posts for this because it is not possible to upload more that 4 pics in one post.

Update 2

Update 3

Wouldn't it have been easier to build yourself a 131 around that gearbox? ;) :D :D :D

Update 4

The first pic here shows a measurement of the position of the actuator arm in relation to the group of photo's in updat 3
The second pic show the actuator arm pulled back as far as it will go and in this position the release bearing is clear of the pressure plate bu 10-12mm. The similar dimension on the second isnt shown but is 55mm.

Is the problem being caused by the inner cable being too short?

keith

Possibly Mirafiori, What would we do without sarcasm. LOL

Anyone can go out and buy a car but to restore a wreck and modify it to accept the running gear from another car, well thats rewarding enough for me.

When this is running right I will have the benefit of a hybrid made up of two of my favourite cars.

Keith

You need about 1mm clearance between the throwout bearing and the pressure plate diaphragm spring. When adjusted like that, how far does the gearbox lever move when the pedal is fully depressed. Can you get a photo more inside the box, showing the thrust bearing on the diaphragm spring? If the diaphragm fingers sit flat, the clutch is probably OK, if they bend out towards the gearbox, the clutch plate is worn and may be part of your problem.

I was going to say that but Mick beat me to it  :) You just need a slight clearance there to stop the bearing rubbing on the fingers and wearing them.

Are the spacers at the bulkhead rubber exhaust hanger rings? That's not good if that's the case. If you need a spacer there use something solid such as a big nut.

The photos are very good but I'm somewhat confused (that happens easily and often  :-[ ;D) as to what's what  :-\

The system should work since the gearbox, cable and pedal box are all from a 131. Adjust the inner cable at the actuator arm to give you the correct actuator arm position. If you are looking at the release bearing to pressure plate gap, set it so the bearing just clears the fingers. Then adjust the outer cable at the bulkhead to get the correct pedal height. The more thread you see in the engine compartment, the higher the pedal will be. If you run out of thread, then you'll need to add a spacer, as you seem to have done, but make it a solid spacer.

Your actuator arm return spring looks too hefty to me. I think you need a spring with less tension than that.

Good afternoon All,

That is not a spacer on the bulkhead, the metal tube as part of the pedal box slides through the bulkhead and then a metal and rubber sleeve slides in to that and then the clutch cable slides into that. The rubber ring you see is only to conceal the joint cosmetically.

The clutch is only 1500 miles old, I bought a complete new clutch and had the pressure plate balanced to the crank as part of the engine balance.

This morning I set the clutch up ( used a large nut ) so it allows me to select all gears smoothly. But to achieve that the release bearing is touching the pressure plate fingers. In this position the cable is too tight to allow me to pull the actuator backwards, but if the the pedal is pulled up as high as it will go ( hitting the dash ) then I can pull the actuator arm backwards and the bearing clears the pressure plate by approx 3mm. I have tried using the bulkhead adjustor to pull the pedal up high but that puts the cable under more tension and the actuator arm cant be pulled backwards. No matter what I try I cannot get the clutch to work smoothly without the bearing being in contact with the pressure plate.  

I tried it with the actuator spring fitted and tried it without the spring and it made no difference to the pedal heigth or the position of the bearing in relation to the pressure plate.

I started the engine and the internal part/centre piece of the bearing is spinning and because it is hitting the pressure plate the actuator arm is vibrating quite a bit. ( thats answered another question for me )

I have attached another group of three photos showing the latest position of the pedal, bulkhead adjustor and the actuator arm. These are the positions required to be able to select gears smoothly but the bearing hits the pressure plate. As requested by mick the I have taken 2 photo's ( 3 and 4 ) which show the position of the actuator arm with clutch engaged and the 4th photo shows the position of the arm with the clutch pedal to the floor. It doesnt look like a lot of travel but with this minimal amount of movement the clutch works fine. Is this correct or what should it be?

Photo 5 is taken with the pedal pulled up high and the arm pulled backwards. You can just see that the bearing is approx 3mm clear, you can also see that the fingers are flat.

Based on this post do you think the problem is to do with the lentgh of the inner cable, if not can someone please tell me where I can get some vallum... cos now I am really frustrated and confused.

Keith  

post continued

I don't think it's a cable length problem and certainly don't think the inner cable is too short. If you pull the inner cable so you can engage it is the actuator arm, the pedal should go up high towards the dashboard and the cable should reach without you having to pull the arm forward and engage the clutch just to connect the cable. If that's not happening, then maybe the cable movement is restricted? You said the cable runs under the sump. Do you have any sharp bends in the cable that might restrict the movement of the inner cable? Where are you based Keith? I'm getting so puzzled about this I'd like to have a look.

Hi Theo,

From the top down the cable bends to go down next to the alternator, then turns under the sump and then turns to locate in the bell housing. I have the bends with as much radius as possible but that may not be enough. Maybe I need a longer cable. I will upload photos showing how the cable is routed in a few minutes, maybe that will help.

I live near Spalding in Lincolnshire.

keith

5 photos of cable route

contd

That looks fine to me.....

Theo,

If I put a block of wood under the pedal a set it slightly higher that the brake pedal and get under the car I can just manage to get the cable through the arm and get the lock nut on, Then I remove the block and the pedal drops approx half the distance to the floor. In this position the bearing is almost touching the pressure plate and I cannpot select any gears. So I need to adjust the cable at the bulk head to to select gears and by the time I have done this the bearing is in contact with the pressure plate.

If we cant sort this then maybe I will come down to see you. I used to live in Wembley and actually bought my 131 in Enfield in 1996, was it from you the reg was BOY580Y ???


keith

Maybe you've got the wrong pedal return spring? The pedal should not drop to half way down to the floor unless the pedal return spring is too strong  ???  Try removing the pedal return spring and see what happens.

BOY580Y was never mine and I don't know the car. In fact I've only sold one 131 (my 1600CL) and that went to Ireland.

Its the original spring but I will try it without it.

Is your cable routed in a more gradual way. I am going out now to undo the cable at the gearbox and see how much resistance I get, and see how difficult it is to pull the pedal up high with and without the pedal return spring.

I really dont know what to be thinking anymore , we have looked at so many things

keith

I may be wrong here but if the pedal can be lifted slightly, releasing the bearing from the fingers then surely you have free play. It sounds like when the clutch cable is correctly adjusted the bearing is just resting on the fingers which shouldn't cause any problems. A relatively large amount of force has to be applied to the fingers by the bearing to disengage the clutch and cause slip. The bearing simply resting on the fingers won't do it.

If the clutch is slipping at high speeds then the speed would stay the same but the revs would rise. Does this actually happen?

Theo,

I think you have cracked it.

I removed the cable from the actuator arm, and tried to pull the cable through with the pedal return spring in place, I could only manage to pull approx 5mm of cable through. I removed the pedal spring and could pull approx 40mm of cable through.
I replaced the cable to the actuator arm and could fit the lock nut easily and still pull the arm backwards so the bearing is approx 5mm clear of the pressure plate. The pedal is now pulled up to the underside of the dash. In this position the actuator arm and bearing moves back towards the pressure plate but I can easily pull it backwards, so
I have fitted the actuator return spring to hold the bearing clear.

I need to find a return spring with lesser tension to pull the pedal back down a bit. I will also remove the additional large nut that I fitted to the bulkhead adjustor and play around with the adjustment, and see what I can achieve now.  I started the engine, there is a quite a bit of slop in the pedal but I could select the gears smoothly but because of the clutch movement the arm is creeping forward again but it is easy to pull the arm backwards again with my hand. So when I play with the adjustment hopefully I can balance the set up with springs etc. to stop this happening.

I cant tell you how pleased I am now, but I wont count my chickens yet. The strength of the pedal spring was obviously suited to the 131 but combined with the bends in the cable it was too much for my set up, who would have thought of it. well Theo would thats who.

I have things to do on saturday and sunday so wont be able to try anything until monday, so I will report back then.

Keith

Mirafioriman,

With regards to the speed thats exactly whats happening, same speed but higher revs.

The bearing was extremely tight against the fingers so it was causing slipping.

But my last post explains the latest

Keith

Yes, as I've said before, the clutch cable goes round the front on the engine. As far as I know, that's how the clutch cable is routed for all RHD 131s. I think you must have a cable for a LHD which is why it's so short. But I don't think that's your problem.

There must be something very wrong if the clutch pedal return spring is able to even partly engage the clutch. Maybe the clutch pressure plate is faulty? But if the pedal seems to behave as expected without the spring, I wouldn't bother fitting a weaker spring, just set the clutch and pedal to the correct positions without the pedal spring and drive the car to see if it works fine without the clutch slipping.

The spring is so strong even with it in my hands I can only pull it apart approx 1/4", maybe I could have installed the wrong spring because this strength seems excessive for the job it is doing. Ihad lots of parts in storage so it is possible that springs got mixed up, I cant be sure.

I probably wont need a pedal spring because I think the additional nut that I fitted to the bulkhead adjustor is holding the pedal so high, so it should not be a problem setting the clutch up now.

Thanks again Theo for taking the time to stick with me on this, it has been a long process, but heh got there in the end.

When I get a chance to look at the clutch again ( probably not till after Xmas) I will keep you updated with how the car runs. Even if the clutch doesnt solve the problem of the speed issue at least I have discovered why I was feeling vibrations through the floor etc. because even at idle tha actuator arm was vibrating quite a bit. I was thinking that the engine mounts were the culprits, plus I wont be wearing out my clutch.

Happy Christmas to the forum and especially everyone who took part in this thread.

Regards

Keith

I'm glad we got there in the end, although we won't know if we got there until you drive the car. You might as well remove the extra nut at the bulkhead so you'll be able to adjust the clutch pedal height to be the same as the brake pedal  :D