131mirafiori forum

Hi All,

I use 15W/40 oil in my 2 ltr twin cam, but which of the following is best?

1)   Mineral

2)   Part Synthetic

3)   Fully Synthetic.

Regards

Keith

Hi Keith,

If i were you i would go for half synth. This is always the oil i have used and it's the cheapest.
There are no bad oils nowadays.

Would advise semi syn too.

mineral for new - rebuilt engines for bedding in
 semi for nomal use doesn't degrade as quick as miineral ...
 fully for new clean engine after bedding in ..

Thanks Guys,

I have been using mineral since rebuild 2000 miles ago and was wondering what grade to start using now. Very helpful info.

Regards

Keith

Hi Keith



I would go mineral for brake in and depending how hard REV the engine  : easy( max 5000  to medium ( max 6000 RPM ) -  semi ; hard to very hard (7000  plus  RPM) -  fully synthetic (one of Motul 300V range (i.e  for summer 20w60 and 10W40 for winter). Expensive but absolutely unbeatable.    

Miro

Thanks MIRO,

I rarely go over 5000 rpm. So semi it is then.

Regards

Keith

Keith,

Remember that all modern engine oils are really very high quality perfectly fitting standard modern cars and most old timers - like ours. The differences are really negligible for standard use !!!!.

What is key is change your oil frequently , make sure you use different one for winter and different for summer.
Make sure you change your oil filter when changing oil, and that the filler has sufficient flow capacity (is really for your model - not just fits the mounting) . Always use a filter with internal pressure valve ! 

Make sure you do not rev the car before it is really warm ( Note : DOHC engines are considered fully warm when the fan has switched on and off twice.  keep the temperature of your oil low and coolant temperature at max 85 deg centigrade.

Otherwise synthetic. mineral or semi is not really not as important as some think. and all major international rands offer exceedingly good quality . with easy driving - semi. synthetic and or mineral oils is not really  that important .

Miro   

You make a lot of sense MIRO,

My engine is fitted in a Morris traveller. You have me thinking about the filter now because it is one that just fits the mount. The original oil filter would hit the chassis so I fitted a filter housing from an Alfa (cant remember exactly from model) but the filter now sits horizontal not vertical.  Hmmmm

Some photo's of the filter I have been using. How can I determine if it is suitable?

Might this affect oil pressure readings? My oil readings, idle is 15psi, 2000 rpm is 55psi and 3000 rpm is 70psi.  In the manual it says that oil pressure should be. 49 - 71 psi at 100c, is this at idle or what rpm?      

UPDATE: I have spoken to Motaquip and they have confirmed that the filter I am using is for Fiat and Alfa but only upto 1.4 ltr engines. This is the filter I was given by a motor factor so big cock up. As you can see in photo I am restricted for space and the original filter spec is larger in both width and length. So I will need to go with a remote filter set up to accommodate the correct filter size. I asked if this would affect the oil pressure and the guy told me that because the filter is undersize it would increase oil pressure. So that means when I change to the correct size filter that my readings will drop again, is that OK?

It is amazing what one can learn on this forum by just posting what appeared to be a simple question, so pleased I did ask now.

Thanks again MIRO for highlighting this.

Keith

Strange how all the Fiat designers got that wrong then  ;D ;D ;D

Theo, where did you get that quote from? Water or oil temperature?

Got what wrong Theo?

Keith

The quote was from Miro's post and he claimed coolant (water) temperature should not exceed 85 degrees.



The coolant temperature. The thermostats fitted by the Fiat engineers/designers will not ensure the coolant temperature stays below 85 degrees but will allow the coolant to reach much higher temperature without considering it to be wrong.

When i was a Fiat mechanic long ago  :D  i learned that the temperature should be around 89 degrees celcius. The thermostat should open around 83-87 degrees. At plus/minus 93 degrees the fan should fall in.

The thermostat in my Abarth however, opens at 75 degrees celcius. Fan hits at around 88/89 degrees.

QED  ;D Fiat designers allow the engine coolant temperature to exceed 85 degrees  ;D

It's no problem if the engine runs a bit more over 93 degrees. Fiat engines are strong. One should more worry about the engine not getting warm enough. That really kills the engine. The right thermostat is essential.

I have used my previous engine for sports for several seasons.( It was  pretty much a good standard engine with twin soled 34's , standard valves, standard rings, cast rods, con rods - standard everything.  When I pushed really hard with high outside temperature (30 deg plus) my oil temperature would top 130 deg centigrade and the coolant got to 110 but the engine survived with no problems. So the engines are indeed very, very  strong. They often run at close to 100 degrees ( 93/96/98) and no visible problems.

The standard engine setup, especially 1600 (single 34 carb) is not exactly a 2.0 with twin 44 's and "sharp" camshafts. Also a car made for general distribution and general standard (non competition use) probably runs with somewhat better efficiency at 93 degs and less fuel consumption, too.

However, I strongly believe keeping a competition engine at full speed and 6-8 K RPM with 85 temp is far better than at 93 degs.

Changing the fan switch and installing the in-head thermostat did the trick for my 131.

Similarly, by using use of proper rated switch and thermostat combination I have been able to keep my 124 2.0 fi also close to 85 degrees at all times.

Finally the car oil temp stays reasonable level no matter how hard I drive it  and no matter how hot  is the outside temp.

The fact is that for winter driving ( wich \i do not fo=do in my fiats at all) I would keep the engine temperatrure slightly higher probably 90 deg max.
    
Miro

Re too low temperature kills the engine - Very true. In fact starting a cold engine causes the greatest damage (priming it with oil pressure from oil accumulator does help a lot). But wear and tear due to cold engine can be very dangerous, as the lubrication/oil pressure and its distribution throughout the oil channels is under low temperature grossly insufficient.

However, with extremely high temperature oil lubrication (its viscosity) degrades drastically killing main shaft bearings and camshaft bearings much quicker and can lead to a engine blow out. Using competition oil can reduce both.  Provided your oil pressure is sufficiently high and oil matches the driving conditions (outside  temperature ) keeping 85 degrees lubricates the engine properly without causing thermal damage to main engine bearings.

The bottom line:  as long as your engine works well and its temperature does not exceed 90 deg under any driving conditions and your style of driving - you should be fine. If you use the car for competitive driving I strongly recommend 85 max , oil accumulator and oil changed according to expected driving conditions.  

I use Motul 20-60 for the summer and 15W-50 for cold weather ( non freezing winter driving).

M    

The grade of oil to use depends on the seals fitted and the bearing clerances.
Most early twincam seals leaked oil if you used fully syn oil.

But the later types are made of a different grade of material and are ok for fully syn oil

If you study the range of oil filters fitted to the twin cam there are many options to choose.

The 131 has a lot of space under the bonnet and they fitted a 'fat' oil filter.  The spec is identical to those used on the Ford (sorry) Pinto engine in the Escort/Cortina/Granada/Taunus etc.  Make sure you get the one with the valve.  look down the hole and you will see the valve at the base.  This keeps the oil galleries primed and therefore helps the engine achieve pressure sooner on startup.

If you need a smaller filter as per your picture, choose the one fitted to the Lancia Integrale 8V or 16V.  If it can live behind the radiator, under the exhaust manifold, and surrounded by the turbo and exhaust, while filtering an engine producing 185BHP+ I think it will be OK for your application!

If you are really concerned about oil pressure and startup damage fit a pressure switch to the filter housing and wire it into a relay in the ignition circuit.  The engine can't fire until the oil pressure builds, and if the oil pressure fails the ignition is cut automatically.

Finally Semi Synthetic is probably best for your engine.  The twin cam loves good oil, and the film strength for semi synthetic is so much higher that normal mineral oil that it provides better protection in all conditions.

Thanks
Duncan

Thanks Duncan for the info, very informative. I will try the Integrale filter as suggested. I will let you know how I get on.

Does the valve look like a spring similar diameter to the treaded hole.

Regards

keith

Hi Keith

If you look down inside the filter you should see a spring-loaded valve at the bottom of the hole.

Many years ago I ran a motor factors and we were often called upon to supply parts for cars not listed in the general catalogues.  Suppliers such as Girling, Champion, Bosch etc are very good at providing the trade with the proper technical specifications for their parts.  This allowed us to find a suitable oil filter for a car based upon the quoted features.

You would be surprised how many 'supercar' parts came from everyday mundane vehicles!

The Minor looks fantastic by the way.  Always good to see one running, and the twin cam adds to the appeal.

Where are you based?  I travel a lot in the UK and I'd like to see the beast.

Cheers
Duncan

Hi Duncan,

I am based near Boston in Lincolnshire. The car is playing up a bit at the mo, if you read my other 2 threads you will understand why, hopefully it will be sorted soon and running to its full potential.

Regards

keith

I used to use the 'slick 50 ' metal coating supliment ..