131mirafiori forum

Im currently rebuilding a 2.0 Fiat Twincam 131 -C4000 engine to drop in my Lada (Yes Lada :))

All is going well and the engine is completely stripped down, my gasket sets and bits are on order.

However my bores have a fine wear ridge at the top, and I am concerned if I fit new rings then the top one will destroy itself on the said ridge.

I have purchased a set of 84mm domed pistons from a 1600 twincam, They are in the post so I cannot tell you anymore about them. They are ultra low miles and have been in a guys cupboard for years.


Has anyone successfully fitted these pistons into a 2.0 lump ?

As far as I have read, the 1600 rods are shorter, the small ends appear to be 22mm for both 1600 & 2000 engines.


The Guy Croft website hasnt generated a reply after three days and 34 people viewing my thread.

Ive read all I can on the subject, GC bible and a Haynes but Im no further ahead.


Any help would be appreciated.


Thanks

You can fit them into 2000, but you need to use the 2000 rods, and, moreover, you may need to make cut outs in the pistons in order to clear the valves (depends on the particular head type that you have and on how much machined it is already) - very careful assembly is a must.
However, if the cylinder wear is significant (show us a photo), then engine reassembly without machining is a COMPLETE  waste of money.  Believe my,we had plenty of these engines in Poland and it has been main toy of young, underfunded tuners - 3 such engines died  in my Mirafioris and I couldn't help it. You can not save  this way.

If the ridge is small and the cylinders still in good nick, you can use a ridge removal tool to get rid of the ridge and negate the broken ring problem.

Thanks for the replies


My current ring end gaps are in the 25thou region, the wear ridge is evident, I have nothing to compare it to so I await your views.

To give an idea of what Im doing, the engine is going into my Lada Niva, which is an occassional off road toy.

I have an 84mm flexihone available if I need it. And have seen the ridge removers on varous websites.

I do not have the pistons yet, so cannot provide any measurements to establish if they will actually fit the bores...

And yes I am on a budget, so Polish advice from your teen motoring exploits is exactly what Im after, will it work ? or will it explode ? lol

Im rather hoping the 1600 pistons are the max size , so I can rebore the block.


(http://i65.photobucket.com/albums/h236/IvanSki66/DSC03164.jpg)
(http://i65.photobucket.com/albums/h236/IvanSki66/DSC03165.jpg)
(http://i65.photobucket.com/albums/h236/IvanSki66/DSC03170.jpg)
(http://i65.photobucket.com/albums/h236/IvanSki66/DSC03171.jpg)

If the pistons dont /wont fit, the existing ones will go back in with the old rings.

The car doesnt do a great deal, any additional power I get will be an improvement on the 1600 Niva engine.... ;)

Looks like a pretty bad wear ridge.

I would be more concerned with the vertical lines in the bore as this could be a sign of ovalisation of the bore or of a very nice roasting at some stage but the only saving grace is the lines dont seem to be on the trust side....

The marks/crazing in the bores have no noticable feel to the delicately placed finger.

The pistons show signs of varnish & washing which isnt good.


Im hoping the 1600 pistons will allow me the room to rebore and remove the ridge etc.

Either way it is going back together, its a low budget off roader in need of some extra power.

I might even re-use the old top rings and fit new second & oil control rings.


Not perfect I realise, but this is no show stopper of a car.


The car is worth maybe ?500 tops, Im not in it to sell it etc so a bit more low budget spending isnt an issue. Im just not spending a fortune on it.


(http://i65.photobucket.com/albums/h236/IvanSki66/DSC02903.jpg)
(http://i65.photobucket.com/albums/h236/IvanSki66/DSC02904.jpg)

it looks like a 127/128 on stilts, whats the model called?

A Niva or Cossack as I have one ask Brensport  ;D ;D

Lada Niva Cossack-

It sits on either 15 or 16 inch wheels. Mine is on 16s with cutback arches. 2" suspension lift and no anti roll bars to hinder the articulation.

It is a very capable off roader.

Watch....

http://www.youtube.com/watch?v=zpLWZkE6uJM

I'm not a  mechanic expert, but I think I can give the answer - it will work with the new pistons, but not for very long. I would say several thousand miles.
Better sell these pistons, buy an oversize set from spiderpoint for not so much more and rebore the engine, it will help a lot. Remember to at least check the factory clearances in the whole engine - cam buckets, cams, aux shaft, crank.

My shims need sorting, I have done the measuring and know what size to order. The cam is fine, as is the crank and bearings. The oil pump is within limits.

I cannot really justify spending 300euro on pistons & rings to fit in a car worth 500 euro at best.

I am really looking to resolve the bore issue as costly (low) as I can manage. The engine in it at the moment is a low powered 1600 unit, the sums just dont make sense.

It does about 1000 miles a year, some off road trialling and carts my builders rubble away to the tip.


Thankd for the reply , and Spiderpoint I hadnt seen before thanks ! ;)

Hone it, clean up the standard pistons, splash out on a new set of rings and put it back together. That's what I'd be doing if it's just a fun toy.

tas131 makes sense there & if you do get a new set of rings please post where they can be bought.

1600 pistons arrived today....


A quick check of my 2.0 pistons with the vernier across the skirt, coming in at 83.93


The 1600 ones are all in excellent nick and do not appear used, slight carbon build up on the crown the rest are immaculate in light oil.

They are all comfortably measuring 84.5/6 mm across the skirt.

Trying not to get too optomistic I need to measure a few more things and see if this hare brain plan comes together.....


The replies have been a good help everyone thanks....


 ;)

I bought standard rings and bearings from Turin imports, Adelaide, Australia about 3 years ago. I wasn't aware that they're hard to come by!

http://www.turinimports.com.au/

I suppose it depends where you are, Im in the UK where Guy Croft is the main man , I was using Vick Autoparts in Texas however they have had supply problems from Europe.

So I have yet to find a dealer Im happy with based on cost & exchange rate.

Everything in the UK is expensive, it is cheaper by a long way to purchase & import parts from Vick in Texas who is supplied from Europe. Ironic the parts I order sail past the UK and then get shipped back at lower cost than if I bought them direct from Europe...

If that makes sense....

well if they were coming to rip-off Ireland from the states the customs & excise people would require a fair amount of euros before they release them to you, i got hit with ?86 euro import duty for a part that cost $45 B@@t@@ds

You have to laugh at customs as they tried to charge me duty on a set of wheels for a Ferrari and that was coming from a member state....