Forged pistons

[catastrada]

One friend of mine is driving a Caterham with the EU2 VVC engine, mainly on track (80%).

 

4,000 miles ago he broke one piston. He then decided to replace the 4 pistons with new ones.

 

Last week he broke again 1 piston

 

He is now thinking of replacing it with forged pistons.

Is it the way to go (all inputs apreciaed).

 

If yes, is it an easy swap or need the conrods to be replaced too?

[Sheds Moderator]

The ppistons are a bit of a weak link at high revs, certainly the R400 race series in France used to wreck pistons. I don't think forged items were legal at the time and IIRC they changed the regs to allow the change. The new items will last longer.

 

I don't know if you need to change the rods.

[oilyhands]

To fit forged pistoms will require the fitting of a Colsibro or similar bush at the small end of the rod so that they can be made fully floating fit. Make sure you buy pistons that come machined for circlips. In theory forged pistons can be fitted interference fit on the rods, but only safely with new rods. With used rods, once the old pistons have been pressed from the rods the inteference fit is pretty much destroyed and is not safe to use again. It is possible to remove the pistons by sectioning the piston and machining the centre of the gudgeon pin so that it can be collapsed out of the rod eye, then the interference fit can be re-used, but TBH, fully floating is much better. If the rods are dual tang then they need some machining to the big end housing to make bearing location safer. The liners will need glaze busting or replacing.

 

Oily

 

Edited by - oilyhands on 12 Nov 2007 15:28:06

[catastrada]

Thank you very much for your valuable answer 😶‍🌫️

 

He is planning to change pistons and rods for forged ones.

Any address / references to buy the items?

[oilyhands]

You dont really need forged rods, the stock ones are good for high RPM and are quite strong, otherwise I would recommend Farndon or Arrow for the rods and Omega for the pistons.

 

If you cant get the pistons at any reasonable price, then I do keep several sets in stock.

 

Oily

 

[catastrada]

Dave, YHM.

[caterhamnut]

Just uploaded these pics whilst I trial Zenfolio

 

here

 

Lovely bits of kit - I got mine from Dave

 

www.mycaterham.com

here

Videos

here

101,000 miles car

[catastrada]

Nice try

[rj]

Beautiful images Agnus!

 

 

/regin

[catastrada]

Fitting forged pistons seems the road to follow.

But one more question : I understand that forged pistons (their design) gives the engine a higher compression ratio than with the standard pistons.

Correct ?

 

If yes, will the standard ECU be able to manage this?

 

[oilyhands]

The difference is marginal it normally liofts the CT from 10.5->1 to 11.2->1, the ECU wont have a problem.

 

The tops of the pistons can easily be skimmed if desired.

 

Oily

 

Edited by - oilyhands on 30 Nov 2007 20:47:51

[catastrada]

Thank you Dave