Can anyone give me any info on these pistons? They are for a std bore 904cc. I assumed they were je but can't find any pics of je pistons that look like these.. Cheers.
If you do a Google search, the pictures of JE that come up have a flat centre on the crown. I have JE 92mms in my engine but can't remember what the crown looks like, but I'm sure they were flat. I may have a pic somewhere. Those ones are definately high comp as the crown comes into the combustion chamber. There's several different possibilities, Weisco, DP, Pistal etc.
Hey Ian, Thanks for the reply. I was trying to id them to see what comp ratio the maker quotes, I'll have another search with your suggestions. These are going in an engine I'm building atm with a couple of other mods too. I'll measure the comp ratio when I get to the top end, don't think I want much more than 10.5 to 1 on a road engine. Can't wait to run it!
My JE are higher than that, they are renowned for being higher than what they quote. I've heard of several folk machining metal off the crown to lower it. I'm replacing with Pistal as I'm going up in capacity to 944
I haven't discovered the make of these pistons yet, they are measuring up at 10.1- 1, thought it'd have been higher.. I've got the squish down to 1mm so going together well Maybe the next engine I do I'll go for the 94 bore.
Nothing cast on the underside to give you a clue? Not Arias (I've got a set of those on the shelf which apparently came out of a 900sl when the PO went the 944 route - using 12:1 Cosworth pistons!)
No, nothing at all, the closest looking ones I've seen are the FBF ones but they are marked on top. So no idea still They do look good and I know they are very low mileage so I have no problem using them. The oil ring is unusual (to me), if you look carefully at the pic you'll see it's all little segments on the outside, I haven't taken the rings off, best to leave well alone sometimes.. Do Yours have any identifying marks?
Makers name (always helps!) and the code 292 (batch number?), both cast in. The high comp pistons I've seen for the 900 (Veetwo, FBF, JE) have all had a flat top to the crown 'projection'. I've also got a set of 94mm pistons/barrels stashed, bought secondhand. No markings on the pistons, but IIRC markings cast on the barrels suggested DP. Also 'flat tops'. See what you mean about the oil rings, not seen that before - something to do with ring expansion I guess? Somebody must recognise that crown and those distinctive oil rings...?
