Looks like I am in the engine rebuilding way at the moment. Finally got feed up with trying to figure out what was wrong with my engine/auxiliary systems so I pulled the motor this weekend.

Probably the last time out on track the motor dropped a valve guide. Found one broken secondary spring. And I still haven't pulled the driver side head!

Fun fun.

Ideally I would like to find quality 95mm pistons (allowed a 1.2mm over bore for the class I am preparing to run) and machine my cylinders to match. There does not seem to be a quality 95mm option on the shelf. (I know AA makes a 95mm piston & cylinder set; I am just not interested in buying it.) My question is: has anyone ordered custom 95mm JE pistons and are willing to share the part number?

Alternatively is there a source for forged 94mm flat top pistons? All the forged pistons I can find are 96mm or bigger.

Thanks,

Miguel

Never heard of 95mm. 96mm is easily available and will give you a 1911 or 2056cc displacement depending on your crank.

98's with the right crank: 2,414

I still have a box with a spare piston.

FYI mine has nickies.

Good for you for trying to go the legal route.

As the local vintage eligibility person for all porsche cars I highly respect your decision. Call EBS. I think they are likely available.

The 2056 is technically cheating

Thanks Brant, I'll call over there today when they open.

M

Brant,

That worked out perfect. Don at EBS quoted me both ways and helped identify the cylinders I have, original 2.0L Mahles. Boring out my cylinders to 95mm and getting matched pistons was only a couple dollars more so I am going that route.

Thanks,

Miguel

You also could have gone 94 and had the crank done a hair longer stroke

No, the rules allow 1.2mm overbore, but no change in stroke.

I agree with chris

Order them from Charles @ LN Engineering. That is where I got my 95mm pistons for my EP engine.

If this discussion is SCCA Solo... here's an interesting change for 2015 in DP. Per Appendix A for DP...

Engines with 2-valves per cylinder: 1.00 x listed displacement (cc)
Engines with 2-valves per cylinder are permitted a displacement change of +10% via bore/stroke changes only and with the weight formula accounting for the increased displacement.

Which should super cede 17.10 ENGINE - DRIVE TRAIN...

H. Block
1. The block may be rebored no more than 0.0472” (1.2 mm) over standard unless otherwise specified in Appendix A.

So if my math is correct... if you replace OEM 94mm jugs with 96mm and keep the same stroke that's 1971cc to 2056cc with a 4.3% increase. Correct?

But that prepared car would need to weigh in at 2056 lbs.

vintage racing... usually to older SCCA GCR's

Copy that. I was surprised and pleased with this change for us. Especially seeing how I've already bought into 96mm
Heck, with those rules you could do 98mm (with the same stroke) and still be legal

who does this cylinder boring,..and do they need to be treated after the bore,...plus whats a good crank size to go with such a set-up,..??? Thanks Frank

Slightly still on topic:
Where can you get a NEW FORGED crank with the stock 71mm Stroke?
(other than that NOS 2.0L crank I saw recently for $3000)

I see lots of new forged cranks (like at scat), but they are all for stroker motors.
If you want NEW & Stock stroke, it seems you are stuck with billet.

The factory cranks are forged, chilled German steel. Not likely to find a better crank material.