JE Pistons

Glen · 08-11-2001, 10:27 PM

Hi All
I'm looking at increasing the displacement of my 3.0 by using bored 3.2 cylinders and JE pistons to obtain a 3.4 with a goal of a realible/smogable 220-240hp motor. Any of you that have experience with JE pistons, I'd like to get your opinions.
Thanks
Glen

Bruce M. · 08-11-2001, 11:09 PM

Good solid pistons. I went with Mahle, but JE was my second choice.

Early_S_Man · 08-11-2001, 11:23 PM

Glen,

If you are referring to Carrera 3.2 cylinders ... they are 95 mm just like SC cylinders! The most you would be able to safely bore them out is 1 mm! That is not a significant displacement increase, and would not justify the expense of having the bored cylinders Nikasil plated!

Andial and Jerry Woods have 98 mm and 100 mm cylinders and pistons that could possibly raise the displacement to the levels you seek.

One other possibility would be the Max Moritz big bore sets ... a used set of those cylinders could possibly be replated and used with JE pistons as you described.
------------------
Warren Hall
1973 911S Targa
1992 Dodge Dakota 5.2 4X4 parts hauler

[This message has been edited by Early_S_Man (edited 08-11-2001).]

J P Stein · 08-12-2001, 07:25 AM

I have Shasta pistons in my 2.7L.
They are machined from JE forgings.

They are considerably lighter than the Mahle
RS piston. I should have weighed both when I had the chance, but blew it. A WAG would 2/3s of the Mahle weight.

The do clatter a bit when the engine is cold as there is more wall clearance. I'm told that they expand more and the racket does abate as the motor warms.

No new holes have appeared, so I assume all is well in there.

JPIII

[This message has been edited by J P Stein (edited 08-12-2001).]

RLJ · RLJ's Garage

Your cylinders can be bored and sleaved to 98mm! JE pistons are great Mahle is good stuff but in the real world JE will work just fine, stay away from Andial and Jerry Woods unless you have a mega budget.
I'm running 98mm 10.2:1 JE pistons in short stroke 3.2 motor and it rocks.

Randy Jones
1971 911

movin · 08-12-2001, 12:03 PM

Interesting configuration. What crank are you using, 3.0? Does that work out to 3.2 using 98mm cylinders? I like the idea a more over-square bore/stroke configuration. Is this something worth looking into during a 3.2 rebuild? Would seem to have a lower piston acceleration and rev-up quicker. What are the differences in power characteristics between a conventional 3.2 and de-stroked 3.2?

RLJ · RLJ's Garage

My 3.2 started life as a 1983 SC motor with a 70.4 mm stroke crank shaft. The plan was to change the pistons to someting that would work with cams and give us more compression with the dual plug heads we were using. When the engine builder pulled it down he found Alusil cylinders, well buying 95mm Nikasil cylinders was a dumb idea so I asked him to bore and sleave them to 98mm, new piston cost from 95mm to 98mm was little. I ended up with a a motor that makes revs like and electric motor. The aloy flywheel and clutch help too.

Alot of guys change the bore on there 3.2 to 98mm and get a 3.4 motor.

Randy Jones
1971 911

WydRyd · 03-15-2002, 03:07 PM

My question is:

ARE JE PISTONS RELIABLE?

I've always heard negative things about JE's, that they don't have proper expansion rates for air-cooled apps, therefore, they tend to fail much quicker and are noisier.

What have you guys found?

porman1 · 03-15-2002, 05:59 PM

Starting with a 1979SC I had a set of 3.2 cylinders bored over and plated to 98mm (can't bore standard 3.0 because of sealing ring cut in top of cylinder), bought a set of JE 10:5-1 pistons, installed camshafts and 40mm rejetted Webers with tall PMO intakes, the heads dual plugged and intakes extrude honed and balanced........Results???????? very fast!!!!!!

Erick

WydRyd · 03-17-2002, 02:21 PM

Hi,
Is there enough "meat" in the 3.2 cylinders to bore out to 98mm and maintain reliability?
When you say "plated", do you mean re-coated in Nickasil?
How much HP do you get with this mod?

914timo · 03-18-2002, 06:19 AM

Mister RLJ,
What do you mean with "Your cylinders can be bored and sleaved to 98mm"?? Do you mean that they can be bored to for example 102mm and then you can slip in an iron sleeve with 2mm thick walls?? Or, do you mean that they can be bored out 98mm and re-plated or re-coated.

What is the difference between Alusil cylinders Nikasils you are talking about ??

Please, tell us more. It sounds interesting. Can you gine the # of JE pistons you have used ??

Timo
SC3.0L needing more power

WydRyd · 03-19-2002, 04:20 PM

Bored to 98mm (3.4L) and re-coated in Nikasil.

I've heard this is what Mahle do anyway. Start with a 95mm cylinder and bore it out to 98mm and even 100mm!

This is a highly specialised job though and I wouldn't trust just ANY old plain machinist to do it. Must be done by someone reputable who knows Porsche hardware IMO.

Thunderbone · 03-21-2002, 09:57 AM

Erick,

Are you able to run pump gas okay with those higher compression pistons?

porman1 · 03-21-2002, 10:57 AM

Yes, I had the cylinder heads dual plugged and am running with an Electromtive HPX crankfire that allows for accurate timing at critical rpms......

WydRyd · 03-21-2002, 03:27 PM

Eric, who did you use to bored out your 3.2/95mm cylinders and re-coat?

Also, did you get the JE Pistons crown made to account for the extra plug?

Interesting!

porman1 · 03-21-2002, 03:38 PM

Engine Builders Supply Co. in Sparks NV, USA did (or had)the work done. Check ebsracing.com. There was not problem with plug interference. I did have to buy a set of "core" 3.2 cylinders. They supplied the JE pistons as well which have very deep valve reliefs cut in. To be on the safe side I installed an extra .50mm spacer under the cylinders.

Erick

Thunderbone · 03-21-2002, 04:33 PM

Erick,

Do you know how much on an increase in hp you realized with your upgrades? Also, how did this affect your torque band and the amount of torque, that is, are you enjoying a torque band from 2500-6500 with a bunch more torque..

hilandscott · hilandscott's Garage

I had heard the same things: anything short of Mahle will be noisy and blow smoke, especially when cold.

Turns out most everyone uses JE and many makers copy them (Shasta, Cosworth). I looked for months for a 9.8:1 set of Mahles, but NO ONE had them for sale-- in fact those few who claimed to have Euro Mahle really had the 9.3:1 KS (which goes with Alusil cylinders). Beware as well the unscrupulous who prey upon those with cheap piston dreams: I heard a few stories to keep me wary of the boards, even ebay. Of course I did end up mailing a guy who did manage the Max Moritz set used for $1500.

In the end, JE is a great product, and for $895 the set uses the stock ring set and has same tolerances as Mahle. The extra benefit of JE is that the piston dome is shaped much better for the spark burn. Why Mahle is the only one to make a CIS piston (hemispherical) crown is a bit of a mystery...

Good luck