'65 2.0 piston options

[718RSK]

All,

I am getting to work on my december '65 Solex equipped engine. I am curious to hear what the current preferred piston option is for a street engine. There appears to be options on both sides of the ocean. I am not looking for a hotrod, but a small bump because of a CR change is something I would consider,

TIA,

JK

[edmayo]

I've used JE pistons at .040" overbore on the original cylinders with good success.

[Merv]

+! on the JE stock size pistons. I also went for the LN Eng. barrels. Nice matching.

[718RSK]

Thanks Ed & Merv. Any of the European memebers have experience with euro piston manufacturers such as Woessner etc.?

[chris_seven]

JE pistons for Porsche 911 engines are generally manufactured from an Alloy specified as 2618-T561.

This alloy, due to is low level of silicon tends to expand more than the original Mahle 124 Alloy which is virtually identical to 4032-T6.

Pistons made with 2618 also tend to suffer from greater levels of ring groove wear as the basic alloy lacks the hard Silicon particles found in 4032-T6.

2618 became the favoured alloy used for Turbocharged engines as it has a higher melting and hence higher softening point due to the reduction in silicon content.

When used with Biral Cylinders the small increase in cold clearance tends to cause some piston slap when cold.

Woessner pistons are made from 4032-T6 and generally don't have this problem.

Their 2.0S stock pistons are the type used in the 1967/68 engines and are not bad for the price.

We have had some issues with the pin bosses and rod width and had to relive the piston in this area but that was only on one set.

There is a supplier in Italy http://www.pistonispeciali.com/EN/cars.htm#.WEZ_1bKLTcs who also make a 4032-T6 piston for the early engine.

It is a slipper design and I think they are vey good.

More expensive than Woessner but look a better job.

We have also used Omega but they rarely have stock and the minimum quantity is prohibitive.

[72targa]

^^^^^^^^

Just incredible info. Thank you.

[718RSK]

Many thanks Chris! I have e-mailled the Italian outfit. What kind of other performance improvements would you suggest while staying within the original framework. Because the car is so original I do not want to deviate to much.

many thanks,

JK

[tfiv]

No piston opinion, but I'd keep it completely stock. Those early 2.0Ls are cool motors. You're paying a premium for a 65 these days because they're unique. I was never tempted to modify my 67S motor when it was rebuilt, same reasoning.

[NeunElf]

+1 on keeping a stock compression ratio. Going from stock 9:1 to even 10:1 with no other changes will get you maybe 4 hp. But, you might not be able to run on normal premium fuel--that might not make for a great ownership experience. Also, going non-original can only hurt a '65 911s value.

The 911S engine ran 9.8:1 but had much hotter cams. The increased static compression ratio was mainly to maintain the same dynamic compression ratio.

[66S]

Isnt that 9.8 to 1 the nominal c.r. and didnt someone here measure the actual c.r. at 9.5 to one for the S? From what Ive learned the low silicon JE piston top ring groove will wear rather quickly because of the cold piston slap unless you use LN cyls for a tighter fit..