What are my piston options?, I finally got the thing apart. Options

[Matt Monson]

Well,
I finally got off my arse this weekend, and furthered the teardown of my 2.0l. The heads are in like new condition. Everything seems to indicate that this engine had the top end re-done right before it was parked for 3 years. But they pistons are the stockers. I want to up the CR, and want to go beyond what the Euro ones will get me. I am looking for between 9 and 9.5:1. I am wanting to hone my stock cylinders, and drop in a new forged unit. So, what are my options? And sorry if this has been asked before, but my searches didn't bring up much outside of getting stuff from Jake. I want to weigh all the options...

[Brett W]

I am not a big fan of JE. They have become too corporate. Wiesco is much better about helping the smaller customers out. I have had many sets of JE pistons in hand and compared them to Wiesco. There is no comparison, The Wiesco pistons have a much better finish and more features that JE charges extra for. Plus Wiesco owns the piston factory unlike some other manufactures that have to buy their blanks from an independent supplier.

That is another one of my arguments against aircooling but I won't start that argument again. Sizing pistons and determining the expansion rates are done for watercooled engines. Although since Wiesco is heavily involved with motorcycles and snowmobiles they should have a very solid grip on the requisite specs you need.

[Jake Raby]

How about running .00090 (thats right, less than one thou) of skirt clearance with a forged piston for skirt clearance????

Thats what Nickies allow and I have a ton of engines running less than one thou of skirt clearance- and you damn right, they are aircooled!

[Brett W]

OK, whats your point. When the cylinder expands at the same rate as the piston there is no need for massive cylinder wall clearance.

[cnavarro]

Yup, that's the point. Just look at the recommendations JE and other forged piston manufacturers make and then look at the piston to cylinder clearances Porsche originally used. They used a high-silicon cylinder with a high-silicon piston to maintain decent clearances, but by no stretch of the imagination did they ever expect us to be able to pull off a .001" clearance on a 105mm bore since the Nickies expand at a very similar rate to JEs.

Just as some don't like JEs, I don't care much for the Wisecos that have passed by my desk. I would use CP, Omega, or Cosworth for pistons, but then there's no need to exponentially increase cost where it's not needed. We all reserve the right to use whatever suppliers we are most comfortable and pleased with, although I do have to say that i'm pissed at JE for loosing two separate custom 911 piston orders in a row that I have placed in the last month, which really screws up my delivery schedule.

[Jake Raby]

Yeppers...
I have ran as little as .00075 piston/cylinder clearance with Nickies and had astonishing results.... That same engine with a cast iron cylinder would have died at less than .002 with those pistons (ask me how I know)

The engine that was running the .00075 skirt clearance was just torn down not very long ago and the cylinders and puistons looked like they had virtually 500 miles on them.. They had 11,200 miles on them and had never had the oil changed in that time period as I was trying to promote wear.

Note: No coatings were used on those piston skirts, nor was there any special preparation of the pistons/rings at all- just slapped together with less than a thou of clearance and ran VERY HARD...

I have the pics of those components of this engine as well as all the other trick aspects of the "Hybrid Annihilator" to upload to my R&D site as soon as I get the chance....

My 3 Liter also has one thou of skirt clearance and it'll be coming apart since I blew the tranny out of the car on Monday, so now its time to see what the wear looks like inside after almost 10K of pure hellacious power makin insanity...

BTW- Both the engines you saw at Mid Ohio that had my name on them had less than one thou of skirt clearance-

Also NO ONE ever promoted the use of this clearance and Charles and I approached it as a pure risk taking endeavor on the first occasion in a previous test engine of mine... We did that because I had noted that with less clearance than the piston MFR called for the pistons and cylinders still measured and looked great..... Its all about taking risks and not listening to a damn soul, no matter their degree, their profession or their experience- I'll find out on my own, thank you very much!

[Brett W]

Yeah Charles I didn't bring up Cosworth, Omega, Perfect Bore, BME, or Mahle. No sense in muddying the waters for everyone else. Yeah price increase exponentially when you start asking for really odd stuff or big name stuff. I know JE has come up with a solution to mircowelding the rings to the lands, but there pistons are the only ones that seem to have the problem. For most people it is good to go through someone like you or Jake or John to avoid all these issues.