PT

My cylinders look to be worn enough that I'm looking for a "new" set of p&c, just want to hear from others out there who had done that.

I understand that other than completely new set, I can bore-&-re-nikasil mine to 98mm & get a set of new JE. Any one done that & will they be issues (e.g. tolerance, longevity, ...)? I also hear using a set of used 3.2 ones are better starting point?

Other than new Mahle p&c sets, are they cheaper alternatives?

thanks...

im4duke

Supertec is sourcing cylinders now at a very reasonable price (~ $1400/set). Henry says they are race proven. Sandman is putting these in his car now.

sand_man

For Henry's brand new 98mm Nikasil cylinders, custom 98mm JE pistons, JE wrist pins, JE circ. clips, and Goetz rings my total came to under $2,100! The cylinders are also fully finned. Now I jumped on this price really fast almost two months ago, I think it's up to around $2,300 or so. The EBS option was almost $2,600 and came with replated cylinders. Henry's cylinders also use a large copper sealing ring between the cylinder and head. My machinist, Neil Harvey, has all of the parts and he says everything looks good. He's perfected his own Nirosist sealing system, so he's a little on the skeptical side, but he sees no reason why these shouldn't work. We'll see. I hope to have my engine done by the end of February...so wait for my results if you can.

Jeff

PT

Jeff, I was looking at Henry's p&c as well. Price-wise, it seems to be a no-brainer. But more real data on the overall quality & longevity would be great. And, I wonder if the copper seal is really a good/bad idea???

sand_man

All good questions...all I can say is that I rolled the dice! We'll see.

sand_man

My thread on Pelican:
http://forums.pelicanparts.com/showt...hreadid=261643

PT

Jeff, yes - I saw your thread there & that's how I discovered these Is there additional comments from your machinist re:use of copper sealing ring compared with the more typical interlocking rings?

Stephen / SteveW, any comments? Is there a standard procedure/approach for going to a 3.4L other than new Mahle?

sand_man

Well the system that Neil of Performance Developments makes requires that the cylinder head be machined to accept his sealing ring. Pretty much EVERYTHING that Neil does is quite honestly TOP NOTCH. I'll post more about this and him when I get my parts back. I was all set to have Neil install his system in my heads and cylinders and that's when I first learned that Henry's cylinders already had a sealing ring. Before Henry came along, I was all set to go the EBS replated route. Again, I've probably taken a bit of a chance, but with the superior ARP head studs that I'm using to hold it all together, I think everything will stay sealed up. I'm also keeping a .80 boost spring in the waste gate to help keep things in check.

Steve Weiner-Rennsport Systems

PT:

Everyone will have an opinion, but I'm no fan of JE pistons for street use where the owner is expecting 70K to 100K before disassembling the engine for an overhaul. I think JE's are fine for racing, especially their "box" type pistons.

There are some excellent aftermarket cylinders being offered such as the Nickies, and Perfect Bore's; there may be others, but I've not seem them first-hand yet.

The real problem is that JE's head land clearances are too loose and the compression rings suffer premature wear; something that doesn't matter much in a race engine that is rebuilt every 50-100 hours. For street use, I'm not pleased with the short life that JE's currently have.

For me, you simply cannot do better than the far too expensive Mahle's, especially where a very high compression ratio is not advisable for pump gas usage. Mahle's have proven their extraordinary lifespan and with proper maintenance, these have proven to last FAR beyond 100K miles.

Ultimately, its a personal decision to make based on economics and engine life expectancies. One simply should not delude themselves into thinking that a JE piston (regardless of cylinder) will last anywhere near as long as a Mahle one will. You simply get what you pay for.

Like I said at the beginning, you'll get a whole host of opinions on this subject based on everyone's long-term experience. Take this one in proper context,...

sand_man

Steve,

All good points. My JE's were custom ordered to specifically fit these cylinders. These are NOT off the shelf 98mm JEs. In other words Henry actually measured the inside bore then ordered the pistons from JE so the tolerances would be closely matched. Believe me, Neil of PD will measure everything. I had Henry ship the Ps&Cs to Neil.

As I've said all along: I'm rolling the dice a little. I disagree though, there is NO reason why the JE shouldn't last just as long as the Mahle.

SoCal Mike

sand man, I'm hoping these work well for you. I know that Henry himself was not initially a fan of JE's until he started custom speccing them, but Steve's main issue is not bore clearance, which is/has been an issue in the past, but land clearances. I wonder if that could be addressed(custom specced) as well. I'll have to talk to Henry as I was planning on using his p/c set as well for my new motor.

PT

Steve,
Thanks VERY MUCH for the comments - exactly what I was looking for.
I have heard similar comments about JE as well. In my case, my car is really for track use only so likely will be opening up the engine more often than a normal street car (I'm hoping it will last 200 hours), so that is one factor going for JE in my mind.
From eveything I have found so far, it seems that there really aren't that many other options out there
Thanks again.

PorschePhD

Steve: You might want to check with Jeff and see the when the last time he speced a JE turbo (3.3 or 3.4 )piston.

They haven’t had the issue you described in years. The issue here has not been JE as a piston per say as it has been the cylinder and the type of rings used with the piston. Used in a street car use and DE they are fine. The issues show up as they would in any piston when people start listening to “others” that heard this or saw that. They are not a plug and play setup if you will. They need to be measured carefully. The biggest issue I have seen is using anything other than the proper ring with these pistons and checking the bore of the cylinders.

The cylinders often grouped with the pistons are rebored and plated. Which as a process is fine as long as the spec and integrity of the cylinder is maintained. Often what you will find is that they are slightly out of spec often causing the JE or any other piston not to seal or excessive piston slap. You will hear of issues of piston slap with the short skirt Ruf pistons as well. So even Mahle has issue from time to time. It may be overkill but we/I also spec and measure new Mahle sets as well.

There are also some inherent differences between the design. Not bad, just different. One of them is the squish area of the piston and how it helps ignite and combust the chamber. I have now seen first hand on the dyno that a JE will not allow as much timing as a Mahle of the same size. Not a bad thing but something to be aware of if you were going to push your car to the limit.

I have used both in my builds and have many sets of JEs out there that have seen no problems. However given the same playing field and all things equal I will use Mahles. These are also only two of many piston makers that do things for Porsche.

m42racer

As Steve said, so wisely, "You simply get what you pay for".

There is nothing more to say! That is so correct. And as he say's, its the use and application that needs to be looked at. I think many times, the application or use is mis used and the problems start there.
I saw a new style Piston from JE the last time I was home. Quite different from their original forging. The original did crack and fail around the Pin boss. I lost an engine that way many years ago. When there are better alternatives, we tend to change, as I did. Change often requires more expense. Quality, which includes design and manufacturing will never be beaten.
The problem as I see it, is that many times people do not do enough research into the parts that are included into the engine. Some engines are spec'ed out with the "easy button".
As Steve mentioned, there are many very good choices, which allow for the builder to design the dome configuration as well. Not just off the shelf types. Why do some suppliers choose JE? Combination of cost and the "easy button".
I think the Pistons included in these less expensive kits will be OK, as long as the application is applied correctly. But as Steve said, don't expect long term use if that is changed.

Steve Weiner-Rennsport Systems

PT:

You are quite welcome.

Given what you are doing and what your expectations are (very reasonable), I think you'll be just fine with the JE's in your application, depending on final CR and boost pressures.

Without question, the piston options are quite limited by both the available alloys (Alcoa supplies virtually everyone outside of Germany) and current designs. I wish someone could replicate the high-silicon, very low expansion alloy that Mahle developed many years ago. Believe me, I've been trying since 1974.

I have some things under development and after some long-term testing, I might have some viable options.