ehall

Zero, before you jump in on your decision to go JE, (nothing wrong with them, great pistons) let me talk to my guy about what specific coatings are needed to allow them to work within the Alusil cylinders. IIRC piston of diff metalurgy, without a proven coating process, can definitely destroy your cylinders. Remember, most JE users, in 951's, (okay nearly all) are using JE's with an iron sleeve application. My sense, and I'm not saying this from experience, is that there's a damned good reason for that. If there were a cheap AND proven way to do this, it would be the method of choice and it's not. I know that my guy does have some experience with this, but he still goes either sleeving/JE's, or reworks stock block, and replaces w/ OEM Mahles. I'll call him first thing in the A.M. and post by tomorrow evening early. E

ehall

Zero, i talked to my guy today. He's built, builds, and races 951's and is a professional mech. shop owner. As far as he knows, there is no reliable way to coat JE's to work within the stock Alusil cylinders. That said, he did thing that if someone has perhaps figured out the exact composition of the coating that Mahle outs on the OE pistons, then "perhap it's possible", but doesn't make much sense in terms of cost/ risk.
The guys above are talking about coatings applied to pistons used in a sleeved app.
Frankly, with the limited damage that you have within your cylinders, I would buy the new 100.5 Mahle's pistons, (not from Andial __too expensive, shop around) have the block worked properly, and rebuild the engine. Unless you want to do some displacement upgrade, and it doesn't sound like you do, then that plan seems least expensive and the most reliable. Good luck! E

Zero10

Everybody would like to increase their displacement, but if I do, then I need a bigger turbo, then intake mods, then fuel mods, etc... It's a daily driver/track fun car, so it needs to get good mileage, and doesn't need to make gobs of power. It's must faster than my N/A was, and that's good enough for me
If somebody could get me a line on some cheap 100.5mm mahle pistons that would be awesome, since I'm sure they would be the best solution.
If not, I'm going to investigate into my repair solutions...
Andial's prices are definately out of my price range unfortunately.

Ski

There is no such thing as cheap Mahle pistons. Now, you can sleeve it and JE pistons, you can buy TC pistons for $1100, or you can take a chance of just cleaning it with a pass on the machine/alusil hone and new rings. You build this engine CHEAP, that is exactly what your going to have. I suggest you bite the bullet or save your money.

I have a set of 101mm TC pistons, your welcome to them for $1000 because I got them a year ago and I have a set of Mahle 100.5 that are not for sale and if they were, they'd be $1800. If interested, PM me and if paying by paypal + 2.9%.

Zero10

TC pistons definately are cheaper than the Mahle ones. I'm just surprised the pistons cost so much. I've bought pistons for other cars for about 1/4 the price of a set of Mahle pistons, from the dealership.
I have no intentions of building this engine cheap. I would rather keep it apart, and save up my cash than do it the cheap way, and that is not the way I do anything with any of my cars.
That is very kind of you regarding the TC pistons. I wish I had some hard numbers from the machine shop...

I've gotten a few good suggestions from the machine shop so far. They reccomend that I have my pistons thermal coated, which will also help bring up the diameter half a hair, or that I get some tolerance group 2 pistons, and coat them, then use custom rings (or just different rings) to get the end gap right with the slightly different diameter.
I wonder how that would hold up in the long term though...

Ski

well let me know. Those 101s aren't going anywhere at the moment. The only reason I offered was to try to help out. I'm building my spare motor with the Mahle and the TC pistons are for the block that has to be machined. jwl, just put a set of 100.5 TC pistons in an 89, they rebuilt the motor and the car fired on the first try, idled well, put it through a couple of heat cycles, and the guy drove it out the door for break in. He's got about 850 miles on it now, one oil change and turning the boost to 10psi and just waiting for 15 because he bought Jims' Vitesse II kit. Jim is building a 2.8 with Vitesse Stage IV kit. I'll have to go help build that one and we can assemble my short block at the same time.

Zero10

I'll keep you guys posted. I think the best solution so far is, if my block is out of spec, finding one as close to new specs as is reasonable. Unless that proves to be very expensive.

What do used blocks sell for usually?...