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So... I picked up these 90.5 forged mahles with the impression they were in "good" condition...

I'm wanting to build a mild turbo, also got a hold of a used forged CW 69mm crank.

What do you think of these? Was this a bum deal, or are they worthy of running? Cylinders have been honed, told they were round...

I've re-used worse... but I'm not using a turbo. How thick are the walls on those cylinders? The piston that's got valve scars on the top would worry me. And the first picture - I've never seen marks like that before, did it break a piston ring? I'd expect that cylinder to be all torn up - I've re-honed a cylinder that had a wrist pin clip break, it wasn't pretty.

Stray

they are the machine in 90.5 cyls. dont know the wall thk till I am home to check...

I guess $150 wasted now is better than trashing a built engine...

lesson learned maybe. trust no-one.

There are actually two diameters of "machine-in" 90.5 barrel, the original ones were 97mm on top and 94.4mm at the case (they're too thin for turbo use IMO, at least without powersleeving) - the modern ones, which I believe these to be, are 98/96mm, same as "classic" 92s. The early pistons used a thicker ring package (2.0/2.0/4.75) than the late (1.5/2.0/4.0).
That one piston started to melt down, probably from a too-lean mixture, and I wouldn't trust it for a high-performance application. I've run worse in low-compression motors. The one that was kissed by a valve looks fine from here, that's a pretty light smack. Looks like it hit once, bending the valve, and then a few more times pounding it into the guide...

at this point, I've emailed the seller from thesamba.com and let him know that this was completely misrepresented...

damnit...

I think I'd rather run a new set of Chinese ("AA") than these, for the same money.
IMO the used set you've got is overpriced by ~50%, even though new Cima/Mahles are going for $390 they aren't worth that much (to me). Ask for $50 back and see what happens. Nobody besides UPS or USPS makes any money shipping these things back & forth, and any time they make the trip with no broken fins it's a near-miracle.
I've got more good-used 90.5 pistons sitting around than I have cylinders for (my son's left his baja out in the rain and let the jugs fill up & rust out several times)...I could probably come up with a decent set of pistons, given some time. Do you have access to a gram scale? Get me an accurate weight and maybe I can find a single to replace the scorched one...juggling wristpin weights opens up possibilities too, best if you can weigh all your pistons and pins separately.


http://www.thesamba.com/vw/classifieds/ ... id=1514324

Response from the seller this morning:

"If you want to send me the two pistons that are questionable I will be happy to send you two that are good.  I have several spares and am getting rid of all of my 90.5 stuff. I have used several sets of these used pistons and cylinders with no problems.  The cylinders have been honed and are straight.
Thanks,"

I may sent the whole pile to him...

I want to build a reliable engine... this direction wont get me there.

He has called me to try to resolve... says he'll send me 3 pistons and a set of rings....

hmm...

That should give you enough to work with. I've got dozens of wristpins if you need any to balance out the pistons.

Sending them back... Getting most of my money refunded.

Going to spend my money on proper parts so i can build a reliable engine....

Thanks for taking a look for me guys.


And while i'm at it... Whats a good P&C choice for a 1776 turbo?

Did you see that set of new Mahles for $300 at theSamba? If you go for them be sure that they're the later size with thicker cylinderwalls.