I'm considering a 3.2 motronic upgrade to my 3.0 CIS 911. Over the years I've built several porsche engines and have always used new Mahles. They are excellent. No excuses. Throw 'em in and forget about 'em.

On the other hand, I've read a number of threads here where various aftermarket sets were used. Something went wrong, but what? What oil did they use...How many miles...What was the break-in procedure...yada yada. Bruce Anderson said in his book using these is like building a worn out engine with new parts due to tolerance issues.

Well, now the $3k I spent on Mahles a couple years ago for my 914-6 are a relative bargain compared to a new Nickies/JE set, and Mahles are through the roof! So the question is: Can you build an engine with these aftermarket sets and expect emissions compliance and reliability?

The rings don't always seat, the nikasil coating flakes off, and the cylinders aren't all the same height. Henry at supertec buys pallets of them, inspects and measures them and sends back the bad cylinders. He gathers the good sets and sells them. Don't buy them on ebay, 1/2 of them or more will be bad. I'd rather have my existing cylinders re-sleeved with iron by a Porsche specialist than buy Chinese aluminum cylinders personally. JE pistons are good. They used to have a piston slap issue when cold, their pistons shrank more when cold than Mahles and would make noise until they were warm. JE says they reformulated their alloy 2-3 years ago to fix the problem. I haven't used them since them so I don't know anything firsthand. The slap issue wasn't a problem with racecars because we warm them up.

.......use the MAHLES....you already stated why you should use them....sww914 stated some of the potential problems with aftermarket P/C.....

Mahles, Nickies or Supertec.

I've use nickies in the past and Charles stands 110% behind his products.
I have a set of 102's sitting here for my type 4, works of art. This will be my 3rd nickies equipped engine I've built (first 2 were for customers).
For my /6 I'm using Mahle's.

Do you think when Henry at Supertec returns half the china cylinders, because they are out of spec, that they scrap the returns?

Many die hard engine builders have bad things to say about Nickies until they actually use a set, then they generally don't go back.

Over time the quality of the OE sets has degraded quite a bit, meanwhile Charles at LN pushes to make the product better in the USA.
I've built well over 100 Nickies engines and have never had a bad experience.

...and I used the very first set that left the LN facility.

the bitterness of poor quality remains long after the sweetness of cheap price fades away

Get yourself a bore gauge and learn how to use it.....or find a trustworthy macninist that has the equiptment and check the bores & piston dias.. Nikasil Mahle P/Cs last & last & last.
I checked a used set that I had aquired and they were within spec. I managed to hurt 4 of 6 in a set in 7 years of hard use (my fault). I could have sent them to EBS for replating @ 150 per cyl....but came across a NOS Mahle P/C (10.5:1) set for a good price. Your 2 year old P/Cs should be fine.

JE Pistons from the 7 year engine withsome mild cleaning.