Mahle nikasil cylinders and pistons

worn · worn's Garage

I bought a set of pistons and cylinders for a 3 liter 911sc. They came boxed with the pistons already in the cylinders. Is it proper to install them as is, or do I need to pull all of the rings and pistons out to check for ring gap. They are as pretty as you would expect.
Thanks.

gled49 · 07-13-2021, 07:04 PM

Take them apart. Check everything.

jbahrami · 08-11-2021, 03:29 PM

I know this is a little late and you probably already got past this step....

Yes, take them apart. I purchased new pistons and cylinders from Mahle for my 3.0 SC motor. The pistons came installed in the cylinders, but the rings were all oriented the same.

Remove the pistons, clock the rings to the proper orientation, and reinstall in the cylinders.

Btw, if you need a wrist pin install tool, I have the Stomski Racing circlip tool for 22mm wrist pins. Made installation of the wrist pins very easy. PM is you want to purchase mine.

This tool ---> https://www.pelicanparts.com/More_Info/STOMSKISR072.htm?pn=STOMSKI-SR072&SVSVSI=791&fs=0

Thanks,
Jeff

faapgar · 08-15-2021, 05:07 AM

Remove the pistons.Buy some white Terry cloth shop towels and a quart of ATF.If you have Ultrasonic cleaning available have the cylinders cleaned that way as it is the best.The heat from the Ulrasonic helps to open the bores to release the black grit from honing.If you clean them yourself spread ATF on the cylinder walls and wipe clean with Terry cloth towel several times until the towel just shows red and no more black.2nd step is get a good pair of gloves.Place cylinders in oven and turn the temp to 225 F.Do this while your wife or mate is not home.There is no smell from this procedure however.After 15 minutes remove a cylinder and redo the cleaning.You will see black on the cloth as the pores of the surface are open more and you getting the last grit out.Failure to clean the cylinders correctly is the biggest reason piston rings do not seat leading to burning oil.The grit will ruin your bores and everything else it comes into contact with.Takes about 5-6 hours to do this by hand for all 6.That is why I recommend the Ultrasonic method.Cost you $120-240 depending on the shop.Clean your rings with ATF as well to remove the black grit from machining.When used to buy P & C from Porsche OEM they were pretty.When you buy Mahle from aftermarket supply house they are not clean.Ciao Fred

faapgar · 08-15-2021, 05:10 AM

I am sure after reading the above caption a lot of you are saying Oh Shart.

jbahrami · 08-16-2021, 09:31 AM

Oh shart, indeed!

Cloggie · 08-18-2021, 01:47 AM

Very interesting that Mahle does not do that cleaning....I am surprised that they neither clean the bores properly and (as I have heard from other threads) that they do not gap the rings.

I have zero issue with checking all those things and will for my build, but I would have thought with the cost, reputation and generally the competence Mahle has shown over the years that they would not have done these things.

Does this kind of thing extend to other components? As an example,I have a brand new Porsche crankshaft, it will definitely get a good Kimwipes cleaning before installation but do I need to do even more?

D.

911pcars · 08-22-2021, 11:05 AM

Your crankshaft. Even if after spending hundreds (or more), don't assume it was manufactured or rebuilt to spec. It should be double checked for straightness, journal runout, out of round and size. An engine builder should perform those checks as a matter of SOP (standard operating procedures).

Do not assume parts received are ready to install. If you don't, you should have a pro do it for you, or assume it was performed, then accept the consequences, if any.

Sherwood

Wizoftk · 08-28-2021, 11:29 AM

Are there any brands that actually do the cleaning? I have seen multiple engines being rebuild and a lot of places take it straight from the box maybe wipe it down and install. Any recommendations for a small home garage ultrasonic parts cleaner?

Emo993 · 08-29-2021, 03:25 AM

Worn, how is the build going. Mark

faapgar · 08-31-2021, 04:18 PM

30 years ago there were a few local shops that would just slide the pistons low enough and just install the pins.I loved those guys .when the rings would not seat. I would fix that.Every thing was already cleaned.

Jeff Alton · 08-31-2021, 09:23 PM

Quote:

Originally Posted by worn

I bought a set of pistons and cylinders for a 3 liter 911sc. They came boxed with the pistons already in the cylinders. Is it proper to install them as is, or do I need to pull all of the rings and pistons out to check for ring gap. They are as pretty as you would expect.
Thanks.

You have received some good advice and some interesting advice.

It seems you bought a used set of P/C with rings installed??? Yes, pull them apart. Check cylinders for ovality. Measure the piston to cylinder clearance. Measure ring gap.

If new parts, do all of the same steps....

Never install a new or used engine part without measuring and verifying, end of story.

If used, choose a method of cleaning that works for you.

Cheers