Mahle Cylinders

[The Dude]

I'm tearing down my 1972 911T's engine and this weekend I finally got the heads off (The Dude's Rebuild; 72 911T). As I was checking out the cylinders, I noticed they had "Mahle" stamped on the bottom. In reading Wayne's rebuild book (page 53-55) he suggests that Mahle cylinders weren't introduced until 1973. Further, he says the Nikasil coating is slightly magnetic - I checked and mine are magnetic. The Haynes book lists Mahle cylinders for '72.

So my question is, did Porsche use Mahle/Nikasil cylinders in 1972?

I don't have any part numbers yet as it was getting late when I noticed.

Thanks.

Landon

[Jim Dorociak]

There were cast iron cylinders, and there were Biral cylinders with steel inside and aluminum fins. Also note that there were alusil, and aluminum with Nikasil coating. There should be some markings on the cylinders telling you the size. 90 mm was 2.7, 95mm was 3.0 and also 3.2, 84 was 2.2 and 2.4 and the 2.4 was a longer stroke crank. Sorry I am remembering this off the top of my head. 2.4T would have been cast iron cylinders. Jim

[docrodg]

Mahle made cylinders for Porsche before 73. On the 2.0 the Birals are from Mahle. You could have any of a number of cylinders, and the diameter will help narrow down what they are.

Strange, I am inspecting a Mahle plant this week.

[The Dude]

Thanks. I'll pull the numbers next chance I get.

L

[The Dude]

Thanks all.

I found this stamped on top of the cylinders:

84ZD3

I think I've seen some threads with serial number themes and will try a search to see what's out there.

Here's a pic.

[Bobboloo]

Those are Mahle biral cylinders that came with the E or S motors. Judging from the look of the pistons they look like they either E 2.2 or S 2.4 pistons. They might even be 2.2S pistons (highest compression available for 2.2/2.4 motors)

At any rate which ever version of the Biral they are they are much better than the stock T set and offer a nice performance boost. If they measure out to be in spec then hang on to them. The only thing better would be a set of new Mahle Nikasils but they are very expensive.

Someone has already modified this motor. There's a good chance you might even have E cams.

[tharbert]

I was shopping for some 2.2E pistons and asked a question about visually identifying the different pistons over on the rebuilding forum. Tom1394racing posted this comparisin picture:

If you search his name, he has a casting number cross reference list posted over there.

[The Dude]

Thanks again for all the expertise. I found several posts by Tom1394racing -- he seems to know a couple of things about P&Cs. Doesn't really matter what they are at this point as everything is coming apart anyway - just thought I'd try to get a head start on my rebuild plans which included increasing the CR from stock T specs. Looks like I might be able to save some money.

Once I get some more data, I'll toss out some questions (after searching the forums...thank you very much).

[The Dude]

Here's some pictures of the pistons and cylinders after I got them off the engine.

All the pistons had "83 95" stamped on the top. The number 1 piston had "MAHLE 84P11+" stamped underneath.

Still searching the forums to find out what these are.

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[Flat6pac]

84P-11 = 2.4S as per Tom racing
Bruce

[JerryL]

Can you point me to Tom's post, I have been searching with out much luck.
I am trying to find out what is in my 71 911 T, had been rebuilt no documentation available at purchase.
Motor looked great Webbers, SSI's fresh Mahle alloy cylinders under it, had the motor out for some minor rear damage pulled chain covers to check on tensioners, it had 930 tensioners as well as wide base 930 idlers, I added safety colars and buttoned it back up, gave me the feeling that the jobe was done right.

BUT I would love to try to figure more out about the motor from the outside if possible, runs strong, was rebuilt about 1995 then car was parked in fall of 96 after rolling out of the PO's drive into a tree, never driven again.

Regards

[bavaria911]

So what pistion do I have in my 2.4E motor? I look at the compression space between the two valve cuts on top of the piston and they look different then the photo Tom posted above for the 2.4S and 2.2E. Do I have the 2.2S mahle piston?
Pls assist if you can - I hope that these photos help you too.
Thanks,

[Dirk Diggler]

Try this one:

2.2L vs. 2.4L "S" Pistons - How to ID??

---------------
Dirk
78'SC minerva blue

[Flat6pac]

911 piston casting numbers

[Flat6pac]

11/06/2008 was the date you want

[JerryL]

I was hoping to be able to get some info from the cylinder on the outside without disassembly. Cyls look great like new are alloy car runs great!! just very curious as th what size they may be if available from any info / code on the outside.

Not courious enough to warrent a teardown.

Thanks

[bavaria911]

Thanks for the link -- I also wrote Tom to have him read this form.
Here is another pic and I zoomed in to see the stamped code- 84P8 making my pistons 2.2S.
This is good news.

[tom1394racing]

Yes...These are 2.2S pistons.

[Flat6pac]

2.2 S pistons..now you need a 2.4 crank and rods=10.3/1 compression, S cams and large port heads. 210 horses
Bruce

[tom1394racing]

Bruce

Don't forget the twin plug at 10.3 CR.