P&C questions
 

Hi folks,
Looking for a little advice and help on my first rebuild, 3 actually, 69 2.0, 74 2.7 and 76 2.7S! Have all the books but I have a few unanswered questions...

Pistons:

- If a piston is damaged, can you replace just one? Does it make sense to buy a used one which is still in spec if only 1 or 2 need replacing? Is this possible?
(Any tips on shrinking photo sizes? I have 2 of the pistons I am referring to)
-Markings: From a 74 2.7 and a 76 2.7S. The 74 has a high dome and the 76 has 2 small indentations. I am trying to figure out what the markings mean and I can't find this info anywhere. Both are Mahle, they are:
74: A2?, 89.97 (for 90MM cylinder right) Sp 0.03? 111M108.8
76: Sp0.03, 89.97, 110M101

The 89.97 makes sense to me but what is the rest and if I am looking for a used piston, what markings do I need to look for?

Cylinders:

How do I know if they are Nikasil or Alusil?
74: 90ZN2W6, some have W5 - what is the difference? They have a 5 with a triangle around it.
76: 90ZN2W5, triangle with a 6 in it and 703M081
Would a 74 and 76 have the same 90ZN2W...numbers?

One of them has a cracked fin, is the set toast?

If I missed a page in the books or a thread somewhere to get this info, just let me know, otherwise any help is appreciated.
I will posting alot of questions in the next few weeks so please be patient. Thanks in advance!

Cheers,
Derek

Differences in cylinders are easy, if someone has those same pictures that were posted for me, you could probably benefit. Once you see what they look like, it's the difference of night and day. For the most part, nikasil is a dark copperish color and ausil is a light gray.

see thread:

http://forums.pelicanparts.com/showthread.php?s=&threadid=113952&highlight=nikasi l+alusil+markings

So the quick answer if I got this straight is if they are Mahle cylinders, they are Nikasil so I am safe to re-use with new pistons and rings. right?
Thanks,
Derek

Generally speaking, yes. However, Wayne is always happy to point out that Mahle made some Alusil jugs, so it is not 100%. The color/magnetic tests are better. Alusil are a flat grey color, Nikasil are shinier, and slightly magnetic, IIRC.

Unfortunately, being able to reuse Nikasil cylinders isn't a sure thing either. They should be measured to make sure they are not overly worn or out of round. The specs are in Waynes book.

Tom

Tom is correct in everything he said but I need to add that only the inner cylinder face is slightly magntic. You have to go by color from the outside. These are 95mm Nikasil on the left and Alusil on the right. The # of fins is also different.
http://forums.pelicanparts.com/uploa...1061414062.jpg
All the Alusils may or may not have the bridge cast down the axis of the cylinder on the top and bottom faces

Here are the KS markings on the side of the base of a n Alusil
http://forums.pelicanparts.com/uploa...1061414544.jpg

Yup, the Nikasils are magnetic - that's the test I use...

-Wayne

James,

I apologize for the delay in my response. Usually it takes a few days for the communication between ourselves and the production facilities in Germany to exchange information. I believe Christoph's email below will answer your questions. In summary, if its a Mahle cylinder it is a Nikasil coating. If there's anything else I can help you with, please let me know.

Best Regards,
Eric

MAHLE, Inc., AFTERMARKET-Engineering, Eric Grilliot
5575 East Andrew Johnson Hwy, Morristown, TN 37814, PH: 423-318-3711/FX: 423-318-3190
eric.grilliot@us.mahle.com, Web: http://www.us.mahle.com

----- Forwarded by Eric Grilliot/MPE-US-MO/MAHLE on 04/29/2004 07:45 AM -----
Christoph Dutschke
04/27/2004 12:35 PM


To: eric.grilliot@us.mahle.com
cc:
Subject: Mahle 911 cylinder question


Hello Eric,

Nikasil (MAHLE) and Alusil (KS) is almost the same, but Nikasil is the best, because this is our company.

I would propose to the customer to use the MAHLE-piston-liner-sets. The MAHLE-Cylinder are coated with Nikasil and the MAHLE-piston will make a perfect job in these Nikasil liners.

90ZN2 ist the casting number of the raw cylinder. Out of this raw parts we produce several cylinderliners. To identify the correct parts, please check the informations in the catalog (engine code, HP, year of production, ...).

If you have any question, please do not hesitate, to let us know.
Best regards,

Christoph
-Technical Service-
---------------------- Weitergeleitet von Christoph Dutschke/MAHLE-GmbH/MAHLE am 27.04.2004 17:20 ---------------------------Von: Holger Roden am 26.04.2004 10:36

An: Christoph Dutschke/MAHLE-GmbH/MAHLE
Kopie:
Thema: Mahle 911 cylinder question

Christoph,
wärest Du bitte so freundlich und könntest Du die technischen Details an Eric beantworten.
Mein technischer Horizont kennt möglicherweise nicht jedes Detail hierzu.
Danke im voraus.
Gruss,
Holger

---------------------- Weitergeleitet von Holger Roden/MAHLE-GmbH/MAHLE am 26.04.2004 10:31 ---------------------------Von: Eric Grilliot am 21.04.2004 08:18 EDT

An: Holger Roden/MAHLE-GmbH/MAHLE
Kopie:
Thema: Mahle 911 cylinder question

Holger,
Good morning/afternoon Holger. Can you shed some light on the question below? I believe he is referencing the PN 503WR24, but I don't have a way to cross that number to '90ZN2W8'. If 503WR24 is the correct PN, then the catalog clarifies the Nikasil question. Is 'Alusil' only a KS trademark and how does this compare to Nikasil? The other coating I see in the catalog is Silumal. Is it possible to get some information on this coating for reference as well?
I hope I have not asked too much.

Thanks,
Eric

MAHLE, Inc., AFTERMARKET-Engineering, Eric Grilliot
5575 East Andrew Johnson Hwy, Morristown, TN 37814, PH: 423-318-3711/FX: 423-318-3190
eric.grilliot@us.mahle.com, Web: http://www.us.mahle.com

----- Forwarded by Eric Grilliot/MPE-US-MO/MAHLE on 04/21/2004 08:05 AM -----
"James Renfroe" <zrenfroe@bellsouth.net>
04/20/2004 07:43 PM


To: <eric.grilliot@us.mahle.com>
cc:
Subject: Mahle 911 cylinder question

Eric,

I have a set of old 2.7L Porsche 911 cylinders. They have MAHLE and
90ZN2W8 printed on the cylinder base. They are in spec and I would like
to reuse them in my rebuild. One guy from MotorMeister ensures me that
these are Alusil, and Dave from Pelican Parts indicates that they are
Nikasil by virtue of being MAHLE.

Some folks in the Porsche community state that Mahle made both Nikasil
and Alusil cylinders. Two Porsche books; The "Porsche Performance
handbook" and and "how to rebuild & Modify Porsche 911 Engines -
1965-1989" mention that Mahle produced both. Please help me set the
record straight.

I want to re-ring my current cylinders but I want to make sure what type
they are so buy the right rings; for Nikasil or Alusil.
Thanks in advance for any info!!

James Renfroe.

-----Original Message-----
From: James [mailto:james@pelicanparts.com]
Sent: Monday, April 19, 2004 10:21 PM
To: Bob at Pelican Parts
Cc: Dave@pelicanparts.com; zrenfroe@bellsouth.net
Subject: Re: Pelican Parts Customer Support Inquiry

My 2.7 911 engine has Mahle cylinders # 90ZN2W8. Please help me
figure what type of cylinders they are (Alusil or
Nikasil). I can't tell that they are magnetic. I'm rebuilding my
engine and assessing what parts should be replaced or
reused. I can't locate any info on these cylinders.

If it is Mahle, then it is Nikasil. Alusil was made by KS
(KoblinSchmidt). KS cylinders will have $$ type symbol. The cylinder
walls will also be dull aluminum in color an Nikasil will look like
chrome plating.

Otherwise contact Mahle directly for more details
Let me know if you have any other questions.

james

Just a quick thought on using an unmatched P&C for the set. You might want to have the piston's balanced to make sure that the odd one isn't significantly under / over weight as compared to the others. It doesn't take much to put the whole thing out of balance.

You can rering in-spec alusils. Search the engine rebuild forum for "rering alusils". All you have to do is order some AN-30 polishing compound from Sunnen, ~$35.