74 2.7 P&C Identification
 

I am rebuilding my 74 2.7 911, but purchased most of the parts I need over 15 years ago and now don't have documentation on what I purchased. I would like some help identifing the pistons/cylinders and suggestions on the cams.

What I know:

I have Mahle rebuild P & Cs. The pistons have two markings on the inside: 90L01 and C021 and 89,978 (I assume this is the piston diameter). They are domed with a small hole in the middle.

The Cylinders are marked Mahle 147 and G.. 90ZN2W5.

They were boxed with a Mahle article # 503 54 90, which according to Mahle's web site is superceded by 503 59 92.

What are the specifications on these P&Cs? My cams were ground, but I don't have any details on what they were ground to. What would you suggest?

(I purchased Wayne's engine rebuild and 101 books and checked the Mahle web site, none of which tell me enough information.)

Thanks.

Post some pictures and I'll tell you what you have.
If the cams were reground to a non stock profile there should be numbers on the end of the distributor side cam.

Attached pics of 2.7 components:

http://forums.pelicanparts.com/uploa...1159292459.jpg http://forums.pelicanparts.com/uploa...1159292498.jpg http://forums.pelicanparts.com/uploa...1159292545.jpg http://forums.pelicanparts.com/uploa...1159292652.jpg http://forums.pelicanparts.com/uploa...1159292698.jpg http://forums.pelicanparts.com/uploa...1159292759.jpg http://forums.pelicanparts.com/uploa...1159292808.jpg http://forums.pelicanparts.com/uploa...1159292856.jpg

I will check the cams tonight and if there are markings, I will photo and post tomorrow.

I would need the see the inside of the cylinders and the piston domes in order to indentify your parts.

Attached are some close up Pics of P&Cs.

http://forums.pelicanparts.com/uploa...1159546771.jpg http://forums.pelicanparts.com/uploa...1159546808.jpg http://forums.pelicanparts.com/uploa...1159546889.jpg http://forums.pelicanparts.com/uploa...1159546928.jpg http://forums.pelicanparts.com/uploa...1159546964.jpg http://forums.pelicanparts.com/uploa...1159546998.jpg http://forums.pelicanparts.com/uploa...1159547040.jpg

Add'l 2.7 Pics
 

Attached pics of cam and head assembly.
http://forums.pelicanparts.com/uploa...1159547245.jpg http://forums.pelicanparts.com/uploa...1159547282.jpg http://forums.pelicanparts.com/uploa...1159547325.jpg

Alusil cylinders and cast 8.5:1 pistons.

Cams appear to be CIS "S".

I believe you will need to replace those cams. The rust on the cam journals will damage the cam bores. I will depend on how smoothe you can get the journal. Polish the journal and check.
good luck

Thanks for your help. I will have the rust on the cams evaluated.

The cams came from my 74 "911", a straight 911 not the 911S. I guess that I had the machine shop grind them to "S" specs.

My primary interest is in a street car, but I would like to increase the performance over the original 74 911. Should I consider replacing pistons (higher CR) or going to 3.0L P&C?

Would any of these mods make a strong case for replacing my CIS. Thanks in advance.