The shop switched pistons on me?

[cmcclain]

o Long time watcher, First time poster. Thanks for all the help. I was installing rebuilt pistons and cylinders and I noticed one piston pin did not fit lengthwise. It had 1/4 inch play between the pin and the clip. All the other pins fit. I took the cylinder off and started checking it out. This piston is different from the rest. It is beat up on the side. It has a different dome, a longer hole for the pin, and is a 0 ++ not a 1-- like all the others. The cylinder is a 1. It also has a different notch on the bottom(see photo).
I think the shop switched pistons. I have photos of the old pistons and cylinders and I don't see this piston, although it is not real clear.
I will take this back to the shop tomorrow and check with them. I had the work done way back in Dec. and i know they will probably not remember.
What are the issues with using this different piston.
The rest of the pistons look like this with a rounded relief


other pistons don't have the raised notch

[john walker's workshop]

that one may be a 3.2 piston. check the pin height compared to the other ones.

[cmcclain]

The pin height seems to be the same. The strange piston weighs 1 ounce more than the others

[304065]

The "1" vs. "0" is an oversize indication. I bet if you measure the diameter it's different. (Probably need a V-block, dial indicator and comparator stand to do that, however or any machine shop can do it.)

In any event, a piston with nicks in the side like that would make a nice ashtray.

I would call the shop and ask them what gives. They aren't located in Downey, CA by any chance?

[Henry Schmidt]

0 vs 1 is a minor difference. The real issue / difference between these pistons is the compression ratio.
Of course these are just pictures and I could be wrong but my guess is we are looking at a 9.3:1 (US 80-83) vs 9.8:1 euro.

I would have to agree that the mismatched piston is beat and should find it's way to the trash.

If the shop responsible for the error will not work with you, give us a call and we might be able to supply the matching piston.


BTW: welcome to Pelican. I believe you'll find it a great source for both parts and information. Wayne has supplied a truly great resource for the Porsche community.
Thanks again Wayne.

[euro911sc]

Also, wont the inside of the piston have a part number that you can compare? My 9.8:1 piston had the following:

Stampings:
95L70
C021

If your #'s don't match in the set it will give you some ammunition. Then again, they might all have the same markings

Welcome to the board and not to kick ya when you are down, but don't trust anyone... check everything when it comes back. Even brand new manufactured parts... Mistakes get made. Its just life

Best regards,

Michael

[tom1394racing]

Check the piston ref # on the inside of the piston.

The SC numbers are:

93L7 - 8.5 CR
95L67 - 9.3 CR
95L70 - 9.8 CR

Don't mix them...CR will be different and the piston weight will not match.

[cmcclain]

Thanks for the help. I took the piston back to the San Diego shop and they are looking into what happened and will replace the piston with the correct one. They are good guys and a good shop. I guess every one makes mistakes.
On a side note I had the chance to meet Henry Schmidt and tour his shop. He is a really good guy and has some very pretty engines.

I purchased my 1980 911 SC for 5K last year. It had 375,000 miles but was pampered like a baby. The body/paint is excellent and the interior just needed a bit of TLC. THe engine had 6 broken head studs and still ran strong. I took the engine apart thinking i was gonna have to spend a bundle and was pleasantly surprised. All parts were in spec. What a motor! I had the crank polished, valve job, cleaned up the pistons and cylnders, replaced the cam chains and cleaned, cleaned, cleaned everything else. I will post pics when I get it running next week. So far I have spent less than 3k on parts and tools.
Thanks again for all your help on my first 911 rebuild.

Craig
1980 91 SC
1971 914