Difference between AT and X engine rebuilds

[dammad]

I've read a lot about AT in the serial number means a rebuild. I've also found some information that an X indicates a rebuild also.

http://www.renntech.org/forums/index.php?s...+serial+numbers

http://www.renntech.org/forums/index.php?s...amp;#entry21213

But I can't find any information on what the difference is between AT and X? AT appears to be factory rebuilt, but I assume that X must also be done by the factory??

I have M96/0166X14358 in a 1999 996 Tip. Cab.

[BruceP]

My understanding is that an AT numbered engine had the crankcase replaced, whereas an X engine just had a top end rebuild and is considered by Porsche to be repaired rather than remanufactured.

At a minimum, this might help you narrow things down when you're Googling. My answer is just from memory, and I can't cite a source.

[ninsei]

My understanding is that an AT numbered engine had the crankcase replaced, whereas an X engine just had a top end rebuild and is considered by Porsche to be repaired rather than remanufactured.

At a minimum, this might help you narrow things down when you're Googling. My answer is just from memory, and I can't cite a source.

FWIW: my engine (2000 C2 Tip) has an "AT" in it, and I can tell, it's all been replaced: alternator, PS pump, A/C compressor, block, heads, ...).

[txhokie4life]

Where to find the serial # on the engine?

m

[Loren]

Where to find the serial # on the engine?

m

http://www.renntech.org/forums/index.php?s...ost&p=82150