Shabib

I am rebuilding the engine of my 1999 911 and believe it is not the original engine. I have been trying to decipher the engine number to compare to the VIN to see if it is the original one or a later M96 engine. The Porsche engine number M96/01AT66X963 and the car's VIN is: WP0CA2996XS655575. I have deciphered the car's VIN but what I have found on the engine number doesn't match the sequence I have. Any help would be appreciated.

DBJoe996

With the engine number having AT in it, it is a replacement engine. So at some point in time the engine has been replaced with a Porsche replacement engine.

Shabib

Thanks @DBJoe996 . I assume the subsequent alphanumeric sequence is irrelevant? I know while we were rebuilding it, the crankshaft for a 1999 996 engine did not match what was in it and would not replace the damaged one. We had to get a different one.

DBJoe996

frederik

Speaking of matching numbers, are we at the level now that a 996 with the correct matching engine is worth more?

TexSquirrel

IMHO, not yet.
I don't really care whether my number match.
The rest of the car has been modified for my taste, and I won't be putting it back to original.
If my kids, who will inherit it, want to do that, then at least most parts I've remove/changed are stored.
But really who cares....enjoy the car and don't worry about this matches that.
I have told my kids my car is for driving and enjoying, not parking and "saving it in case it might someday become worth a lot of money."
Invest your savings well and don't look at cars as investments.

808Bill

How would one even know if the motor came with the original car?

islaTurbine

The only way I’m aware of is to purchase a PPS (formerly known as a CoA) from Porsche. It’s my understanding that they run your car’s info against the Kardex in order to confirm your info.

Porschetech3

The original engine and trans serial numbers are also located in the DME.

A few years ago someone got a COA for 996 that didn't even list the engine ser# , rumor was that so many 996 had replacement engines that Porsche stopped putting it on the COA's. If that's the case, when/if the 996's really become "collectable" , low mileage with matching DME and engine/trans ser #'s will be the key.....

az968gpw

My engine number matches on the outside but what's really important is that the insides match what a lil ol' engine builder in GA put in it

jobyt

same.

frederik

To be clear, my remark was tongue in cheek... it’s actually refreshing to not worry about this so much! Fully agree that a car shouldn’t be an investment. I drive them.