Q&A

In my pre-purchase research of a special 964, my special attention fell on it's engine number. I have seen multiple other 964 engine numbers, but they all have a much more ' deeper punched in' number than this one. This one looks much more 'thin, on the surface' and it makes me wonder if this could be done afterwards.

As you can imagine: This car is currently sold as being a 'matching' engine.

Hopefully i am wrong, and can someone take my fear away by posting their 1991 engine number and show me the way it's machined is similar to their example.

Out of respect for the seller, and me not having bought it, i have covered up some numbers.

Thanks in advance

warmfuzzies

Is it me, or does there look to be a 2 stamped underneath the M.

-Teme-

Looks fishy to me - like the original number has been filed off and replaced with...?

crg53

Definitely looks like the surface has been either machined or filed down. I have added a couple of pictures of my engines serial #. It is easy to see the difference.

cobalt

I impressions stamped tens of thousands of sand castings over the years.

The area used to stamp the engine number is always filled clean. From my experience there is a 2 that has been stamped over by the M. However it doesn't mean they didn't screw up and have to file it off and start over at the factory. It takes a skill to get it right if done by hand. What I am seeing is that the impressions are clean vs ragged edges as most of the engines I have seen. This might have been someone trying to clean it up but it is hard to say.

Too bad it wasn't an 89 or 94 then you would have the vin sticker on the engine block.

Don't know if this helps but this is from a 93 but they mostly all look like this from those I have seen.

Another thought is the 2 is from the initial stamping. When you use a heavy hammer to make the impression sometimes the stamp will jump and leave a shadow of an impression if the stamp wasn't held firmly in place. After closer inspection it has definitely been filed down but the numbers are not as deep of an impression as the others posted. It is possible it is original there may be no way to tell.

Steve Weiner-Rennsport Systems

Definitely looks modified to me. Note the machining marks above and to the right of the numbers indicating that someone machined/ground the pad flat and restamped the serial numbers.

Possibly stolen or a replacement (used) engine case.

Q&A

Thanks guys.
My worries and doubts got confirmed by all of you.
I'd prefer a non matching car over a faulty matching car.
This car is not going to be mine.

I love Rennlist !!!

Thanks again guys

-nick

Looks odd for sure. I'm guessing that Steve W is referring to the thin rib at the top right that looks milled? Any more details to the story?

I don't know that quality control at the factory was like for engine case stamps, but this cam had never been touch before I pulled it (paint marks are mine, '91 USA C4). I've heard anecdotes of strange stamping/re-stamping by the factory on occasion, especially for unique bits.

<img src="http://i562.photobucket.com/albums/ss64/rnd964/D9E494DA-52EB-487E-896A-43626AD41E73.jpg" alt="http://i562.photobucket.com/albums/ss64/rnd964/D9E494DA-52EB-487E-896A-43626AD41E73.jpg" height=50% width=50%>

Derek911

I was going to ask how can you tell what engine serial number came with the car, but I just looked at my certificate of authenticity and it has the engine and transmission serial numbers and vin on the certificate.

cscrogham

Spot on Steve, I guess the practice of using un-numbered cases and making them say what you want is spreading from early 911's to newer ones. Following the $$!

One thing people often neglect to do, however, is to check the engine type number which is a little further back on the main case but still visible. It should "match" the engine number range.

I recently looked at an early RS with the engine stamp (looked pretty good too!) matched to the VIN, but the type number was 911/10 and not 911/83 as it should have been. Be vigilant!

tfitch03

Is this something a pre-purchase inspector should find or is this all on the buyer to discover?

cscrogham

First thing I look at. I have a personal library of VIN and engine stampings for reference because no one can be an expert in all models and years.

I have tried to share that info on relevant sites for 356, early 911 and now I guess later 911's too. I put an entire page of sample engine VIN stamps in my new 356 engine handbook, so people can see what they are supposed to look like.

As prices go up, so does the potential for fraud, let's tell it like it is. It is fraud to cut a number off a case and re-stamp another one.

JasonAndreas

I wonder if anyone that purchased a $$$ suspect engine has tried etching the serial number with ferric chloride and concentrated hydrochloric acid (> 35%) to reveal the number that's been machined/ground off?

Porschenut_Lee

My 964 has a Porsche remanufactured engine that was installed back in 2005 by the dealer. My case does not have a serial number. Nothing but bare steel. .........a clean slate. Wouldn't surprise me if this car had a Porsche replacement engine with no serial number stamping and the owner at some point tried to make his own. .......

cscrogham

Good point, and a factory case replacement is not a terrible thing as long as its documented. There were several 3.8 RSR engines with no serial number and that caused a fuss over originality years later, although they did have the correct type number. In this instance it looks as if something else was there because they removed material and then re-stamped. That would be a no-no for me.