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Engine Serial Numbers

Posted: Thu Mar 16, 2017 10:24 am
by Bob Kierejczyk
Could an early Pre-A ('54 Production Year Speedster) have been fitted without a stamped serial number??

Re: Engine Serial Numbers

Posted: Thu Mar 16, 2017 12:12 pm
by Curt Dansby
Hi Bob

Welcome to the club. I would say highly unlikely. Have you ordered a COA on the car?


Re: Engine Serial Numbers

Posted: Thu Mar 16, 2017 1:07 pm
by Jules Dielen

this should be an interesting article for you. it's about early 3 piece cases which is what your 1954/55 car would have had.


Re: Engine Serial Numbers

Posted: Thu Mar 16, 2017 3:16 pm
by Bob Kierejczyk
Kurt - Yes - I just ordered a CoA.
Jules - Thanks for the article. I believe mine has a 2-piece case.
Thanks again to both of you.

Re: Engine Serial Numbers

Posted: Thu Mar 16, 2017 5:10 pm
by James Davies
Hi Bob,


Original 2-piece case motors built at the Porsche factory on pre-A cars had very specific stampings done at Porsche Werk II during assembly:

1) Engine number, i.e. P-3xxxx for a type 546 1500 as what may have been originally in your Speedster
2) Internal number, a 4-digit number that was sequential and agnostic as to engine type, stamped on the front bolt boss
3) Engine type, "546" in the case above, stamped below the internal number
4) Initials of the engine builder, stamped next to the generator tower

If none of these are there, then it's a replacement, i.e. not built at Porsche Werk II in 1954. And replacement was *very* common. These old magnesium cases were not strong, and they did not last if the car got any sort of use after its original owner. The replacement cases (like the originals) were just machined VW cases of current vintage. VW cases up through 1960 could have been used by any dealers in the USA to replace a worn original engine case. Generally they got these from Porsche already machined, but they could be sourced from VW distributors as well. And of course these replacement cases were unstamped.

Each case half also has a date embossed into it giving the day and shift (1, 2 or 3) it was cast, and of course these correlate with the production date of the car. The casting dates are on the side of the generator tower and next to the tach drive down at the oil pump. They are of the format (DD)(MM)(SY) where S=shift and year is 195Y.

Feel free to post photos of your engine and tell us about your Speedster! Lots of Speedster fans here, some quite knowledgeable and able to answer whatever questions you have.


Re: Engine Serial Numbers

Posted: Fri Mar 17, 2017 7:03 pm
by Bob Kierejczyk
Thx for the advise.
After doing some additional research we found the engine was completely rebuilt about 15 years (5,000 miles) ago.
As such - likely - the generator pedestal may have been replaced as it appears the balance of the engine appears to be in order.
Will post pictures, etc. once we get her settled.
Nice to be onboard.

Re: Engine Serial Numbers

Posted: Fri Mar 17, 2017 8:55 pm
by James Davies
Hi Bob, if the engine has a detachable generator stand, then it is not a 2-piece case, but a 3-piece, the 3rd piece being the front piece which may carry the engine number. Type and internal number markings are still on the case halves.

Anyway, photos will help us ballpark date it for you. =)