Case Casting Numbers, Isn't there a Maestro book about them?

[Jefferson Wood]

Dear Forum,
I would like to get an engine case that is pretty close to the one that would have been in one of my cars. It will never be the original engine, but I just want it to be close. I noticed that cases also have a round stamp like: (37/58). Is this the week and year of the casting?
I thought I remembered hearing about a Maestro book where he catagorized a thousand engines and came up with some date, time frames for case casting numbers. Which one was it?
Thanks
Jeff

[Larry Brooks]

"The Maestro's little spec Book" is the one you want

[Mike Acebo]

Jeff,
The volume "Secrets of the Inner Circle" has the Maestro's Engine Truth Table and the Case Casting Number versus Date Stamp graph. My C Coupe engine works out to the 40th week of 1964.

[Jim Breazeale]

"The Maestro's little spec Book" is the one you want

No, you want the "factory" spec book........"Porsche Spec's 3rd edition information. please" It was printed by the factory and is the basis for all the information that is in printed/digital form. Not to take anything away from the Maestro, but the engine serial number stamped on the 3rd piece is the only thing visible that determines the "year" and series of engine. The date stamps are on the inside cover and are not visible unless the engine is dismantled (Harry was a master at engine dismantling).
Buy, borrow/steal any book related to 356s (Brett Johnson's book, Jim Schrager's book, Conradt's book, Harry's books and the Spec book should be in everone's library, not necessarily in that order). We should all lobby the factory to reprint the spec book. The last printing was in 1980 and is currently unavailable.

Regards

[Bert Leemburg]

Hi to all 356 Friends,

I will be bringing some new 356 Spec books to the West Coast Holiday, if you want one see me there, I will be at the swap meet.

Bert Leemburg

[Chris Markham]

Dear Forum,
I would like to get an engine case that is pretty close to the one that would have been in one of my cars. <snip>
I thought I remembered hearing about a Maestro book where he catagorized a thousand engines and came up with some date, time frames for case casting numbers. Which one was it?
Thanks
Jeff

For thiis activity, you son't need the Maestro's Little Spec Book (though its an interesting read in its own right--Harry didn't take apart all those engines, many were "phoned in" by their dismantlers to add to the database). You don't even need "Secrets of the Inner Circle", though that is also a fun read.

What you need, since you'll be shopping for a new engine, is The Formula, which Harry published in "Secrets", which allows you to look at the case casting number (not the 3rd piece, but the one on the case-half boss near the fan shroud) and calculate the week/year of that engine. I'm writing from the commuter bus or I'd go to my bookcase right now and post the formula. He had a version you could carry around in your head (at swap meets) that was accurate to a few weeks. Good enough for your purposes?

[Chris Markham]

Here's the equation that the Maestro said would be easy to remember for your flea market (now eBay) cruising.

Code: Select all

              (casting number-2nd perimiter bolt)  X 1.1
Manuf. Date=      ___________________________________     +  55.55
                                    10,000

The above is good for +/- 7 months in the later numbers (912 engines) and as good as two months in the 356 era. I believe, from looking at the data, that very early 356 engines, before 1954, might deviate from this linear equation significantly.

The examples he gives for how to work this in your head are the below.

First a case number of 10000. divided by 10,000 = 1. Times one point one= 1.1
1.1+55 = 56.65, or two-thirds into 1956, or August.

The other example is 100,000. Divide by ten thousand for 10. Times 1.1 = 11.
11+55.55 = 65.55. The Maestro calls this a "July" case.

If you're plugging this into a computer, you can use Excel (or Google Docs) and
this formula:

use A2 for the Case Number=<case>
B2 can have: =((A2/10,000)*1.12603450553)+55.4131418
// Extra parens for clarity

Enter the case casting number into cell A2 and cell B2 will describe the date.
The conversion of decimal remainder to month-of-year is left as an exercise for the reader.