Harry Pellow's "case casting number"

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Bill Romano
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Harry Pellow's "case casting number"

#1 Post by Bill Romano »

The "case casting number" is the number stamped on the left half (driver's side if LHD) of the 2nd top perimeter bolt boss from the rear (pulley end) of every engine case. I don't know how Harry came up with that name but he did determine that it was a unique number sequentially assigned to every engine case and he did come up with a formula that allows one to approximate when the case came through the assembly process.

Has anyone discovered the true purpose of that number? Someone in the factory had a source for those numbers and someone had to take the time to impress them on the perimeter bolt boss. I suspect it was done almost as soon as the three parts of the case were selected from the castings inventory and that it was a work-in-process identifier used to track the case as it went through various machining processes. At some point in that process, each of the three pieces would be impressed with the case mating numbers. Since these were two or three digit numbers their value during assembly was limited to a relatively brief period before the possibility of duplication and mismatching of parts existed. Since the parts weren't interchangeable it was important to avoid such mismatching.

Has anyone documented or obtained documentation from Porsche that defines the operations performed during the building of a 356 engine. What record keeping was done to keep track of each engine as it progressed through the factory?

All cases were the same until cranks, pistons, heads were added. At some point, a case was withdrawn from the finished case inventory and the engine type decided and the engine type number would be impressed on the right side (passenger side in LHD cars) of the same perimeter bolt boss.
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Wes Bender
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Re: Harry Pellow's "case casting number"

#2 Post by Wes Bender »

This has been discussed quite a few times on the forum. What Harry called a "case casting number" was actually an assembly number that was stamped when the engine was assembled. It's the only number that runs consecutively through the various engine types. The number that was stamped by the machinist when he took a left, a right and a third piece and mated them, is a three digit (usually, but some have seen two digit) number that you will find on all three pieces of your case. It was unlikely that 1000 engines would be in process at any one time, so three digits would suffice. There doesn't appear to be any particular sequence to these. You can probably find more out about these if you use the search feature.

Harry's assumption that it was a casting number lead him to try to correlate it with the dates cast into each case half. Kind of close, but with a bit of error due to the cases not necessarily being used in perfect order.

Be careful about assuming that all cases were the same. There were changes through the years that resulted in different cases.
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Re: Harry Pellow's "case casting number"

#3 Post by Dick Weiss »

Harry made a chart for recording all the engines which he rebuilt (or serviced) over the years which passed thru his shop.
The #s were showing the approximate month per year from the lower left to the upper right.
The 3-match #s for the 2-or 3-piece case has nothing to do w/the date #s, but the internal case #s are cast on the face 1/2s.

Dick

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C Richey
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Re: Harry Pellow's "case casting number"

#4 Post by C Richey »

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Last edited by C Richey on Fri Apr 06, 2018 10:29 am, edited 1 time in total.

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Alan Hall
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Re: Harry Pellow's "case casting number"

#5 Post by Alan Hall »

Harry lists hundreds of them in "Secrets of the Inner Circle" between those numbers

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James Davies
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Re: Harry Pellow's "case casting number"

#6 Post by James Davies »

I wish that "case casting number" nomenclature would go away. The 1954 Porsche Service Manual pretty much on the first page identifies this number as the "Internal Number", and it's purpose is pretty much exactly what Wes describes.

We do know this internal number was stamped in the case when the engine was assembled by the Porsche technician, not when the case halves (or 3rds) were machined to be a matching set. We know this because during the pre-A period, the case halves were matched up as a set at the VW factory with case matching numbers already stamped, then sent over to Porsche, where they did further machining. These machined sets sat on a shelf until a mechanic grabbed one to start building a new engine.

There are photos in the engine assembly area at Porsche were a mechanic is assembling the motor, but it does not yet have the internal number stamped on it (or the type, or the motor number). The stamping seems to have taken place after the internals were installed and case halves mated, and pistons, cylinders and heads installed. During the pre-A period, the mechanics initials were also stamped on the case half at this point. This internal number was also grease penciled on the muffler and lower pulley for easy identification on the shop floor.

The internal number was linearly increasing with production date, regardless of engine type.

Correlation between the casting date of the case halves and the internal number are going to have a big variance, as cases were cast in batches, but engines were built continuously each day, the cases grabbed off the shelf were not grabbed in consecutive order. Much closer correlated would be the internal number and the production date of the car the engine was mated to. Of course both these numbers are difficult to come by. You need the original engine showing the internal number of a lot of cars, and you need the Kardex date (or preferably the slightly earlier production completion date).

Porsche did keep records of the chassis number, engine number, internal engine number for every car built.

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Re: Harry Pellow's "case casting number"

#7 Post by Dave Erickson »

James Davies wrote:Porsche did keep records of the chassis number, engine number, internal engine number for every car built.
Is that information available from Porsche? My kardex lists the engine number but not the internal engine number. I've been unable to locate the original engine, but I found one with a very close internal number I plan on using. I based the internal number on Harry's table of case numbers. The engine number is not close to the original, but that is because it is from a different series (Euro heater vs. American heater).

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James Davies
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Re: Harry Pellow's "case casting number"

#8 Post by James Davies »

DaveErickson wrote:Is that information available from Porsche?
No. They only make the Kardex info available. And today, unless you provide them with the engine number and transmission number that matches their records, they will not give that information out. Too much forging/restamping of engines going on. The internal number is one tool they can use to easily authenticate engines. It's information they have that you don't, unless you have the original engine.

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Re: Harry Pellow's "case casting number"

#9 Post by Dave Erickson »

Makes sense. I wonder if Porsche will authenticate an engine for a customer who asks. i.e. someone buys a Speedster with matching numbers, can he send the engine number, internal number and transmission number to Porsche and have them verify that they all match?

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Re: Harry Pellow's "case casting number"

#10 Post by Jim Alton »

DaveErickson wrote:Makes sense. I wonder if Porsche will authenticate an engine for a customer who asks. i.e. someone buys a Speedster with matching numbers, can he send the engine number, internal number and transmission number to Porsche and have them verify that they all match?
Yes, that's exactly what Porsche now does on Certificates of Authenticity. Apparently, Porsche was concerned that someone would use the CofA data to fraudulently restamp an engine and Porsche might get sued.

You can still get a Kardex from certain people. It will have those numbers.
 
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Re: Harry Pellow's "case casting number"

#11 Post by Dick Weiss »

A slight correction; There aren't any stamped numbers inside the case--just casted.

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Re: Harry Pellow's "case casting number"

#12 Post by David Pateman »

I have taken what I can find of Harry's list, and keep adding to it. I do try to ensure that the mating numbers match on three pieces when they exist. I gladly accept information from anyone who wishes to submit it to me. The practice of an internal number continued with the 911 2.0 liter engines until the end of 1969 model year. With the 911 engines I can easily show that the internal number is perfectly in sequence with the engine serial numbers; there could be typos that screwed up the sequence occasionally. The data on the 356 engines is not as clear, but in most cases it is sequential. In the 911 production book the internal numbers are included with the engine serial for at least the first dozen pages. The Kardex are very useful sometimes, but not infallible. One I obtained only had the engine #, and another had a very wrong paint description.
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Re: Harry Pellow's "case casting number"

#13 Post by John Brooks »

Here is one
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Re: Harry Pellow's "case casting number"

#14 Post by Vic Skirmants »

One reason for the variations in the 356 engine assembly number, is that those numbers included ALL 356 engine numbers; industrial engines, etc. 911 engines were pretty homogeneous; standard engines, with only an occasional race engine.

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Re: Harry Pellow's "case casting number"

#15 Post by Doug Darrah »

Jim Stephenson asked that I post this for him as his computer is under the weather.
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