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MG MGA - Engine numbers part 2

When I had my engine apart,I found a date stamp on it which tells you when the engine was made.Has anyone else seen these numbers? It is stamped on the gasket surface of the block on the oilpan rail where the pan meets the block.Mine is stamped 5 22 59 E and my car was made on 6-1&2 of 1959. Gary
gary starr

Not likely to be a factory date stamping - UK dates run day / month / year and I can't imagine a factory worker would have used the american date format... neither is that surface one that is normally used for numbers. A serial number is usually stamped into the front corner of the block above the water pump on the exhaust side.

Normally the casting date of the block appears on the side of the crankcase but that will be some time before the engine is assembled.

Engines were made at Longbridge and it is unlikely (but not impossible) that the engine made it from there to Abingdon within 9 days.

I guess that the stamping was made by someone who rebuilt the engine at some time - I see all sorts of strange markings inside and outside of engines.
Chris at Octarine Services

I recently found quite a few stampings in exactly the area that Gary found his while doing a rebuild this summer. I am out of town currently but will check these out when I return. I wrote down all of them for the record and am anxious to see if it may correspond to my production date in 1960.

Ken
Ken

I too have noticed the stampings on the gasket surface. This would preclude them being a cast date. I have always assumed them to be original machining dates. I have certainly not seen as many engines as Chris, but there are simply too many of these examples to discount them being factory placed. And the format seems too much like a date close to the expected manufacturing date give or take a few weeks. There must be some logical explaination.
Chuck schaefer

Both my engines - '59 and '60 1600s - have numbers stamped into the block in exactly the same place as Gary Starr's.

Only the '60 is to hand at the moment; the numbers read:

148
48
60

in that format; ie, one above the other and right-aligned to the outer edge of the gasket flange. Since this particular Tourer was built on 24-25 August 1960, the stamped numbers seem to me to be more than coincidental. HTH.

Alex

A. W. Risk

This same question came up in the mga twin cam discussion group about 2 or 3 years ago. One dedicated member volunteered to compile the data and to date he has recorded numbers from close to 60 Twin Cam engines. He has also recorded Car #, Engine # and Main Bearing Cap # as in Twin Cam engines the caps are numbered as well. Not sure if that is the case with pushrod engines.

As more data was collected a pattern emerged from which a theory has been proposed. My assumption is that an identical numbering system was used on the MGA pushrod engines and if this is the case then 5 22 59 E may indicate the following.

This engine block was machined or possibly assembled in 1959.

Machining and / or assembly was conducted in small batches. This engine came from the 5th batch completed in 1959.

Each batch consisted of a number of engines and this engine was the 22nd engine in that 5th batch.

Twin Cam engines only have 58, 59 or 60 as the last number which agrees with their years of manufacture. The highest known batch number is 19 and the highest known number within any batch is 99 possibly indicating a maximum batch size of 100 engines. These numbers in combination work well within the theory and make sense given the limited number of Twin Cams produced.

The meaning of the E is not understood. Some engines alternatively have G, M or T in place of this E letter suffix. Other engines also have an additional, 2nd suffix letter, most often T but G is used as well.

Perhaps a similar collection of data from 1500, 1600 and 1622 pushrod MGA engines would confirm a similar or possibly alternate theory.
Robin Barker

That would make sense that they would build, perhaps in lots of up to 100, hense the 99 as a max number. even if they didn't build in lots, perhaps the first 2 number could be combined to form a 4 or 5 digit number, i.e. Gary's number would be serial # 522 in '59.

If you take on faith that a years run rate was level and use Original MGA as a guide, then there were 234 engine build lots in '59 and 170 in '60. If you assume that each engine started over a new lot #. then in 1959 there would be some eigine stamped with the same # because they finished the 1500 builds and started the 1600's.

Now applying Gary and Alex's engine stamped numbers, Gary had 5 22 59. That would have put his engine as the 5th run of the 1600's which should have occurred on or around the 18th week of the year or mid May. Alex's would have been in the 45th week (early Nov).

Ok not an exact science but it was based on a large assumption of a steady run rate over the year.

I've got too much time on my hands if I've gone thru all this. And it is all an assumption.

Chuck
Chuck Schaefer

Robin:

Very interesting; and would make sense for Twin Cams.

Chuck:

Don't think we can assume continuous production rate for 1600s - the "Orphan Annie" of the BMC range; besides which batch production was quite normal throughout most of the British motor (and other) industry at the time. However, I'll check the numberings for my Coupe's engine also and post them soonest. If others would do the same we should be able to make progress on this.

Alex
A. W. Risk

Aah! The conspiracy theory has afflicted MGA's also! I don't really want to pull my engine out and apart just to check, so I'll take everyones word for it and I hope that all of us have a Happy Christmas and a cold Fosters instead
maurie prior

Robin
Could the letters E,G,M,and T be for the machinist who milled the block or the inspector who approved the assembly?
MLS Somers

MLS Somers
My theory on the suffix letters is very similar to yours.
My understanding is that all MGA cylinder blocks were machined on an automated transfer line. This included milling of all faces, boring of all holes, honing of the cylinder bores and drilling and tapping of all threads. Essentially an un-machined casting went in at one end of the line and a fully machined engine block came out at the other end.
If so then there were no traditional machinists but instead highly skilled mechanics who set up the various machines in the transfer line.
There would also have been inspectors at key points along the transfer line to check machining quality.
At least for the MGA Twin Cam blocks the first suffix letter appears about 90% of the time. This may indicate certain dimensions, machining finishes, etc. were almost always checked.
The second suffix letter appears about 30% of the time. This may indicate another occasional but more thorough inspection.
It seems unlikely that this forum has the interest to gather more data from a significant number of MGA pushrod blocks to see if any new patterns in the engine stampings arise. Too bad.
Robin Barker

This thread was discussed between 16/12/2004 and 24/12/2004

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