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I don't see an egine number


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Bought this '75 last month, PO said the engine was replaced in the early eighties. I see the date code stamped with a 80 inside and the hash mark looks to be at 3 o'clock so that makes sense but when I look above the starter for an engine number I see nothing. Here is a picture of where I think the number should be. Is there meant to be engine number in this location? This also makes me wonder why they had to replace the engine at such a relatively young engine. 

DSC_3713.JPG

DSC_3715.JPG

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7 hours ago, JohnH said:

I'm certain I can see an X. I would give it a rub with some sand paper.

 

 

+1

 

And if that reveals nothing, try some oil and a wire brush on the surface of the engine number boss. Replacement short blocks sometimes had no markings whatsoever but I agree with John, that I think I see something.

 

Many blocks have casting dates on the right side.  Here's a thread to locate and interpret those:

 

 

So, yes, the engine's head was cast in June 1980 (six nubs for six months, beginning at 1 o'clock).

 

As to replacing the engine, '02's were driven, on average, 15,000 miles a year.  Engines, in the '60's and '70's, generally ran 100,000 miles before needing major service -- head jobs and/or bottom-end rebuilds -- and parts just plain failed.  This means that around 7 years, the average '02 engine (and virtually any engine of the era) was ready for rebuilding or replacement.  My '76's engine, with 99,536 miles on the odometer in August 1983 (see photo taken that month) needed this and I simply stored the car because (a.) a '76 '02 was worth virtually nothing; and (b.) an engine rebuild was expensive.

 

Replacement engines -- factory and aftermarket -- were a common solution because economies of scale often meant they could be offered less expensively than one-off engine rebuilds.

 

Regards,

 

Steve

 

image.jpeg

Edited by Conserv

1976 2002 Polaris, 2742541 (original owner)

1973 2002tii Inka, 2762757 (not-the-original owner)

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Let me first stress that I do not know the following as fact...! 
But many, many years ago an extremely knowledgable BMW technician working at a BMW dealership in Denmark, told me that up through the 80's BMW offered two different type of replacement M10 engines.  The cheapest option was a factory recon, which had the original engine number removed from the block and then had the two X's stamped on the block instead.  The more expensive option was of course a brand new engine, and these apparently came with a totally blank engine number area.  No X's or anything.

 

I could add to the story that this BMW technician was the third and previous owner of my '73 Verona red 2002, which he owned from '81 right up till I bought it from him in '92.  He also worked as the Head Technician at the BMW dealership which my father co-owned in the late 70's.  When my father bailed from the auto industry, he of course continued working as Head Technician at the same dealership.  The story goes that in the late 80's he ordered a recon M10 from BMW for his 2002.  But when the Bavarians learnt that it was for his own 2002, apparently they sent him a brand new M10 engine instead, and still only charged him for a recon.  And yes! the block in my 2002 is totally blank - no engine number, no X's, no nothing...

O==00==O
With BMW-Regards,
Anders.

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I adjusted my vales for the first time this afternoon and changed plugs while I was at it.  When I finished I spent some more time cleaning the engine and searching for other ID marks. I think I do now see a light X at either end of the plate where the numbers should be.  So perhaps maybe it was a factor recon. I plan to take it on it's first longish trip tomorrow to visit my Mom, roughly 170 miles. Hope the trip is uneventful, no way to tell except to give it a try I should be able to get an idea of highway mpg. Wish me luck!

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This is only slightly off track and mostly to help me answer some of those lingering questions we all have about our 40+ year old cars. 

 

I have an engine with no X's or numbers.  A local expert independent BMW mechanic of 40+ years told me it was a factory replacement engine.  He and I both noticed a painted blue bolt near the distributor that he said was the other clue to the engines origin.  Anyone ever hear of that?  Anyway, when I had new rings, valves and stems put in to the engine about a year ago we discovered that it also had the first overbore and piano top pistons (from factory?).  I wonder if your engine is similarly configured?

1974  02  Inka

1975  02  Chaminoix (parts car)

1995  318ti  Hellrot

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I believe there is a distinction between a replacement block (or short block) and a replacement engine (or long block), and probably between new replacements and a factory-remanufactured replacements, as well.

 

Short blocks likely came with minimal or no marking.  Could an absolutely un-marked engine number boss represent a new short block and an engine block with dual "X's" represent a factory-remanufactured short block?  Here's a prior thread on the issue:

 

 

As to long blocks (complete engines), it's fairly well established that there was a systematic and complete marking system, as is outlined in the attached document from BMW:

 

http://www.bmw2002faq.com/applications/core/interface/file/attachment.php?id=129207

 

And there are few good threads which illustrate the use of this identification procedure on remanufactured engines, e.g.: 

 

 

and especially:

 

 

Of course, companies other than BMW were also remanufacturing BMW engines.  I have no idea how they may have marked, or not marked, remanufactured long blocks!

 

Regards,

 

Steve

Edited by Conserv

1976 2002 Polaris, 2742541 (original owner)

1973 2002tii Inka, 2762757 (not-the-original owner)

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8 hours ago, venoak said:

This is only slightly off track and mostly to help me answer some of those lingering questions we all have about our 40+ year old cars. 

 

I have an engine with no X's or numbers.  A local expert independent BMW mechanic of 40+ years told me it was a factory replacement engine.  He and I both noticed a painted blue bolt near the distributor that he said was the other clue to the engines origin.  Anyone ever hear of that?

 

This slipped my mind until now: I recently purchased an M10 crate engine either 1.6 or 1.8 liter, which has one painted head bolt. It has the marking of a 3rd-party rebuilder. (I am not clear, however whether the rebuilder was an authorized BMW rebuilder or not),

 

BTW - anyone interested in a NOS 1.8 / 1.6 liter rebuild engine, send a PM. I bought this a while back from the fellow who was selling the NK a few months ago. -KB

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My 74 came with a factory replacement engine.  The boss by the starter is blank, but engine number is stamped on the block behind the head.  The full number is 21  A 10 7 (you can't see the full number in the pic).  There is no monthly serial number before the A.  It also has the painted head bolt by the distributor.  

 

Conserv, thanks as always for the great info!

 

redbolt.png

eng_tag.png

headnumber.png

Edited by planb
typo
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On 9/25/2016 at 11:07 PM, planb said:

My 74 came with a factory replacement engine.  The boss by the starter is blank, but engine number is stamped on the block behind the head.  The full number is 21  A 10 7 (you can't see the full number in the pic).  There is no monthly serial number before the A.  It also has the painted head bolt by the distributor.  

 

Conserv, thanks as always for the great info!

 

redbolt.png

eng_tag.png

headnumber.png

 

So "21   A  10  7" translates to:

 

1.  1974-75 U.S. 2002 engine ("21"),

2.  Exchange engine ("A"),

3.  Manufactured October ("10"),

4.  1987 ("7")

 

These codes and the reading of them come out of the BMW technical bulletin linked in my prior post.  The one point I'm hazy on is how or when, for instance, a "7" signifies 1987, versus, say 1977 or 1997?  By the latter date, 1997, the exchange engine program for 2002's may well have been dead, but how was a 1977 exchange engine distinguished from a 1987 exchange engine?  That's a missing detail!

 

Regards,

 

Steve

 

Edited by Conserv

1976 2002 Polaris, 2742541 (original owner)

1973 2002tii Inka, 2762757 (not-the-original owner)

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Steve,

thanks for all this great information and the links to the supporting docs. Now I'll have to go back to my car and take better pictures of the engine block to see what codes are on mine. 

Also thanks to planb for showing us his numbers and painted bolt.. But most interesting to me is the guarantee card and the description of what was delivered. 

 

Mark

1974  02  Inka

1975  02  Chaminoix (parts car)

1995  318ti  Hellrot

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3 hours ago, venoak said:

Planb, do you know if your engine has the first overbore?

 

Mark

 

I wouldn't be surprised if BMW's -- or any engine rebuilders' -- approach was not to (a.) insist upon a given overbore for each and every engine rebuilt but, rather, to (b.) overbore each rebuilt engine to the extent demanded by the block's condition.  First overbore may, indeed, be quite common among these factory rebuilds but there might also be examples of second overbores -- or perhaps even stock bores -- out there.

 

My two cents...

 

Regards,

 

Steve

 

 

 

1976 2002 Polaris, 2742541 (original owner)

1973 2002tii Inka, 2762757 (not-the-original owner)

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11 hours ago, venoak said:

Planb, do you know if your engine has the first overbore?

 

Mark

Sorry Mark I don't know.

 

Steve - re year of reconditioning.   The head (E12) was cast in 1987, so if BMW would put a new head on a reconditioned engine it could be a 1987 otherwise it is a 1997 engine.  This car has had more than one replacement engine so I would guess 1997, where I have a gap in the original owners records.

 

I wonder how many engines without numbers actually have the numbers stamped behind the head like this one?

 

Cheers.

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