Lotus Elan

Engine Determination

PostPost by: DABARTH » Fri Feb 09, 2024 7:45 pm

Happy Friday, all -

At the risk of repeating a previously discussed thread I'm wondering if someone might be able to tell me what I have on my hands?

Engine is reportedly the factory one out of an early '67 +2. It appears my head and block have matching numbers, but I'm not certain how to decipher the rest of them. Is someone able to do so for me? Pictured are what I have on both block and head.

Thanks in advance.

Cheers!

Aaron
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Attachments
Head Stamping 3 2-9-24.jpg and
Head Stamping 2 2-9-24.jpg and
Head Stamping 1 2-9-24.jpg and
Barn Find 5 8-19-23.jpg and
Barn Find 4 8-19-23.jpg and
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PostPost by: billwill » Fri Feb 09, 2024 8:24 pm

I never heard of matching numbers for head & block; they come from totally different sources, don't they?


The Blocks from Ford & the Heads from Lotus.

I suppose someone could have stamped them on but what on earth for?

The Head number is at the back (I think) under the gap used for spark leads. You can't easily see it when the engine is in the car. Perhaps with a mirror?
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PostPost by: billwill » Fri Feb 09, 2024 8:30 pm

Any numbers cast into the metal are likely to be mould numbers, not serial numbers.


Serial Numbers are usually punched on with Letter/Number stamps.
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PostPost by: ncm » Fri Feb 09, 2024 9:39 pm

Hi Aaron,
According to the Plus 2 serial number list that has been posted on here in the past, your engine was originally fitted in 50/0164 which was built on 23/11/67.

Brian.
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PostPost by: rgh0 » Sat Feb 10, 2024 12:02 am

billwill wrote:I never heard of matching numbers for head & block; they come from totally different sources, don't they?


The Blocks from Ford & the Heads from Lotus.

I suppose someone could have stamped them on but what on earth for?

The Head number is at the back (I think) under the gap used for spark leads. You can't easily see it when the engine is in the car. Perhaps with a mirror?



Up until around 1967 the engine number was both stamped on the block and on the back of the head. This practice appears to have stopped when Lotus took over production of the engine from JAP with the move to Hethel. The Hethel produced Twincams used a two digit and two number code on the back of the head rather than the engine number
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PostPost by: rgh0 » Sat Feb 10, 2024 12:08 am

As for the other numbers

26E311 is the Lotus head part numbe
15LL I am not sure and are possbly a number stamped by an engine overhauler at some time
WM 9403 is the Williams and Mills foundary that cast he head part number
The Ford numbers on the block ahve all been desribed extenvely elswhere. The 6015 number is the Ford part number for a block. Lotus or Ford around this time ground off the front number such a 120E which was the type number of the Block

cheers
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PostPost by: DABARTH » Sat Feb 10, 2024 4:59 pm

Thanks, all - and Brian - that is exactly what I have. Cheers!
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PostPost by: Quart Meg Miles » Tue Feb 13, 2024 11:54 pm

billwill wrote:I never heard of matching numbers for head & block; they come from totally different sources, don't they?
The Blocks from Ford & the Heads from Lotus.


I disagree, though I may be naive!

The stamp on the back of the head 'LP10089' should match the one on the block, which looks more like 'LP10033' but could conceivably be 'LP10089'. Certainly mine match though they are much earlier.
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