Lotus Elan

mysterious head number

PostPost by: Elan45 » Fri Sep 30, 2016 4:16 am

I bought my pre-airflow coupe in 1978, partly because the turrets had rusted on my SS DHC, and I knew it would be off the road for an extended period. So, it did not bother me that the engine and gearbox were out of the coupe and supposedly rebuilt. It had been off road for as long as 10 years and I was told that the head had been replaced because the PO had put too hot a spark plug in it and damaged a combustion chamber. I was told the replacement head or maybe just the cams were Cosworth L1s, but at any rate, I put the newly acquired engine and box on the shelf and used the known quality of the motor and box I removed from the SS. I drove that coupe for the next 6 or 7 years while the SS was restored.

Back in the '80s, I had some head gasket surfaces welded on the head, but otherwise it has sat on the shelf waiting to power the coupe in the future. The SS was rebuilt on a new galvo frame in 1985 and after years of vintage racing a Lotus Eleven and now a formula Jr, I am in process of restoring the coupe. So, the head came off the shelf tonight for a look over.

I'd always known the head number was strange and didn't match the engine number stamped into the block or the VIN plate in the engine bay, but does anyone recognize what it might mean?

The number stamped into the back center of the head is: P125 SBH 607. The valve sizes are standard early Elan 1.530 intake, so I doubt any Cosworth connection. Anyone have any ideas?

Roger
'67 Elan S3 SS DHC
'67 Elan FHC pre-airflow
'67 Elan S3 SE upgrade to 26R by Original owner
'58 Eleven S2 (ex-works)
'62 20/22 FJ (ex-Yamura)
'70 Elan +2S RHD
'61 20 FJ project
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PostPost by: rgh0 » Fri Sep 30, 2016 11:17 am

Early cylinder heads were marked with the engine number. From around 1966 - 7 they were marked with a 4 digit combination of letters and numbers. That is maybe what your P125 is? I have never been able to figure out if this code has any date or other reference or is just some sort of sequential listing.

Occasionally you see other numbers and letters stamped on the rear or lower face of the head. I believe these have probably been added by rebuilders to record their work. This maybe what you SBH 607 is ?

cheers
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PostPost by: Terry Posma » Sat Oct 01, 2016 4:08 am

I have a head on a 66 Elan which has the numbers B573 SS H18 and a P above that row.

Have researched it a bit and have come up with no logic to the numbers. The B573 fits with Rohan's reply.

Has a block with the numbers 53671 but I know this is a replacement as the original was knackered when I purchased the car.

Terry.
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PostPost by: Elan45 » Sun Oct 02, 2016 1:39 pm

I should mention that the "P125" is stamped into the head off to the left, maybe 1-1/2 to 2 inches to the left of the center, while "SBH 607" is stamped in the center where I would expect the "LP-----" number that matches the block would be. They are both w/ the same size stamps.

I also have a +2S, made last day of 1969 and that head/ engine and VIN tag is stamped LP------, 5 digits. Probably late enough to have been sold as a 1970 model, so the LP stamped numbers survived past the mid-60's.

Roger
'67 Elan S3 SS DHC
'67 Elan FHC pre-airflow
'67 Elan S3 SE upgrade to 26R by Original owner
'58 Eleven S2 (ex-works)
'62 20/22 FJ (ex-Yamura)
'70 Elan +2S RHD
'61 20 FJ project
Elan45
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