Lotus Elan

Valve clearances help needed

PostPost by: Yellelan » Sun Nov 17, 2024 5:59 pm

Hi, I'm a newbie on here....thanks for any knowledge offered. I want to check the valve/cam clearances on my 69 Elan S4 and my workshop manual states one figure for inlet and two figures for exhaust depending on engine number, changing at engine 9951 to 9952.
Mine has a 'C Type' cam (1 groove) and Stromberg carbs. The Ford cast-in number is 681F6015 (beside nearside engine mount) and the Lotus stamped number of L20679 (above offside engine mount) - this latter number is very feint as it has been painted.
I have two questions; firstly, although I know 20679 is a higher number than 9952, but can someone confirm the number I have is about right for a '69 S4?
Secondly, are the clearance figures in my Revised Reprint, October 1974 Elan Workshop Manual of (cold)Inlet 0.005/0.007", and Exhaust 0.009/0.011" (from engine 9952) correct for the 'C Type' cam?
Thanks
Yellelan
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PostPost by: rgh0 » Sun Nov 17, 2024 10:08 pm

Yes engine number is in correct range for a 69 Stromberg S4. The clearances quoted are also correct.

chers
Rohan
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PostPost by: berni29 » Sun Nov 17, 2024 10:32 pm

Hi

My understanding is that on engines like the Twincam it is wise to err on the wider side of the tolerances as it reduces the chance of burnt valves.

All the best

Berni
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PostPost by: Yellelan » Mon Nov 18, 2024 11:38 am

Thank you for your advice Rohan and Berni!

Steve
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