tedtaylor wrote:can someone point me in the right direction to find OEM specifications on the Lotus twin cam Weber head?
i'm having an engine rebuilder/machine shop check mine, but need the original OEM specifications to check against. thickness, openings, etc.
thanks
TED
The head depth, together with maximum permissible metal removal, is given in the technical data of the workshop manual. Mine says;
Small valve, 4.638" to 4.643"
Big valve, 4.598" to 4.603" (higher compression ratios)
Max. Permissible metal removal,
Small valve 0.045"
Big valve 0.010"
No doubt heads have been skimmed over the years and it wouldn't surprise me to find a BV head below the limit. Equally if someone is using the head for racing they might want a higher CR and skim more than these figures.
I'm not sure what else you can check. Flatness would be my first call and following that answer you'll have an idea of how much you'd have to remove and what that'll do to the CR.
The head diameter for inlet & exhaust valve inserts and valve guides are also in the same section of the manual, together with oversized items. You'd only need this if you're doing a complete overhaul though.
Brian