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davevr6car

Valve clearances question

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Hi everyone. Just got a question yea might be able to answer. I have the engine out of my S4s for a bottom end rebuild. While I have the engine out, I decided to check the valve clearances to make sure that the shims are all within tolerances. lotus manual says the Inlet clearances are .13mm - .18mm. Where exactly do you measure the clearances between valve bucket and the cam lobe. I presumed it would 180' from the highest part of the lobe, ie when the valve is completly shoot. This is where I measured on mine and got readings of .15mm , but when I turned the cam maybe 10' to 15' I got readings of .2mm. So my question is should the largest clearance between cam and bucket be .13 & .18mm no matter where on the cam lobe the measurements are taken from.

Cheers

Dave

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At TDC (top dead center) for each piston, so when the cam lobe is 180 away from the follower.

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Cheers Travis for the quick reply. I thought the same, but I thought with the lobe at 180' away from the follower that this should be the largest clearance between the cam and the follower, but on mine it wasn't. For referance, iIf you where to say that the lobe was at 12 o'clock and 180' away was 6 o'clock. the clearance I have at 6 o'clock was .15mm, but measured at 4to 5 o'clock position I was getting a clearance of .2mm. Is this normal or are my cams showing signs of wear?

Cheers in advance for any advice / help on this.

Dave

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Theoretically the diameter should be the same on the fat end of the cam until the tangent point where the lobe goes out. The measurement should be the same at TDC and roughly ~90deg on either side...

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