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timing and power loss

Posted: Wed Oct 13, 2004 9:34 am
by jbennett
Does anyone know how much power loss would occur, if after a timing chain replacement, it was discovered that there was a misalignment by half a tooth? Would power loss be noticeable or not? This is for a 948cc minor.

Posted: Wed Oct 13, 2004 9:37 am
by Kevin
I am slightly puzzled as to how the alignment would be out by only half a tooth.

Posted: Wed Oct 13, 2004 9:47 am
by rayofleamington
I am slightly puzzled as to how the alignment would be out by only half a tooth.
I would guess they meant that the dots didn't line up perfectly so had to choose whether to go half a tooth clockwise or ccw on the cam. (I'm guessing as I''ve never had a problem like that). If it was within half a tooth I don't see there should be a problem, however if the alignment mark on a new sprocket was the problem (as they should line up well) then there's no guarantee it is just haf a tooth out.. :-?
If they meant 'a whole tooth out' then it may be enough to affect power. Engines were at one point designed so that they would tolerate 1 tooth out on cam chains or cam belts to reduce the cost of rework from Friday afternoon engines but I don't know if that dates back to 1960's engines.
On modern metal I doubt if they are as tolerant of a cam position error (probably wouldn't meet the Euro4 emmissions regulations etc..), but the new car vs old car debate is already a bit stretched :lol:

Posted: Wed Oct 13, 2004 3:28 pm
by Peetee
I am slightly puzzled as to how the alignment would be out by only half a tooth
Is that possible with a stretched chain?