Line honing crank journals

69_340_GTS said

How's a tensioner going to "fix" a possible timing issue? If the distance between the two gears is too close with a standard chain, the chain is too long. I don't care if the chain is pulled taut by the tensioner or by natural forces, the chain is still too long which throws the timing off a little. Obviously a shorter chain is the only real answer, or you can start playing around with the gearsets that have offset keys/keyways.

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A chain tensioner stabilizes the cam timing at what ever value it ends up at with the tension side of the chain pulled taut. Any corrections to timing are made with offset keys, etc. A tensioner would be worthwhile IMO if you moved the crank CL a lot, just to help keep timing from jumping around, and keeps the tension on the chain smooth and even. (But I don't know how much tension the aftermarket SBM ones provide, and thus how well they can stabilize cam timing.)

As far as the math..... if the crank CL moves up .010" into the block, then the cam timing is retarded by about 0.21 degrees with the SBM cam sprocket sized as it is..... yeah, pretty much a non-issue! (If you are curious, it can be easily approximated as the acrtangent of [the CL move divided by the cam sprocket radius].)