MGB Mgb timing and T.D.C.

[restorejag]

Installing timing chain and sprockets on 71 Mgb rebuild.
When I line up the dots on gears I am not at top dead center
on number one.The piston is one eighth from top of bore.Is this normal?
Thanks

 

[bob67bgt]

As i recall the crank key will be directly at 12 o'clock when the no. 1 piston is at TDC. This will not move. the dots should align with the crank in this position. Bob

 

[DrEntropy]

Something puzzling there. Bob's right: keyway should be at the "noon" position, piston at ~precisely~ TDC... Is this p'raps a replacement sprocket on the crank or cam? First thought is: be dead certain to position the crank at TDC and ignore the dimple in the crank sprocket. Use a straightedge (NOT a "ruler" or yardstick) to align the cam center and 'dot' to the crank center.

Otherwise you'll need to degree it with a proper degree wheel and dial indicator(s).

 

[Hap Waldrop]

I would degree even a stock engine with a stock cam on this job, just to confirm where I'm at, and make sure you not badly off, alot easier now to do the work, than later. A stock cam should be in the low 110s for center line, if you see you are at say 82 or 128 for example, you then know you're a link off, each link represents 18 degrees. Don't trust the dots, confirm by degreeing. If you end up needing a offset key, now is the time to find that out.

 

[restorejag]

Thanks for the info. Degree wheel it what I will use use.