• Hey Guest!
    British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
Tips
Tips

MGB Mgb timing and T.D.C.

Share this page

R

restorejag

Freshman Member
Country flag
Offline
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
 
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
 
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).
 
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.
 
Back
Top