MGB MGB Timing

[beachbumbarry]

I have a 72 MGB-GT engine that was rebuilt, not started yet. In the distribitor the rotor does not point to #1 at 10dg BTDC compression stroke. The rotor points inbetween #1 and the next post when the dissy cam lobe is breaking the points. I have taken out the shaft to cam and made sure that it was per book.
I removed my timing chain cover and checked cam timing at TDC compression stroke. The #1 valves are closed and I can move the rockers, about .015 clearance. The dot on the cam sproket is 180 dgs out from what the book says. The dots should be together. When I put the dots per book the #4 valve rockers are loose and #1 is tight. I have a double sproket timing chain. Does anyone have any idea what to do next? ? I want to start my engine next month. I'm trying to have my car drivable by end of May. Reno in June.
BarryE

 

[ralph_s]

I'm far from an expert on timing, but make sure the "dots" are together, you're # 1 is at TDC AND the dizzy drive sprocket is in the correct position. You should be good to go w/static timing.

 

[Hap Waldrop]

The dots should be together at TD at compression stroke on #1, and not even then if you advanced the cam by any means, like offset key. You may have the dizzy drive in wrong. With dot aligned on a stock cam in a MGB you should have the crank keyway at 12 oclock and the cam key at aprox 2 oclock. If this is a new cam and crnak gear never trust them to be dead on, I seen them 3-4 degree off brand new. I use vernier adjustment cam gears on my rebuilds for this reason, for me, it's either the customer is paying me extra money to fiddle with a non adjustable cam gear, and often still have to use offset keyways and still mis the cam timing by a degree, or just buy the adjustable cam gear and nail the cam timign for the same money. Now for a guy in his home garge, time may not be as importatn, so they may take more time to do something and save money, but the last non adjustable cam gear I used was off three degrees, it just luckily was adanvnced three degrees and that s was where I needed to be, if using stock cam and and non adjustable came gear you still ned to degree the cam to confirm you are correct. Sure they will people that will tell you they did not degree thier stock motor, but all these parts are created equal, so what works for one guy may not work for the next guy.

 

[beachbumbarry]

Thanks for the info Hap, Even with the dizzy out when the points are breaking the rotor points between the posts. The engine that I have was in garbage car and hadn't ran for years. I think that I will try a different dizzy. The cam is the one from the engine but I had it built-up and reground, a little higher lift and better duration.
BarryE