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I've seen those cam and dizzy shaft gears worn to razor blade thickness, Jack. It can happen.

Vince, you're likely feeling the mechanical advance mechanism. It *should* spring back to a "zero" advance position on it's own. If it doesn't, you could have weak or missing springs. And perhaps have found your run-on cause. I'm not gonna hold me breath, tho... /ubbthreads/images/graemlins/grin.gif
 
Easy enough to check. Think I would do that when I pulled the Dizzy to check the bearing.
 
And the plot thickens. Something else to recheck. If I remember correctly, I could turn it a mite to the left and it would stay. And when I turnred it a mite to the right it statyed. Again, I'm gonna have to recheck just to be on the safe side.
 
It *could* just be gummed up, too.
 
I think your right Doc, about the mechanical advance being gumed up. It could be at least one of the contributing factors to the problem. 93 octane would certainty help a lot. How about a pin hole in the vacuum diaphram? Just throwing in another idea. /ubbthreads/images/graemlins/cheers.gif PJ
 
THe diz on his B is likely the 25D, if the vacuum advance is "hampered" the likely outcome would be less power at the top (3K RPM and up). I don't think it'd contribute to the run-on tho. Static timing was set @ close to 10° BTDC. We'll see. /ubbthreads/images/graemlins/grin.gif
 
Yeah it's a 25D and I tried my darndest to get it at exactly 10ÂşBTDC.
Could I spray any type of cleaner like contact cleaner into the dizzy to un-gum it?
I still need to get it out on the road, blow out the engine a bit & see how it performs at higher revs.
Vacuum advance seems quite old.
 
I'd say worry over the dizzy after you've blown out the cobwebs a bit. Since you have no good "comparitor" you won't *notice* the advance not working just yet. /ubbthreads/images/graemlins/jester.gif
 
Yeah that makes sense.
 
I do try. /ubbthreads/images/graemlins/wink.gif
 
Ahile back I had quite a bit of run on with my 76 MGB. Tried lots of things suggested here, but nothing worked. My dad ended up soldering a diode in the "ignition warning light" ciruit to prevent any stored electricity from flowing backwards. Worked like a charm and no run on since.

With so many intricacies and modifications on our cars, seems like everyone has their own personal Silver Bullet that worked for them.
 
With electronic iggy, that would make sense. The GT vping has is a "conventional" pionts-n-condenser type.
 
I wonder if that would work for me if when I get her on the road I still experience problems.

I had a couple guys in the MGCCLIC tell me the same thing in regards to the FP in my TD. I added 15ma resistor between the 2 terminals inside the pump. I need to go and check to make 100% sure that is what it was and I don't remember why. I think there was a thread on the BBS about this as well.
 
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