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help needed please!!!!!

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drance

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I have a 77 mg midget 1500

in the book the spec for ignition and valve timing is 10deg BDC, POINT GAP 22thou and DWELL ANGLE of 53deg.
this is for standard head and cam......BUT the car has a kentcams th2 cam and the unleaded head can someone tell me the new specs pleaseeeeeeee e.g how much to retard the ignition
 
I would start at the specificed numbers and advance it 'til it pinks or pings. The cam might change things, the unleaded head should make no difference.
 
I agree with John except I would get someone to sit in the car and keep the rpm at a constant speed and advance the timing until the engine misses and lock it down and drive it.
 
I'm sorry but I have a problem with adjusting timing that way. The factory specifies an initial timing figure that allows for the built in advance of the centrifigal timing of the distributor. An engine has a full timing value that you shouldn't go past usually around 32 degrees at peak RPMs. So if the distributor has a built in advance of 20 engine degrees (10 degrees at the distributor) then you adjust the initial timing for 12 degrees to achieve the 32 degrees of full timing that comes in at usually fairly high in the RPM range.
If you set your timing until it pings at a low RPM then when your engine gets into the high range it may go up in timing way too high and result in damage over a period of time.
The full timing figure shouldn't be effected by a hot cam. You may want the full value to come in at a lower RPM in which case weaker springs on the distributor weights will allow this. When I bought a Crane cam some years ago for another car of mine, Crane recomended that I use weaker springs to allow the timing to achieve full timing at 2500 RPM's which I did and the difference in power was very well felt.
To see what the built in timing of your distributor is, put the timing on top dead center at idle with the vacuum advance disconnected and plugged, then watch the timing while you rev the motor up through the entire RPM range and see how far it goes up. This will be the built in timing of the dizzy. Then adjust your initial timing to achieve around 30 to 32 degrees of full timing. You will probably find out the factory already figured that out.
My '72 B has a '75 distributor on it and I have checked to see when full timing comes in and it was before 3000 RPMs. Most MG distributors don't allow full timing until over 4500 to 5000 RPMs.
OK, I will get off my soap box now.
Bob
 
Bob,

I certianly didn't mean to advance it so it pings at a low RPM, I meant in the higher range. I agree with your point, pinging at low RPMs could definitely cause damage.
 
But, for the short time that you're adjusting the timing, it won't damage anything...I've been setting time on my MG's for years be ear, just the way John described.
 
Best way to check your timing map is with a dial back timing light. Have a helper advance the engine in 500 rpm increments while you dial the ignition back on the light and you can find out exactly where and how much advance is coming in. At that point you can experiment with springs and weights to adjust the advance curve. I agree with the above anything much more than 35 total advance and you're looking at possible burnt pistons. Bob
 
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