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MG MGB Technical - 79B Ignition System

I acquired my '79 MGB about six months ago, its a fairly decent daily driver and I have been going through the car and replacing what I feel to be known weaknesses (fuel pump, cooling system, etc.)

Now I am looking at the ignition system - the car appears to have a 45DM4 distributor; I cannot read the model number on it but it has the external amplifier mounted on the fender well. Are there any adjustments or maintenance required for this unit other than setting the timing? Is reliablility an issue with these systems? If reliability is suspect, what are the alternatives given the fact that the car has to meet CA emissions? The Haynes manual has no info for this unit.
Tim

Tim,

That ignition system is very reliable. No points, no worries. Just replace the cap, rotor, and plug wires when necessary, perhaps once a year depending on annual mileage. You also might ensure the base plate turns freely and that the vacuum can will indeed hold vacuum. If it is completely stock, you only get vacuum advance in 4th gear anyway.

Does the vacuum advance line from the dizzy go to a small solenoid valve mounted on the pedal box cover, and from there to the intake/exhaust manifold? This is the stock setup, but it can be improved upon, by bypassing the TCSA solenoid valve and conecting the vacuum advance line with a T to the EGR sensing line. That will give you ported vacuum advance in all gears. You may need to adjust your static timing slightly if you get pinging, but this should help (slightly) drivability.
Paul K

Paul, I have a 79 MGB too. The PO had the MGB 11 years, I've had it now for 3 years. I don't know when the last time the cap/rotor/wires were changed by the PO...but It's been 3 years (about 3500 miles) that I am sure about (wires look old).

Seems like this should be a weekend project soon... any recommendations on what type of wires,etc. to use?

Any concerns on parts from Victoria British?

I'll have to check but it seems like I have the same set-up as Tim...however, I don't have to worry about emissions...registered as a "Classic" in Pa.

Have a Great Day, looking forward to your reply.
Don Wheeler, Penna.
Donald Wheeler

Donald;
You might try The Roadster Factory in Armagouh(or whatever the name) PA, or The Proper MG. I have recieved what I perceive to be better quality parts from them at reasonable prices.
Pete Haburt
76MGB
Pete Haburt

Paul,

In answer to your first question, my car has a single hose from the vac advance to the inlet manifold, No tee or solenoid valve. I don't know if this is original or legal for smog but it passed like this before.

Tim

This thread was discussed between 26/11/2002 and 27/11/2002

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