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It appears that I have no vacuum advance. I was suspicious just hitting the throttle at high rpm. I've drove the car with and without it and I cannot tell any difference. Should I just replace the vacuum advance unit or buy a new distributor. The car has a Lucas 45D4 distributor on it. Vacuum was hooked up at the back carb. I think this may be why the car hasn't lived up to expectations. Any info would be appreciated. K
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No vacuum advance
- Thread starter mgtildth
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John Moore
Luke Skywalker
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No vacuum advance would definitely effect your higher RPM performance. Have you checked to see if would work, by sucking on the tube to see if the points plate moves with the dist cap off? Or if you do that at idle the engine should increase RPMS slightly.
I just looked at the cost of the vacuum unit from Moss, $70! Considering that price, I would consider buying a new unit. You can get a rebuilt one from Advance Auto from around $60, but you don't know what curve your getting. Or you could do what I did. I bought a 45D Eurospec from Brit tek.
https://www.brittek.com/ultimateignitionkit.html
I just looked at the cost of the vacuum unit from Moss, $70! Considering that price, I would consider buying a new unit. You can get a rebuilt one from Advance Auto from around $60, but you don't know what curve your getting. Or you could do what I did. I bought a 45D Eurospec from Brit tek.
https://www.brittek.com/ultimateignitionkit.html
Stewart
Darth Vader
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On my 45d after 30 years was gummed up fairly bad and what I thought was a bad vacuum advance was just a gummed up distributor. I removed the distributor and dismantled it and cleaned it up and freed up the plate the vacuum advance moves. Lubed it up put it and put it back together and the engine's runs fantastic now at high rpms. It wasn’t a hard job to do and it might be worth a shot before junking it or buying a new advance. Its a very easy job and should take less than an hour to do.
John Moore
Luke Skywalker
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I'm VERY happy with that set up. Before, I had ignition problems, so rather than patching I went for new. It's been great. Only other thing I might consider is adding a petronix.
Banjo
Yoda
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The most common condition in MG dizzys is a frozen mechanical advance. Like "Stewart" said about the points plate, it's probably all gummed up too. Remove the distributor cap take hold of the rotor and Gently wiggle it back and forth. It should move freely a few degrees in the clockwise direction and retun on its own. If it dosen't then the advance mechanism is frozen. If you remove the rotor, then you will see either a small disc of felt or a slotted screw in the top of the distributor shaft. This is supposed to receive a few drops of oil at regular intervals (i.e. every oil change) to keep it free. But it is often neglected and it dosen't take long to quit working.
.The mechanical advance is the system of weights and springs on the distributor shaft down beneath the points plate.Usually it can easily be dismantled and repaired (refer to a service manual)and with the proper care you won't ever have that problem again.
You can check the vacuume advance by removing the dist. cap and seeing if the actuator rod and points plate moves when vacuume is applied to the port. That is a common problem as well.
.The mechanical advance is the system of weights and springs on the distributor shaft down beneath the points plate.Usually it can easily be dismantled and repaired (refer to a service manual)and with the proper care you won't ever have that problem again.
You can check the vacuume advance by removing the dist. cap and seeing if the actuator rod and points plate moves when vacuume is applied to the port. That is a common problem as well.