Checking the condition of my distributor

[Lawrence S.]

I have a 67 L-79 and want to check the condition of the distributor with a dwell meter. However, I have a breakerless ignition. Can I still hook up the dwell meter and get a reading? If so can I use the same guidelines to check the distributor using the dwell meter as if I had a point system?
Hope this makes sense.

Thanks,

[Joe R.]

Re: Checking the condition of my distributor

Lawrence,

I'm pretty sure that dwell is specific to points. I think dwell means how many degrees the points are open. So, I don't think you can check it with your distributor.

Joe

[Gene M.]

Re: Checking the condition of my distributor

Some of the breaker less systems have a variable dwell time as RPM increases. I have no understanding of how it is controlled. But some advertise this feature.

[Ken A.]

Re: Checking the condition of my distributor

Some of the breaker less systems have a variable dwell time as RPM increases. I have no understanding of how it is controlled. But some advertise this feature.

OEM TI system is designed to retard at high RPM.

[Larry M.]

Re: Checking the condition of my distributor

I would checkout TI Specialty at www.tispecialty.com/ They should have the info you need.

Larry

[Donald L.]

Re: Checking the condition of my distributor

I believe a dial back timing light & tachometer are better tools for testing your distributor. The more important factor is that the ignition map is appropriate for your engine and that there is not excessive end gear play.

[Duke W.]

Re: Checking the condition of my distributor

Assuming you're talking about an aftermarket conversion of the single point distributor all we are talking about is replacing the mechanical switch with an electronic switch, so a dwell meter should provide a reading. IIRC I've been able to get dwell meter readings off both TI and HEI systems, but it's been a long time. Dwell is a measure of how long current is flowing in the primary circuit, so whether it is switched on and off mechanically or electronically is irrelevent.

Hook one up and see what happens.

You can also do a physical check by using a vacuum pump to check the function of the VAC, checking that the centrifugal advance is clean and operates freely, and recording the curve with a dial back timing light.

Wiggle the rotor laterally and up and down. There should be virtually no lateral play. End play should be 2 to 7 thou, but as-built, most were 60 to 120 thou.

Duke

[Michael W.]

Re: Checking the condition of my distributor

Your dwell meter will give you a reading, but the number will be meaningless as compared to a stock system and is not something that is adjustable.

Sort of a pointless exercise.

[Dennis O.]

Re: Checking the condition of my distributor

Your dwell meter will give you a reading, but the number will be meaningless as compared to a stock system and is not something that is adjustable.

Sort of a pointless exercise.

You just made my day!

[Jim T.]

Re: Checking the condition of my distributor

I have a 67 L-79 and want to check the condition of the distributor with a dwell meter. However, I have a breakerless ignition. Can I still hook up the dwell meter and get a reading? If so can I use the same guidelines to check the distributor using the dwell meter as if I had a point system?
Hope this makes sense.

Thanks,

Without the factory installed point ignition points to adjust/change you can still service the centrifical advance system. It can be taken apart, cleaned and lubricated to function properly. The tach drive gear can also be removed cleaned and lubricated for a longer life.

[Paul L.]

Re: Checking the condition of my distributor

I don't know what you will read if there are no points.

[Paul L.]

Re: Checking the condition of my distributor

Without the factory installed point ignition points to adjust/change you can still service the centrifical advance system. It can be taken apart, cleaned and lubricated to function properly. The tach drive gear can also be removed cleaned and lubricated for a longer life.

Yes. They can self-destruct. And do make an interesting knocking noise. Note the brass particles everywhere and the scoring on the lower shim and mainshaft. This happened 10 days ago with my 1974. Not a pleasant experience. What is left of the brass plug/cup you can see in the middle of the 2nd pic.

[Lawrence S.]

Re: Checking the condition of my distributor

Assuming you're talking about an aftermarket conversion of the single point distributor all we are talking about is replacing the mechanical switch with an electronic switch, so a dwell meter should provide a reading. IIRC I've been able to get dwell meter readings off both TI and HEI systems, but it's been a long time. Dwell is a measure of how long current is flowing in the primary circuit, so whether it is switched on and off mechanically or electronically is irrelevent.

Hook one up and see what happens.

You can also do a physical check by using a vacuum pump to check the function of the VAC, checking that the centrifugal advance is clean and operates freely, and recording the curve with a dial back timing light.

Wiggle the rotor laterally and up and down. There should be virtually no lateral play. End play should be 2 to 7 thou, but as-built, most were 60 to 120 thou.

Duke

Duke, you got it. I just replaced a mechanical switch with an electronic. I really dont care what the gauge reads. What I am trying to ascertain is if I have a current flucuation and subsequent bouncing needle on the meter which could tell me if I have a worn distributor.

My distributor has 102K miles on it. When I restored the car the distributor slipped through the cracks...stupid me.

The reason for this exercise is a miss at 4500 and then again at 5000 rpm. Otherwise the car pulls very hard. I have good plugs, cap and wires.

I will check the lateral and end play.

Thanks,

Lawrence

[Duke W.]

Re: Checking the condition of my distributor

Worn bushings, excess end play, or a wobbly breaker plate will cause dwell to drop more than the acceptable 2 degrees at 5K and above revs.

Excess wear from any of the above will probably also show some dwell drop with an electronic switch, but probably not as much as points since electronic switches don't put as much mechanical load on the distributor as points, but it's a good test to run along with the other mechanical inspections.

If you don't light the fire with reasonable timing precision for each and every cylinder every other revolution, the engine will never achieve peak performance.

The distributor is probably the most overlooked components on vintage engines.

Duke

[Joe R.]

Re: Checking the condition of my distributor

Lawrence,

Have you thought about having your distributor restored and / or run on a distributor machine?

Joe