TR2/3/3A TR3A dwell

if someone could provide the correct dwell angle for a 1960TR3A it would be much appreciated.

Thanks.
Ron

I set mine at 60

Since Lucas didn't provide for running adjustment of dwell I have always just set the points gap, then static timing, then confirmed all-in timing with a light, then fine-tuned on the road.

Book gives 60 degrees, +/- 3 degrees. But I'm with Geo, just set the gap & go on. I don't even bother with a light, just set the final timing on the road.

One of the things I have found when I set the dwell with the meter at 60 is the idle drops down better in traffic.

sp53 said:

One of the things I have found when I set the dwell with the meter at 60 is the idle drops down better in traffic.

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Have you ever checked to see what points gap that produces?

Well it looks tighter than normal Geo when I set them with a dwell meter. Perhaps I have lost some of my precession with the feeler gauge. What I do set them at 15 then check it with the dwell and then I usually have to tighten it up until I get around 55 to 60 on the cam angle. I can barely see the difference, but I believe it is there, and I can see when the idle drops cleaner.

I seem to have a slightly defective set of points. The adjustment slot in the base plate is not long enough to open the points to .015. However, with the points open as far as the defective points will allow, the dwell angle is at 58 degrees.

George,

I know this is a mighty basic request, but would you describe how you use your timing light?

Is it an advance timing light? If so, what advance setting to you use for your TR3?

I have been using an advance timing light to check my timing, and I have followed the instructions that came with the light, but something just doesn't seem right. Here's what I've been doing after setting the initial timing:

(1) Disconnect and plug the vacuum

(2) Turn the advance knob to 15 degrees advance setting (recommended by Jeff Schlemmer on my rebuilt distributor).

(3) Press down and hold the power button.

(4) View timing marks. Loosen distributor hold down bolt and turn the distributor until the moving mark on the pully is stationary with the "0" degree mark (the stationary pointer on the TR3).

(5) Tighten distributor hold down bolt securely.

(6) Reattach the vacuum.


What doesn't seem right is that the car seems a bit sluggish on hills, and someone has told me that this might be because the timing is a bit "retarded."

This person, who has worked on Triumphs for years, said that he doesn't look at the low end of the advance. Instead, he gets the total advance right -- according to specs -- and sets the timing there. I believe the total advance on my car, with rebuilt distributor, is 32 to 35 degrees BTDC. I got this information from Jeff and another mechanic who has worked on my car, but I've never seen it written in a manual.

All other systems are good: carbs balanced, air/fuel proper, points correct, regulator in good shape, new battery....

Any ideas or suggestions?

Ed -

I do not set the timing with a timing light. I use the traditional static setting prescribed in most every manual.

I then use a timing light to see that the total advance at high RPM is a reasonable number -- watching the timing mark as I rev the engine lets me more or less confirm that the advance mechanisms are working and not hanging up. I don't look for a specific number but for the TR3A I think the all-in advance will be somewhere in the 35-40° range.

In any case the final adjustment is made on the road as variations in engines, altitude, gas, etc will dictate what is the most advance you can get away with. IMO no one can tell you what that is unless they have driven your car.

Hi, George,

Thanks. I see now that is what you said in your earlier posting. I knew that you used static setting for setting the initial timing, but I wasn't sure how you used the timing light. I, too, set the initial timing using the static setting, and double check it with the timing light (more or less). But I also use the timing light to watch the the advance... as you do. By that method, I see that my timing mechanisms are working... But as you say, I don't have a specific number for it. I believe it is around 32 to 35 degrees.

I probably could get away with a little more advance. My mechanic friend said that it appears that my setting is a little retarded. He told me that the setting is fine, but that I might notice a little loss in power. He recommends that I leave it where it is.

As for final adjustments, I agree with you that only I can tell what works best.

Geo Hahn said:

watching the timing mark as I rev the engine lets me more or less confirm that the advance mechanisms are working and not hanging up.

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Ditto. In addition, it can give you some indication as to the state of wear of the main bushing (especially if you are still running points). With a worn bushing, the shaft will flop around at certain rpms, and the mark jumps around under the light.

I suggest verifying that the advance is working (mark moves smoothly as you rev the engine slowly up, then slowly back down) at every tune-up. If you have a Mity-Vac (hand-held vacuum pump), you can also test the vacuum advance module.