TR2/3/3A Timing with Pertronix

[smdichter]

TR3A with Pertronix electronic ignition. So, how does one static time the ignition when there are no points to observe opening to set TDC?

 

[TR3driver]

Use a test light, just like you would with points. (You can't accurately see when the points open either)

But, be sure to do it reasonably promptly (within 15 minutes or so). Pertronix warns that leaving the key on with the engine not running can overheat and ruin the module.

 

[dklawson]

The warning is actually for a much shorter period than 15 minutes. The tech people at Pertronix have told at least two of my acquaintances that the "ignition on" time without the engine running should be limited to 3-5 minutes.

However, during static timing this is not a problem at all. Simply remember to unplug the Pertronix module's "hot" wire when you are not actively working with setting the static timing. The remainder of the process is as Randall said, use a test light to see when the module is conducting and when it is not. (i.e. With the ignition on and module powered up, connect a test lamp between the contact breaker side of the coil and ground. When you rotate the distributor and the light turns "on", that indicates when the module stops conducting. That is equivalent to when the points open and is where you would lock the distributor down).

 

[Geo Hahn]

Or, if you have it close enough that the engine is running, you could tune by ear and throw a timing light on it as a double-check to see what advance you're getting at high RPM (when the centrifugal advance should be all in). I use points and static time but generally end up tweaking it a bit anyway once I drive it some.

 

[smdichter]

The car idles very nicely, steady at about 800 rpm, with the Carter low-pressure electric fuel pump. Problem was/is that I seem to not have sufficient power when accelerating/driving. If the mixture is correct (lift the piston in the SU and the engine rpm increases slightly), then aside from timing, what else could it be? Plugs and wires are new. Also, without any timing marks, hows does one dynamic time the car? All there is is the little hole and, with the cowl in the way, I am not sure how I could shine a timing light on the hole, even if I help it by painting the hole and the surrounding area white.

 

[poolboy]

Is the Pertronix something added recently ?

 

[glemon]

Before I had a timing light (and even now after I have one) I always thought one of the best and easiest ways to set timing was something I read in one of the TR4A shop manuals, start the car with the distributor clamp bolt loosened a little so you can move it. Put on a thick glove to avoid possible shock, advance the timing until the idle speed stops going up, back it off just a skosh, when fully warmed up drive up a hill full throttle in third gear about 2500 rpm, if you get a little clatter or pinking back off the advance til it goes away, if you get none advance a little and see if you get any. I do like a timing light because it can give you a better idea if your vacuum and mechanical advance are working correctly. I know when my vacuum advance on my 4A spring a leak the acceleration suffered.

Of course no guarantees your power issue it ignition timing, a little history on the car might help with a virtual diagnosis, recently rebuilt or worked on parts? or was it running fine all sorted out and the problem just cropped up. If not freshly rebuilt have you worked on or replaced anything in the carb/intake/exhaust ignition area lately?

 

[smdichter]

Rebuilt the carbs, new needles, centered jets, new Gross jets, cleaned everything. I have had the Pertronix points in for a decade or more. New is the Carter fuel pump and removal of the AC pump and a blocking plate to cover where the opening was to the cam shaft. Plenty of gas.

 

[poolboy]

And is after doing that when you noticed the change in performance ?

 

[Geo Hahn]

... I seem to not have sufficient power when accelerating/driving... aside from timing, what else could it be?...

I would check that the centrifugal advance is working well -- with the cap off, when you tweak the rotor advanced a bit it should snap back sharply. Advance can also be easily checked with a timing light.

... Also, without any timing marks, hows does one dynamic time the car? All there is is the little hole and, with the cowl in the way, I am not sure how I could shine a timing light on the hole, even if I help it by painting the hole and the surrounding area white.

The marks on my TR4 are present and pretty easy to see. I paint both the hole and the pointer (it's on the timing chain cover):

Note - that is a double exposure I did to verify TDC, Mine (and yours) will have only one hole.

 

[smdichter]

Thanks for all the assistance. Turned out not to be timing. Turned out to be the gross jets. After I removed the fuel filter before the carbs - the Carter electric fuel pump uses a fuel filter between the tank and the pump - the 2-4 psi low pressure Carter fuel pump now has sufficient oomph to push the ball bearing fully down within the gross jet and permit the fuel to enter the float chamber, allowing the rear carburetor float chamber to fill with fuel. I was running the car on the front carburetor and that, of course, is where the power loss came from. If the problem repeats itself, I would first go back to the older style SU Viton tip needle and seat, as I believe the needle will be less resistant to the pumping fuel more easily than the ball bearing in the gross jet. Any further problems of that type might suggest a higher pressure fuel pump and appropriate regulator. Meanwhile, it runs very nicely. Since it starts almost instantly, without any spit back when fully revved, I believe the timing - set by rotating the distributor until max rpm achieved and then backing off 100 rpm - is OK. I have it set at 800 rpm.

 

[dklawson]

I removed the Grose Jets from all the cars I had installed them in and switched back to the Viton tipped valves as you suggested. I am very glad I did.

That being said, after I removed my cars' Grose Jets I learned that the product is shipped with a Cosmoline-like coating on the parts to keep the balls from rusting when in storage. I was advised (too late) that you need to really clean them thoroughly with carb cleaner (multiple times) to insure all the coating has been removed. The coating has been attributed with both preventing the valves from closing and sticking them shut.

 

[smdichter]

Aha! Never knew that. But, among the many things I did trying to figure this all out was to spray the crap out of the gross jets and even hit them with a little oil. If it comes back, I'll soak them in acetone for some time.