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mrtexas
05-26-2012, 02:12 PM
My post has gotten a little windy so I'll ask my question first. What is the correct pertronix flame thrower coil for an electronic ignition in a TR3, 1.5ohm or 3.0ohm?

I'm in the process of helping a friend get his 62 TR3 running correctly. Someone gave him the car about 10 years ago. It has been repainted and a new interior, a nice looking driver if it could be driven. My friend is not mechanically inclined and has spent a lot of money taking the TR3 to mechanics who don't know old cars. The car has never run right since he got it. He had his dual carbs redone, then put electronic ignition and then replaced the dual carbs with a single holley carb thinking it would cure the poor running of his motor. Nothing helped much as I suspect it never was timed correctly.

My friend asked me first to help bleed the clutch cylinder. After we did that we drove it around the block. The complaint about the engine was it was running rough and fouling plugs, possibly old gas causing the problems. My first ride in it was around the block and I was unsure whether we would have to push it home it ran so bad. It stumbled, coughed and sputtered.

I own 2 Model A Fords, a 36 Ford woodie, and a 63 Corvette so I know a little about how to tune an oldie.

It needed to be timed correctly which I did with a timing light. I twisted the distributor until I got the knob adjustment where it should be. I used an advance curve posted here and set 1,000rpm at about and inch advanced (8-10 degrees before TDC I'm guessing) on the pulley. I then retarded it enough so that it would start. I checked to make sure that it advanced beyond the 1,000rpm. I haven't check pinging at high speed since he doesn't have insurance or a current tag for the car which never ran right since he got it.

https://i371.photobucket.com/albums/oo153/pjsauber/Tr3Advance.jpg

My friend had replaced the dual carbs with a 2 bbl Holley. I looked up the tuning specs and set the holley up how it was supposed to be. The install on the holley was botched as well. It was set to always be on the high speed circuit and the low speed mixture was wrong.

He has the original distributor. He has a pertronix electronic ignition and he didn't replace the original coil like he should have which is recommended. spark at idle is weak. It runs rough at high speed indicating to me wrong coil. Idle is OK.

My question is should he buy a 1.5ohm or 3.0ohm pertronix flame thrower coil?

LexTR3
05-26-2012, 02:22 PM
Sorry... but I would be inclined to recheck the rebuild of the original carbs to make sure everything was done properly and reinstall them, and then either reinstall the original distributor or sent it off to be checked, repaired, rebuilt (?) and then reinstall it.

The folks on this Forum can lead you through much of this.

Just an idea....

mrtexas
05-26-2012, 02:28 PM
Sorry... but I would be inclined to recheck the rebuild of the original carbs to make sure everything was done properly and reinstall them, and then either reinstall the original distributor or sent it off to be checked, repaired, rebuilt (?) and then reinstall it.

The folks on this Forum can lead you through much of this.

Just an idea....



Good point. But I know that the pertronix should be installed with a high energy coil. I'll try that first.

I've fixed the holley problems.

LexTR3
05-26-2012, 02:32 PM
If you can get the new arrangement working, that's great. Bottom line is: the ability to take the car out on the road and enjoy it no matter what's under the hood ("bonnet").

mrtexas
05-26-2012, 02:39 PM
If you can get the new arrangement working, that's great. Bottom line is: the ability to take the car out on the road and enjoy it no matter what's under the hood ("bonnet").

If I owned the car I probably would put the original carbs back on. I'd buy the car from him if I had room in my garage as I already have 4 antique cars as it is.

TR3driver
05-26-2012, 02:44 PM
Unless you have added a ballast resistor, the Pertronix must be used with a 3 ohm coil. The Pertronix module is even more susceptible to overheating than points.
In spite of their attempts to sell you a coil, it should work just fine with the original coil if it is not failed in some way.

I'll echo what Ed said, IMO the best course would be to restore the engine to stock and get it to run properly in that condition. The factory components actually work very well (when they aren't horribly worn out or misadjusted), and trying to "improve" them can introduce all sorts of strange problems.

My TR3 still has points & H6 carbs; just a few minutes ago I hit the throttle a little too hard when pulling out into traffic and left a black stripe around the corner. Fortunately no cops within earshot!

Also, please note that the above graph was not intended to be an exhaustive survey. There were several other distributors used on both TR3/A and TR4/A. I did the curves just for comparison between some of the more common ones. (The 5 digit numbers in the legend are the Lucas model numbers for the graphed distributor.)

8 degrees is only about 3/8" as I recall.

mrtexas
05-26-2012, 02:48 PM
8 degrees is only about 3/8" as I recall.

Thanks for the info. This of course can be calculated by measuring the circumference of the pulley and dividing by 360.
I figure I need as much advance as possible and keep good starting and no pinging.

LexTR3
05-26-2012, 04:08 PM
I have found that it takes some doing to get all these stock items adjusted "properly" -- a bit of trial and error for a newcomer -- but once everything is working well, and with proper maintenance, the car gives very little trouble (except for oil leaks).