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TR2/3/3A Pertronix and timing in TR3

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woody1091

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Yesterday I was able to drive my TR3 on it's first real run since I've had it(late summer 2008). It felt good to finally take it for a spin. I sent my distributoer off to Advanced Distributers last Fall and Jeff did a great job with the unit. He put in a Pertronix pos ground and the distributor looks like new. He recomended that the timing be set at 10 BTDC. I think the old set point is 4 BTDC. With the TR3 having only the pointed tab on the pulley instead of hash marks how far to the right or left would 10 degress be using a strobe?

Right now I have it set by ear. Keep in mind that I don't have a trained ear. It seems to run okay but it would be good to know how far off I am. It seems like I read in a Moss catalog or publication that you can set the timing to the highest idling RPM then back it off 100 RPMs?

The manually adjustable vacum advance throws me a curve. I really don't understand it's purpose. My best take on it is that you can fine tune the timing. I could use a primer on that one.

You guys have been a big help in getting the my TR3 back on the road.
 
Hey, Steve -

One generally accepted method of timing is trial-and-error. Take it on a drive; advance it bit by bit until it starts pinging when accelerating under light load (going up a hill, etc.), then back off a tad. Periodically check the plugs for color - nice, even tan or grey is optimal.

The manual dial is for fine tuning. Best advice is to start at its midpoint when you're doing the above, then after you're satisfied with the performance, you can "play" with that for varying situations.

Mickey
 
Mickey Richaud said:
until it starts pinging when accelerating under light load (going up a hill, etc.)
Click to expand...

I'm unclear as to what "pinging" means... and more importantly how to audibly identify it. Is it a particular sound or feel?
 
Originally, the timing was set statically on the TR3. The procedure was to set the venier adjuster at the midpoint (the longest hash mark). Then put the engine at the TDC pointer. Static time with a test light. Then advance the venier two hash marks, as each one is two degrees. I suppose you could just set the venier five hash marks.

The problem with the Pertronics, is that you can't leave the ignition on without the engine running from what I understand, so setting statically is probably out of the question.

But, to answer your original question, If you can measure the size of the pulley, figuring out the distance ten degrees is away from the TDC mark is very easy.

If, for example, the pulley is 5" in diameter, multiply that by pi (3.14). That equals 15.7". Since you want ten degrees, divide the 15.7 by 36 (360 deg/10 deg). That would equal .436" (7/16"). You want to make that mark BEFORE the TDC mark according to engine rotation, which in this case is clockwise when looking from the front...in other words, the mark will have to go to the right of TDC as you're looking at the engine from the front.

I think I got that right!! :laugh:
 
Old timers method, where the timing indicators "disappeared": use a vacuum gauge. Hook up to manifold vacuum(below the throttle plate(s) of the carburetor). Start the engine, after warmed up dial in the timing to the highest vacuum, resetting the idle speed, as it will change with timing change, then back off 2 degrees.... I know kinda hard without marks. We used to(as I was trained by a shop owner in Riverside where Jim Hall used to bring his cars for prep for the race) back them a "smidgen", just tapped them back slightly. So usually dropped about 1-2 inches of vacuum.
 
newmexTR3 said:
Mickey Richaud said:
until it starts pinging when accelerating under light load (going up a hill, etc.)
Click to expand...

I'm unclear as to what "pinging" means... and more importantly how to audibly identify it. Is it a particular sound or feel?
Click to expand...

Sorry - knocking - sounds like marbles being rattled around a coffee can. You'll know it when you hear it.
 
Aloha Steve,

I changed to a Pertronix ignition in my TR3A last year and I needed help on how to do static timing with the new set up. I found a lot of help from sources right here in the BCF. I've cited those sources in the description of how to do it with both points and a Pertronix ignition:

TR Ignition Timing

Ignition timing is a poorly understood, very important and a frequently done wrong part of a tune up. While most distributors are designed to be timed with a strobe or an electronic timing light and running, the TR distributor is designed to be timed with a static light and with the engine stopped. If a Triumph 2 or 3 is timed with a strobe while running all you will get for your trouble is a poor running engine with badly retarded ignition timing.

Procedure with stock contact breaker point ignition system:
1. Remove the coil to distributor low-tension lead at the distributor, usually located in the distributor base and next to the cylinder head. Connect a static light (any 12 volt lamp) between the distributor terminal and a convenient hot lead (the battery will do).
2. Using either the crank or by pulling the fan, move the pulley around in a clockwise direction as viewed from the front. Place the hole drilled in the rear half of the pulley 3/8” to the left of the timing pointer. The timing pointer is attached to the timing chain cover, just off to the right of the centerline as viewed from the front of the car. DO NOT turn the pulley in a counter clockwise direction, as the crankshaft motion is not directly transmitted to the camshaft due to the timing chain tensioner. The fan must be moved in a smooth and continuous movement clockwise to the correct location.
3. Loosen the clamp at the base of the distributor and very slowly turn the distributor in a counter clockwise direction until the static light just comes on and then clockwise until it just goes out. This is the exact point of ignition and it is possible that the light may come on as you tighten the clamp, making it necessary to readjust until the light just goes out. Then reconnect the low-tension lead and you are ready to go. 3/8” measured on the circumference of the crankshaft is about 8 deg, which is more initial timing advance than the factory recommends, the engine however seem to run more effectively at 8 deg than 4 deg of advance. Original: Ken Gillanders, January 1985. Transcribed by: David Templeton, June 29, 2002

Procedure with Pertronix electronic ignition
1. Set the TDC hole in the fan pulley as described above.
2. Fully connect the Pertronix module, coil, etc.; then connect a test light as follows: remove the black wire off the coil, and connect your test lamp from the black wire (negative ground cars) and a 12V source. With the key on (power to the coil & Pertronix), the test light will be on when the Pertronix is "on" (equivalent to points closed) and the light will be off when the Pertronix is "off" (equivalent to points open). The test lamp will only require about 90 mA to power and shouldn't cause significant heating of the module. Adjust the distributor as described above. Rather than running back and forth to the ignition switch to limit the "on" time of the Pertronix module... I simply unplug its red wire which is connected to my coil (+) terminal. CAUTION when the Pertronix is powered, around 4 Amps is flowing continuously through the module and if it overheats can burn out. Pertronix tech support says that "too long" is about 5 minutes. To be safe, try to limit yourself to 3 minute. In normal running the duty cycle is reduced so overheating is not a problem. Provided by Randall (TR3Driver) and Doug Lawson from British Car Forum

The procedure has worked well for me.
 
FWIW, I vote for using the Vacuum Gauge as a starting point as per Ron, followed by the test drives as per Mickey.
Mickey, hope you found some "swimps".
 
poolboy said:
FWIW, I vote for using the Vacuum Gauge as a starting point as per Ron, followed by the test drives as per Mickey.
Mickey, hope you found some "swimps".
Click to expand...

~~BURP!~~

Deanie's Sunday evening.

Great finally meetin' up wit ya, PB. Your turn to travel north in October for the Nashville show!

Mickey
 
Mickey Richaud said:
Sorry - knocking - sounds like marbles being rattled around a coffee can. You'll know it when you hear it.
Click to expand...

EXCELLENT description, expecially the "you'll know it when you hear it." That is SO right.
 
Mickey Richaud said:
until it starts pinging when accelerating under light load (going up a hill, etc.),
Click to expand...

I think I've always called that spark knocking
 
Jay, If my wife saw your garage she would label you as a bad influence. Hats off to you!
 
You guys are a wealth of knowledge.

To static time with the pertronics: My car is a positive ground. I have two wires coming from my elelctronic pick up. Would I disconnect the wire going to the coil from the pertronix to a test lamp lead with the other test lamp lead connecting to the negative post of the battery?
 
woody1091 said:
You guys are a wealth of knowledge.

To static time with the pertronics: My car is a positive ground. I have two wires coming from my elelctronic pick up. Would I disconnect the wire going to the coil from the pertronix to a test lamp lead with the other test lamp lead connecting to the negative post of the battery?
Click to expand...
That would work; or you could just connect the test lamp to the coil terminal where you took off the Pertronix wire (and turn the key on). Either way will work, but be sure the key is off before you reconnect to the coil.
 
The easiest method is to leave the Pertronix wires connected and hook a test lamp between a ground point and the coil terminal with the white/black wire. Switch on the ignition and turn the dizzy until the test lamp lights. When the light is "on" it's the equivalent of the points being open.

As stated earlier, the time limit for leaving the ignition on during static timing is 3-5 minutes.
 
Hey Guys
I have the new petronics in my 3 and left the key on overnight. Totally drained the battery, Had to jump start the engine and it started with out any problems. Did I get lucky?
Dan
 
IMO, yes. Not even all that lucky, as I think the chances of any specific incident damaging the unit are only perhaps 1 in 4. But the overheating problem is real.
 
tinman58 said:
Hey Guys
I have the new petronics in my 3 and left the key on overnight. Totally drained the battery, Had to jump start the engine and it started with out any problems. Did I get lucky?
Dan [/quot

Only time will tell. I have tryed two Petronics systems. They lasted about 2 years each. The 2nd one I watched how long I left the key on and would unhook it when I needed the key on longer. Both started missing under loads. Went back to points and all the problems went away.

Don
Click to expand...
 
Mickey Richaud said:
Take it on a drive; advance it bit by bit until it starts pinging when accelerating under light load (going up a hill, etc.), then back off a tad.
Click to expand...

I took it out on the open road and I was getting a ping under load. I didn't have time to time to back it off and try it again but I'll do that first chance I get.The TR3 has much more pep than my Spitfire had.

I took a look at my soft fuel lines and there is one under the car directly under the fuel tank that is in critical condition. I'll need to drain my tank and replace that line before I proceed. The Moss explosion is showing this line being steel all the way to the tank. Pehaps it has been cut and patched with the soft line at some point.
 
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