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TR2/3/3A Setting the timing on TR3

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Hi, George,

I had the points replaced and set a few weeks ago by the mechanics in the shop where I have most of my work done. They did not check the timing.

When I decided to check the timing, another mechanic friend of mine showed me how to use the advance timing light. What we found was that the timing was "off" just a little bit, and when we rotated the distributor a very little bit and took the rpms back up to 1000 (from 500 where we set it for adjusting the timing) it idled better than it ever had.

As for running, acceleration, etc., the car runs extremely well -- very smooth, very peppy, no pinging.

With high rpms, the timing light remains "right on the mark." I don't see any wandering at all.
 
bnw said:
With all due respect, I don't buy it. IMO, it's not the idle timing anyone should be concerned with. It's the driving down the road, accelerating to pass timing at road speed that really matters. You're only going to see if everything is working properly with a timing light.
Click to expand...
Ok, how are you going to watch the timing mark, while accelerating to pass?

And, what timing specification are you going to use?

I agree a light is useful; but AFAIK we were talking about setting initial timing, not total.
 
A timing light let's you see the total advanced timing (within the confines of running the engine up with no load).
I use a timing light to get the initial setting because I've got pertronix and have not gotten the hang of static timing with the electronic gizmo.
John
 
LexTR3 said:
I had the points replaced and set a few weeks ago by the mechanics in the shop where I have most of my work done. They did not check the timing.
Click to expand...

Changing the points usually changes the timing.
 
Dr. John,

Then the mechanics who changed the points and set them, should have checked the timing. I'll ask them to do that next year when I go in for my "spring tuneup."

On this subject, will installing a new vacuum advance unit (Moss has reduced the price of their new ones) change the timing if I am careful to mark the position of the distributor and make sure it is returned to that position after I install the new unit?
 
LexTR3 said:
On this subject, will installing a new vacuum advance unit (Moss has reduced the price of their new ones) change the timing if I am careful to mark the position of the distributor and make sure it is returned to that position after I install the new unit?
Click to expand...
Very likely, yes. If you are doing the "mark the position" thing, then you'll also need to mark or note the posiiton of the timing vernier, since it has to be undone completely in order to change the vacuum module.
 
LexTR3 said:
But wouldn't the procedure of lowering rpms to 500-600 and using a 4 degree advance timing light when adjusting the timing make up for the difference?
Click to expand...
Depends on where the advance starts. ISTR the book gives 0 to 2 degrees at 350 rpm for the early distributor, checked with the rpm falling.

The hand crank may not be the reason it has such a screwy advance curve. Maybe it's just a 50s British thing like Lucas fuse ratings, I dunno. But it does have it, while those other cars didn't (at least not mine).

And that still doesn't solve the problem of where you buy 95 octane gasoline today.
 
TR3driver said:
[And that still doesn't solve the problem of where you buy 95 octane gasoline today.
Click to expand...

Randall,

Wasn't that 95 octane rating specified then the RON measurement versus today's AKI or PON rating? From what I've read that 95 RON would be 90-91 AKI today.

Scott
 
Randall,

If I install a completely new advance vacuum module, and I have to remove the timing vernier to get the old one off, it seems to me that either (a) I would have to reset the timing with the dynamic/timing light method, or (b) I would have to reset the timing using the static/vernier knob method. I don't think I can mark the old vernier knob and get the new one to conform exactly.

At present, it appears that my old vernier knob has absolutely no effect, so it doesn't seem to matter what its position is. I ignored it when setting the timing with a timing light (and rotating the distributor).

One thing to remember about all these "proper settings," I am told, is that the Triumph people estimated as optimum when they designed the system. But their guess was limited by all the variables of temperature, altitude, humidity, quality of the gas, and half a dozen other things. In otherwords, it was a wild guess. Their testing was in cold, drizzly England. I am learning that these old cars never do better than an approximation.
 
karls59tr said:
JohnnyMead What is the process for setting the initial timing with a timing light if you have pertronix?
Click to expand...

As I recall it was attached in place of the points without touching the dizzy's position, then started and adjusted. Maybe that was the "dumb luck" approach.
John
 
Well.... after all this time and effort... and many tries to set the timing properly on my Triumph (using static and dynamic methods), it has all been a futile waste of time....


.... because I discovered that the spring in the distributor is either broken or shot.

With the distributor not working properly, it is nearly impossible to balance the carbs, set the mixture, etc., etc., and certainly to set the timing.

Also determined that the idle has been set too high (1100 rpms) with needles that make the mixture too rich with the consequence that too much fuel has been pumped into the system... contributing to the dieseling problem I have had.

So.... First to replace the spring in the distributor....

Then to check and replace the needles in the carbs....

Then to set the timing properly (most advice is to use a timing light) and then to adjust the carbs, mixture, and idle...

The spring probably costs about 8 cents, but has cost hours of fiddling with the other components! An expensive lesson.

I hope this helps others...
 
Just curious, Ed, are you talking about the spring that links the vacuum module to the point plate, or one of the centrifugal advance springs?

Also, regardless of what needle is installed, the idle mixture is still controlled by the mixture adjustments. A "rich" needle only admits more fuel off-idle.
 
HerronScott said:
Wasn't that 95 octane rating specified then the RON measurement versus today's AKI or PON rating? From what I've read that 95 RON would be 90-91 AKI today.
Click to expand...
Yes, that is true. However, the relationship between AKI (which is the average of RON and MON) and RON is not fixed, and is only recommended to be 5 or less.
https://www.faqs.org/faqs/autos/gasoline-faq/part3/

Plus, at least around here, 89 is the highest available and many places only carry 88.

Unless you buy racing fuel or avgas, of course.
 
Randall,

Interesting. Here in VA, you still have Regular (87), Midgrade (89) and Premium (91) available almost everywhere. Any idea why CA would have more limited choices? And what do owner's of cars that specify or require higher octane do (My wife's 2005 Thunderbird and my brother's Infiniti G35 both specify 91 octane minimum for example)?

Scott
 
Sorry, my bad. We do have 91, just not 93 and up.

But practically any car made in the past 20 years will have a knock sensor, allowing it to run on lower octane fuel without damage. They just burn less if you use premium.
 

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Stop fiddling. Send the distributor to Jeff Schlemmer at Advanced Distributors and get it back the way it's supposed to be, advanced weights, springs, advance module and free of slop.
 
Its one of the centrifugal advance springs. Actually, a mechanic friend of mine found the problem, and he is going to install the new proper spring (from the five available).

Further inspection may show that one or both of the bushings are worn and need replacing. there is a lot of play in the unit.

Poolboy -- you are right. This winter, when the driving season is over, I plan to have the distributor entirely rebuilt, along with some other work on the car. I depend on a shop north of me that specializes in British sports cars, and they will send the distributor off for me and reinstall it, tune the car, etc., etc.



In the meanwhile, it's driving time around here.

Many thanks.
 
Ed, suggestion. Buy a used one, if so available, and send that out now and then install when it arrives.
No loss of driving and you get to enjoy earlier
 
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