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Triumph TR6 - timing roaming

Hi all - I have inherited my father's pride and joy. No, not me or my sister but his beloved 1969 signal red TR6. it is pretty darn clean and almost all original. It has 180,000 on the odometer and we rebuilt at 150,000. It has been running rough so I'm trying to learn my way around the engine from what little I remember from my childhood (other than being terrified of going near the vehicle for fear of leaving a fingerprint on it.)

As of now the engine is missing when under a load below 2000 rpm. I have set the static timing to 10 BTDC and the warm idle (800 rpm) to 4 ATDC measured with a stroboscopic timing light. I replaced the plugs, wires, coil, cap, rotor and points/condenser. The cylinders 1,2 show normal burn but have a bit of fuel on the threads - 3,4 look to be burning hot (a little whiter electrode) - and 5,6 look very similar to 1,2.

It also seems to not want to settle down to a low idle (800 -850) after being run for short intervals (i.e: driving around town) but when it is run for a longer stint and coasted to a signal she settles down nicely.

Any information that can be passed to me would be greatly appreciated and may help my father to rest peacefully while I tinker with his fun toy.
R D Brodman

Two things come to mind. First, since its a '69, does the car still have the vacuum switch that controls the vacuum retard at idle? If not, or if it has failed, then you have to disregard the factory spec timing and be more creative. Secondly, if the distributor shaft is worn it is difficult to get the points set correctly. Pertronix or a distributor rebuild fixes that.

Tony
A. J. Koschinsky

Thank you Tony (my father's name).

Would it make sense to switch to the electronic ignition? You mentioned Petronix and this is the name of the electronic ignition i found online. It seems the idle becomes smoother when I'm closer to the recommended timing. the vacuum switch is the flat round disc held with a wire clip on top of the engine and I believe it's working fine. When I pull either of the vacuum hoses off the distributor it makes a difference.

I would think the distributor had been rebuilt when he had the whole thing rebuilt (power train, drivetrain and suspension 30k ago adn about 12 years).

Thank you for your help
R D Brodman

Try looking further into:
1)increasing your timing to 15 to 20 btdc to see if it makes it better or worse. I say this because you said your father had the engine rebuilt and chances are, it may not be to original specs. A lot of people change or regrind their cam shaft on rebuilds.
2)Check for vacuum leaks in the 2 systems on your distributor. (If you have the original distributor, it has a vacuum on each sides of the distributor.)
3)Check if your carbs are running too rich by listening if the engine tumbles inconsistently at idle. Verify by checking your plugs to see if they are black or grey.
These are just some quick ideas to try for instant gratification before summer driving ends.
Regards,
Benji
benji

Rob,

The large round thing on top of the manifold functions effectively as the PCV valve. The vacuum switch is down on the throttle linkage below the carbs near the bell crank. You should have two vacuum lines going to the distributor, one from a carb port to the advance unit and another from the vacuum switch to the retard unit.

If I'm recalling correctly, the retard unit is on the side of the distributor nearest the tachometer cable and the advance unit is on the side nearest the cover plate for the tach drive gear set.
SteveP1

To add to Steve's comment, the vacuum retard module should only operate at idle. If it is having any effect at a partial throttle opening, it is either faulty or has been removed from the vacuum circuit.

A lot of folks run the Pertronix; I use it in several vehicles. It fits nicely under the distributor cap and the engine shows no visible signs of modification. The only thing I've noticed is that it does seem to cause some radio interference on the AM band.

Tony
A. J. Koschinsky

The dampener could be toast by now. Your timing marks might have slipped as it has aged.So timing by a visual could be off target. I would do a timing trial by vac. gauge and see if there is a difference.
DON KELLY

This thread was discussed between 29/08/2010 and 31/08/2010

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