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Triumph TR6 - Low Idle Miss

Some help would be very much appreciated. I have a low idle "miss" that is driving me crazy. 1971 TR6 with Crane EI. I have changed Plugs, using Magnacore cables, new Rotor and cap. The "miss" is most prevelent as I engage the clutch and put a load on the engine. I have played with the timing to no success.
The carbs have been maitained and I am confident they are not the problem.

The distributor does have 1/8" shaft play in it up and
down. Is this normal. The advance plate also springs
up and down if you push on it. Is this normal.
I did order a new Bushing. Is this easy to replace, will the old one come out relatively easily. I appreciate some feed back.

Jeff Shirhall

Check out my posting " Rough idle/popping on deceleration". I am having exactly the same problem. I think you are OK with the up down play..left-right play is more critical. Also when you change the bush (not sure on difficulty) make sure that when the distributor is removed look at position of the rotor (ie. facing 1:00) it must be reinstalled same way. DO NOT turn the engine over with the distributor out!
I am adding to my thread...check it out.
Good luck
Rick C
Rick Crawford

Thanks for your comment Rick.
I did take the time to read through you thread. It sounds as though our problems are very simular. Frustrated I am....but I will win eventually. I have worked through the ignition and it all checks out very well. The Crane Cams people were a big help as I sorted through the ignition to make sure that the EI
was in phase as well to see that enough current was making it to the coil. Everything checked out and Crane was not worried in the least regarding the up and down play of the distibutor shaft. Plugs, rotor
and cap as well the cables are new. I also checked the engine compression and all 6 cyl. are between
145 and 155. I checked for vaccuum leaks as well
with starter fluid spray on the intake manifold and all hose fittings, no leaks were apparent. Also tested
the advance/retard checks out fine.

To refresh your memory, my main issue is an engine miss as I engage the engine and put a load on it. Once the RPM's increase it smooths out and runs very well. It is very annoying....I guess my next step will be to change or test the fuel pump.

Any suggestions or advice from anyone would be very well appreciated. Thanks
Jeff Shirhall

About the only thing I have not done yet is the compression test. By the way...I would be very carefull with that ETHER as it is extremly explosive. Try carb cleaner next time for leak tests. Frustrated is an understatement. Now that my memory is refreshed, it sounds like you are getting fuel starvation on take off. Are your dampers toped up with a 20 weight oil? Clean fuel filter...good pump??
Rick C
Rick Crawford

Have been following this thread as I have similar problems. I know that replacing points is kids' stuff to most of you guys, but this will be the first time for me. Does anyone know of a good diagram. None in Bently.

I had similar symptoms with my 74 TR6. I use the Petronix ignition system. The final solution to the problem was changing out the ditributor itself. Replacing the upper bushing in the distributor should do the same as replacing the distributor itself. I think just a little bit of play in the shaft is the reason for the miss.

Interesting!! I also have pertronics. I contacted them and the gap between magnets and the sensor can be between .005" and .050". I am around .030" now. You said change out the upper bushing. I have looked at TRF catalogue (PLATE DU) and see no bushing. What are u refering to John? I presume you are talking about lateral (rotational)play as compared to vertical play?

Keith Consider going with the Pertronics EI. It really is kid stuff and is suppose to take up the slack in a worn distributor....maybe I just need to reduse my gap between the magnets and sensor. I am not sure where u would find a diagram. Simply remove the distributor, rotate the engine over (if by hand it would greatly help if the plugs are removed) and turn till the points plastic piece is resting on the high lobe of the cam...points open. Check your gap for the heck of it..should be around .014" tp .016". Remove the single screw holding the points in place...this also acts as the adjusting screw for setting the points gap. Replace the points and also the condensor. Set the gap and tighten down the screw....done. Oh Ya put a little bit of vaseline on the cam for anti-wear purposes of the plastic piece. You might want to consider a new rotor also )can only go on one way). Clean the contacts on the distributor cap or replace. I use some dielectric grease on the brush and rotor contact point.
Have fun and remember..we all learn by doing.
Rick C
Rick Crawford

Having worked with a certain brother of mine so named above on the above mentioned vehicle, I have a question about ignition timing. The service manual setting, which matches the setting so stated on the underhood emissions plate is 4 degrees ATDC. This setting may have been a factory compromise aimed at obtaining sufficiently low NOx emmisions to pass emission regulations here in the states. Is there a setting that will make the engine idle smoother?

My own toy car is a 1970 Buick GS455. The factory ignition setting is 8 degrees BTDC. However, most of us Buick folks-in-the-know run anywhere from 14 to 20 degrees BTDC because these engines simply perform much better at this setting. Would like to apply similar practice to the new British ride in the family.
Brad Shirhall

Jeff, Replacing the bushing is an impossible affair unless you have a hydraulic press as the bushing is press fitted. Any auto electrical shop should have this tool so you might be able to get them to do this for you.

Brad--Advancing the TR6 timing is best done by the seat of the pants. Some (including myself) have found 4BTDC to be good, while others have gone just shy of the pinging limit.
Rick Orthen

This thread was discussed between 29/08/2002 and 16/09/2002

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