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Triumph TR6 - 1974 TR6 Misses/Stuttters

Driving the other day and after 50-60 miles, the car developed a miss. Replaced cracked rotor, repaired ground wire from distributor plate to distributor side screw, replaced electronic ignition (from crane to pertronix) and coil. Still has miss. Distributor cap and plug wires recently replaced. After all these replacements, timing way off. Set timing to 4 ATDC with retard disconnected (retard connected it is ~4 BTDC). Car still has a miss at low RPMs and when under load. Also noticed that distributor retard unit is almost pointing towards engine (direction of the battery tray) after timing set - which does not seem correct. Carbs were adjusted less then 1000 miles ago by reputable service station. Out of ideas at this point. Any advice would be greatly appreciated. Thanks - Dave
DJC Cates

Do you notice if the temp is different?
DON KELLY

Did not notice a difference. Does not run hot.
DJC Cates

Is the miss constant or just when accelerating? I assume you checked the oil level in the carb dashpots. If the miss occurs mainly when accelerating it could be the fuel filter is getting a bit restrictive.
Brent B

You might want to check the plugs as well. All showing good burning? All gapped correctly?

My retard seems to point to battery and not almost to engine. See picture attached. (69 TR6)

I still have points so I am not really familiar with how the electronic ignition timing is set but you may want to explore that a bit more.

Defective rotor? defective pertonix?

Michael Petryschuk

I will repost with a bigger picture this time.

Michael Petryschuk

The miss is mostly seen when accelerating, but also at low RPM >2500. Oil checked in carb dashpots. Checked the plugs and they seem Ok, gap was checked. Probably will change plugs just for completeness....Changing the fuel filter is also pretty simple and inexpensive...

Thanks Michael for the pics - my retard is pointing another 20-30 degrees towards the engine. Not sure what year I am looking at, but mine is a 1974 and only has a retard (looks like yours has a retard and advance??). Nice clean car!

Any credence to the distributor possibly jumping a tooth?
DJC Cates

I don't think that distributor has "teeth" but I may be wrong, I think it has the typical UK two prong set-up on the bottom. The distributor can be installed 180 out and believe or not I had my Midget in 180 out and it still started and ran (but poorly!)
JT White

Thanks JT - it has not been removed so that rules that out as well. Grasping at straws here....
D Cates

Start it up in a DARK garage and rev it up and see if there are any arc's coming from the ignition system under load (make sure to leave the door up!) I've lifted the hood and put a blanket over and have found a few stray arc's that way.
JT White

Have you checked the carb. diaphrams for holes?

Rob
rw loftus

DC

it is a 69 TR6 that came with both an advance and retard.

Regards
Mike
Michael Petryschuk

RW - I did check the diaphragm for holes. Thanks for the suggestion.

JT - I'll do the blanket check in the next couple of days. Thanks
D Cates

Dave

I don't think you have the timing quite right. The distributor I don't believe should point that far to the engine but I don't know what the settings are for a 74. I know that it is quite different from my 69 with little emission controls on it.
Michael Petryschuk

Thanks Michael - I'll check it again tomorrow when I swap the plugs and fuel filter. I agree that the retard should not be pointed that far into the engine when set correctly...started me wondering if it had jumped a tooth on the distributor gear....
D Cates

The distributor on my '69 is pointed exactly like Michael's. Who needs a timing light?

Tony
A. J. Koschinsky

Dave... sorry to jump in so late here. I had the exact symptoms you describe on my way home to Ontario from BC. After all troubleshooting was done after breakdown in Kamloops an LBC specialist found that my new distributor cap was defective. The problem only presented when the car was warmed up. This could be a long shot but the new distributor cap you put on could be a bad one. Swap it out and see.

Ken
Ken Shaddock

Mike- That's why I asked about the temp. His timing marks could be correct, just that his damper has slipped. Wouldn't be the first,by far.
How old is the damper.
I would time it by vac. and see what's up then
DON KELLY

Where is the number 1 at on the clock
DON KELLY

Dave

I would like to touch on the distributor jumping a tooth idea.

If you have too much space between the distributor drive and the drive gear I believe it is possible for the gear to jump a spot. It would happen when driving (like when the symptoms first developed for you.)

25 years ago I had a 68 Spitfire quit running on me while driving down the road. The engine gave a loud pop or bang just before it quit running. Scared the heck out of me. I thought I blew up the engine. It would not start again. I stripped that engine down (since the engine made such a horrible pop) found nothing wrong, put it together and it ran fine. I can only assume the distributor or timing chain jumped and it went out of timing but I was never able to prove it.

So I wouldn't rule it out. Best way to tell is set the engine to number one firing position. See where the distributor rotor is sitting versus where the cap should be for number one piston firing. In my car the rotor is near the south west position when looking at the distributor from the distributor side when the number one piston is ready to fire. (With North pointing to the engine) - Clear as mud??
Michael Petryschuk

What teeth are you talking about.
Rotor should point about 7:00 PM
DON KELLY

Teeth we are referring to are on the distributor drive gear that meshes with the camshaft drive gear. The distributor drive gear then meshes to the distributor which has the 2 prong connector that JT refers to above.

7 pm position in my example would be slightly south by South west. 7:30 position is south west.
Michael Petryschuk

Thanks guys for all the help.

Any easy way without pulling the valve cover off to know if #1 is at TDC? I've heard of putting thumbs over the spark plug hole or wooden dowels into the spark plug hole....seems like either is not very scientific. Need to know for sure that I'm on the compression stroke....Also, what size socket do I need to turn the crank?

Broke the tach cable with all the adjustments....so will probably change the distributor cap and rotor again while I'm ordering....
D Cates

Doesn't really need to be scientific...I've used a pencil before...worked well enough. Have someone hold the dowel loosely in the plug hole while you slowly turn the crank and when she gets up and then just begins to fall then you squeak it back to the high spot....easy peezy.
JT White

Dave

As an option you can use the timing marks on the front pulley - harmonic balancer to show when number one cylinder is at TDC for firing.

I think the bolt head is 1 1/16 inch but don't hold me to it.
Michael Petryschuk

MIchael,
1 1/8.
db
Doug Baker

Use a 12-point socket, as a 6-point will slip. Don't ask how that was discovered!
Rod Nichols

I would only use the damper as a reference if it's original
DON KELLY

If the Brit distributor "jumps" it can only be 180 out....there are no "teeth" On my 74 my vacuum can on the distributor points at the throttle shaft bushing as it enters the firewall.
JT White

Thanks guys for all the help. A lot going on in my life right now....but hope to get to it sometime next week. Will post the results as soon as I can.

D Cates

This thread was discussed between 17/10/2010 and 25/10/2010

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