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MG TD TF 1500 - Points rub-block against distrib cam

Is your distributor like mine? Do I have a problem?
(D2A 40367B, High lift distributor cam, TF-1500)

The rub block on my points does not contact the peak of the lobes of the distributor cam evenly. The bottom of the rub block contacts the lobes. The top of the rub block does not. The block is wearing and will eventually contact the lobes completely. The distributor cam has wear marks where it contacts the bottom of the rub block.

The points are gapped correctly (for now). Even if the points have the correct gap, will the shortened rub block affect the dwell and therefore the length of time that the coil is "on"? My coil runs very hot. One coil may have failed. I changed it just to be sure.

The breaker plate sits firmly on all supports and does not appear to be warpped. The shaft is firmly seated. The head does not wobble ... although a former wobble was fixed by a club member.

Just want to see if I actually have a problem before I source a TF distributor and ship to Jeff Schlemmer for tweaking. Otherwise I'll just replace the points a little more often.

Thanks,

Lonnie
TF7211
LM Cook

Lonnie.
Sounds like the pivot post is slightly bent. Try replacing just the plate with another.
Sandy
Sandy

Sandy -

That is TOO EASY. Even if it's not bent, maybe I can tweak it. Only needs a few degrees.

Thanks

Lonnie
TF7211
LM Cook

Lonnie, if it was me I would slightly bend the post. I have done this in the past succesfully.
John...Sydney
John Walton



Lonnie, if you have another set of points, recommend you try them first to see if same condition exists. If they both show the same problem, bend the post sounds like a reasonable fix.
Richard Cameron

When you say "wobble" do you mean the aluminium head was loose on the steel housing ?. If so then maybe when it was swaged back it was not concentric to the housing, this will mean the rotor is not true to the pickups in the cap.
I have seen this where the rotor has been filed back to give clearance.
If it is just the pivot pin then it will soon wear back and make full contact.
Ray TF 2884
Ray Lee

Thanks for your help everyone.

I checked the gap between the distributor cam and the top of the rub block on a new set of points. The rub block on the new points was off at the same angle as the old points, so the problem is not with the points.

I moved the pivot pin a tiny amount by placing the breaker plate in my bench vice with the pin against a padded jaw and the edge of the plate against the other jaw. The pin is press-fit into the plate, so I guess that it moved at the joint and didn't actually bend. It is still firmly bonded to the plate.

The rub block on the new points contacts the distributor cam almost perfectly -- at least as nearly as I can get it.

> Ray -
Yes, the head was loose from the steel housing when I bought the car a couple of years ago. A club member peened the head to the housing. It is now firmly attached. It is probably not perpendicular to the shaft. However, the rotor does not show any wear and is not scoring the pickups in the distributor cap.

Lonnie
TF7211

LM Cook

This thread was discussed between 09/10/2015 and 12/10/2015

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