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Daddylonglegs - 31/8/11 at 07:45 PM

Why is it when you get so close to the end, something pushes you further away from the line?

I had some issues today with the alternator belt touching a lower cooling hose so made some amendments and hopefully sorted it. Went to start the engine again just to get it up to temperature but it kept banging and popping and eventually quit altogether.

So I whipped the dizzy cap off and found that the points were not opening when on the cam. I have found this twice now and assumed I had not tightened the screw on the points enough. But this time I noticed that the heel which runs on the cam was all but gone! looks like it has slowly melted and now there is a danger of the body of the points touching the shaft even if i can get any more adjustment out of them.

Can anyone tell me what might be causing the points or shaft to get so damn hot? It runs freeley enough by hand and I can see no reason for it.

I really am getting P'd off with these constant setbacks

JB


r1_pete - 31/8/11 at 07:58 PM

Has the cam worn to the extent that the points heel is constantly in contact??

Or,

Are you using cheap points with a plastic heel? IIRC points were made of a paxolin type material, which wouldn't melt and held a fine film of oil..


Russell - 31/8/11 at 08:00 PM

I had that same problem back in the 80s on a crossflow dizzy. Turned out to be a crap set of points, the plastic cam follower was just poor quality and slowly melted into a flat blob, throwing the timing out then killing the ignition.

Try a new set of points from a different manufacturer - OEM ideally!


spiderman - 31/8/11 at 08:09 PM

Check your engine earth lead as the engine may be earthing back through the distributor and coil.
Although I have not seen it do this before but I have seen it earth back through things like the throttle cable and seen them melt the outer cable within a few minutes. Worth checking especially as you say the distributor turns freely so the heat is not from frictional losses.
Also check the distributor shaft where the contact breaker points heel rests on the shaft, it should be nice and shiney with no rough areas or rust as this will just file away the heel by abrasion. You should also have a small felt pad in the centre of the shaft which should have a few drops of light oil, i.e. 3 in 1, as the cetrifugal forces will help lubricate the shaft when engine is running.
Just a couple of easy checks for you to try.


mark chandler - 31/8/11 at 08:18 PM

Lack of ballast resistor, if you have a 9v coil then this will happen without one fitted.


Daddylonglegs - 31/8/11 at 08:41 PM

Thanks for the input guys

I don't think the earth is a problem as I have got a 3/4" braided earth connected from the engine to the chassis which was cleaned before fitment.

Mark, I did think about the coil voltage as I know some cars had 6V coils and a 12V electrical system. How does the wrong voltage cause the points to get hot though? From what I remember, the idea of the ballast was to allow a 6/9V coil to be used with a 12V system and it just gave the engine a better chance of starting when the voltage dropped due to starter motor loads. I am not sure if I have it right.


adithorp - 31/8/11 at 09:50 PM

Usual cause is lack of grease on the cam/follower. Only needs a dab (too much risks getting it on the pionts) but without they don't last long. Used to be a regular one that they'd turn up about Wednesday running bad after the owner had serviced his own car on Sunday.


Mr Whippy - 1/9/11 at 07:19 AM

ditto above, grease the cam or you'll just wear out the plastic follower


Daddylonglegs - 1/9/11 at 08:52 AM

I would be suprised if it is wear because the plastic part that's rivetted to the spring arm has actually got signs of melting at the back and the side where it touches the metal arm so it definitely looks like it's been getting hot. The heel just looks like normal wear with slight scuffing but not melted at all.

Points-1
Points-1


Points-2
Points-2


Not great pictures but hopefully it shows more what I mean. You can see in the first one how it's melted around the mount and in the second the lack of heel!

JB