8 replies to this topic

[Phil69]

1990 H reg Studio 2 998cc, no mods
59D Distributor

Hi folks,
I fitted a new vacuum advance unit...the connecting rod on the new unit is slightly shorter than the original but it fits without bother, for all I know it may be that the old one is pulled out of shape a touch. The ignition timing was a mile out after I fitted that (makes sense) so I reset it with the strobe and it idles fine again, now.

But when I try to reconnect the vacuum advance pipe, it immediately stops running. It runs smoothly with the pipe open or blocked but any kind of suction stops the engine.

I'm sure it's the right part, Minispares only sell one that fits the 45 and 59D and aside from the length of the rod it is identical. It works by the suction test, and I don't see any reason to think there's anything wrong with the distributor because I've never had any trouble with it. I suspect though that the old vacuum advance was broken a long time before I knew it.

Any ideas what might be wrong here?

[Phil69]

Anyone? Any hints or clues much appreciated!

[lrostoke]

Did you set the timing with the vac advance disconnected ??

As your strobe got an advance knob on it...??

[Phil69]

Hi thanks for the reply,
I set it with the pipe off, as per Haynes/Rover - the smooth spot was right where it should be.
The strobe isn't an advance type, just a light and an led for the rpm.
With the pipe off it sounds fine to me. Points/valve clearances were all checked only days ago.

[lrostoke]

If I'm reading right blocking the pipe makes no difference , I presume you mean its still plugged into the carb and your blocking the other end.

So it suggests the problem lies with the advance mechanism on the dizzy.
Either your getting to much advance which at tickover shouldn't make it cut out..

Long shot but is anything shorting inside the dizzy, eg points, or a loose wire that when the pipe is connecting causes a short and makes the car cutout.

[Phil69]

Blocked or unblocked it runs fine...suction either from the carb or by sucking the pipe makes it stop.
I don't think anything is shorting in the distributor, but I'll have another look anyway. I think the mechanism is a more likely cause.
I did have to turn the distributor quite a lot, the mark on the pulley was about 3 or 4 inches around when I fitted the new unit - but the HT leads are still in position with no.1 at the top right of the cap now that I've reset the timing.
Maybe if I put the HT leads back in one place around on the cap and reset the timing again it would work?

[lrostoke]

jeez 3 or 4 inches, I suspect the pulley is only about 16 inches so thats 90 degrees out..

If its running sweet at tickover though with no pipe, the HT leads doesn't sound likely

You can tell if the leads are in the right position, turn so the timing pointer lines up with the notch in the pulley and make sure the valves on No 1 (nearest rad) are closed (you can wiggle rockers)...then look were the rotor arm is pointing..it should be pointing to the No 1 HT lead or near enough

maybe a picture of the inside of the dizzy would help

Edited by lrostoke, 10 July 2012 - 01:12 PM.

[Phil69]

I've checked again and everything is correct with the leads, so maybe I should think about taking the distributor out and having a good look at the mechanism. I'll try a spare condenser first just to rule out moving wires. Thanks again!

[Phil69]

Found it - the edge of the metal spring on the points was fouling the pin on the baseplate that normally has a forked plastic thing on it (same pivot point as the points themselves). While poking about with the multimeter I could see a little orange arc as I sucked the pipe.
So it was a cheap and nasty set of points that didn't sit high enough from the baseplate. Amazing to see the differences when you have a few sets lined up together...
Anyway, thanks loads! Onwards and upwards!