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Now for my next stupid Question, Distributor

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Jayrz

Jayrz

Jedi Trainee
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Ok guys, please refresh my memory as the last time I re-timed a Midget or Sprite I was 17 years old and had just gone to the Go-Gos/Flock of Seagulls concert the night before.

To re-time or check the timing on my 63 (should be 62) Midget, I should dis-connect the vaccum advance and set the timing to 8 degrees. And if very close I can adjust with small knob on distributor. Correct?

Problem is I keep expecting the idle to slow after the vaccum advance is disconnected and nothing happens. So next I checked the the vaccum advance mechanism by applying some vaccum and watching the plate with the cap off. There is NO movement. Now I have a distributor off the 1275 I am planning on building and when I apply vaccum to it the points plate moves the way I expect it to.

So is there a difference in the distributors vaccum action between the 63 and the one off this 70 1275 motor? I am thinking perhaps the vaccum advance on my car is froze or something.

Thanks in advance guys

Jay
 
I think you hit the nail on the head, Jay. The advance mechanism should function the same on both distributors.
Will the vacuum cannister hold vacuum? If it will, then chances are the advance plate is rusted or stuck. If the unit <u>won't</u> hold vacuum, then the pot is bad.
Jeff
 
Thanks Jeff,
well it is coming off then. I would think te distributors are interchangeable but I'd like to get the one thats on the car working correctly if possible. I may just take the dizzy to the folks at Sports Car Craftsman and have them go through it and make sure its right. Years ago I remember shops having a distributor testing machine that made it easy to see whether the advance curve was correct. These still exist I would assume.

Jay
 
I can't comment on the difference between the cars you mention, but I can tell you this: there won't be much vacuum advance, if any, until you get a few inches of vacuum. So, disconnecting the vacuum line probably will make little difference on timing, at least at idle. Still, it's a good practice, because on some cars it might make a difference; be sure to plug the hole in the manifold, in any case, after you disconnect it.

On the other hand, these things do fail sometimes. I just recently discovered that the vacuum advance in my Bugeye wasn't working--the diaphragm mechanism must have been binding. No leaks, just didn't move.

And, yes, you can usually adjust the timing 5 or 6 degrees with the knob, maybe more; depends how close it is to its limits when you start, of course.

Here's a nice treatise on Lucas distributors, with particular emphasis on advance:
https://www.starchak.ca/tech/pdfs/lucastuning.pdf
 
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