Points and Timing

David Sturn · 05-23-2005, 02:01 AM

My 1975 2.0 was not idling when warm so I was going throught the list to fix it. I just got a dwell meter so I hooked it up and it read the dwell was 36. I changed the points which turned out to be really bad and adjusted the dwell to 47 (may have hit 47 by luck because I was just moving around the points and retightening the screw). The car ran great and no problems with the idle when the car was warm. I didn't have a timing light so I didn't adjust the timing. The next day I went for a ride and the car acted really gutless. I could floor it in 5th and not get it to go over 70. I drove to a friends house to borrow his timing light and on the way home the car started backfiring and the tach was all over the place. When I finally got home, I couldn't get my meter to read the dwell angle. I checked the distributor cap inside center and it was dirty/black (this is a new cap) and maybe worn down (not springy like the old one, just flush?). I adjusted the points and got it to run better but the idle would stay too high. Still no dwell on the meter. I read in this forum something about greasing the points which I didn't do. Did I ruin the cap? Are my points so far off it makes the dwell not read. Any thoughts that would help me fix this? I still need to figure out how to adjust points. I see the Haynes book page 63 shows rivet heads and a notch to reposition. I didn't use those and I didn't move the car so the moving contact rubbing block is on one of the peaks of the cam.

David Sturn · 05-23-2005, 08:53 AM

I swapped the dist cap back to my old one that was in pretty good shape, greased the thing that rubs on the shaft and a little on the shaft, moved the car until the lobe was at a peak, and gapped the points. Then I hooked up the meter and I'm still getting ever-changing readings. Once in a while it hits some numbers I like and stays there (like 48), but most of the time it's all over the place. What's going on? It's still idling a bit fast and doesn't seem to want to come down although I haven't warmed it up totally. Should I go on to timing or do I need to confirm a good dwell reading?

Alfred1 · 05-23-2005, 09:50 AM

It could be that your distributor shaft bushings are worn and that would cause the constant changes in the dwell readings. If that's the case, installing a Pertronix or Compufire module may solve it.

SGB · SGB's Garage

I believe Alfred has got this one figured.....
I could never get my timing right (consistantly, just right- now wrong- over and over) with my old distributor. If the diz iz the problem, you will be amazed at the dramatic improvement a new one makes, since it will advance linearly and you will be able to establish the correct specs.

David Sturn · 05-24-2005, 11:20 AM

I set the timing assuming that my dwell was OK. I was able to get it to stay on 27 degrees at 3500 rpms. The car now idles OK and runs good UNTIL it is warmed up and then it starts gutting out. I think I'll change the fuel filter since I saw someone mention that helped them in a similar situation. The distributor cam does seem to have some play up and down, but not side to side. I also don't see a felt tip on top of it like mentioned in the Haynes book on page 66. I'm not sure what the felt tip on top of the cam does.

Questions:
1) Will the Pertronix or Compufire work if there is play in the distributor cam?
2) What are the odds off getting a rebuilt distributor?
3) The dwell may be off since I can't get a good reading. Could my symptoms of bucking when the car is warm be related to dwell?

Some other thoughts I've gathered from posts on this site and the 914 club site:
1) Try grounding the head temp sensor. I metered it and it looked good, but I may check it again. Make sure it is not in contact with plug wire.
2) Unhook TSP to see if it stops bucking. If so, clean or reposition.

Any comments or ideas are appreciated. I'm new to working on cars so anything will help.

Alfred1 · 01:05 PM

A Pertronix or Compufire module should work much better with a worn distributor than points. The modules are superior to points anyway just make sure it's compatible with your coil. I think they are only around $60 or $70 so it's worth trying before getting a rebuilt distributor.

Here's an easy to follow troubleshooting guide that you can use to test your d-jet components.

David Sturn · 05-24-2005, 04:05 PM

Thanks for the test information. I have been reading more about the Pertronix. I assume the Ignitor on Pelican will work for my 1976 2.0 if I have the right coil (my is black).

In the Pertronix installation pictures I've seen it looks like people had to drill a hole in the side of the distributor for the wires.

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Have you looked through the timing article on this site? It has more detail than Haynes does.

The points-replacement gizmos will usually work better than points in a distributor with play in it, but they can only go so far. Some folks have had luck with rebuilt distributors from their FLAPS (Friendly Local Auto Parts Store). A-1 Cardone does them, but they seem to have something like a 50-50 success rate. Luckily, most of those places will let you trade in one that still has play in it.

27 degrees of dwell is not good. You're shooting for something near 50 degrees. The timing will be way off with the dwell that far out--remember, dwell changes have significant effects on the spark timing! And that could cause lots of driveability problems.

--DD

David Sturn · 05-25-2005, 08:44 PM

I was hoping you'd comment Dave. I was talking about timing with the 27 BTDC. I see now that wasn't clear. I think the dwell is close to spec based on gapping and the fleeting meter readings I've seen. I was also wondering what FLAPS stood for (knew it had something to do with auto parts store). I have studied the timing article and it was very helpful. I've also seen your caution on the used distributors. If I could get one that worked I probably wouldn't mind dealing with points for a while. I'm not looking to drive the car a lot so I don't mind normal wear and tear and the related tune-ups at this point in time.

It seems that I have very little distributor play side to side, but much more up and down (quarter inch maybe). Should there be any up and down play at all? As I said, I can't get dwell or tach readings at all lately for some reason and it sounds like that is because of the cam (worn or wobble). If you know of any other reasons, let me know so I can investigate. I want to go back an check the point gap again to see if it is near .016 and check the timing again to see if it is still looking good at 3500 rpms (looking at dash tach) and vacuum hoses plugged.

Oh, and do you know about the felt pad (part 27 on page 66 of the Haynes book)? As I said, my appears to be missing. Maybe that has some impact on the rotor?

Alfred1 · 05-25-2005, 09:41 PM

Does anyone know the telephone number for John Larson's shop. I bet John could help him out.

Dave at Pelican Parts · Dave at Pelican Parts's Garage

I bet you could find it on Yellowpages.com , or whowhere.com. West Coast Garage, in Santa Maria CA.

The felt pad is down inside the distributor shaft. You can see it if you pull the rotor off the shaft and look down in there with a flashlight.

A quarter-inch of up-and-down play in the distributor shaft (note that the rotor can pull off the shaft without too much effort) is not good. Having flat cam lobes on the distributor cam is not good.

Might be time for another distributor. Having another pair of eyes, ones that have 914 experience, on the problem would probably be a good way to tell how worn out things are.

--DD