Setting dwell on a 4.5

[Litton]

OK, I can believe how much I have forgotten about tunning engines. Went out and bought a bunch of stuff like tach/dwell meter, timing light, remote starter and etc. Checked the dwell and found it to be about 10 degrees so opened up the dist. figured out how to move the points.....now things are really screw up. Hooked up the dwell meter and tried to set things by rotating the engine on the starter. Nothing on the meter, now it won't run at all. Crap. Guess I have to go buy a metric feeler gage and try it the old fashioned way..

Hmmmm, wonder if I have to have the ign on to set the dwell?

While I'm at it, what should the plug gap be? The store sold me some Bosch platinum and said the gap should be .032 but the plugs in the car are bosch Super and are set to ~.040.

[Litton]

Well, at least it's running again......kinda. Set the points at ~.3mm and the new plugs at .032. Now the dwell is at ~5 and the idle rpm dropped from ~850 to 600. Guess I still don't have this dwell thing understood yet.

Still missing on one cylinder so I pulled the injector plugs until I think I found one not working. Now to pull that injecter and give it a cleaning.

[psfred]

Litton:

Gap is about 0.030" -- make sure you CLEAN the feeler gauge first, of the points will burn...

Spec for dwell (the time the points are closed in degrees) is 30. Don't forget that you must re-set the ignition timing any time the dwell changes.....

Great fun, eh? I'm going to get a Pertronix setup for mine!

Peter

[tosbt]

Litton: While you are at it consider the pertronix or the Crain, lots of posts on these two, hit your SEARCH on these. I went with the Crain and really like it.

[Tomguy]

I still have the stock transistor ignition on mine, it gives me no troubles - though I HAVE thought about switching just to prevent a breakdown if my transistor box dies.

About setting the dwell: You have the (+) and (-) terminals hooked up on the ballast resistors, before the coil, correct? And you have to have the meter set on "Dwell" and not "Tach." You can hook it up to the coil itself, but I believe the proper way is to do it before the resistors, unless you have a Bosch tester (mentioned in the maint book I have). A dwell of 5* would prevent the car from running, I would think! 30* is proper for new points. How new are your points? If you don't know, then replace them! Bad points will almost definetly cause a miss.

Once you set the dwell, you have to re-adjust the timing. I think 1* dwell difference is about 2* timing - every time I touch my dwell, my timing is off by about 5*. Yours might be WAY off! Remember, 5* ATDC with the vacuum line connected. 7* BTDC with it off (idle should raise when you pull the line, as well). If your line leaks or doesn't work - FIX IT!

[Litton]

Thanks guys. the points look like new but they sure are tricky to adjust. I did hook the dwell meter to the coil terminal as I didn't see a ballast resistor....nor come to think of it a condensor on the distributor. If I remember correctly, the last time I did points they had two screws....one to loosen and another to adjust. This one has only one screw and a sdrewdirver slot ot pry on. So, what I guess is that I set the poinst by feeler gage to ~0.3mm then reassemble, start, check dwell, disassemble, and repeat until I get to 30.....right?

Actaully, I would have popped in a breakerless if someone had them in stock but none were quickly available. Is there any big differance between Petronix and Crane? I did read another post on this topic but I left a bit confused over the electronics used for the system.

I have to go to OHIO for a few days, so I think I will order one of the systems for install after I return.

[psfred]

No condesor -- if there is one connected, remove it. The points are only a trigger switch on this distributor, there is very little current flow, and the condensor causes more trouble, not less. There was one originally, but it is almost always removed or the lead clipped for this reason.

Ballast resistors are on the fender up by the coil.

Pertronix uses a Hall Effect pickup and connects directly to the old transistor switching unit. The Crane uses an optical trigger unit and requires it's own swtiching unit. Comes with a coil, too, I believe.

Either will work fine, although I prersonally prefer the Hall effect pickup -- immune to dirt and oil where the optical can get fouled by oil.

Peter