Checking Dwell - User Error I am Sure.

[Gary J.]

[Tom K.]

[Gary J.]

Re: Checking Dwell - User Error I am Sure.

Clarifications, points ingnition standard from factory, no required power to tester from battery and I was able to read volts when I rotated the dial. No dwell reading.

[Bill S.]

Re: Checking Dwell - User Error I am Sure.

Been a while but connect the red lead from the analyzer to the positive side of the coil and the black lead of the analyzer to the negative side of the coil. Select 8 cylinder on the front of the analyzer.

[Dan A.]

Re: Checking Dwell - User Error I am Sure.

Gary,
From what I recall (always dangerous) the black lead goes to a ground source and the red goes to the negative lead on the coil.

[Mark E.]

Re: Checking Dwell - User Error I am Sure.

How many leads does this thing have? Most tach/dwell meters I have seen use three leads:

Red: +12v source (on your car, the junction block on the horn relay is handy)
Black: Ground
3rd lead (often Green): Neg (-) post on coil

This will also enable the meter's tach.

Check dwell with engine running; adjust as needed while running using an allen wrench on points adjustment screw accessed through distributor cap window.

[Larry M.]

Re: Checking Dwell - User Error I am Sure.

I have the exact same analyzer. Red connection to coil negative (-) and black lead to a good engine ground. Analyzer master knob on Position 6 (DWELL). THEN....... you also have to adjust the dwell/rpm baseline by clicking the correct toggle switch to calibrate....... and adjust the pointer/needle adjustment screw with a small screwdriver to read the 4/8 engine cylinder baseline. Then let the toggle switch go to its preset position and read the correct dwell.

Make sure you are on the correct master switch setting, as it gets a bit tricky in the # 4-6 position range. Also check you HI and LO RPM and see if you get a reading (Positions 4 and 5).

You already said you installed new batteries and that the analyzer/meter was correctly reading on the voltage scale?? If so, it should be working, but each function has it's own internal circuit. The Dwell circuit could be bad...........but if so, I would suspect the same for RPM.

Larry

EDIT: Position 7 is for point resistance. Make sure you have not selected this position when trying to read dwell.

[Gary J.]

Re: Checking Dwell - User Error I am Sure.

Thank you all, I give it a try again tomorrow and advise. Appreciate all the feedback. Gary

[Gary J.]

[Joe R.]

Re: Checking Dwell - User Error I am Sure.

If you forgot to disconnect the vacuum advance before checking the timing with a timing light, it would be normal for the timing mark to be off the tab. And, setting the timing to an indicated 10 degrees with the vacuum advance connected would lead to severely retarded timing and poor idle characteristics. Since you imply that that the idle is good at 750 rpm, you probably remembered to disconnect the vacuum advance before setting the initial timing. I just thought I should mention this, since it wasn't clear from your post,

[Gary J.]

Re: Checking Dwell - User Error I am Sure.

Joe, I did remember to disconnect the vacuum line before checking/setting the timing. I do appreciate the reminder. I just installed the heat riser butterfly below the exhaust manifold, for some reason they had replaced it with a spacer. Still having poor cold idling issues but I think it is a choke adjustment. The carb butterfly opens but it does not appear to go to the high idle step. Thanks, Gary

[Joe R.]

Re: Checking Dwell - User Error I am Sure.

Joe, I did remember to disconnect the vacuum line before checking/setting the timing. I do appreciate the reminder. I just installed the heat riser butterfly below the exhaust manifold, for some reason they had replaced it with a spacer. Still having poor cold idling issues but I think it is a choke adjustment. The carb butterfly opens but it does not appear to go to the high idle step. Thanks, Gary

Hi Gary:

It sounds like you did everything right for setting up your dwell and initial timing.

Regarding the heat riser valve, many people replace that with a spacer in an effort to keep the carb a bit cooler. Today's gas seems to boil at a lower temperature than gas from the 1960s, so reducing or eliminating the heating effects of the exhaust crossover can help prevent problems during hot weather driving.

I made this change in my otherwise stock 327-300, and never noticed much difference in how long it took the engine to smooth out after a cold weather start. However, given that I don't drive the car in the dead of winter, a "cold weather start" is typically never below 30 degrees. If I was trying to start the car at -10 degrees, the benefit of the heat riser valve might have been more noticeable.

The 383 that I now have in the car has aftermarket heads that have no heat riser passage at all. It still seems to do okay with cold starts at 30 degrees.

So, you may find that better behavior in very hot weather is worth the tradeoff of slightly worse behavior for cold starts in cold weather.