Set Dwell and Tach and Points Gap
To help you to understand a few things I will start the lesson with part 1. LOL
No really here goes.
When people refer to a Tach and Dwell meter, it is a tool for measuring 2 things
The first is the Tach portion - which measure engine rpm.
The second part of the meter checks the dwell (which is adjusted according to the space in between the points. This space is referred to as Gap.
I hope you are ticked, I'm just trying to help.
For your motor the Gap depends on motor cubic inches.
For a 170 or 200 cubes the gap is .027 with a dwell of 35-40 at idle.
for a 250 cube, the Gap is .025 with a dwell of 37-42.
If unsure of the motor size, I would Gap the points to .025 and you will be very close.
That is the end of part 1. Now on the part 2 - Setting the points.
First several comments:
A. - When changing points it si a good idea to change the rotor, condensor and points together. The rotor sits just under the cap and has a brass pointer. The condensor looks like a little can about 1 inch long with a single wire.
Now for setting the points. I will go on theassumption that for now you are just setting the points. If you are infact replacing, it requires removing 2 screws that hold the points and if replacing the condensor, it has a screw as well. SPECIAL NOTE - -When tightening the screws even for adjustment, just use finger pressure to tighten. You can strip the hole pretty easy if you overtighten.
Here are the steps for adjusting the points
1. - Put car in neutral/ apply e-brake - even block the tire
2. - Remove key from ignition
3. - Remove distributor cap. The cap has 2 springs on opposite sides. You place a screw driver blade between the cap and the clips and pop the clips off. (They will be attached at bottom so don't worry.
4. - Lift cap and turn it out of the way.
5. - Inside the cap remaining in the distributor you should see the rotor. May be black in color and have a brass tip. This part lifts off. It is made to only go on in one position.
6. - Now look at the distributor shaft and you will see the rubbing block. (SEe pic)
7. - Grab fan and rotate the motor. You may have to apply light pressure to the belt if it slips and the motor doesn't move. You want to get the pointer of the points at a high spot on the rubbing block.
8. - Loosen the 2 screws that hold the points and adjust the "Gap" between the 2 contacts of the points.
9. - The gap is best set using a "Feeler Guage"
10. You really should use a feeler gage available from parts stores for about $3-$4.00 .
There is a little trick to keep in mind. When you gap the points and a tightening the screws, don't use to much force because you could strip the holes and also you could change the Gap.
I am attaching a picture of a the inside of a dizzy but I think it is an 8 cylinder if i recall. Your's will be very simillar.
After setting points - reassemble (Don't foget the rotor and be sure it sits all the way down (Look for the groove in the shaft.
In the picture - -A points to rubbing block or lobes
B points to where you adjust the space (Gap) of points
C. - is the condensor.
Screws E and H need to be loosened to adjust the gap. I try to just lightly loosen screw E and loosen screw H more. Kinda use E as a base and use the H screw to allow more movement of the points. When you look at the base of the points near the contact area (B) you will see a notch that allows you to pull or push the contact area open or closed.
I think you'll be OK but ofr now..... Class Ends... LOL
If any trouble just post...... Print DAd
Last edited by Print Dad; 12-29-2009 at 01:15 AM.
Reason: Forgot picture