Thanks for the link on the distributor... I think I can see how it works, and I think I have an old one in the garage back home, I should go play with it-

Yeah, a simple yes would have sufficed for the dwell meter, eh?

Andrew

Ah, but then we wouldn't have learned anything.


This is the phrase that opened my eyes.

If the dwell varies, at idle, with a points dist, it indicates a bent shaft and/or worn bushings. Even though HEI has a fixed dwell normally, a bent shaft should show up on a dwell meter, right? Wrong. This would be one of my many mistakes that the clowns are unable to find. Unlike points, changing the position of a magnetic or optical trigger will not change the dwell.

Norm

Good point.

It would have an effect though, wouldn't it? It won't change the length of time it has spark, but it will change when it has spark, right?

I am comparing it to a small engine magneto, where the flywheel has a magnet on it that acts as the trigger for the mag to fire. Air gap is important, and if the upper bearing gets worn, and there is some play, the engine will sometimes act as if there is an ignition problem, when the real cause is the play in the crank.

Maybe that is a poor correlation?

Needed some time to think this one through.


Longer spark duration should be limited to mags. Only work I've done with them, was to service the points.


More point dwell (less gap) will cause them to open later, and the spark will occur later.


With points, a larger gap lowers available voltage. I don't think that would apply to mags, as I know them.


Same with points, but it only takes a few thousandths. Don't know how much it would take with HEI. Must not be much of a problem, or we would have heard about it.

Norm

Perhaps in an auto setup the air gap is unimportant, but on a small engine it is crucial. With an improper gap, spark becomes less consistent, and weaker. But now I know there is at least one flaw in my comparison...



I agree.

My distributor and all components checked out fine.

My Vacuum gauge that I bought off ebay has arrived, and I will be picking it up tomorrow.

Sean

Picked up my Vac/pres gauge today...looks to be good quality. Thanks Brando for pointing it out on ebay.

Now I just have to figure out how exactly I use it.

Anyone feel free to tell me where I should start.

Sean

Should have advised, you to get a propane torch, also.

With the engine at idle, turn it on but do not light it. Use the tip to probe all areas where vacuum leaks can occur, including the power brake booster, and modulator. If the idle speed goes up or down, you've found one. Less messy than WD-40 or carb cleaner.

Does the idle speed change when you remove and replace the PCV valve?

Attach the vac gauge to any source of full manifold vacuum. At idle, the needle should not fluctuate.

Information only: Pressure portion is used to test your fuel pump. Directions that came with the gauge, will explain it further.

Norm

Well, I don't have a propane torch but I do have some carb cleaner. So I used that and sprayed just about everywhere I thought there was a possibi;ty of leak, but didn't locate any. I used the vac gauge and checked a few different areas, and they all showed about 18 inches. According to the instructions that came with my gauge, any figures between 15 and 22 indicates a mechanically sound engine.

That leaves the carb.

Go here and check fig. 13 at the bottom right. Power valve should be accessible by removing the top of the carb. If it has vacuum, and moves freely, its not the problem.

If it's not your carb in the illustration, or you aren't comfortable going into it, let us know. If the PV isn't the cause, I don't know where to go next.

Norm

Ok, thanks anyway.
I may have to just take it into the dealer and get them to look at it.

But you are sooooo close to being done! You can do this, if you have been able to do the other steps-

JMHO

Andrew

Well, I'll have a look at how difficult it will be to get the top of the carb off.

Should I replace the old gasket that I would remove?

I would. It could leak.

Not if it comes off intact.

If it does tear, you could make a replacement from some cardboard that's the same thickness. If not, you'll need to buy the whole kit in order to get a replacement.

Norm