I know points sucks. But untill I get the points to set right I see no point in changing to anything else. Everything is new except the distributer housing. But I can't not get the point gap and dwell to come together. If I close the gap(under .016) the dwell gets close to the 26-30 range. Like 25. But if I set the gap to .017 the dwell goes down to near 10! I even pulled the distributer and and sure it was on the TDC. I just need to drive to work a little longer til the new 390 is done. With Electronics!

 

Everything new but the housing? New bushings in the housing or old? If the shaft is floating around on loose bushings you'll never get the dwell and gap to agree. See if you can push the shaft straight back & forth in the housing.

Another thing overlooked is the batteries for your dwell meter, provided it isn't using the truck battery.

Pat

 

Thanks for the info. Gives a new area to look. I racked my brain all day on this. I even looked up dwell to get the scientific explanation of what it is. It said degree of time the points are closed. That made the whole problem seem worse. And should not be happening at the same time. Are points really this hard on Fords? Never had any trouble on GMs or VWs. Thats why first reaction was no problem I don't mind changing points. But was I wrong!

 

Also just checked dwell meter. It has no batterys inside? And does not have power cords to the truck? Weird. It is the simple dwell, rpm and volt check type.

 

That's normal for an analog tach-dwell-voltmeter. Just a handful of parts and a meter. I have one like that, I built it from a kit when in High School, a long, long time ago. It could be out of calibration (Capacitors or resistors inside changing value), but that's unlikely. Check it against a friends sometime just to be sure.

In addition to loose shaft bushings I mentioned, a worn points cam, vacuum advance plate, or centrifugal advance mechanism can also cause your problem. A rebuilt distributor should resolve all of those.

Oh, it ain't a Ford points thing, it's just a worn out distributor thing.

Pat

 

Since it's a short term thing, as long as it's running correctly, don't get too hung up on numbers. Set them where it runs the best.

 

Well I have tried that. Problem is when I get dwell right the idle and bottom end sucks. And with gap right it has no top end and misses bad. But today I dug a 390 out of the scrap pile. "Advantages of working in a metal yard" Only to compare shaft slop. The junker is tight as a drum. And mine has a little play. I think that must be the problem. I would have took that distributer but the housing was chipped by the claw. Just a matter of time or a trip to the parts store to get a good one.

 

Anyone have any input on distributors? I know there is a myriad of different ones, with different advance curves, total advance, etc.
Found this out when I replaced the distributor in my 69 one time. Ended up having to find a book with part numbers to get one that would work best for me.
There were ones for the smog years in CA with extreme amount of advance built in to accommodate the retarded timing used at idle, for example.Ones for cars with HP 390's. When you go to checker or autozone, they just give you a rebuilt one off the shelf, with no vehicle specific specs (or at least that is what I found.)
Probably better to just buy an accel mallory or msd, where you can easily change the curve to fit your liking.
It'll cost more, but you can use it on your project motor.

 

Thanks for the info!

 

When I first got my '68 the distributor was so warn out that I could gap it perfectly only to rotate the engine 180 degrees and get NO GAP!!

It took me longer than it _should_ have to figure out :-)

 

Put in a new distributer and now the dwell stays put. But this Holley reman. carb. is junk. Don't buy one! The back of the accl. pump hungs up on the float. And Holley won't respond to me!