Timing changes when I tight distributor

[moper]

Two things to check would be the base of the shaft perhaps bottoming in the slot of the drive, and pull the oil pump drive and see what condition the bushing for that is in. S0me distributors used an O ring so a gasket may not be needed, or it might... Regardless the tang should not bottom in the slot.

 

[HALIFAXHOPS]

Here I am,! I would definitely pull the oil pump drive out and look at the gear and also the bushing it rotates in 20 is a ton to advance, cannot even think of why except the drive gear or possibly the mechanical stuck open?. I have no clue what happened to that bushing surprised it did not grenade in there, they are really brittle after 50 years. I just toss them and have a steel one I put on in place of them, do not use the ones with the set screw two reasons one they can loosen up and two it blocks oil from getting up into the bottom of the distributor.

 

[70Bronco]

Yeah - I think mine reads a little higher when tightened. Seems it's always a bit more than I intended so I have to loosen it and pull a little out.

Thanks. That's what I'm learning here. I'm accustomed to working with a small block ford & didn't have this particular issue. Not a complaint--every engine is different and I'm new to a MOPAR big block (361).

 

[66Satellite47]

The slot in the oil pump drive is the likely cause. Check that and replace the drive. They do wear. Take a good look at the distributor and see if the tip still is a square slot. I've never seen a badly worn piece, but take a good look.

 

[70Bronco]

Here I am,! I would definitely pull the oil pump drive out and look at the gear and also the bushing it rotates in 20 is a ton to advance, cannot even think of why except the drive gear or possibly the mechanical stuck open?. I have no clue what happened to that bushing surprised it did not grenade in there, they are really brittle after 50 years. I just toss them and have a steel one I put on in place of them, do not use the ones with the set screw two reasons one they can loosen up and two it blocks oil from getting up into the bottom of the distributor.

Is this the bushing you're suggesting? https://www.summitracing.com/parts/dur-ad-584
I've seen brass, but none of them have a pin going through them like mine does. Does that get disregarded? Do I need a special took to install a brass or steel bushing?

 

[66Satellite47]

That bushing is pressed into the block no pin. There is a bushing on the distributer shaft that I think folks are talking about that is pinned. The bronze bushing in the block is much better than the aluminum.

 

[HALIFAXHOPS]

Those are tower bushings for the oil pump drive. The ones I have are for the bottom of the distributor. I would definitely check that shaft and the distributor bushings it should have around .002 side play. All the plastic oem bushings come new ith one 1/8" hole drilled in it, you have to drill it out on the shaft, none are ever straight through. I have the metal ones with a pin and a few shims if needed, you knever know until you place it on, if needed I ask $10 shipped.

 

[HALIFAXHOPS]

If needed I probably have a distributor. What year, engine, 4bbl or 2 bbl and also is it a AT or MT?

 

[70Bronco]

Those are tower bushings for the oil pump drive. The ones I have are for the bottom of the distributor. I would definitely check that shaft and the distributor bushings it should have around .002 side play. All the plastic oem bushings come new ith one 1/8" hole drilled in it, you have to drill it out on the shaft, none are ever straight through. I have the metal ones with a pin and a few shims if needed, you knever know until you place it on, if needed I ask $10 shipped.

Cool. Tomorrow, I'll pull it and get a better idea what's going on. It runs good and holds time pretty well, occasionally bouncing a degree or so. It's a points unit. 1966 Plymouth Belvedere 361.

 

[Darthomas]

Thanks for pointing out it's points.
The gap is too small, making opening critical.
I just went through this 3 weeks ago on my 66.
Got to get it to 14-17 thousandths.
Then it won't be quite so touchy about being clamped down.

Also, the gap changes as the vacuum advance pivots the plate the points ride on, and THAT changes timing.
In cases where the points are barely opening, you can have really freaky surging or no-starts.

Shouldn't be much play in the dist bushings side to side or up-n-down.
Up-n-down easily fixed with a washer or 2 under the nylon bushing.

 

[HALIFAXHOPS]

I have had some weak points springs and they do some weird stuff, mostly point float though. lets see what he finds.

 

[70Bronco]

The shaft and the nylon bushing (spacer) are both tight--no play in either one. The lack of a gasket could be a problem as the dizzy won't quite go all the way down when pressing it in by hand. I will get one.

I don't see where anything would have rubbed the nylon bushing. Maybe that happened when somebody was working with it on a bench. What does it do exactly? I can't see where anything would touch it.

Is there a brass bushing missing at the gear in the block?

 

[PP1RT]

Get all that grit cleaned up around the hole too

 

[HALIFAXHOPS]

That nylon bushing just holds the shaft in position to the case. fix it before it grenades, no idea what happened to it.

 

[HALIFAXHOPS]

The bras bushing is under that oil pump gear.

 

[70Bronco]

That nylon bushing just holds the shaft in position to the case. fix it before it grenades, no idea what happened to it.

Will do. I'm thinking replace that and put in a gasket between the block and dizzy and see how it goes.
Anything else that looks out of whack?
Mine has an oiler fill cap that's not staying closed, but I don't know how critical that is.

 

[HALIFAXHOPS]

Not critical, put a piece of something in it to keep grit out though.

 

[miller]

The lack of a gasket could be a problem as the dizzy won't quite go all the way down when pressing it in by hand.

Something that might be worth looking at. Pull the oil pump/distributor drive gear, and look at the bearing it goes into. Has a lip on the top side...make sure it's bottomed out. If it's up any, it will hold the drive gear up, too.
There's no reason, if the parts are right, the distributor shouldn't bottom out, with a little clearance.
Distributor housing...some take an o-ring, in a cut groove. If none, yeah, takes a gasket.

 

[HALIFAXHOPS]

you have to watch those o rings also some are really thick and hold the dist up a bit also should just slide in pretty easily.

 

[HALIFAXHOPS]

Looks like in the pic yours uses a gasket.