Locked out distributor advance question

Dave Muller · 05-12-2019, 09:34 AM

I recently locked out the advance in my distributor. I took the car out for testing with my backup engine last night and while the engine has some issues, the distributor worked out fine, and I had no trouble cranking when hot. But the timing did wander back and forth a couple of degrees, and when I put it in I could feel the rotor moving back and forth just a little.

I'm pulling the distributor out anyway to swap back to my good engine now and I'm thinking of putting a little tack weld between the plates to prevent any movement at all. There's no electronics in this, just the magnetic pickup. I don't think that would be bothered by one second of arc.

What do you guys think, good idea, bad idea? Any drawbacks other than the obvious increased difficulty in restoring centrifugal advance later on?

Dragsinger · 05-12-2019, 09:41 AM

Dave,

another option is to drill through both the fixed and movable plate and install a roll pin. Doing so gives the option to go both ways.

Hacksaw · 05-12-2019, 09:54 AM

That's a good suggestion by Larry. If you decide to put a small shot of weld on instead, take out the pick up and cover the sensitive areas with tin shield or pull out the shaft. Always place your ground cable as close to the weld area as possible and put the weld where it could easily be removed with a thin grinder wheel.

gmonde · 05-12-2019, 09:59 AM

the timing wander could also be caused by the timing chain and or the gear lash on the cam/distributor

Dave Muller · 05-12-2019, 10:26 AM

Quote:

Originally Posted by gmonde

the timing wander could also be caused by the timing chain and or the gear lash on the cam/distributor

Before I installed it I held the gear in one hand and the rotor in the other. I could feel a little back and forth movement in it.

ss3011 · 05-12-2019, 03:17 PM

Two things come to mind . First , if you tack weld the plates ,t will be very hard to index the distributor cap . It would be better to drill a hole through both plates then file a slot in one , so you can move the reluctor around to get the timing and the cap index correct . Second is to shim the shaft to get minimum endplay on the gear .

Alan Nyhus · 05-12-2019, 05:32 PM

MSD distributor?

Dave Muller · 05-12-2019, 06:19 PM

Quote:

Originally Posted by Alan Nyhus

MSD distributor?

No, It's a Summit brand, whoever they got it from.

Dave Muller · 05-12-2019, 07:07 PM

I'll know more tomorrow morning when the distributor comes out, but my plan at the moment is to remove the gear, pull up enough to be able to slip in one or more flat washers as needed to take up the gap, then reassemble. With the right thickness of washers it should hold the plates together firmly when I tighten down on the nut.

Totally reversible too.

Alan Nyhus · 05-13-2019, 08:36 AM

Quote:

Originally Posted by Dave Muller

No, It's a Summit brand, whoever they got it from.

The MSD units are known for not having enough threaded section on the little pin that locks the plates together. A flat or locking washer behind the nut takes care of it.

Something to check, anyway. -Al

05-12-2019, 09:34 AM	#1
Dave Muller Member Join Date: Apr 2014 Location: Mesa, AZ Posts: 497 Likes: 162 Liked 223 Times in 73 Posts	Locked out distributor advance question I recently locked out the advance in my distributor. I took the car out for testing with my backup engine last night and while the engine has some issues, the distributor worked out fine, and I had no trouble cranking when hot. But the timing did wander back and forth a couple of degrees, and when I put it in I could feel the rotor moving back and forth just a little. I'm pulling the distributor out anyway to swap back to my good engine now and I'm thinking of putting a little tack weld between the plates to prevent any movement at all. There's no electronics in this, just the magnetic pickup. I don't think that would be bothered by one second of arc. What do you guys think, good idea, bad idea? Any drawbacks other than the obvious increased difficulty in restoring centrifugal advance later on?

05-12-2019, 09:41 AM	#2
Dragsinger VIP Member Join Date: Jul 2008 Location: Liberty City [East Texas] Posts: 1,760 Likes: 5 Liked 99 Times in 60 Posts	Re: Locked out distributor advance question Dave, another option is to drill through both the fixed and movable plate and install a roll pin. Doing so gives the option to go both ways. __________________ Larry Woodfin 471W

05-12-2019, 09:54 AM	#3
Hacksaw Senior Member Join Date: Sep 2016 Posts: 882 Likes: 206 Liked 310 Times in 174 Posts	Re: Locked out distributor advance question That's a good suggestion by Larry. If you decide to put a small shot of weld on instead, take out the pick up and cover the sensitive areas with tin shield or pull out the shaft. Always place your ground cable as close to the weld area as possible and put the weld where it could easily be removed with a thin grinder wheel.

05-12-2019, 09:59 AM	#4
gmonde Senior Member Join Date: Nov 2007 Posts: 615 Likes: 56 Liked 165 Times in 59 Posts	Re: Locked out distributor advance question the timing wander could also be caused by the timing chain and or the gear lash on the cam/distributor

05-12-2019, 03:17 PM	#6
ss3011 Senior Member Join Date: Feb 2002 Location: Southeast Michigan Posts: 909 Likes: 70 Liked 239 Times in 114 Posts	Re: Locked out distributor advance question Two things come to mind . First , if you tack weld the plates ,t will be very hard to index the distributor cap . It would be better to drill a hole through both plates then file a slot in one , so you can move the reluctor around to get the timing and the cap index correct . Second is to shim the shaft to get minimum endplay on the gear .

05-12-2019, 05:32 PM	#7
Alan Nyhus VIP Member Join Date: Dec 2002 Location: Lower Dakota territory Posts: 1,180 Likes: 1,074 Liked 799 Times in 236 Posts	Re: Locked out distributor advance question MSD distributor? __________________ "That'll never work....."

05-12-2019, 07:07 PM	#9
Dave Muller Member Join Date: Apr 2014 Location: Mesa, AZ Posts: 497 Likes: 162 Liked 223 Times in 73 Posts	Re: Locked out distributor advance question I'll know more tomorrow morning when the distributor comes out, but my plan at the moment is to remove the gear, pull up enough to be able to slip in one or more flat washers as needed to take up the gap, then reassemble. With the right thickness of washers it should hold the plates together firmly when I tighten down on the nut. Totally reversible too.