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Re: Clamp to stop distributor from hopping
[Re: 360view]
#1595759
03/24/14 05:00 PM
03/24/14 05:00 PM
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Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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Real world advancing/retarding wouldn't happen since the dizzy ain't doing the triggering but rotor phasing (distance from rotor edge to cap terminal edge) could be affected in other words if the arc distance was borderline close to being further than what the available voltage could handle & the "hopping" shifted the rotor just beyond that distance then it could/would misfire. I would check/correct rotor phasing & I redrilled the reluctor just like Andy did way back with his machined reluctors & if you're good you're set. The hopping would be the worst when getting on or off the gas when accelleration (or decell) tightens up the clearances (or relaxes em) in the other direction however required voltage is the greatest at WOT (greatest cyl psi) & available voltage decreases as RPM increases (less time for coil saturation between firings). EDIT an Echlin MO 3000 rotor at your NAPA dealer ($8 & change out the door, NAPA ain't cheap) has a .060" longer blade & will reduce the radial air gap & help with phasing problems & is way easier than redrilling the reluctor
Last edited by RapidRobert; 03/26/14 11:17 AM.
live every 24 hour block of time like it's your last day on earth
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Re: Clamp to stop distributor from hopping
[Re: 64dartsb]
#1595760
03/25/14 01:28 PM
03/25/14 01:28 PM
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Joined: Mar 2008
Posts: 5,746
Ontario, Canada
Dodgem
master
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master
Joined: Mar 2008
Posts: 5,746
Ontario, Canada
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If there is (and almost always there is) a gap between the bottom of the slot on distributor shaft and the depth of the slot hole in the distributor/oil pump drive gear the the gear can bounce or move up and down that amount. Now as the gear moves up and down it turns back and forth which advances and retards the timing the more gap the more it advances and retards. Remember as you install the gear you turn gear down in it turns as it goes in and has to be turned opposite way to gear gear back up and out. this action if not controlled by the collar happens all the time if it's a bounce will be seen as timing bouncing all over if it is more smooth as mine was as load was applied timing would retard and go back as load was removed. found mine was retarding about 5 degrees under load so after installing the collar did not move and picked up 1.5 tenths in the 1/4 mile! :-) I had seen these on Hughes engines and thought some day I'll spend a minute and get my head around how it can help. so late one night after going to bed started to run it through my mind. then realized the direction my dizzy spins and visualized installing the gear that it would want to turn and climb under load. Built a shaft stop collar the next day and problem solved e-mailed all my buddy's explaining what is happening and why an now we all have the shaft collars! Thanks Dave Hughes. 
Last edited by Dodgem; 03/25/14 01:30 PM.
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Re: Clamp to stop distributor from hopping
[Re: burdar]
#1595761
03/25/14 01:37 PM
03/25/14 01:37 PM
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Joined: Mar 2008
Posts: 5,746
Ontario, Canada
Dodgem
master
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master
Joined: Mar 2008
Posts: 5,746
Ontario, Canada
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Quote:
So this collar keeps the oil pump drive gear from bouncing? The plastic collar higher up on the distributor holds the distributor shaft from bouncing. 
Yes keeps the oil pump/distributor drive from moving or bouncing up and down that little bit which in turn stabilizes the timing. 
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Re: Clamp to stop distributor from hopping
[Re: RapidRobert]
#1595762
03/25/14 05:25 PM
03/25/14 05:25 PM
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Joined: Sep 2006
Posts: 3,020
Sac, CA
mopowers
master
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master
Joined: Sep 2006
Posts: 3,020
Sac, CA
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Quote:
I ain't sure if the intergear/shaft wants to come up but what works for me is (1) to remove the roll pin/collar & add shims to reduce that axial play to .005". (2) add the aftermarket collar down below (3) then if the rotational play on the rotor is anything more than a c hair I either peen the lower tang or I have even built up the recess in the top of the intergear with weld then dremel it out for a good fit. A pain but blueprinting is never easy & all the minor details add up & keeps me on top of the chebrolet boys & maintains Mopar superiority. Next on the check list is possibly adding a shim on the top shaft under the clip to reduce that axial play and to drill/tap the outer ends of the slot plate so I can add a setscrew (one on each end)) to be able to adj total thru the vac can window & do Nacho's trick of bending the magnet so the vac adv changes the reluctor gap as little as possible (as is there is too much change) & I'm considering adding one of those 60's spouts on the side so you can add drops of oil to lube the bushings tho they do seem to get lubed somehow adequately but I do reduce the play right there at that opening where the oil vapors enter to .005" by adding shims above the OE collar/roll pin. EDIT Big blocks, yes absolutely
How much shimming is usually needed under the stock lower distributor collar? Getting ready to order up some shims...
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Re: Clamp to stop distributor from hopping
[Re: RapidRobert]
#1595764
03/26/14 12:16 AM
03/26/14 12:16 AM
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Joined: Sep 2006
Posts: 3,020
Sac, CA
mopowers
master
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master
Joined: Sep 2006
Posts: 3,020
Sac, CA
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Quote:
Quote:
How much shimming is usually needed under the stock lower distributor collar? Getting ready to order up some shims...
I'll check tomorrow (Wed) on a couple of em I have
Thanks Robert. No need to though. I just checked mine on the bench with a dial indicator. It's got .028" of play. I guess I need around .020"-.023" of shims.
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Re: Clamp to stop distributor from hopping
[Re: mopowers]
#1595765
03/26/14 12:37 AM
03/26/14 12:37 AM
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Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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If you are ordering www.speedwaymotors.com (1 mile from me) their kit has (2) ea of .010", .020", .053", $4.95 plus the ride
live every 24 hour block of time like it's your last day on earth
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