Repositioning the distributor???
Thread Starter
Le Mans Master
Joined: Jan 2001
Posts: 6,741
Likes: 1,383
Repositioning the distributor???
I would like to rotate my distributor ~90 degrees (wiring and all that). Am I correct in understanding that I can do it in the following manner:
1. Place engine at TDC.
2. Note position of #1 Sparkplug/Distributor rotor position in reference to engine compartment.
3. Pull out distributor and reinsert in desired(rotated) position while ensuring that the rotor points to the same place in engine compartment after insertion.
4. Install distributor cap
4. Restring plug wires starting with the new #1 location.
1. Place engine at TDC.
2. Note position of #1 Sparkplug/Distributor rotor position in reference to engine compartment.
3. Pull out distributor and reinsert in desired(rotated) position while ensuring that the rotor points to the same place in engine compartment after insertion.
4. Install distributor cap
4. Restring plug wires starting with the new #1 location.
Le Mans Master
Joined: Sep 2000
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From: Westfield Indiana
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Re: Repositioning the distributor??? (biltogo)
Only thing I can think of is that he doesn't like where the vac advance is located. Can't think of any other reason than that.
Melting Slicks
Joined: Oct 2000
Posts: 3,023
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From: TEXASTEXASTEXASTEXAS TEXASTEXASTEXASTEXAS
St. Jude Contributor
Re: Repositioning the distributor??? (Captain Morgan)
That'd be my guess. I may do it myself--I get some interference with bracket for the ignition sheilding every time I try to tweak the timing on my BB.
JB
JB
Burning Brakes
Joined: Dec 2000
Posts: 1,183
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From: Des Moines Iowa
Re: Repositioning the distributor??? (carriljc)
NO!!!!!!!!!!!!!!!!!!!
You CANNOT do it the way you described!!!!!!!
The orientation of the rotor must be the same for it's relationship to the distributor housing itself, NOT the engine compartment. The distributor cap will only install one way on the distributor.
You can do it the way you describe, but you will have to add the step of removing all spark plug wires from the distributor cap and then placing them around the distributor cap in the engine firing order, beginning with your number one plug wire.
You CANNOT do it the way you described!!!!!!!
The orientation of the rotor must be the same for it's relationship to the distributor housing itself, NOT the engine compartment. The distributor cap will only install one way on the distributor.
You can do it the way you describe, but you will have to add the step of removing all spark plug wires from the distributor cap and then placing them around the distributor cap in the engine firing order, beginning with your number one plug wire.
Tech Contributor
Joined: Aug 1999
Posts: 14,379
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
Re: Repositioning the distributor??? (carriljc)
In 1969, GM issued a Service Bulletin that allowed the dealers to rotate the C3 distributors 90 degrees clockwise in order to straighten out the tach drive cable. This 90-degree rotation brought the vacuum advance control unit out from behind the distributor shielding on the passenger side instead of in front of the shielding (pointed the vacuum advance unit out towards the rear edge of the passenger side valve cover). In doing this, the distributor was NOT pulled out of the engine. The housing was simply rotated 90 degrees, and then the spark plug wires were all moved 2 positions counter-clockwise in the distributor cap, thus maintaining the same plug wire positions and rotor position relative to the engine. This was done to avoid potential "clocking" problems by actually pulling the distributor out of the engine. So you can rotate the distributor 90 degrees without pulling it out, and then simply move the plug wires 2 towers back.
[Modified by lars, 9:34 AM 5/12/2003]
[Modified by lars, 9:34 AM 5/12/2003]
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Tech Contributor
Joined: Aug 1999
Posts: 14,379
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
Re: Repositioning the distributor??? (Surfer69)
Surfer -
Just a suggestion... you might want to do the distributor rotate operation and remove that 90-degree adapter. The 90-degree unit puts just a little more torque on the distributor cross gear, and this pushes the cross gear into the side of the distributor housing with a little more force. This tends to lead to the cross gear hogging out the housing, seizing up, and stripping the gears off the mainshaft. So in the insterest of shaft life, I'd pull the 90-degree adapter and rotate the housing.
Just a suggestion... you might want to do the distributor rotate operation and remove that 90-degree adapter. The 90-degree unit puts just a little more torque on the distributor cross gear, and this pushes the cross gear into the side of the distributor housing with a little more force. This tends to lead to the cross gear hogging out the housing, seizing up, and stripping the gears off the mainshaft. So in the insterest of shaft life, I'd pull the 90-degree adapter and rotate the housing.
Tech Contributor
Joined: Aug 1999
Posts: 14,379
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
Re: Repositioning the distributor??? (Tex71BB)
Tex -
When pulling the distributor and dropping it back in, it's really easy to get it engaged 1 tooth over. When this happens, the distributor has to be clocked (rotated) differently in order to get the timing set right, and this altered rotation tends to make the vacuum advance unit interfere with the manifold or with the distributor shielding. It has no effect on performance, but the novice mechanic often struggles quite a bit with this "clocking" issue resulting from the distributor not dropping back into the same position. For this reason, GM had the mechanics not pull the distributor out for the 90-degree re-positioning. The distributor was simply rotated, and the plug wires were re-located 2 towers counter-clockwise. This also put the wires back into their same positions relative to the engine, so the wire lengths and routings did not have to be changed.
Obviously, if you know what you're doing with the distributor installation, and you understand the correct installation process, yanking and installing the distributor is no big deal, and it certrainly does not screw anything up.
[Modified by lars, 12:37 PM 5/12/2003]
When pulling the distributor and dropping it back in, it's really easy to get it engaged 1 tooth over. When this happens, the distributor has to be clocked (rotated) differently in order to get the timing set right, and this altered rotation tends to make the vacuum advance unit interfere with the manifold or with the distributor shielding. It has no effect on performance, but the novice mechanic often struggles quite a bit with this "clocking" issue resulting from the distributor not dropping back into the same position. For this reason, GM had the mechanics not pull the distributor out for the 90-degree re-positioning. The distributor was simply rotated, and the plug wires were re-located 2 towers counter-clockwise. This also put the wires back into their same positions relative to the engine, so the wire lengths and routings did not have to be changed.
Obviously, if you know what you're doing with the distributor installation, and you understand the correct installation process, yanking and installing the distributor is no big deal, and it certrainly does not screw anything up.
[Modified by lars, 12:37 PM 5/12/2003]
Thread Starter
Le Mans Master
Joined: Jan 2001
Posts: 6,741
Likes: 1,383
Re: Repositioning the distributor???
Actually I'm installing a Ram Jet 350 in my 68 and I don't have any room at the firewall(well, about 0.5"). I like the idea of rotating 90 degrees and just moving the wires though....no thought involved....I shoulda thought of that.
Thanks guys
Thanks guys
