Moving Distributor over one tooth the easy way

[Gary C.]

I am sure someone here can help me. I have a 427 that is probably off by one tooth on the distributor. The timing is 10deg BTDC at idle and cannot be retarded any more because the vac advance can is hitting the radio shielding (the distributor body is turned as far clockwise as is possible).

I have done this type of procedure many times but always seem to muck my way through it until I finally hit it just right, and it always takes me much longer than I think it should.

So my question is "does anyone have a step by step, idiot proof procedure for turning my distributor back one tooth?"

Thanks in advance and Merry Christmas.

Gary

[Roy B.]

Re: Moving Distributor over one tooth the easy way

Remove Dist use a long screw driver and just a little move the oil pump rod to the right then reinstall Dist

[Michael H.]

Re: Moving Distributor over one tooth the easy way

You sure you wanna go to the right, clockwise, with that shaft?

[Mike McKown]

I believe you want to go counter clockwise

with the distributor body to retard the timing. Many recommend using a screwdriver to fish the oil pump shaft around so the distributor will drop all the way down when it's installed. At this stage, and especially since you're having trouble, I'd pull that distributor up REAL EASY, turning the rotor as you go. You'll feel it kick off the camshaft gear. As soon as it does, let it drop back down. It may not drop on the pump shaft but that doesn't matter. All it takes is a bump of the starter and it will fall down by it's own weight, usually. In any case, it won't jump time and you won't lose your reference point.

I've done the screwdrive trick on new engines, assembled on the stand. That's the only place I see the advantage.

If you don't like this way you can go the long route, start over, put the rotor just before #1 with the engine on TDC, align the oil pump shaft, drop the distributor all the way in, turn the distributor to #1. Get your test light out...................... Ah, never mind. I coulda' already had it done and be ten miles down the road the other way.

[mike cobine]

Re: Moving Distributor over one tooth the easy way

When I actually move the distributor, I pull the cap off first. Then I lift the distributor just enough to clear the teeth on the cam gear, and move it using the rotor. You should be able to feel the teeth on the teeth so you know when you moved one tooth.

When you drop it back in, it won't go all the way since the pump shaft is now wrong. Hand turn or bump the engine over and the ditributor will fall back in that last 1/4 inch or so.

Put the cap on snug the hold down clamp, and set the timing.

However, I have frequently bubba-ized it by simply moving the plug wires around one spot. Simpler, quicker, faster, and usually with better results.

[Verne Frantz]

Re: Moving Distributor over one tooth the easy way

You can walk the rotor tip around clockwise (along with the oil pump shaft alignment) until the rotor tip points in the direction you want it by this method.
First, bounce the motor until the timing mark is somewhere near where you want it on #1 compression stroke. Take off the distributor cap, hold onto the body of the distributor and turn the rotor clockwise against the mechanical advance stops then lift the distributor housing up slowly until it's disconnected from the cam and pump shaft. While you are lifting it, the rotor will want to turn, but keep holding it clockwise as far as it will go (excessive pressure is not necessary). Release the turning pressure on the rotor and nest it back in place and the rotor will be pointing one tooth further clockwise than it was and the distributor will find it's home on the pump shaft notch. Keep doing that until it's pointing in the direction you want #1 to be. If you miss it, you can keep doing that and take it all the way around and try again.
Now turn on the ignition and use a test light to position the body of the distributor so the points "just" open. (don't twist the rotor when you're doing this)! Now put the cap back on and plug in #1 wire so it lines up with the rotor. Switch the rest of the wires in the firing order on the cap, start the engine and set the timing with a light.

Hope this helps. I've done it MANY times.

Verne

[Joel A.]

Re: Moving Distributor over one tooth the easy way

The EASY way? Move the wires over one notch!

sorry...I couldn't help myself!

Have a safe and Happy Holiday, ya'll!!!

[Larry M.]

Re: Moving Distributor over one tooth the easy way

Gary:

Are you sure that moving the distributor over by one tooth will give you the clearance that you need, or will it be too much and cause interference on the other side? Since the distributor has 13 teeth, moving it one tooth will change things by approximately 27-28 distributor degrees, which is a lot.

A lot has been written in the archives regarding distributor interference and the need to reverse the position of the distributor bottom gear to provide a ONE- HALF tooth difference, or 13.8 degrees. This may be what you need to do.

The distributor gear has a mark or dimple that should normally be aligned with the distributor rotor tip. Sometimes this gear position gets reversed during a motor overhaul or distributor rebuild, causing the type of interference you described.

Obviously, reversing the distributor gear requires pulling the distributor. The archives has a procedure for doing this. Let me know if you cannot find it.

Merry Christmas to you and the family. Regards, Larry

[Phil P.]

Re: Moving Distributor over one tooth the easy way

excellent description you gave ---i call pick and drop, motor heads know---if i get carried away and miss my mark i go 180 with the rotor and save some time---i have had alignment problems with after market cams and hei dist.---critical in first gen camaros to clear firewall---but eventually get it done---merry christmas

[Duke W.]

Re: Moving Distributor over one tooth the easy way

Bubba lives!

Set the damper notch on the proper initial timing mark BTC #1. Pull a plug and verify compression on #1 as you approach TDC to verify if you have ANY doubt.

Pull the dist. and verify that the dimple is pointed in the same direction as the rotor tip, assuming you have an OE cam.

Get out your CSM and verify that the plugs are indexed properly.

Install the dist and rotate the housing until the points just open then back a hair. If TI rotate the housing until the rotating pole piece tips are just past (CW) of the stationary pole piece tips.

On a C1 or C2 SB the VAC should be about half way between the interference points and the cap window should be near normal the the engine longitudinal axis. I think it's the same for a midyear BB.

The above is called: "Doing it by the book". You can do it this way or bubba's way until you get something that sort of works. Your choice.

Merry Christmas!

Duke

[Verne Frantz]

Duke......You have mail!!! *NM*

[Duke W.]

Often times...

...you have to look beyond the actual question to find the root cause of the problem. In this case, as Larry Mulder pointed out, there is likely more to this story than given, and merely moving the distributor one tooth will probably not solve the problem because then the VAC will be at the other interference point.

The symptom is typical of the drive gear being indexed 180 degrees out from the correct orientation, and correcting the gear indexing and verifying that the plug wires are properly indexed IAW the applicable service manual and reinstalling the distributor per my instructions will move the distributor housing one half a tooth, back to approximately the centerpoint of the rotational freedom limits at the correct initial timing.

If I had a buck for every screwed up distributor installation I've seen., I'd be living in luxury. The problem often starts because the drive gear is indexed improperly upon distributor assembly in the field. It's still happening today because no shop manual mentions this critical assembly detail. It's only on the distributor assembly drawings. Or like me, you figure it out as I did over 40 years ago.

Many times the "bubba fix" is moving the wires. That won't work either, and now you have a real mess on your hands, and you will never sort it out.

That's why whenever this question comes up, and it's come up a zillion times, I quote the "back to basics, by the book" way to install the distributor after providing the system knowledge about verifying proper gear indexing.

If you follow the instructions as written you cannot go wrong.

Duke