Distributor off 1 tooth?
Thread Starter
Instructor
Joined: Sep 2012
Posts: 107
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From: memphis tennessee
Distributor off 1 tooth?
So the vacuum advance is hitting the shielding/coil and I have no way of advance the timing any more. I have the timing set to 8 dbtdc and it does great there. The book calls for 10 degrees. I'm reading its off 1 tooth and it needs to be rotated 180 degrees. Is that right? Is there a simple procedure taking out the dizzy and put it in correct without going through all the procedures I'm reading from Lars's page? Never removed a distributor. L-79 with pertronix. Thanks
Race Director
Joined: Jan 2003
Posts: 17,721
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From: Central Arkansas
Actually the usual procedure is to pull the distributor, drive the roll pin out that holds the gear to the shaft bottom, turn the gear 180 degrees on the shaft and re-install the drive pin.
I would first pull the cap and rotate the engine until the rotor is pointing at something you can put a mark or tape on to mark it's position. Also note or mark the relative position of the distributor housing although it will change somewhat after rotating the gear. Then disconnect the wire lead, remove the clamp and bolt and pull the distributor straight up. Note that the rotor will rotate as you pull it up due to the gears. When reinstalling you have to allow for this and start with the rotor rotated so that as it drops in place the rotor will rotate back around to your mark.
You will need to re-time the engine and you are done.
I would first pull the cap and rotate the engine until the rotor is pointing at something you can put a mark or tape on to mark it's position. Also note or mark the relative position of the distributor housing although it will change somewhat after rotating the gear. Then disconnect the wire lead, remove the clamp and bolt and pull the distributor straight up. Note that the rotor will rotate as you pull it up due to the gears. When reinstalling you have to allow for this and start with the rotor rotated so that as it drops in place the rotor will rotate back around to your mark.
You will need to re-time the engine and you are done.
Race Director
Joined: May 2006
Posts: 15,554
Likes: 555
From: Eagle, Idaho
So the vacuum advance is hitting the shielding/coil and I have no way of advance the timing any more. I have the timing set to 8 dbtdc and it does great there. The book calls for 10 degrees. I'm reading its off 1 tooth and it needs to be rotated 180 degrees. Is that right? Is there a simple procedure taking out the dizzy and put it in correct without going through all the procedures I'm reading from Lars's page? Never removed a distributor. L-79 with pertronix. Thanks
Least complicated way would be to move all the plug wires one hole left or right if you aren't concerned about the number 1 wire being in the correct location.
Race Director
Joined: Apr 2015
Posts: 17,571
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From: Fresno California
The first thing to do is to actually verify if the dizzy is off one tooth. You need to find TDC and see where the rotor is actually pointing. And then go from there. If off, you can pull the distributor up slightly after the hold down is removed, and rotate it and re-seat it. Sometimes, you need to turn the oil pump shaft with a long flat blade screwdriver so that the dizzy will seat in the right position. No need to pull the gear off, IMO.
Pro
Joined: Aug 2013
Posts: 633
Likes: 36
From: Cincinnati Ohio
Actually the usual procedure is to pull the distributor, drive the roll pin out that holds the gear to the shaft bottom, turn the gear 180 degrees on the shaft and re-install the drive pin.
I would first pull the cap and rotate the engine until the rotor is pointing at something you can put a mark or tape on to mark it's position. Also note or mark the relative position of the distributor housing although it will change somewhat after rotating the gear. Then disconnect the wire lead, remove the clamp and bolt and pull the distributor straight up. Note that the rotor will rotate as you pull it up due to the gears. When reinstalling you have to allow for this and start with the rotor rotated so that as it drops in place the rotor will rotate back around to your mark.
You will need to re-time the engine and you are done.
I would first pull the cap and rotate the engine until the rotor is pointing at something you can put a mark or tape on to mark it's position. Also note or mark the relative position of the distributor housing although it will change somewhat after rotating the gear. Then disconnect the wire lead, remove the clamp and bolt and pull the distributor straight up. Note that the rotor will rotate as you pull it up due to the gears. When reinstalling you have to allow for this and start with the rotor rotated so that as it drops in place the rotor will rotate back around to your mark.
You will need to re-time the engine and you are done.
Race Director
Joined: May 2006
Posts: 15,554
Likes: 555
From: Eagle, Idaho
Actually the usual procedure is to pull the distributor, drive the roll pin out that holds the gear to the shaft bottom, turn the gear 180 degrees on the shaft and re-install the drive pin.
I would first pull the cap and rotate the engine until the rotor is pointing at something you can put a mark or tape on to mark it's position. Also note or mark the relative position of the distributor housing although it will change somewhat after rotating the gear. Then disconnect the wire lead, remove the clamp and bolt and pull the distributor straight up. Note that the rotor will rotate as you pull it up due to the gears. When reinstalling you have to allow for this and start with the rotor rotated so that as it drops in place the rotor will rotate back around to your mark.
You will need to re-time the engine and you are done.
I would first pull the cap and rotate the engine until the rotor is pointing at something you can put a mark or tape on to mark it's position. Also note or mark the relative position of the distributor housing although it will change somewhat after rotating the gear. Then disconnect the wire lead, remove the clamp and bolt and pull the distributor straight up. Note that the rotor will rotate as you pull it up due to the gears. When reinstalling you have to allow for this and start with the rotor rotated so that as it drops in place the rotor will rotate back around to your mark.
You will need to re-time the engine and you are done.
This is an example from an AMC distributor.
Le Mans Master
Joined: Aug 2005
Posts: 6,545
Likes: 1,977
From: Temple Terrace Florida
Dist.
There is no need to line up the oil pump with the distributor. Once you are comfortable with where the distributor is to be set, bump the starter and the distributor will fall into place once the oil pump lines up. Now you are ready for your timing light. Jerry
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Michael S. Palmer
Team Owner
Joined: Mar 2003
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From: Greenville, Indiana
That is a true statement if the OP has a GM ground camshaft. Not necessarily true if the OP has some aftermarket camshaft.
Team Owner
Joined: Mar 2003
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From: Greenville, Indiana
You are bursting lots of bubbles here. Many here are scared to death to try this.
Race Director
Joined: Apr 2015
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From: Fresno California
Including myself. Much safer in my experience to simply position the op shaft manually. Easily done and nothing gets sheared or broken. Thanks for the vote of confidence, Mike. BTW, I am running aftermarket cams in 2 out of 3 performance cars. Better safe than sorry, IMO.........
Race Director
Joined: May 2006
Posts: 15,554
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From: Eagle, Idaho
Since he says he's going by the "book" it's a good idea to start with all components set up according to the "book", rather than starting out dismantling instead of adjusting.
Race Director
Joined: May 2006
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From: Eagle, Idaho
Exactly. Chasing the oil pump with a screwdriver is a waste of time.
Team Owner
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
Including myself. Much safer in my experience to simply position the op shaft manually. Easily done and nothing gets sheared or broken. Thanks for the vote of confidence, Mike. BTW, I am running aftermarket cams in 2 out of 3 performance cars. Better safe than sorry, IMO.........
The OP said he can't get enough advance, yet his distributor hits the coil and he can't ADVANCE it anymore because of that. That means he's trying to RETARD the timing.
Don't know why he think the distributor is 180* out either. If his cap is wired right, the vacuum nipple is pointing at at the right rear inboard valve cover bolt, he is probably not a tooth off, he is probably off on the distributor gear and half turn. That's why I mentioned the aftermarket cams. It's well known they are not indexed on the distributor gear to the GM print in every case.
I have no idea how many distributors I've installed in a V8 Chevy over the years. Has to be a 100 times. I've never sheared anything nor have I ever had a problem. Never fiddle faddled with that screwdriver deal, it's not necessary but if that's the way you like to do it, it works, just takes longer.
I think the first SBC distributor I dropped was in 1957 and I didn't use a screwdriver then or now.
Drifting
Joined: Jul 2005
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From: Putnam Valley, New York. Amateur Radio Operator K2NS
Race Director
Joined: Jan 2003
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From: Central Arkansas
I may have made a bad assumption in my #2 post - his mention of rotating the distributor 180 degrees led me to think that he had read up somewhere about the orientation of the distributor gear to the distributor shaft - and he confused the issue of rotating the gear 180 degrees on the shaft to slightly change the rotor orientation and allow advancing the distributor further - with rotating the distributor 180 degrees. I believe this is about the same as a 1/2 tooth change.
Simply pulling the distributor and moving it one tooth is easier and may be a better fix if that much additional rotation is needed.
Simply pulling the distributor and moving it one tooth is easier and may be a better fix if that much additional rotation is needed.
Team Owner
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
..his mention of rotating the distributor 180 degrees led me to think that he had read up somewhere about the orientation of the distributor gear to the distributor shaft - and he confused the issue of rotating the gear 180 degrees on the shaft to slightly change the rotor orientation and allow advancing the distributor further - with rotating the distributor 180 degrees. I believe this is about the same as a 1/2 tooth change.
Simply pulling the distributor and moving it one tooth is easier and may be a better fix if that much additional rotation is needed.
Sounds to me like he needs to move the gear but not enough info yet to say that.
Instructor
Joined: Oct 2013
Posts: 122
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From: morgantwn wv
Hi guys
Samething happened me so here's how I fixed. Bring the motor to tdc. Next I take a straight edge and lay it on top of the dist. wires and aligned it through the #1 plug wire and the center coil wire. Standing on my toes I looked down the edge and made a mark straight down on the dist. body. That's the position where the rotor should point at tdc. on compression stroke. Remove the dist. cap and if the rotor points to the rear of the car you need to turn the engine once more 180 degrees. The rotor should point near #1 marked on the dist. body that you made. Look to see if it points before or after that mark. Mine just happened to point slightly before so I needed to turn the dist. body clockwise so it would point dead on the mark. Now carefully and slowly lift the dist. up. The rotor will turn counter clockwise. You will feel it come loose. Not far up maybe 1/2". Now I slowly turned the body clockwise stepping it about 1/64th" at a time. It will drop down over the next gear. With very light downward pressure on the dist. click the starter and the dist. will drop all the way down to the stop. You are changed 1 tooth...no screw driver needed.
Good luck.
Samething happened me so here's how I fixed. Bring the motor to tdc. Next I take a straight edge and lay it on top of the dist. wires and aligned it through the #1 plug wire and the center coil wire. Standing on my toes I looked down the edge and made a mark straight down on the dist. body. That's the position where the rotor should point at tdc. on compression stroke. Remove the dist. cap and if the rotor points to the rear of the car you need to turn the engine once more 180 degrees. The rotor should point near #1 marked on the dist. body that you made. Look to see if it points before or after that mark. Mine just happened to point slightly before so I needed to turn the dist. body clockwise so it would point dead on the mark. Now carefully and slowly lift the dist. up. The rotor will turn counter clockwise. You will feel it come loose. Not far up maybe 1/2". Now I slowly turned the body clockwise stepping it about 1/64th" at a time. It will drop down over the next gear. With very light downward pressure on the dist. click the starter and the dist. will drop all the way down to the stop. You are changed 1 tooth...no screw driver needed.
Good luck.
Last edited by chuckaroo; Oct 1, 2015 at 09:24 PM.
Pro
Joined: May 2012
Posts: 707
Likes: 45
From: Portland Oregon
BTW if your plug wires are indexed correctly the #1 plug wire should be in the first tower clockwise from the window for the points
Randy