Problem with distributor bushings
Thread Starter
Melting Slicks
Joined: Mar 2008
Posts: 2,023
Likes: 6
From: Austin Tx
Problem with distributor bushings
OK, I'm rebuilding my distributor, but I've run into a problem. The bushings are in, but the shaft is too tight, and I can't find anywhere to buy a reamer.
I went by a machine shop, and they said they 'might' be able to get to it next week!
I saw a reamer on harbor freight's website, buy when I went by, they don't sell it anymore.
Does anyone know where I might be able to go to pick one up? Or anotherway to open the bushings up.
Thanks,
Mash
I went by a machine shop, and they said they 'might' be able to get to it next week!
I saw a reamer on harbor freight's website, buy when I went by, they don't sell it anymore.
Does anyone know where I might be able to go to pick one up? Or anotherway to open the bushings up.
Thanks,
Mash
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
Well, I guess that the aftermarket bushings and the aftermarket dizzy shafts are NOT made by the same shop! 
Sorry...not a laughing matter. 
How to resize the bushings depends on how small they are. If you need to remove a thousandth or two, you could make up a hand-drill fly-lap out of a small diameter shaft with a split in one end. Put some medium/fine grit abrasive paper in that split, wind it up on the shaft, stick it into the bushing and start your drill. Use back and forth motion to remove a bit of metal as evenly as possible. Not as accurate as a reamer....but if you don't have a reamer...
If the size difference is greater than a few thousandths, you need to have the bushings reamed to proper size or grind down the shaft size. Ah...modern manufacturing "quality"....
Sorry...not a laughing matter. How to resize the bushings depends on how small they are. If you need to remove a thousandth or two, you could make up a hand-drill fly-lap out of a small diameter shaft with a split in one end. Put some medium/fine grit abrasive paper in that split, wind it up on the shaft, stick it into the bushing and start your drill. Use back and forth motion to remove a bit of metal as evenly as possible. Not as accurate as a reamer....but if you don't have a reamer...If the size difference is greater than a few thousandths, you need to have the bushings reamed to proper size or grind down the shaft size. Ah...modern manufacturing "quality"....
Melting Slicks
Joined: Nov 2001
Posts: 2,668
Likes: 43
From: Eastern US XX
Well, I guess that the aftermarket bushings and the aftermarket dizzy shafts are NOT made by the same shop! Sorry...not a laughing matter. How to resize the bushings depends on how small they are. If you need to remove a thousandth or two, you could make up a hand-drill fly-lap out of a small diameter shaft with a split in one end. Put some medium/fine grit abrasive paper in that split, wind it up on the shaft, stick it into the bushing and start your drill. Use back and forth motion to remove a bit of metal as evenly as possible. Not as accurate as a reamer....but if you don't have a reamer...
If the size difference is greater than a few thousandths, you need to have the bushings reamed to proper size or grind down the shaft size. Ah...modern manufacturing "quality"....
Sorry...not a laughing matter. How to resize the bushings depends on how small they are. If you need to remove a thousandth or two, you could make up a hand-drill fly-lap out of a small diameter shaft with a split in one end. Put some medium/fine grit abrasive paper in that split, wind it up on the shaft, stick it into the bushing and start your drill. Use back and forth motion to remove a bit of metal as evenly as possible. Not as accurate as a reamer....but if you don't have a reamer...If the size difference is greater than a few thousandths, you need to have the bushings reamed to proper size or grind down the shaft size. Ah...modern manufacturing "quality"....
Tech Contributor
Joined: Aug 1999
Posts: 14,373
Likes: 6,371
From: At my Bar drinking and wrenching in Lafayette Colorado
I've installed several hundred of these bushings, and the problem is usually not in the size of the bushings - it's in the installed alignment.
If the bushings slid nicely onto the shaft before you installed them, chances are that your upper bushing is not installed in perfect alignment to the lower bushing. You can test this by inserting the lower end of the shaft up into the lower bushing and verify that it fits, and then inserting the lower end of the shaft into just the upper bushing to verify the fit. If the fit is good, you have an alignment issue.
The lower bushing will almost always go in straight. The upper bushing, however, can easily "****" a little in the distributor housing when you pound it in - it only takes a very slight misalignment to cause a problem. To fix this, you need an old, scrap mainshaft. Stick the shaft down through the top bushing until it hits the top edge of the lower bushing - using a flashlight, and rotating the shaft, you should be able to easily see the misalignment direction. With the scrap shaft sticking out of the upper bushing, use the shaft as a lever arm and give it a few good whacks with a heavy deadblow plastic hammer. This will **** the upper bushing back into the desired alignment. It will usually take a few trial and error hits to get the alignment perfect, but it will work.
I have made myself an upper bushing installation tool from an old shaft with a special machined top end. This allows me to slip the upper bushing onto the shaft, stick the shaft all the way through the distributor and into the lower bushing, and then use the aligned shaft to hammer the bushing into place while aligned on the shaft. This assures that the 2 bushings are in-line without the need to do any align reaming after assembly.
Lars
If the bushings slid nicely onto the shaft before you installed them, chances are that your upper bushing is not installed in perfect alignment to the lower bushing. You can test this by inserting the lower end of the shaft up into the lower bushing and verify that it fits, and then inserting the lower end of the shaft into just the upper bushing to verify the fit. If the fit is good, you have an alignment issue.
The lower bushing will almost always go in straight. The upper bushing, however, can easily "****" a little in the distributor housing when you pound it in - it only takes a very slight misalignment to cause a problem. To fix this, you need an old, scrap mainshaft. Stick the shaft down through the top bushing until it hits the top edge of the lower bushing - using a flashlight, and rotating the shaft, you should be able to easily see the misalignment direction. With the scrap shaft sticking out of the upper bushing, use the shaft as a lever arm and give it a few good whacks with a heavy deadblow plastic hammer. This will **** the upper bushing back into the desired alignment. It will usually take a few trial and error hits to get the alignment perfect, but it will work.
I have made myself an upper bushing installation tool from an old shaft with a special machined top end. This allows me to slip the upper bushing onto the shaft, stick the shaft all the way through the distributor and into the lower bushing, and then use the aligned shaft to hammer the bushing into place while aligned on the shaft. This assures that the 2 bushings are in-line without the need to do any align reaming after assembly.
Lars
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,851
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
One issue with distributors that might also need to be addressed is the center line bore issue. I've only seen this three times in my life, but twice in the past six months. This is where the center line of the bore is slightly different from top to bottom. Try telling a customer that the distributor he's been running for thirty five years has been eating up gears from a factory defect!
You can further research this problem in David Fielders article shown at the link below. It is a very informative write up and was pointed out to me by one of our customers with a center line issue late last year. Look in Section G.
http://www.masacc.org/Documents/T_%2...20Restoration%
Our installation too is similar to what Lars describes above and was made from an old shaft with a drive collar at the top. This home made tool seems work better and it is a good tip off to a center line issue when you can't pull the shaft out after the bushing is installed.
If using the bushing installation tool sold by most vendors (and us), you can run in to a problem of the bushings swedging down when installed. This sounds to me like the problem you have and the only way to resolve it would be to ream the bushings to fit. I would suggest you stick with your machine shop on this one vs. doing the ream yourself.
Willcox
You can further research this problem in David Fielders article shown at the link below. It is a very informative write up and was pointed out to me by one of our customers with a center line issue late last year. Look in Section G.
http://www.masacc.org/Documents/T_%2...20Restoration%
Our installation too is similar to what Lars describes above and was made from an old shaft with a drive collar at the top. This home made tool seems work better and it is a good tip off to a center line issue when you can't pull the shaft out after the bushing is installed.
If using the bushing installation tool sold by most vendors (and us), you can run in to a problem of the bushings swedging down when installed. This sounds to me like the problem you have and the only way to resolve it would be to ream the bushings to fit. I would suggest you stick with your machine shop on this one vs. doing the ream yourself.
Willcox
