Distributor shaft bushing

kopeck · Nov 19, 2013

I know there's a lot of talk about replacing the bushing to remove shaft play but how do you do it?

Are there any special tools required? I have the distributor close to being broken down on my BN and it does need a new bushing. Seemed like a good cold weather project to tackle this winter.

Thanks,

K

TractormanNC · Nov 19, 2013

Press the old one out and press the new one in if you can find one. They were still available a few years ago, don't know if they still are.

Janicholson · Nov 19, 2013

If not IH, McMasters Carr, or Motion Industries will provide. Jim

D Slater · Nov 19, 2013

Unless they quit furnishing the bushing its number 373577R91 at the dealer. Thinking the last time I checked around $40 to $50.
Most times you won't need to size the bushing after installation if you use a shaft .4910 diameter with a shoulder the same size as the bushing OD.

Anonymous-0 · Nov 19, 2013

We used a valve g bushing ,I think the od was the write sice the id made to fit the shaft. the guid cam from the m parts.

the tractor vet · Nov 19, 2013

Ah we just did the Dist. on our 706 and we had to make the bushing for it , could not get them . even tryed getting a new dist , ah yea that went well also . On the first try the machinest made the bushing to tight and did not cut the oil groove in the bottom bushing and that did not turn out well as it seized up the shaft and twisted off the oil pump shaft . I was not a happy camper because i had just put a new oil pump in a month before the dist. And plus the fact he just used bushing bronze not OIL LITE bronze Now that he knows how to do this we can do it again . NOW as to getting the old ones out , them puppys are really in there .

Owen Aaland · Nov 19, 2013

The distributor bushings are not listed with the distributors in the tractor parts manuals. For the 4 cylinder engines the bushings are listed at the end of the listing for the distributor parts break down in the engines books. I don't think I have ever seen a listing for the bushing for the six cylinder distributor. Was it ever available as a separate part?

kopeck · Nov 20, 2013

This sounds like a bit more work then I was expecting!

Now I see why rebuilds are $200 dollars plus, especially when you start with a $50 bushing.

I'll check to see if the part is still available.

I guess the other option is to go electronic ignition, correct me if I'm wrong but with the points out of the picture the shaft wobble is no longer an issue?

Thanks,

K

Janicholson · Nov 20, 2013

Not true.in most cases it can have maybe .001 to.002" play, but not much more. Jim

kopeck · Nov 20, 2013

(quoted from post at 12:21:59 11/20/13) Not true.in most cases it can have maybe .001 to.002" play, but not much more. Jim

You mean it can have .001 to .002 of play and still be fine with points?

I'm quite sure I'm past that, it's noticeable.

K

Janicholson · Nov 20, 2013

The electronic ignition systems have a required clearance between the sensor and the spinning trigger wheel. Some are close (.004") and some are greater. Use the net to determine what the spec is for the system you choose. At some level of wear, the rotor begins to touch the terminal points in the cap. When you check the real looseness of your shaft/bushing, be sure to measure in more than one orientation. Some wear egg shaped patterns. Points will not provide good accurate timing if the wear is more than .001" Jim

kopeck · Nov 20, 2013

(quoted from post at 17:26:40 11/20/13) The electronic ignition systems have a required clearance between the sensor and the spinning trigger wheel. Some are close (.004") and some are greater. Use the net to determine what the spec is for the system you choose. At some level of wear, the rotor begins to touch the terminal points in the cap. When you check the real looseness of your shaft/bushing, be sure to measure in more than one orientation. Some wear egg shaped patterns. Points will not provide good accurate timing if the wear is more than .001" Jim

Looking over the Pertronix site I don't see any specs. I guess that it would be a band aid, then again it could be a band aid and a upgrade all in one.

Then again I like things to be right.

Decisions...

K

Janicholson · Nov 20, 2013

I found specs on line indicating .010" to .075". This is quite abundant, and seems to imply it can be used with a bad bushing. However variable gap caused by wobbly cam also causes inaccurate timing due to variability of the moment the sensor triggers, as the magnet wheel changes its axis. Jim

kopeck · Nov 20, 2013

(quoted from post at 19:48:49 11/20/13) I found specs on line indicating .010" to .075". This is quite abundant, and seems to imply it can be used with a bad bushing. However variable gap caused by wobbly cam also causes inaccurate timing due to variability of the moment the sensor triggers, as the magnet wheel changes its axis. Jim

Holy Cow! .075" would absolutely flopping around!

Mines not that bad, I'll get my dial indicator out and see if I can't get a better idea.

I'm usually pretty good at turning up those sort of things, I guess I wasn't asking google the right question. Thank you for doing the leg work.

K

D Slater · Nov 20, 2013

Don't know where you are checking play at, but be aware you can also get play between the point cam and the distributor shaft. Cam shaft has 2 bushings in it and slides over the upper end of the distributor shaft.

kopeck · Nov 20, 2013

(quoted from post at 20:29:30 11/20/13) Don't know where you are checking play at, but be aware you can also get play between the point cam and the distributor shaft. Cam shaft has 2 bushings in it and slides over the upper end of the distributor shaft.

You know, that's a good point, I haven't removed the cam yet, it's not completely broken down yet.

If that's where the wear is then that would make things easier if those parts are still available.

The primary reason I'm breaking this thing down is the advance doesn't seem to be working quite right. That might be some what related to cam play.

K

Janicholson · Nov 21, 2013

My number is for positioning the sensor, not allowable slop. Jim

kopeck · Nov 22, 2013

(quoted from post at 12:08:48 11/21/13) My number is for positioning the sensor, not allowable slop. Jim

Gotcha,

I took the whole thing apart and the slop isn't in the shaft but the cam. It's also not quite as bad as I thought.

The good news is everything looks pretty good in side, not sure why I was having trouble with advance. I'm going to clean everything up and put it back together.

I might try a new set of point and see where that gets me. The electronic ignition fascinates me. I didn't see a lot of reviews on the bigger Farmalls but it seem there's a whole pile of cub owners out there that swear by them.

K

Distributor shaft bushing

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