273 Pilot Bushing/Bearing Problem / Fix

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"Dart67"

"Dart67"

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I ran into this problem when I went to drive in the standard National PB 286 bronze pilot bushing.
View attachment BronzePilotBushing.jpg

I also tried using the Dakota National FC 69907 Pilot Bearing.
View attachment DakotaPilotBearing.jpg

Neither one would work due to the crank register.

The crank is from a 1965 273 4bbl engine that "had" a 904 automatic bolted to it.

The pilot bushing hole in the crank is a unfinished bore and the large hole has a 45* chamfer instead of a square sholder for the dakota bearing to seat in. See photo below.

My solution was to measure the inside diameter of the large crank register hole which was 1.544".
Then chuck the dakota bearing up in my metal lathe and turn it to 1.549 so that when driven into the crank it will be a snug fit.
I also cut a small 45* chamfer on the back side of the bearing so that it would seat against the crank hub.
I drilled and tapped three 10 x 24 holes evenly spaced on the diameter of the bearing so that I can thread long machine screws into them to push the bearing from the hole in the future for replacement.


View attachment Crankpilot.jpg

View attachment PilotDrilledTappedChamfered.jpg

I then made a driver tool that will work for either the bronze busing orn the dakota bearing.

View attachment PilotDriver.jpg

The tool is made from a scrape piece of 3/4" steel shaft and a 3/4"
washer welded square on the shaft.

Here is the modified bearing installed in the crank hub.
I used a little loctite blue around the outside diamter and the back side of the bearing when I tapped it in place.

View attachment PilotInstalled.jpg

Here is the how the bearing is removed from the hub. Tighten each screw a turn or two at at a time to push the bearing out.

View attachment PilotRemovalScrews.jpg


Herb
 
That 3/4-1 INA SCE bearing is the same one that's in a T&D rocker....Nice job. I heard you could pack grease into the pilot and hammer a input ahft in there and it would pop out the brass bushing hydraulically? I like your method better.
 
Just FYI here, but there's TWO different bushings for Chrysler engines. One is the standard size and one is .030 smaller....NAPA has them. I believe the Smaller one is called the "Conversion" bushing.


Rule of thumb, if the car was an automatic and your going 4-speed, you will most likely need the conversion bushing...This is NOT always the case though, but if you find one bushing doesn't fit, try the other one.
 
I am aware of the smaller bushing.

None of the NAPA stores I checked with could find a current listing for it or said it was discontinued and unavailable.

Herb
 
Just now reading this, and I have the same problem with my 1965 273. Summit has the conversion bushings now I think. I was googling pilot bushings and I saw a picture of one of those conversion bushings, and I clicked on it and it brought me to Summit. By the way, my clutch kit that came from rockauto came with both bushings in the box.
 
Don't know about 273, or other SB, but be careful of the DEPTH as well. This is a problem I ran into "in the seventies" with a 440 / was automatic. I pulled the crank and had it drilled.

Many "back then" advocated chopping 3/8 or so off the 4 speed shaft, which I did not want to do
 
If it didnt work, I could imagine the shot of grease coming out the hole under a 5lb sledge whack.
 
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