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Cut Off 4 Speed Input Shaft?

zslacker

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I bought a very solid 68 Sport Satellite, taken apart in 1987 then put in a shed. 4 speed car built with a 383 that is gone but it came with the original rebuilt transmission and a very well built 440, I think 1975 (5 T 440 E). The crank bore measures about 1 3/4" from the top of the rim on the end of the crankshaft to the bottom of the crank bore. I ordered a Timken FC69907.1 bearing. I will have the machine shop cut and chamfer the shaft. There is much online about this process but not much about results. I would like to know if anyone that has cut the input shaft and driven the vehicle has had any issues and any suggestions they may have.
Thanks

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I did this 25 years ago in my driveway with a 4spd going into a 383 with a non-drilled crankshaft. I had to cut off about 1/2" off the tip of the 4spd so it would bolt up to the motor. This was back before application specific bearings were available for this so i took my measurements and went down to a local industrial bearing supply house and searched through their catalogs until I found a bearing that would work.
 
Did it to mine, no problems at all. I had measured mine like you did, and it "should" have fit, but didn't. I asked Brewers, he gave me the procedure on how to correctly measure and cut. So give him a shout, I followed his instructions and it worked perfectly first time. (I only had to lop off about 1/4")
 
I've never done this before, so excuse me if i'm wrong but couldn't you take a mag base drill and drill the crank
that 1/2" deeper? I'm a retired Machinist and wonder if that would be achieveable? I just hate cutting an input
shaft! Ouch.
 
It’s a good way to go. I did it couple years ago, no problems.
 
If your bellhousing came with the engine from factory your all set. If not you should check alignment. A dail indicater like makes it easier with magnetic base.
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I'm not sure that drill has the ability to drill a hole that precise, you would have to put some force on the drill to get into that crank but thats why I'm asking about this process.
 
Did it to mine, no problems at all. I had measured mine like you did, and it "should" have fit, but didn't. I asked Brewers, he gave me the procedure on how to correctly measure and cut. So give him a shout, I followed his instructions and it worked perfectly first time. (I only had to lop off about 1/4")
I read that bolting up the transmission to the engine is a pretty good way to determine how much needs to go but if Brewers has a better solution I will use that
 
I read that bolting up the transmission to the engine is a pretty good way to determine how much needs to go but if Brewers has a better solution I will use that
That's what he told me to do, except just use the bellhousing, not the trans. I can't find the email, it's from a dead account. And I used the same bearing
 
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I'm not sure that drill has the ability to drill a hole that precise, you would have to put some force on the drill to get into that crank but thats why I'm asking about this process.
That's why he suggested a Mag drill... A Mag drill is sort of a drill press with a big electro-magnet on the base, get it close, flip a switch and the magnet locks the drill in place, you can bump it around to precisely align it & go to town.....

That said I've also cut input shafts without an issue... Don't need a machine shop, a 4" grinder with a cut-off wheel will have it cut in a minute... Then swap out to a 80 grit sanding disc to chamfer the shaft...
 
I'd rather fire up the ol' black and decker and hog out the crank with a 3/4" drill bit for clearance to use the timkin roller bearing in the converter hole than cut the end off of a perfectly good 833 input shaft, but that's just me. The hole doesn't have to be precise, it just has to clear the input shaft.
If the input shaft is already chewed up then by all means hack away, it will take all of about 45 seconds to slice it and put a chamfer on it with an angle grinder and cut off wheel.
I've drilled out the back of a cast crank before while still in the car with a drill and a dull bit, on my back with hot shavings landing on me, trust me it isn't pleasant but that's the way I would go.

Take this advice with a grain of salt, I've been told that there is something wrong with me by multiple people and that i'm a glutton for punishment.
 
Caution, if you drill the crank too deep it's possible to break into an oil passage.
There is a Brewer's drawing out there which believe is shorter on the 2.225" depth than what I came up with on an auto crank I have.
The hole depth is plenty deep but the bushing diameter is unfinished..........

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A mag drill can do the job but I think I'd bolt a stout plate across the block to attach it to.

IMO, if you go to the bearing make sure you dial in the bell.
 
Yes, this isn't texas you're not drilling for oil, just enough clearance for the input shaft.
 
Yep: I remember the Dodge dealer installing a 4 speed behind a 440 in a truck and hitting oil in the crankshaft as well.
I used to think all those 4 speeds swapped into Chevies were junk with their cut inputs, I wish I could go back and buy them all now.
The last stroker Hemi I put together didn't have the pilot drilled deep enough. I left the bellhousing on the engine made the measurement with a caliper and loped off the input about 1/4" as well. Easy peasy. I zipcut mine and dressed it with a hand grinder, 5 minute job after measuring.
 
Caution, if you drill the crank too deep it's possible to break into an oil passage.
There is a Brewer's drawing out there which believe is shorter on the 2.225" depth than what I came up with on an auto crank I have.
The hole depth is plenty deep but the bushing diameter is unfinished..........

View attachment 1446380

A mag drill can do the job but I think I'd bolt a stout plate across the block to attach it to.

IMO, if you go to the bearing make sure you dial in the bell.
Yep: I remember the Dodge dealer installing a 4 speed behind a 440 in a truck and hitting oil in the crankshaft as well.
I used to think all those 4 speeds swapped into Chevies were junk with their cut inputs, I wish I could go back and buy them all now.
The last stroker Hemi I put together didn't have the pilot drilled deep enough. I left the bellhousing on the engine made the measurement with a caliper and loped off the input about 1/4" as well. Easy peasy. I zipcut mine and dressed it with a hand grinder, 5 minute job after measuring.
This is the easiest way. You are getting some complicated advice about drilling the crank that isn’t necessary and might ruin your crankshaft.

I gave you the short version of my story, here’s the long version.

I swapped my car from 318 auto to 413 4 speed in about 1985. Believe it or not, seems like parts were harder to find then (no internet.)

The hole in the 413 crank was drilled but not finished. It was not only undersized but ran out about .015” IIRC. I made an eccentric bushing on a lathe, but still only got it to run within about.007”
I installed it and ran it like that until 2020.
I had a couple of transmissions in and out multiple times over the years for road / track use.

When I rebuilt the motor in 2020 I had two issues I wanted to address in this area:
1. a high rpm vibration, that I believe was caused buy the bearing runout, since the clutch disk runs on that shaft.
2. Since this was an automatic car and all of my parts came from who knows where, I could barely get the trans in and out. I had to remove the upper tail shaft bolts and grind a little groove in the bellhousing for clearance. In other words the trans is a little too long.

So buy cutting a bit off the shaft (I’d have to go through my notes to see how much) it definitely helps no 2.

I indicated the snout hole in the crank at .001”, much better than the bushing hole. The vibration is gone so I’m calling no 1 fixed as well (this is subjective since it was a slight vibration .)
 
Back in the day, NAPA through their BALKAMP line had the undersize, on the od, bushing for that. I remember seeing the listing for it when I worked at a store in the early 90's. No clue if you can still get. Some others have mentioned using the bearing for the 92-02 magnum 3.9/5.2/5.9 engines as a fix too. Uses the t/c register hole instead of the much smaller bushing hole.
 
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