Four speed input shaft troubles

[Scott Kiger]

I have been dicking with this thing for almost a week. It’s the numbers matching original engine and transmission to the car. The original bell housing too. I know that because one of the dowels had pulled out of the block and was still in the bell housing. The engine came in pieces though but the crank was still bagged fresh from the machine shop. Assembled the engine and everything was good. I decided to put a pilot bearing in instead of a bushing. Went to put it together and I will be damned if it stayed off about 3/8” and would not bolt up. I backed up and pulled the bellhousing off and made sure it bolted to the transmission. Yep. Pulled the pressure plate and clutch and did some measuring. Son of a bitch. It’s drilled, but not drilled deep enough. It measured 1.781 deep roughly. Supposed to be 2.25”. Evidently the crankshaft was trashed and they swapped it out. I should have checked everything. But just glancing at it looked obviously drilled for a four speed. You live and you learn I guess. Still sucks. Posting pics of the diagrams Wayne at Brewers provided for me to double check things by. I figure others may could use these as well. I sprayed dry graphite on the input so you can plainly see where it was stopping.

 

[Dutchrebuild]

That sucks

 

[dadsbee]

Get out the cut wheel..

 

[davek]

Well at least the engine is not already in the car. 1 step forward 2 steps back

 

[Daliant]

Bust out the drill and hog out that crank. The hole doesn't need to be precise, just large enough and deep enough to clear the input shaft.

 

[R413]

No input shaft trouble, drill that crank out. That's how it's done. Don't cut the input shaft.

 

[493 Mike]

Rent a mag drill and stick it on the flywheel.
Mike

 

[PurpleBeeper]

I ran into this 30 yrs ago with the engine already in the car. I cut 1/2” off the nose of the transmission & put a slight bevel on the end. It’s been working for 30 yrs. I was afraid of throwing the balance of the motor off. The shop that did the crank said “we were afraid of drilling into an oil passage in the crank” (when I asked them later).

 

[moparwacko]

Since it's out of the car, rent a mag drill and set the depth. I've done this before. It is much more difficult once it's in the car.
Edit:

Oops, didn't see the post about the mag drill earlier.

 

[gdrill]

No mag drill required. Patience. Mag if you want, it wont hurt, just not necessary.

 

[R413]

I ran into this 30 yrs ago with the engine already in the car. I cut 1/2” off the nose of the transmission & put a slight bevel on the end. It’s been working for 30 yrs. I was afraid of throwing the balance of the motor off. The shop that did the crank said “we were afraid of drilling into an oil passage in the crank” (when I asked them later).

You,won't drill into oil, the cranks are made to drill out the end for a 4 speed.

Off balance. You are drilling on the crank centerline, anything off center will be such a minuscule amount it won't matter. Plus the hole is partially drilled already. So even less material coming off. Drill baby drill!

 

[rmchrgr]

No input shaft trouble, drill that crank out. That's how it's done. Don't cut the input shaft.

If the crank is forged, it is hardened and is a BITCH to drill out. You need a specialized drill bit or you will be there for a month. Cut the input shaft as needed, chamfer the end and move on.

I've cut at least 1/2" off an input shaft and drove the trans thousands of miles without issue. The tip of the shaft does nothing, especially the part that sticks out into the crank beyond the bushing or pilot bearing. There only needs to be enough material to ride on the bearing. Just go a little at a time until it fits.

The blue marking is what needed to be trimmed on this trans. Don't worry, it was nice and straight when finished but again it doesn't matter. Again, the only thing relevant is that there is enough material to cover the circumference of the shaft. Anything beyond that is along for the ride.

 

[RemCharger]

If the crank is forged, it is hardened and is a BITCH to drill out. You need a specialized drill bit or you will be there for a month. Cut the input shaft as needed, chamfer the end and move on.

I've cut at least 1/2" off an input shaft and drove the trans thousands of miles without issue. The tip of the shaft does nothing, especially the part that sticks out into the crank beyond the bushing or pilot bearing. There only needs to be enough material to ride on the bearing. Just go a little at a time until it fits.

The blue marking is what needed to be trimmed on this trans. Don't worry, it was nice and straight when finished but again it doesn't matter. Again, the only thing relevant is that there is enough material to cover the circumference of the shaft. Anything beyond that is along for the ride.
View attachment 1816231

If someone could post a video of hand drilling out a crank at home ,I'd enjoy watching it. I wimped out and chopped the 1/2" off.
Can always buy a new input shaft.

 

[rmchrgr]

If someone could post a video of hand drilling out a crank at home ,I'd enjoy watching it. I wimped out and chopped the 1/2" off.
Can always buy a new input shaft.

LOL. Exactly. I wouldn't call it wimping out - it's just coming to the realization that there is a better method.

Before cutting the input shaft I showed in my earlier post, I tried to drill out the crank register but threw in the towel after about 20 min. of getting nowhere and destroying a couple drill bits in the process. BTDT.

 

[dadsbee]

The OP is running a bearing anyhow... cut it and forget it.

 

[493 Mike]

If someone could post a video of hand drilling out a crank at home ,I'd enjoy watching it. I wimped out and chopped the 1/2" off.
Can always buy a new input shaft.

Or a crankshaft!
Mike

 

[R413]

Use the correct drill bit, correct speed, cutting fluid, no problem. Do what you will.

 

[RemCharger]

Well they did drill them from factory so it can't be that hard. Pun intended.