Engine/Transmission Mismatch

[65 Dartman]

i’ve got a nearly assembled 66 273/235 Motor that has the early small converter register. And I’ve got a performance rebuilt 904 by Proformance Transmission (a subsidiary of Dynamic Converters). To go with that transmission I’ve Got a brand new Dynamic performance converter with the larger snout. I need to mate the two together.

I figure my choices are disassemble the motor and swap the crank for one with the large pocket (which I have) OR disassemble the motor and have the pocket machined to accept the large snout converter OR to pull the transmission pump and swap for a pre-67 (which I’d have to find) OR send the converter back to Dynamic and hope they have a now near impossible to find small register front for the converter - that would be the easier IF they can do it. Any thoughts on what to do?

 

[Plymouth 65]

Hey Dartman, changing the torque converter is the most straight forward solution. The issue will be availability of higher stall converters with the small register. If it just stock, it's not a big deal. If you decide to change to the small input shaft and pump in the transmission you will also need to change the clutch housing. If you decide to go that route let me know, I have everything you need! 65'

 

[Locomotion]

Couldn't the converter snout be machined down without changing/cutting the converter apart?

 

[brian6pac]

If they can't put the convertor in a lathe and turn down the nose I would find another convertor Co.

 

[65 Dartman]

If they can't put the convertor in a lathe and turn down the nose I would find another convertor Co.

It's an 8 or 9 inch converter from Dynamic. I tried to call and talk with them about it but they are on vacation and won't be back till next Monday

 

[brian6pac]

It would be easier for them to turn it down than replace it with the smaller size.

 

[AJ/FormS]

Is there enough meat in the snout to do that?

 

[Locomotion]

I'm under the impression that it's a solid piece.

 

[AJ/FormS]

So it's like a metal puck,I guess. I've never had a TC apart, so have no idea.

 

[Locomotion]

I'm not 100% sure, but it seems like it would be soild. Only concern I can see is if the machining takes too much of the weld off. But hopefully someone will be able to confirm or refute my theory.

 

[brian6pac]

I don't think it goes that far into the crank, If you look at any convertor it only has about a 1/4" spot that fits the diameter of the crank the rest is undercut.

 

[65 Dartman]

Here is the converter in question:

 

[65 Dartman]

And here is the crank in question. Yes, it’s drilled for a pilot bearing as the motor came out of a 4 speed 66 Barracuda

 

[brian6pac]

How much of a difference is there, crank looks pretty rusty take some sandpaper to it and then measure it with a caliper if you have one.

 

[65 Dartman]

Although it appears the motor might be on the floor, it’s still on the stand. My camera focuses pretty good for getting a closeup between the part holding the motor and the motor. If I take it off the stand I could get a better idea and easy to measure.

 

[65 Dartman]

I was able to get a Caliper into the crank pocket and came up with 1.70 inches in diameter. The converter snout measures 1.80 inches. I’ll have to see what Dynamic says when they reopen Monday.

 

[Plymouth 65]

Hey Dartman, what stall is that converter? Dynamic builds a nice converter but they are not cheap! 65'

 

[65 Dartman]

I'd have to find my paperwork - no it wasn't cheap!

 

[lkopaska]

Early crank pilot measurements are 1.550 ( - 1966)
Late crank pilot measurements are 1.810. ( 1967 up)
Unfortunately the pilot can't be machined that far due to fact that the pilot is hollow for the input shaft.
Check your input shaft spline count early trans 18 .
Late shaft 27. If you have late trans and early crank a special convertor will need to be built, most companies have no problem doing this .
With the dimension you listed on crank I would clean it out really good and remeasure it.
Good luck Lon:

 

[65 Dartman]

To bring closure to this thread I called Dynamic this morning and talked to the main tech - Sean Wiley I believe was his name. He did not recommend turning the nose hub as it would make it too thin and cause problems with the bushing that's inside the nose. As I suspected, his recommendation was to pull the crank and let the machine shop enlarge the pocket. He then brought up another point based on the converter - by the part number it was built and assembled to go behind a mildly modified 340 and I would be less than pleased with it's performance behind a stock 273/235 Commando motor. His recommendation was if I did the crank would be to send the converter back and they would rework it to use behind the 273. So I have these options to think about as well as go with a 4 speed since the crank already has the bushing or go with a 5 speed T5, Dakota or Colorado 5 speed conversion as detailed in another thread.

 

[Marcohotrod]

I would take a metal removal tool to the inside of the crank area and then remeasure. no way would removing a maximum of .050" radially make the hub too thin . a good machinist could do that in 25 minutes. how much $$$ for another unit, I would try the 1 u have. reread lkopasta post

 

[Killer6]

This has been done to death on the Slanty forum & over at .org, and cutting the converter hub has been tried,....don't. It's possible to cut the hub register in the crank O/S
to accept the larger later converter, and has been done w/o problem, there is no real radial stress there once everything is installed and torqued down, it ensures the crank
& converter are in axial alignment. There are a couple, but not many, who will build hybrid converters....basically a late unit w/a small hub-nose.....but they sound like they
are less and less fond of bothering to do it.