Different size torque converter knob 170 vs 225?!? Are you kidding me?

Trevor B

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I struggled and failed to get this engine in. It would not mate up properly with the transmission. 1968 Barracuda originally had a 225 turning a 904 Torqueflite. The 225 is out and am putting in a 170 while the 225 is overhauled. Used the same motor mounts from the 225, same flex plate. The 170 was originally in a '68 Valiant but with a 3 speed manual transmission.

Got the engine dowel lined up on the right side, good contact, but something was in the way and I couldn't get the left side closer than about 1/2". I tried using the engine-to-bellhousing bolts to pull the two pieces together but if I did that, it felt too tight and then I couldn't spin the engine. "What could be in there?" I thought.

After many hours, I finally gave up and pulled the engine back out. The knob on the torque converter looked like it had seen battle. Then I checked the diameter of the hole on the end of the crankshaft... the 170 has a smaller hole than the 225 by what looks to be about 1/8"!

Now my back is toast, and it's drink-o'clock. Is this a problem other's have run into? Do I have to find a different torque converter for the 170?
 

C130 Chief

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Just change to a 67 or earlier converter. 68 was the change year to the large crank register. It could be that the remaining inventory of small register engines was used up in manual transmission applications, where it wouldn't matter.
 

Locomotion

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Quite some time ago a friend & I ran into that problem when we were installing a fresh 340 with an early 273 forged crank. Had division finals coming up & discovered the difference the hard way during the thrash. We got it after he ground out the register as carefully as he could. But I don't think I did well at the race.
 
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The difference isn't 170 vs. 225, it's that the torque converter nose and crankshaft counterbore were enlarged for the '68 model year.

You cannot put a '67-down torque converter (with small nose) in a '68-up transmission; you'd also have to change the input shaft and some other parts.

Sounds like the 170 you want to put in is in fact a '60-'67 engine (or at least has a '60-'67 crankshaft).
 

Trevor B

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The difference isn't 170 vs. 225, it's that the torque converter nose and crankshaft counterbore were enlarged for the '68 model year.

You cannot put a '67-down torque converter (with small nose) in a '68-up transmission; you'd also have to change the input shaft and some other parts.

Sounds like the 170 you want to put in is in fact a '60-'67 engine (or at least has a '60-'67 crankshaft).

Thank you for this information. I think you just saved me hours of searching and who knows how much money on a torque converter that wouldn't have worked anyway!

Seems like I'm out of luck with this engine, huh? I'm not going to replace the torque converter AND the transmission (or any part of it) in order to have a replacement engine to tool around in while I rebuild the 225. And there's no way I'm tearing into the 170.

Bummer.

Anyone have any creative solutions that I can afford?
 
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You're in kind of a tough spot. The only transmission that would be a drop-in and make this swap work would be '66-'67, and those are not at all common any more. The early crank counterbore can be enlarged (machined) to accept the later torque converter, but that involves an engine teardown. If you don't want to go shopping for another get-by engine, better dry-dock this car til its 225 is built.
 

Trevor B

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I made a mistake. The engine came out of a 1967 Valiant, not 1968. So the problem would have been expected if I'd thought to do more research first. Always something new...
 

5.7 hemi

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Take the tc to a machine shop and have the snout turned down. Problem solved. Now after your other engine is built, replace the tc with a new one.
 

iw378

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Well this sucks. For everyone that doesnt know, I'm the guy trevor got the 170 from. I had no idea either about the tc differences.
Give me a call Trevor
 

Killer6

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Well this sucks. For everyone that doesnt know, I'm the guy trevor got the 170 from. I had no idea either about the tc differences.
Give me a call Trevor
Oh, He's hammered by now, give'm some time to sleep it off! Lol! Hey, it happens dude...........
 

RedFish

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A custom torque convertor can be built. Years ago it was Stegalls Transmission that did this locally. J.P. Stegall was the torque convertor man around here. Those were the good ol' days.
I don't know where I would find that service today, Google I guess, call the local trans shops, etc...
On a positive note... If/when you go to put the later 225 back in, a little bushing poked into that crank makes the custom torque convertor still fit.
 
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RedFish

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You know what? I'll bet that there is a way to mount something like a plunge router to the back of the engine block and re machine the crank. A lot of rigging ( all threads and angle irons ), dial indicator, and a special cutter. Simply too much imagination on my part?
 

Trevor B

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You know what? I'll bet that there is a way to mount something like a plunge router to the back of the engine block and re machine the crank. A lot of rigging ( all threads and angle irons ), dial indicator, and a special cutter. Simply too much imagination on my part?

I'm sure there is a way but it is certainly beyond my capacity. I'll be sure to ask my machinist, though - thanks for the suggestion!

Regarding the torque converter - does anyone know the thickness of the torque converter snout? On SlantSix.org, LINK there is a series of pictures of the slant six head cut in half with a bandsaw to show the various thicknesses. Has anyone ever done this with a torque converter?
 
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The custom torque converter (splines for '68-up input shaft, nose for '67-down crank) is a sure-fire way forward, shouldn't be too costly, and as Redfish notes, it's compatible with either type of crankshaft (just add an easily, cheaply available spacer ring if using it with '68-up crank).
 

Trevor B

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Dan - do you mean that I should try to modify the existing torque converter (have it turned) or find someone to make me one? Thanks!
 
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5.7 hemi

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Take it to a machine shop and have the snout turned down.
 
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Dan - do you mean that I should try to modify the existing torque converter (have it turned) or find someone to make me one? Thanks!

Get a custom torque converter made; we know that works. AFAIK, nobody's ever tried turning down the snout on the later-type torque converter, so we don't know if there's enough metal to do so without spoiling the converter -- the people suggesting it here are guessing without knowing if it will work. if you're up for doing that experiment and taking the gamble that you'll have to buy a new converter anyhow (immediately when the machining operation breaks through metal or later when the too-thin remaining metal breaks in service) then go for that, but if you're not a gambling man, do it the way that is known to work.
 

5.7 hemi

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I'd rather spend 50-80 at the machine to get me by for now instead of big bucks for a custom built tc.
 
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I'd rather spend 50-80 at the machine to get me by for now instead of big bucks for a custom built tc.

That might be reasonable if your idea were a sure thing instead of a never-been-tried gamble...or if it were skin off your (torque conver) nose when it doesn't.
 

5.7 hemi

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Dan, I respect you and your knowledge, but either he takes a gamble on a machine shop or he waits till the 225 is rebuilt or he pays big bucks for a custom made converter. Those are the options, and given he wants to drive the car while the 225 is being rebuilt, his cheapest option is to have the snout turned down. But it's not our car and the op will make the ultimate decision.
 

Charrlie_S

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Call Dacco at 1-800-443-2226, and ask about a converter for a TF-904 with a 1.550 pilot and 27 spline. This is a "stock" style converter. They might be able to adjust for a little more then stock stall speed. They used to have them available, but I can't find the part number right now. Was priced around $100.00
 

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