Hot Rods How to Make Engine to Tranny Adapters.

Misalignment is death on clutches and front bearings. Don't do it. Thats why they make dial indicators. I have seen brand new Lakewood bellhousings much further off that any I ever did. Way off.And the mounting face needs to be flat and parallel with the block back face also. Measure two or three times. Cut once. But go the Bonneville or a big Antique drag race. People do it all the time. Just takes time, patience, and logic.

 

You have to remember, some of the guys here are racing legends, with examples of their work in museums.

Many of the rest of us need a computer to do the math for us.

My drill press comment was not a dig. Show me one that is accurate to 0.002".

 

I didn't take offense. And yes, I know that the drill press may not be that accurate, but as RickFox just pointed out, some of the manufactured stuff (and factory parts) are pretty far off and probably couldn't conform to your 0.002"

 

That's for sure.

 

After I get everything where I want it and I have the screw in transfer punches in place, I give it a couple of wack with a big, old rawhide hammer. Then drill it a 32nd over. I drill the dowel pin holes 1/16 under. You can do this on a drill press. Put it back on the engine and dial it in again. Bolt it down tight and check the alignment. Then drill the dowel pin holes through. If I have the right sized reamer, I'll ream them. Now the dowel pin holes are true but oversized. So I make dowels to fit. I like ro use a good bolt for the raw stock. Usually I use Chrysler hemi headbbolts. Good steel and I have a lot of them. Didn't need no cad/cam. Don't have a drawing or even know the bolt hole locations. But it will be dead nuts.

 

That's why every old hot rodder I cross paths with knows who you are.

 

This is the recommended procedure for replacing the flywheel housing on older Cummins diesels. It works!

 

You got to start moving in better circles,

 

Can't learn anything about hot rods from people that don't care about hot rods.

 

See. How are you going to plot these bolt locations? Take your block to someone with a CMM? Then when he is dome you can convert that to a program for a CNC. And finally set up and start cutting. But your very hi tech. Meanwhile, I never left home or hired somebody and his machine. And mines done and on the motor.

 

Nice work!

 

I'm with you, it is possible to be accurate with out the computer, it just takes care, patience and a lot of double checking.

 

Thankfully no machining was ever done to anything before the 90's when CAD was introduced.

 

Back in the summer '69, when I was young, foolish, and indestructible, I built a D/SR for SCCA road racing with a 3 cylinder, 2 cycle, 850cc SAAB engine married to a Fiat 600 tranny. Granted this was a 700 lb with 100 hp, but it won 2 championships in 4 1/2 seasons, until it was totaled, by it's new owner.

Basically, both the SAAB and Fiat had aluminum bell housings. The Fiat imput shaft determined the total depth of the modified bell housing. Using that depth dimension, it was determined where both bells had the same outside diameter. Both bells were cut proud with a hack saw and cleaned up with an angle grinder. Don't remember if I needed a pilot bearing adapter. Stood the engine on it's nose, bolted the front part of the SAAB bell to the motor and the rear part of the Fiat bell to the tranny. Used the input shaft to align everything, indexed the two parts and had it welded together.

Never had any bearing nor clutch problems. About once every 12 race season, I would have to reweld a crack or two. This would probably work for a low stressed, trailer queen.

 

I guess there is always a possibility that a friend may own an adapter and it could be copied and/or copy drilled.
Sadly, I'm generally not that lucky.

 

The one I made to mate a T5 to my 260 was pretty simple. 3/4" Aluminum plate which made the input the proper depth. 2 holes already lined up so it was a simple matter of drilling the 4 new top holes. 2 for the countersunk allen heads to the bell housing and 2 threaded for the tranny. Also had a step machined in the big hole and a collar made to go in there and keep the piece centered or indexed in the bell housing but I might have got by without it. Then my machinist made me a pilot bushing from my old one to fit the smaller T5 snout.

 

There sure is a huge range of variations as to what constitutes a tranny adapter just looking at this array.

 

There was a very good video a guy made where he makes a prototype out of I think lucite? Or some material like that, which allowed him to mark up holes because it was translucent. Some dude on YouTube put a Honda single cam in the back of a corvair and the way he did it was really back yard style (cutting up multiple bell housings and marrying them together) but it worked well.


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I used offset dowels to get my bell housing within .003. This process works with store bought or home made parts exactly the same.



-Abone.

 

This was a 394 Olds to a Ford C4 automatic. I used a flat plate for the Olds, I can't remember what in the middle then another plate to fit the Ford. Welded it all up, machined both surfaces parallel, indicated the center hole then bolted everything together. Nothing to it. Sorry for the shitty pic.



-Abone.

 

This is how I thought it would be done

 

The GM holes were easy, print out an engineered drawing and transfer the measurements. I played heck trying to lay out the Packard holes. At one point I took my Packard bellhousing down to Kinko's and had them put it on the scanner and make me a paper copy of the mounting holes. It was a nice idea but in the end it didn't work very well, I still had inaccuracies in measuring the holes. I measured, remeasured, measured, and remeasured several times then made posterboard and sheetmetal templates...no good, my measurements weren't close enough and I had too much error. I eventually made another posterboard template using transfer punches. But that was another challenge. Due to the shape of the Packard bellhousing there wasn't much room on the inside to push a transfer punch through, especially up at the starter. I had to fabricate my own transfer punches. In the end, I got it where I liked it and I'm pretty confident that my alignment of the crank centerline and the Packard and GM alignment dowels is dead nuts....well, its dead nuts enough that everything slipped right together without any forcing or cussing.

 

That is probably where he started out though.

 

Maybe go it like the dragster chassis builders do. A metal bar centered to the engines main journals, and build off of that? I am Butch/56sedandelivery.

 

I adapted a Daimler bell to a ZF box. It started like this

 

Nice wok. To bad there were not more of those engines here in the US. I have only seen one in a roadster pickup running at El Mirage. Long time ago.

 

Years ago I did a hemi to a powerglide . It was not all that bad as I remember . Took the glide apart and used the register for the front pump as a center. Took a 1/4 inch aluminum plate and bolted it on the hemi block . Set the glide front on it with a couple of c clamps to hold it to the plate. Dial indicator on the crankshaft and just turned the engine over and recorded how far out the powerglide center hole was . Then took a small hammer and tapped the glide case around on the plate till it was center( don't take the c clamps off while doing this). Eventually the glide case will be aligned and the hemi is bolted to the plate. I then drilled four places thru all three pieces and drove in small dowel pins. Marked and drilled bolt holes for the glide to plate bolts . The dowel pins will allow you to align all three every time you assemble. Some of the bolts would interfere but the 1/4 plate allows you to use tapered head screws on either side. You can use a 55-56-57 starter that bolts on the aluminum plate and it fits the glide ring gear . A machine shop can easily do a crank to chevy flexplate adapter.

 

Some folks fail to fully visualize how the parts must be married and what is allowable in something as basic as clutch spline engagement, starter engagement, how many bolts are needed to hold stuff together or the often mis-understood parallel misalignment.
As to whether or not a computer driven milling machine is a requirement, I'll suggest that doing a one-off in the shop is entirely different than doing even a short run of five units.... The guys that have successfully done the one-offs in the 'garage' get an applause; but for each of them I'll wager that there are 100 that never get finished or end badly.

.

 

Great stories and tips which have been most helpful to me.
I appreciate all the input and hope others will also share their ideas and experiences.
Certainly has been informative, believe me.
One day I may just muster up the courage to have a go at this when I find a nice match of engine and tranny that I like for a future project.

 

I have only met 73RR once. I am sure he is a very nice guy. But my thought is that making an adapter require some equipment. But it's not rocket science. I never made an adapter before I made my first one. Stu Hilborn never made a fuel injector before he made his first one. The Wright Bros. never built an airplane before their first one. So give it a try. You can probably do it. But even if not, in failure you learn something.