Hot Rods How to Make Engine to Tranny Adapters.

I am looking for input from guys who seem to do this with ease in their shops with little or no outside help.
If any of you guys are out there, could you please tell me/us how you go about it and what things you are looking for to get it all matched up.
Some guys seem to be able to adapt just about any darn tranny to most engines that we tend to play with on here.
I'm no fool but it is an area of interest that I just have zero experience with...
Some handy hints and explanations would be greatly appreciated.

 

Need to go down this route also as not prepared to pay big bucks for a off the shelf adapter, might even have to make a complete bell housing yet
Got some ideas but would also like some advise

 

I've done it a couple times, most recently was around the turn of the century to hang a New Process 5 speed from a mid 70's C60 dumpster truck on the back of a 6.9 diesel in my 75 Ford F350. The 6.9 has an aluminum bell housing which made welding an easy option. The 2 biggest considerations are being absolutely centered on the crankshaft and the length of the input shaft. The transmission front bearing retainer outside diameter was too big for the hole in the bell housing, so I put it in the lathe and cut the O.D. down until the retaining bolt heads were just barely inside the edge. The hole was still too small, so I bolted the bell housing to the engine and put a magnetic base for a dial indicator on the flywheel with the end sticking through the hole in the housing and a scribe mounted on it. I scribed a line on the transmission mounting face slightly smaller than the bearing retainer by turning the engine. Then used a die grinder to cut the hole out to the scribed line, about 3/16 if I recall correctly. Then I put the dial indicator on the magnetic base with the little movable button (hahaha, whatever it's called) inside the hole and rotated the engine to find high and low spots, while continuously measuring the diameter of the hole while I finished cutting it with the die grinder until I had about .001 larger hole than the size of the bearing retainer and it was perfectly centered. The input shaft was about an inch too long, but the splines were plenty long because it was for a double disc clutch, so I shortened it in my lathe and cut the new pilot shaft location to the size for my Ford. Not hardened anymore, so I needed to be sure to use a ball bearing pilot bearing instead of a bushing. I generally do anyway.
The mounting bolts were in the wrong places of course, but 2 of them were in a nice thick area of the bell housing face, so I just drilled and threaded them. The other two I made threaded aluminum slugs from 1" round bar, drilled the bell housing and welded them in place with the housing bolted to the engine block. Then took the bell housing to a machine shop and had it surfaced to remove the warping of the transmission mounting face caused by the welding. Welding didn't move the center hole luckily. It's been in the truck and working for more than 15 years. My poor boy methods apparently worked.
Every job will be different, but with a few simple tools and some ingenuity you should be able to make about anything work.

 

There was a thread on here a few years ago where a guy did just that. Try to search for it. There was a lot of good help in it and he didn't use a CNC machine either. Mostly done by hand if I remember correctly.

 

I have never done one, but I would model the back of the engine in CAD, then do the same for the bellhousing and transmission, down to all the Z axis features. Then look for things that lend themselves to marrying it all together.

 

i have the bellhousing adapter. i need a crank adapter to mate a y block crank to a pontiac hydro flywheel.

 

Adapter design 101 would be good for starters.

 

Might be as simple as redrilling the flywheel, or you might need an adapter built. If it's beyond your imagination and experience, there should be someone at your local industrial machine shop that can figure it out and build the stuff you need. Automotive machine shops are staffed by good skilled people, but generally their jobs are repetitive and their machines are pretty much job specific, so they normally don't have the experience and the tooling to do much custom work. An industrial machine shop takes on whatever job comes in the door and the guys are used to solving problems and seeing solutions continuously.

 

Tranny adaptor has a whole different meaning to a mechanic.

 

This is a very short and incomplete run down, there will be lots of measuring along the x-y axis of all of the bolt holes on the block, bellhousing and transmission mount holes (for manual trans) while making sure the input shaft of the transmission stays concentric to the crank shaft. Measurements should be as accurate as possible down to the last thousandth, any excessive misalignment will wear out any rotating components in short order. Then machining a crank spacer to make up the difference of the thickness of the trans adapter itself, usually your engine /trans overall length grows by an inch and must be compensated for so it can all be bolted together correctly. Not having a milling machine makes this job much harder. I would just buy an adapter off the shelf if it's available for your application. Paying a local job shop to R&D an already existing adapter seems like it would cost significantly more.

 

Earlier this year I built an adapter to mate a modern T5 5speed trans to my early 50's Packard straight 8.
In my case the input shaft on the T5 was 1" longer than an original Packard manual trans. So, I took a couple of chunks of 1/2" thick plate. I laid out the alignment pins and mounting holes for each, drilled and tapped holes as necessary and then welded the 2 plates together...no biggie.
Sounds easy right? There was definitely some challenges but I pulled this off with basic tools; drill press, holes saws, cutting torch, jigsaw with a metal blade, etc.
I used a common "big" Chevy bellhousing. That was the easy part, its easy enough to find and engineered drawing of a Chevy bolt pattern with measurements. The Packard side was a little harder. No drawing or measurements to be found.....I had to try and lay them out by hand. Due to the same of the Packard bellhousing I could only use a transfer punch on a couple of the holes. I did make my own transfer punches for the harder to access holes.
I made several posterboard templates, and a sheetmetal template before laying things out on my 1/2" plate.

 

bobby,
that's dang good work for having limited tools/machines
cutting the hole for the starter nose must've taken a few minutes, eh?

 

Thanks!
LOL..you ain't kidding.
I had the idea to drill some relief holes so that the chips from the hole saw would have some place to go. But I didn't get them close enough to where the hole saw was. So, every minute or so I'd have to take a magnet and clear all the chips out of the saw kerf or risk ruining the hole saw.....It took forever to get through the 1" of material.

 

Yup. Not worth the heartache of destroying a transmission or engine (or both).

CAD/CAM/CNC. If you don't have those at home, it ain't gonna be all that accurate. A mill with a DRO would be a the bare minimum.

 

Without CAD/CAM/CNC how did the traditional guys do it in the good old days?
I'm assuming as per BOBBYTMN's method.

 

Some got lucky, some did not.

 

This is a picture of me indicating center of a 390 blow shield on a 368 Lincoln. I think I did a whole thread on this. I have also put a Ford top loader behind a 392 Chrysler and a Packard V8. I have put a Ford Pinto 4 speed behind a Lotus 907, a 32 Plymouth and a 26 Dodge Bros four cylinder. Never used no stinking cad cam. I used transfer punches and a dial indicator. I did use a lathe and mill as well as a welder. I did a thread on the Packard adaption on a Packard forum. And a story in the Bonneville Racing news on the Chrysler. Since the Chrysler flywheel wouldn't fit on the Chevy bellhousing I used between it and the top loader. I machined the aluminum flywheel to accept a Pontiac ring gear that I had and did fit. Used a chevy starter with a Pontiac dear on it. I don't know why someone would put a Pontiac flexplate on a Ford. I might adapt the Ford flexplate to accept the Pontiac torque converter or if you are using an aftermarket torque converter from someone like Diamond, they can make you a converter to work. My Nissan in Jack Costalla's 'liner used a Chevy blowshield to bolt to a C4. Jck cut open a Nissan torque converter and installed the Ford stater, I think, that had the correct splines for the C4. Then he brazed it back together. Records at El Mirage and Bonneville, so I guess it worked.

 

Probably this thread, but the pics are all gone: https://www.jalopyjournal.com/forum...a-bellhousing-for-a-flathead-cadillac.328096/

 

Well stated Rich. There were a lot of transmissions adapted to engines they didn't fit before the space program brought computers to a state of usefulness. The best computers in the world are placed between the ears of men.
You just have to picture the end result in your mind then start finding ways to get there and overcome whatever obstacles you encounter along the way. I particularly like the fact that you used a Pontiac ring gear.... because that's what you had and it fit in the space available. That's where hot rodding began and supposedly what this site is all about, traditional hot rods and traditional hot rodding.

 

First of all, adapters are not for the faint hearted! My first suggestion is to figure out what two pieces need to be mated and research if there is a stock bell housing that would work. In my case, I am grafting a dual range hydramatic to a Buick 225 V6. The V6 is the common BOP pattern. The hydramatic is from a 1955 Pontiac, which uses two bell housings. The front bell housing fortunately has the two top holes the same as the BOP pattern. So that is where I referenced from. I then carefully did measurements along the Pontiac bell housing and transferred to the Cad program. Then I printed (paper) the adapter so that I could see where my adjustments had to be made. The dowels are the most critical. Then put the BOP pattern on same cad file and printed again. Between the two patterns the crankshaft center can then be created. Given that the starter is a block mount, the nose cone sticks out into the where the hydramatic flywheel will be, so this gives a thickness of the adapter for clearance. Given the clearance, this is where the crankshaft adapter will be created. Pretty simple with the two flywheels to use for dimensions.

A machine shop nearby my employer has a water jet cutting machine, which I will use to make the adapter. He just needs a DXF file of the adapter and he can program the machine. Told me a couple of hundred dollars will get the adapter made. The crankshaft adapter I will make, since my employer has a lathe and a CNC mill. Should be interesting.

 

There is a big difference between one of the more talented machinists in racing history, with decades of experience, and the proper equipment, and some dude with a drill press.

 

Some dude with a drill press is not going to be helped by Cad Cam. Transfer punch, maybe. And if you know that guy with all the experience. Could you drop by with him. I got some stuff that needs work. PS Bob called and I think I talked him into going to the World Finials. I can't go, but he always likes help.

 

Looks to me like the "Dude with a drill press" did a damned fine job. I'm not saying a shop full of machine tools is not an advantage, or not necessary sometimes. If you need surfacing or something else you can't do accurately yourself, hire that part done by a shop with the tools. But, don't discourage the little guy with limited tools by saying they need a computer controlled machine shop to build every part on their car. They don't. They just need a good mind, an imagination and the desire to do it themselves. Granted not everyone will be able to build their own transmission adapter, but it's certainly not an impossible task.

My dad who was taken by cancer this spring shortly before his 101st birthday used to say, "It's amazing what a man can do if he don't know when to quit."

 

That's true. And it's amazing what you can do if nobody told you that you can't do that.

 

When we put the DJ Louver flathead rail together, we wanted a blow out shield but not the clunky old method of a steel box around the flywheel/clutch area. We took an 8BA flathead with the crank in it, stood it on its nose and squared/leveled the back of the block. We had a pilot bearing turned of oilite to the ID of a chevy 3 speed. Bolted the trans, which was a neat flea market piece of a '55 chev box,no tailshaft but a bronze adaptor on the back to put a '55-'57 three speed in a earlier Chev with a torque tube. That back allowed us to direct couple with u-joint to the quickchange. Anyway it turns out a Chev Lakewood blow shield has the right depth to put the trans front shaft into the pilot bearing and enough meat on the mounting flange to capture the bolt pattern on the back of the 8BA. Redrill the flange and bolt it up with a flathead clutch disc and a three finger clutch pressure plate, early Chev throw out arm and bearing. Simple, elegant, made Dick and I feel much better when in the pilot's seat, and you got scatter shield and adaptor all with flea market finds.

 

Yeah. That's pretty much what I did with the Lincoln above. Except I made a stand to mount the indicator top the crank flange. So I could sweep the pilot hole and center the trans front bearing with the rear main. If the input shaft is to short, you make a stub shaft that presses into the crank center and contains the pilot bearing with the proper depth. If your input shaft is to long you make a spacer to mount between the transmission and the bellhousing that has proper locating diameters machined into it to locate the transmission central. If you are using an automatic transmission, shame on you. I thought we were talking about hot rods.

 

.....and along those same lines....

Its amazing what you can do when people tell you that it can't be done (or that you have to have CAD/CAM/CNC)

Of course, it could all go south on me, I don't have the engine and trans up and running yet but I don't foresee any issues. Long live hot rodding!

Bobby

 

We only ever hear about the successful. How many out there tried and failed?

 

Yes Gimpy, I'd like to hear some of those stories as well as a warning to what can go wrong.

 

I'm sure that misalignment could cause all sorts of badness. Everything from nasty vibrations to broken parts. I'd be willing to be that the more horsepower you are trying to apply through the contraption and the nature of the use has a lot to do with it.
My old Packard was advertised with 185 ponies back in the early 50's. I'd be willing to bet that a good part of the heard has escaped from the corral by now. I'm not building this little roadster to be a 1/4 miler or road racer, just a standard everyday cruiser so I think I'll be OK. We'll find out.....someday

Bobby