I'm trying to help a friend who's bound and determined to swap a 4-71 Detroit Diesel into his 1979 F-250 SC. (Kids and their bright ideas )
He's got the 4-71 mounted in the chassis with an AT 540 trans. We've figured out the plumbing, exhaust, driveline, oil pan mods, etc. The snag he's hit is connecting the flywheel to the torque converter. (The engine and trans weren't a unit, the engine was from a payloader and the trans from came from something else).
There needs to be some sort of "adapter" plate betweem the flywheel and converter but I'm coming up empty handed in my search. The DDA dealer wasn't much help. Any thoughts?

 

Did the 4-71 come in anything mated to the 540? If so that's be the easiest way to do it.

Either that or take the flexplate and have it drilled to mount the converter to and then have it rebalanced.

Justin

 

An Allison shop, or a truck wrecking yard should be able to help. The AT should have an SAE#3 bellhousing, and you need the adapter for a Detroit to a #3. That's close to what I'm doing. Mine is a Kornbinder DT466, and will be mated to an AT545 Allison.

 

The AT has a #3 bell housing and mates to the flywhel housing on the engine via an adaptor. The problem is connecting the flywheel to the torque converter. He needs a flywheel/flex plate combo. He has a flywheel that is half of the coupling to the hydraulic drive unit from the payloader. (It looks like a normal Detroit flywheel with an internal ring gear).
The only truck junkyard in the area isn't willing to help him figure out what he needs, and I'm out of my league as far as knowing what to look for.

 

Gorilla glue? That stuff will stick anything together...

I have no idea... but good luck!

 

maybe he has a flywheel (for a manual) instead of a flexplate (for an automatic)? thatd cause the issues youre talking about.

 

At a previous place of employment, we swapped a Cummins diesel in place of what previously used to be a Perkins LP engine in a Cat forklift. The dealer that sold us the Cummins actually made the flywheel that we needed. Except for some plumbing issues, this worked out great as is still being used 5+ years after we did it.
You may need a shop like this to make your adapter.

 

The flywheel that he has appears to be a standard Detroit Diesel flywheel with an internal ring gear to drive the Hydraulics and Hydrodrive on the payloader. I'm almost sure it won't work for this application.

What I'm unsure about are the parts needed between the crankshaft and torque converter.
I always thought (on larger Diesels with Auto Trans) that it should be:
Crankshaft---Flywheel---Flexplate---Torque Converter
Instead of the: Crankshaft---Flexplate---Torque Converter setup found on gassers and smaller diesels.

 

He's NUTS! He'll never be able to suppress the noise generated by that overgrown Lawn Boy, but at least it's not a 53 series. Here's another problem: 71 series engines only turned 2150 RPM in a no-load situation, so what about the gearing? If he cranks it up to 2500 RPM, he's tempting fate.

 

Mot my truck, not my project. I'm just the guy he turns to when he needs help. I'm too old for that silliness.

 

71 series detroits turned upwards of 3400 rpm in marine applications, and didn't make power at all until 2200 rpm in truck applications. He'll be fine.

 

By the way, what kind of horsepower is that 471 rated at? How much does it weigh?

 

I can't comment about marine engines, but Detroit truck engines had a power band between 1800-2100 RPM. I've driven 71 and 92 series engines for years, both naturally aspirated and turbocharged (some even with twin turbos), and I've yet to see one pass 2250 RPM in a no-load situation. Those that did, especially the ones above 425HP, tended to chunk out vital parts like rods.

 

I've put hundreds of thousands of miles on several different 671's, and I have a fair amount of experience with the silver series 8v92 @ 475 hp. Our 8v92 turned 2400, most of our 671's turned 2450, except for one that didn't run right - it turned 2100, but it wasn't ours, we leased it from another guy who didn't have it set up well at all.

I've never driven a 671 that made over 250 hp. The 425 hp engine you were talking about was a 92 series?

The newer 60 series engines are low rpm diesels, but the older two strokes were called "screaming jimmies" for a reason.

 

I can't speak from any real experience on the HP ratings. Although I went to school for Diesel engine/HD Truck repair repair in the 80s, I never did much with it and have forgotten more than I remember. I'm guessing that 4-71 NA makes right around 100HP. The 2300-2400 max speed sounds about right. The kid plans on getting the engine mounted and running, then removing it for rebuild and a turbo, so that should add a bit more oomph.

He's found a flexplate for it. I guess the flexplate and torque converter together act as a "flywheel" like in an automotive application. He now has to locate the 1" spacer that goes between the flexplate and crankshaft to get the fore/aft alignment of the parts correct inside the bell housing. It seems the 4-71\AT 540 combo was actually wsed in some MD truck applications.

I met a fellow many years ago who put a 4-71 into a 26 or 28' motorhome after wearing out the original 440 Chrysler engine. It was no powerhouse off the line, but he claimed a constant 60mph top speed and 13-15mpg. I don't know what the rear gearing was, but he said it was the original. I saw the rig in use but never drove it to actually see how it performed. I "think" he used the original 727 trans, but I don't remember for certain.

Thanks for all of the input guys. It's helped awaken some long dormant brain cells.