Thread: Way over my head with a DT466 Diesel

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Hello,
I am new to the site and I am hoping I have found a home. I am building my first hot rod and I have selected a set up that I think might have a old timer scratching their head - maybe not though. I have a '31 Buick and I am building a rod that is using a DT466 engine and a Allison 545 tranny. THIS WILL NOT BE A RAT ROD. Nothing against them, but this isn't that type of car.

I have a million questions, but I am starting with suspension and frame.

I was thinking of going as simple and robust as possible. It can look bulky and weight is not an issue. Keep in mind this engine is used in school buses and it's offspring powered my 15 ton Maxpro MRAP, so it'll be fine.
I need any and all advice I can get. What do you guys recommend? How would you build it?
I don't really want to go airbags. Nothing against them, I just want to keep it as simple as possible. Now, if someone thinks I should - let me know.
I kind of want to go with a solid beam type set up, but should I go a different way?
Now, before you answer- please don't shoot down the engine and tranny. They are critical to the theme and they gotta stay.
With that said - let er rip. I am really look forward to hearing from you guys. As I said I am in over my head, but I am DETERMINED to finish this rod and get it back on the road (first time since 1955).

-Al

Better first find the weight of the engine and transmission, and whatever the body is to determine what is needed for frame and suspension, as well as the length and width of the body....Sounds way too heavy to use any of the normal Hot Rod parts......

I have all that. the body is a 1931 Buick and it's on an old truck frame. The engine weighs 1400 lbs and the tranny is just under 300 lbs.
I was thinking of using an I-beam out of a 4700 series truck, but I am wondering if there is something from an old truck (30-40's) that might be an I-beam that is bigger and stronger than what I currently have which appears to be the stock I-beam. I was thinking of using a custom leaf spring in the front. Any thoughts?

Would I be stupid to drop it on a newer truck frame? I know guys use these engines inthe tractor pulling world and they are put on F250's and so forth. I am just worried that will look really stupid and not like a hot rod. Any opinions on that?

IMO using a complete chassis from a newer truck (like an S10 Chevy) gives you an S10 Chevy with an old body, and it is not accepted as a "hot rod". It's a neat way to get modern drivability, but for resale you're not going to have much going that way. Much better to box the frame, and build what you want, again, IMO.

Originally Posted by Al Scarlett

Would I be stupid to drop it on a newer truck frame? I know guys use these engines inthe tractor pulling world and they are put on F250's and so forth. I am just worried that will look really stupid and not like a hot rod. Any opinions on that?

You're right---it would look really stupid!!!

Yeah I kinda figured. I don't think I would go that route either. Just spitballin'. Does anyone think I can find a traditional set up that can handle that load? If so please give me some specific ideas and parts to consider. I was thinking of using the beam out of a box truck (4700 International was one I was looking at).
What I was thinking of doing is narrowing that beam and throwing a custom spring.
The other way is to go again with the big beam and then going with a set up like the Piss'd Off Pete (If you are familiar with that monster).
Any thoughts?

I think you will have contradictory features here.....a frame cross section strong enough to hold a 1700 lb engine/trans will be pretty thick (tall). A 31 Buick had a straight eight (I think) but the frame was not anywhere near as massive as needed. The engine torque will also suggest a stout frame. Supposing you are going full-fendered, you have some limits as to what will fit under there......and how much underhood volume you have vs the engine size. I think you have a significant challenge getting the look right.....it cannot look like a 31 Buick on a semi truck frame.

You are probably on the right track to look for axles and other components from vehicles with similar weight engines. A Mustang II front end it way too wimpy......as is a late model independent suspension.

You need to take some measurements and get someone to do a drawing or CAD representation. You should also do some basic calculations regarding the minimum frame strength that you need.....you might get away with a boxed 6" tall rail with a third vertical plate....like two sections of 2.5 x 6 rectangular tubes welded together to make a 5 x 6 tall box....that would give you four vertical sections....OR maybe a really thick wall tube.

We have had good luck with having a CAD file laser cut for frame sides. To those, we weld the top and bottom straps to make the boxed frame. This way, the frame doesnt look like a straight tube.....it can match the original frame but be scaled larger and thicker.

Thinking about a 31 Buick...is the original frame wide enough for the engine and tranny? You probably are not going to get a wider frame to fit under the existing sheet metal......another problem.

Good luck with the project

mike in tucson

Thanks Mike,
The frame that is in there right now is an un-boxed one that measures 2.5 x 6. I am told it is from a 30's heavy duty truck, but I have no idea if that is A) in fact - true and B) what kind of truck. It appears, aside from the lack of boxing to be stout indeed. It has created some cabin space issues, but I think I can work around that. The engine itself will fit between the rails and the placement of the mounts should work out okay. Length wise it will have to be modified up front to allow for the engine to fit properly.

I have two questions for you: Do you think I can narrow a heavy duty I-beam from say a 4700 series International? I ...think...they are forged, but they may be cast
The track width from something like that will be just too wide otherwise

Second You mentioned you have had a frame laser cut. Do you design them? I am trying to find a professional to tackle this part. I can only do so much with my resources and skill and realize I will have to pay a pro for some things.

-Al

Regarding your question about designing a frame rail for flame cutting.....most of the laser cutters will be able to take a cardboard pattern that you made and digitize it so they can cut the shape. This should make it easy. Your data says that you are in Hopkinsville....if that is KY, I am not familiar with local laser cutters but you should be able to ask around. A sheetmetal shop usually has a laser but those lasers are always powerful enough to cut thick stuff. However, that shop will know who to send you to that can cut thick stuff.

Regarding the narrowing of an axle, I would say NO....do not do it. Axles are usually forged and require very specific welding. You will get 1000 replies that say "I welded one and it held fine" but the dead guys who had an axle break didnt see your question. Consider another solution....find a narrow axle, have a tube axle fabricated, etc.

Another thought is to plan your build with respect to tires. You should be able to estimate the vehicle weight (heavy) and figure out what is available in the tire line with a good load rating with margin. For instance, if you car is estimated to weigh
6000 lbs, each tire would see at least 1500 lbs (the fronts probably more). Using a 50% factor, you would need a tire with a load rating of at least 2250 lbe....maybe more. That rules out those 6.70 x 13 tires you had your eye on.

Thanks, yeah I have that part covered the first set I have in mind are rated at 2270 up front and 3195 in back so I should be good if I go that route. If I decide to go more like the piss'd off pete and go with commercial tires I am more than ok. I am just trying to stay away from those tires if I can. I am looking more in the light truck/suv world only because there are more choices in the D and E load ranges.
Do you know anyone that can fabricate a tube axle for me?

You need to choose your spindle type, brakes, etc......spindles will size the kingpins, kingpins will size the axle ends, etc. There should be a local fabricator who can do an axle....in parallel, keep looking for a HD beam axle.....maybe a late 30's heavy truck......later trucks have wider tracks as you have found.