Engine swap questions

Hi all,

I have a 1999 Peterbilt that I’m restoring. This truck has sentimental value and I want to keep and build it as I would’ve wanted it from the factory.

I need guidance on engine swapping. It has a Cummins ISM in front of an Allison HD4560, and I want to swap in a 3406E (it will fit). I’d like to know a rough idea of what it’ll take to make this swap happen (cost isn’t a factor), and how to do it the cleanest and simplest way.

I’m not sure how Paccar controls the gauges and switches, or how they’ll interface from one engine manufacturer to the next....so I’m thinking I might have to replace all of the wiring harnesses in the truck? I’m sure some out there have done similar. Or just run standalone independent gauges reading off various sensors on the engine itself, like a mechanical motor?

And then, there’s the Allison hookup. Since the ISM (MY1998) can communicate, I figure a CAT can too. Should be over a J1939 port if I’m not mistaken.

I appreciate the help. A local fab shop is available to help with many types of things I may need during this process.

Thank you!

 

Thanks for the reply.

I’ve spoken to Rush Truck Center and two other Paccar dealers already, and they “don’t want to take liability for such a one-off situation”. Basically, the potential issues the truck could cause down the road (probably getting sued by someone for something) doesn’t equal the revenue from tying up their shop. *shrug*

Guys at a local fab shop don’t care about things like “risk” and will do whatever is asked if the price is right. But I also feel they’ll do what is easiest and not care about making a Frankenstein monster, because they likely won’t be dealing with it later/routinely.

I’ll see if some other dealerships might be more willing to undertake the project. I’m anticipating this will cost around 40k to complete, end to end, if I can find someone do it all. I really prefer local so I can check in on it weekly, but I could send it to one of the big performance shops as a last resort.

I already have the 3406 built, just need to ship it and the tractor wherever this is going to take place.

 

I’m not sure if it’ll let me upload a picture, I can’t PM people I’ve come to find out. VIN=711901

(If upload works) Lets see if I get bashed as bad as I do by my hauler friends at the depot....here she is!



^This is the truck I delivered my first load of chemical with, and my TE was the original assignee to this unit until he passed away. It used to be a straight tank truck but the municipality pulled the tank and pump. They planned to scrap the truck, and offered it to me. So I bought it for $2,000, and its halfway through conversion into a 5th-wheel-tractor for pulling ISO tanks.

It’s getting new frame rails put on right now at the fab shop (old doubles were a little rusty for my liking), and I started building a super sleeper for it. I’m taking the front-drive PTO off since I have a Hydrachem waiting for this project to complete.

Given time, it might end up looking like this:

 

I’ve measured it out, and it will. There is 6” of height difference overall (3” at either end), and there’s 18” of space under the cab. It might require custom motor mounts but that’s not an issue.

 

The thing on the upper right is part of the induction system.