M37 4bt Swap details

[MoparNorm]

I bought the bread truck today. It is a '79 with the 4BT a TH400 and has 124,000 miles. I figure there is a pretty good chance it has been rebuilt. It runs and drives and is about 4 hours from my house. It looks like it is going to be a fun trip to go get it.

Good luck with it!
There are a LOT of folks here that have a lot of experience with Cummins and can help you out when you have questions.

[JimmieD]

I bought the bread truck today. It is a '79 with the 4BT a TH400 and has 124,000 miles. I figure there is a pretty good chance it has been rebuilt. It runs and drives and is about 4 hours from my house. It looks like it is going to be a fun trip to go get it.

Rebuilt? No way! That engine is hardly broken in at 124,00 miles. This engine is from the family commonly referred to as "Million Mile Motors" and they're famous for logging really extreme miles before a rebuild, like 500,000+!

You're going to LOVE IT, I guarantee it ha haha, GREAT engine!! You just reminded me of the day I drove mine home, wow, what a fun time. Take notes and take LOTS of pics with a GOOD CAMERA, you'll be happy you did later. Enjoy yourself, work safe and post your progress.

[Doc Dave]

It sounds like either option is going to run me about $2500 which is fine because my M37 was essentially free. With the ZF will I have any issues with engine placement or will it stay confined to the engine bay. I would once again like to thank everyone for their knowlodge and more importantly their willingness to share it. This forum is incredible!

Hey Altered,
I live down in St. Mary's County, and I have a 4BT for my M37 project also. If you find a yard with the 5 speed ZF's (after you get yours of course), let me know as I am also looking. My Cummins came with the Ford Bellhousing adaptor set up.

[Altered_Auto]

I have a dew more quick questions before I embark on this adventure. I am going to add a few extra springs to the front end to clear the pan and I am wondering where I can buy longer U bolts. Is it possible to bypasss the power steering pump on the 4BT? I do not want to do the brake upghrades right away for cost reasons. And finally what kind of flywheel came on the 4BT from the factory when it was mated to the SM465. Is it dodge or chevy. Thanks to everybody for your continued assistance.

[mcinfantry]

chevy flywheel. you want just power steering? or nothing? if you want nothing just remove the pump and cover the hole with a plate.

[Altered_Auto]

I want to get rid of the P/S all togather. I might eventually want to upgrade brakes to hrdroboost but I would like to get it running and driving first. I worded my question wrong. I should have asked if I can get a belt that will work the accessories minus the P/S. Thanks.

[mcinfantry]

???? the power steering is gear driven on every cummins 4bt i have ever seen.

so i guess yes, you use the same belt you have now. since it doesnt drive the PS pump

[JimmieD]

P/S removal: What mcinfantry said. But hey, I wonder if what you think is power steering on your engine is actually the vacuum pump some were equipped with? Vacuum pump sits up topside front and is beltdriven, PS pump sits just behind timing gear case, driver's side below injection pump, and is gear driven. No magic removing it, as Lee said, pull it out and slap a plate on there.

[Altered_Auto]

I had no idea it was gear driven. I have no experience with there engines. Thanks for the tips! Also will a stock rear leaf fit in the front spring pack to give me my lift? All I can find are NOS rear springs.

[MoparNorm]

P/S removal: What mcinfantry said. But hey, I wonder if what you think is power steering on your engine is actually the vacuum pump some were equipped with? Vacuum pump sits up topside front and is beltdriven, PS pump sits just behind timing gear case, driver's side below injection pump, and is gear driven. No magic removing it, as Lee said, pull it out and slap a plate on there.

If you want power brakes youi'll need to retain that vacuum pump!

[Altered_Auto]

If you want power brakes youi'll need to retain that vacuum pump!

I do want to do something with the brakes eventually but I am on a somewhat tight time line and budget. The truck is going to have to be stored and my M37 is going to be in a mini storage facility. The joys of living in a condo!

[JimmieD]

If you want power brakes youi'll need to retain that vacuum pump!

That or use the Hydroboost power brake system which is powered by the power steering pump. The vacuum pump can be used for actucting an exhaust brake too, so don't lose it or give it away if it has one!

[CGarbee]

Meanwhile, if you want to run the engine with the power steering pump installed, but without the hydroboost or power steering installed, you can... just run a rubber line (use the higher pressure rated stuff) from the outlet over to the inlet and just let the fluid loop around... If you have three ports on the pump (like mine), just run three hoses from the nipples to a tee fitting and let her rip.

I've done it to more than one engine while running it around debugging a setup before I got around to installing the accessories... (or in one case on and elder GM product, when the power steering box failed while on the road...).

Enjoy.

[Altered_Auto]

Thanks for the advice. I will eventually want to run some accessories but I would like to get it running first. I am going to pick it up next wednesday and i have a few more questions. What kind of oil do they take? It would be nice to have a back up plan in case but I see no issue because the seller said it was one of the better old trucks they have. Also if I buy NOS u-bolts will they have enough meat to add in 3 new leaves? And one more out of left field. What rear axel does the van have? I am assuming a 14 bolt. If so it will go nice in my CJ7:)

[MoparNorm]

Geeze!
That 14 bolt will weight more than the CJ....ha!ha!