Cummins 4BT

[wildmanjoe]

For those who are not aware, the Cummins 4BT the same engine as what's found under the hood Ram pickups, but with two cylinders lopped off.

Many people like to swap them into their full sized vehicles because they can net you over 20 MPG, like these guys:

http://www.dieselplace.com/forum/showthread.php?t=392580

http://www.fullsizechevy.com/forum/general-discussion/duramax-forum/engine-swaps/374390-4bt-cummins-turbo-diesel-05-silverado-pictures.html

So I was thinking, what if instead of the six cylinders usually used for base engines in full sized trucks, GM were to use something like this? They already have the 4JJ1 4 cylinder diesel in the Holden Colorado and people like the above posted aren't against a 4 cylinder in a full sized.

Do you people think GM should offer a 4 cylinder diesel in a full sized vehicles for the economy minded or would be a giant waste of time and resources? It wouldn't be a power monster like the 8 cylinder Duramax, but it could be an interesting base engine that would give Ford and their Ecoboost something to worry about.

[z28luvr01]

I would say yes. With the amount of base trucks that are sold to fleets, having a 20+mpg engine option would put a serious dent in GM's efforts to meet CAFE requirements.

I bet an engine like this would still be a little torque monster, making it perfect for a Silverado/Sierra destined for work truck duty. Having an inline 4 in a full-sized engine bay would make maintenance tasks a relative breeze.

[G. David Felt]

I totally agree, if you had a torque monster 4 banger that got you in the low to mid 20's in a full size pickup so you could still haul a days work of material and tools, I think it would work out really well. Especially if the interior was designed to be hosed out so you would not have to worry about mud, etc.

I think Chevy could do this in their full size truck using the 2.8L Duramax Diesel engine. That would totally rock.

Edited April 10, 2012 by dfelt

[Robert Hall]

Would be an interesting option. I can't see the macho crowd that buys full size trucks going for a 4cyl, though...

[Drew Dowdell]

A properly designed modern 4-cylinder diesel should be able to do a lot better than that with fuel economy. The V8 Oldsmobile diesel was good for about 30mpg by 1983 when it got an overdrive gear... and that was a V8... and old...

[occupant]

There is a guy on 4btswaps with a 1995 Explorer Sport 4x4 who put in a 3.3 liter Cummins B3.3 engine and he averages 34mpg in the thing.

Another guy put the 3.9 liter 4BT and an NV4500 into his 4x4 Durango and it was also getting 30+mpg.

And then there's the guy with an early 80s Chevy pickup, half ton, put in the 4BT backed by an A833 4-speed with overdrive and 3.08 gearing. He gets 37mpg in his truck.

All US measure, not Imperial.

It's seriously good but the biggest hurdles are getting power brakes working (you need a vacuum pump and reservoir) and putting on your power steering pump, AC compressor, and alternator. It's easiest on Dodges because the brackets already exist from Ram pickups for the Chrysler PS pumps/compressors/alternators. If you have a 4x4 your front differential will be in the way of the oil pan. So you have to cut it up and weld it into a funky shape to keep enough oil in there (you need at least 2 gallons preferably 3 gallons capacity). And then you've got to make the trans/throttle linkages and modify the engine mounts and hope you clear the firewall. Then there's hood clearance issues because the intake is straight down on top of the engine.

My personal opinion is for an SUV or pickup, the 3.3 or 3.9 Cummins are great. But for a car, I'd lean towards the 6.2L/6.5L GM truck diesels for a GM car, and the Mercedes OM616/OM617 for a Chrysler or Ford product. If I ever put a diesel in my Gran Torino it'll probably be a Mercedes unit. They have adapters for the Ford AOD so I'm covered there. The oil pan and engine mounts will be the biggest problems for me.

[G. David Felt]

I wonder if we can order as a Crate Motor the New Duramax 2.8L, that would be a kick ass 4 banger to put into a modern cuv or truck.

[Drew Dowdell]

Are there states that you can get away with a gas to diesel swap? I know you can't do it in PA

[wildmanjoe]

Are there states that you can get away with a gas to diesel swap? I know you can't do it in PA

In Alaska, Arkansas, Indiana, Iowa, Kentucky, Michigan, Minnesota, Montana, North Dakota, South Carolina and South Dakota you can do whatever you want.

I'm guessing if you lived in the right state that only required emissions testing in certain counties or didn't inspect collector vehicles you could get away with it.