anyone do a cummins swap/older chevy?

[Keith Richards]

I am interestted in hearing from anyone who might have done this swap or anyone with this kind of experience.I will also check with the cummins conversion guy I read about in the members forum,but he's all the way in Montana.Thats quite some distance from New Jersey.Oh,the truck I'm interested in using is the 79,thanks.

[odee]

I seen a nice looking dually of that body style on ebay with a cummins in it. I thought it was gonna end later than it did, I wanted to email the guy and see what kind of issues he ran into. I've got a 80 model dually that is in good shape that I have given thought of swapping a diesel into.

[jbell]

call jamie at diesel depot about their gm bread truck 4bt cummins/th400 or cummins/np465 combo's. It already has GM v-8 motor mounts on it, just drop it in and go. The 4bt takes the same hop up fuel delivery plate as the 6bt, in marine trim it'll make 300hp. I considered that for my jeep before finding a 6at, and putting a nv3500 behind it.

[odee]

Has anyone on the board drove one of the converted trucks with the 4bt in it? I have given this swap some thought also.

[NH2112]

A friend put a 4BT/TH400 in an 84 C2500 w/3.73s, it gets 30mpg and will beat a Powerstroke off the line.

[Ratau]

Could you give the difference in cyl volume between the 4bt, 6bt and 6at engines? Are they all inline 6 cyl? How much difference in weight comparing to the GM6.2?

Danie

[TimK]

The 4bt is a 3.9L, inline 4 cylinder engine. The 6bt is a 5.9L, in line 6 cylinder engine. Both engines are very similiar in components such as piston size, bore, stroke, bearings... I don't have weigth information on the Cummins engines handy. I thought our 6.2L/6.5L engines were about 750 Lbs. The 4BT (automotive variant) was very popular in the US in Panel Vans.

TimK

[Craig M]

Like Tim states the 4bt is 4/6 ths of a 5.9 Liter engine, or 3.9 Liter. Basically same components as the I-6 just I-4.

[KEVIN MUNCASTER]

Does a 4cyl really work in a full size pickup ?

Is it possible to swap into an ex-gasser, or just in place of an existing diesel ?

[jbell]

http://harvesting.com/ford/

Fullsize for a 4bt? Well ford thinks it's good enough for the overseas crowd in a f350!!! with an allison behind it. I think they're only using the 160hp tuning. The 4bta3.9m tuning is rated at 250hp, 420ft.lbs. Sound full size enough? The 4bt is 4/6 the same as the 6bt that banks set the world pickup speed record, running 80psi boost. You CANNOT overboost this motor -- the only way to destroy it is not managing egt. (or not changing the oil......)

As far as gas to diesel -- easily done, but your axle ratios WILL have to change. 4bt max's out @ 2800rpm, but are happiest at 1800. And think of it this way, GM used them in 1 1/2 ton bread trucks... Interchangeably with the 6.2/6.5 -- so yes, it is a full size motor. And the weight is 780lbs dry, no accessories.

[Keith Richards]

wow,quite interesting.I had no idea about that motor.I wouldn't know where to find one,but thats plenty of power compared to what I have now.I think the 6.2 will be the most likely engine to swap,and the most bang for the buck,but never hurts to toss some ideas around.I would love to be different and toss an I-4 diesel in there.If anyone hears of a used one at a fair price,please let me know.6.2,cummins whatever,thanks

[jbell]

call jamie at diesel depot. Last I knew, $2500 got you a 4bt, radiator, turbo, intercooler??, and 10" donaldson aircleaner, as well as PS pump, vacuum pump, and a TH400, from a fleet maintained GM p-van with close to 100,000 miles on it. If you get the rotary VE bosch pump, turn up the fuel delivery screw exactly like you would a DB2. If you get lucky and get a p7100 series inline pump, change fuel plate, injectors, and HOLD ON, it's going to make power. Weight wise, 6.2 and 4bt are a toss up. Install wise, it's a toss up. 6.2 has edge in quiet and lower vibration. 4bt has big edge on durability, max power, fuel economy (DI). The trade off is that a 6.2 max's @ 3600, and has no problem with 2800. A 4bt doesn't like much above 2400, and likes 1600-1800 REAL well, which means 3.03 axle gears, or something like that with a TH400. The way cummins bolts a th400 up to a 4bt, is a little odd. The th400 is 'tilted' a little, so you have to know that in advance when connecting it up to your trans crossmember, and has an additional stiffener plate that connects the bottom of the th400 and the 4bt together.

[gavio]

This is awfully interesting - I'd LOVE for my van to get 30 mpg :D

Is there another transmission choice that can take the torque plus add an extra gear (overdrive) into the mix? Without, need I say, adding another 3 grand to the price?

It looks like the 4bt is a bit smaller in overall bulk, which would be a major plus in a van, although the noise tradeoff could be an issue to those of us with sensitive ears. :rolleyes:

Just thinkin'......

[TimK]

Just like the 6BT's, the 4BT's can be mounted to a variety of transmissions. The 5 Speed NV4500 is very popular as a manual transmission. I am not sure I would go with a tranny any lighter in strength then the TH400. A 700R4 may survive if you are easy on the go pedal. A TH400 with a Gear Vendor OD is a reasonable option.

The 6BT's and 4BT's were advertised by Cummins for repowering commercialy used vehicles that needed engine reubuilds. I still have a flier from several years ago that listed the 4BT being rated to for 10,000 GVWT vehicles such as panel vans. The repower kits listed the TH400, 4L80E, NV4500 and another 4 speed manual transmission popular GM heavy duty pick ups (but I forget the name, SM465?). This was just for the GM vehicles. They also had a host of Ford vehicles they could repower. I am not aware of Cummins actively advertising the repower kits any more but I am told if you go to a Cummins dealer they still have the parts to mate their engines to the trannies listed above.

The other route is to do what my dad did. He bought a Cummins 4BT from a truck recyling yard. The recyling yard was selling the engine, transmissions from Frito-Lay vans that had been decommisioned. The engines were guaranteed to run. The engine and tranny came attached to the original frame rails of the Frito-Lay van that had been decomissioned. He was able to take the 4 speed tranny back to the recycler and use it as trading wompum for the NV4500 he is using. He placed this whole combo into a 1965 Series 2A Land Rover. The vehicle, with all of his gear weighs in at 5500 lbs. The truck averages 29 MPG and has plenty of horsepower to move down the hiway at 75 MPG. (Although I have to admit going that fast in a Rover is damn scarey.)

TimK

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[odee]

So what do you guys think a 4bt would do in my 80 model 4door 2wd dually that I haul my jeep-dragcar sometimes daily driver do? The truck runs a 235-85-16 tire and 4.10 gears with a nv4500 tranny right now. I just don't want to do a engine swap and come out under powered and not be able to keep up with the traffic.

[jbell]

2400 @75.... with your 4.1 gears. that's pretty high for a cummins. (basically redline) Above 2100 the fuel curve starts up and economy goes down.....

[brandonwortley]

Does anyone know anything about the 4 cyl Isuzu diesels, comparable to cummins 4bt? I have the opportunity to buy a 4 cyl isuzu bolted to GM 4 speed trans. Probably real cheap, but no turbo. I guess the guy had it on a tow truck, not sure where he got it though.

[Jgreemo]

Just FYI. This site mostly deals with Cummins into Ford conversions, but they do talk about GM's as well.

http://www.fordcummins.com/

[TimK]

It's hard to comment on the Isuzu engine without knowing the model and size or what tranny it's connected to. Isuzu has been making quality diesel engines for a lot of years. The most popular Isuzu engine on this website being the GM Durmax Diesel. GM and Isuzu have done several joint venture projects and I thought I remember reading somewhere that GM owns 49% of Isuzu.

The small diesel out of the pickup trucks were about 2.0 to 2.2L and isn't something to consider for repowering a heavy GM SUV like a SUB. However if it's out of one of their delivery trucks, that's a completely different motor. I have seen the internals of Cummins 4Bt and it is beefy. Comparing a connecting rod from my 6.2L to a 4BT is almost embarrassing. I like to convince myself that the lightwieght con-rods in my 6.2L helps performance. It comforts me to know not a lot of people write about bending or breaking connecting rods on this site.

TimK

[rubar]

I've got a 4bt/th400 combo in my 68 bronco. It's got 4.88 gears and 38" tires on it. It maxes out at 70 mph. It seems to do fine in this application, but I think it would be underpowered in its present form in anything over 6000 lbs. There are almost limitless upgrades you can do to this engine though. Most of them I have seen have the VE pump on them and I would imagine that somewhere in the 200 horsepower range would be your limit with that pump. If you could find one with the P7100 on it, you could slap on a hx35 or a hx35/40 hybrid turbo and upgrade the pump, and you should be able to get in the 300+ range. You would probably want to get a 300 or a 3500 GSK for it, but I don't think that would be a problem either. The 6b's seem to hold up pretty well spinning that fast.

[Diesel Dan]

Since I installed a 3K GSK it's a whole different motor now. Doesn't de-fuel untill 3,000rpm and when on the dunes we were shifting at 34-3500rpm. Plus they will run 26-2700 rpm all day long, if you get the fuel curve taken care of.