Is it possible to put a Cummins in half ton gas operated 1989 to 91 Suburban 4x4?

[campfire]

Also, the vacuum pump on a 6.2/6.5 will run a brake booster, lots of the ford diesels used vac. boosters, with the same vacuum pod on the pump.

I don't have a vaccum-boosted square-body to measure, but the 6.2 vacuum pump outlet line is significantly smaller than what usually runs to vacuum boost units. The reduced flow would cause the brake booster to react slowly, no? I don't know GM's reasoning in forcing all 6.2 trucks to have hydroboost brakes, but I reason that they would have used normal brake systems in the 1/2-ton and 3/4-ton rigs if it had been feasible.

 

[diesel4me]

I would never trust the dinky 6.2 vacuum pump to operate a power brake booster,even if you added a storage can...
I cant seem to keep one working long enough to let the TH400 's modulator shift the trans properly,never mind run anything else...

The pump's diaphram on my Suburban's 6.2 is dead too,and several that I looked at in junkyards on Fords and later GM diesels that use pods that will work, were also either NG or had very low output..

A new pod from GM or online sources is well over 100 bucks..(they used to be like 25-30 bucks when the 6.2's were popular 20 years ago--for something not much different than a mechanical fuel pump,thats a lot of money IMO )..

I've thought about looking for a used electric vacuum pump off another vehicle,but I'm told they are not designed to be running constantly,and will not last long...they do sell some pumps rated for power brake use and constant run ,but those are not cheap either..

 

[black dawg]

The pump outlet (on all that I have seen) is 3/8. Healthy, they make over 20 inches of vacuum. The vacuum pod that is currently on my ford (with vacuum booster) came off of a 6.2 and works fine. From what I have seen, you will notice heater control problems, and trans vac. modulator problems from a weak pump before you notice a problem with the brakes. Also on the fords, (and dodges with vac boosters) they have a low vacuum switch that turns on the brake warning light if vac is low.

 

[longbedder]

Have you (or anybody) actually seen frame failures due to a Cummins swap? I've seen my fair share of frame issues on the square body Chevy's but never one directly because of a Cummins swap, mine has ~200K on the swap (first swapped in '97) and the frame is all stock, no issues (although it is a K30 frame).

Well, no, but I did say "unless some serious frame work is done first." I don't have to look in a hooker's mouth to know getting a beej from her is probably a bad idea.

Every one I've seen has had the frame boxed and the crossmembers replaced with custom units. That goes for the 4BT as well as the 6-cylinder conversions I've seen. All the ones I've seen have also been undoubtedly cool rigs.

I don't mean to discourage the OP - I had a Cummins sitting in my shop intended for a swap. After figuring out what it would really take, however (and having a new family and priorities), I sold the engine. The tongue-in-cheek advice is: find a complete Dodge, pull the body off, and figure out how to put whatever other body you want swapped onto the Dodge chassis and drivetrain.

 

[campfire]

The pump outlet (on all that I have seen) is 3/8. Healthy, they make over 20 inches of vacuum. The vacuum pod that is currently on my ford (with vacuum booster) came off of a 6.2 and works fine. From what I have seen, you will notice heater control problems, and trans vac. modulator problems from a weak pump before you notice a problem with the brakes. Also on the fords, (and dodges with vac boosters) they have a low vacuum switch that turns on the brake warning light if vac is low.

Noted. I'm surprised. I always thought the Ford/Dodge diesels with vacuum brakes had larger pumps. But I never had the opportunity to check.

Color me surprised. Why did GM feel the need to go hydro? Would the O.P. see any downsides if he kept his current setup and simply hooked it up to the 6.2 vacuum pump?

 

[black dawg]

The one thing that I didnt think of, is that on most 6.2s, the vacuum pump is drive is driven off of the cam. I wonder if the speed is the same as the others that are belt driven...I will have to find some pulleys to measure.

 

[blackandgold51]

I don't have a vaccum-boosted square-body to measure, but the 6.2 vacuum pump outlet line is significantly smaller than what usually runs to vacuum boost units. The reduced flow would cause the brake booster to react slowly, no? I don't know GM's reasoning in forcing all 6.2 trucks to have hydroboost brakes, but I reason that they would have used normal brake systems in the 1/2-ton and 3/4-ton rigs if it had been feasible.

Well, no, but I did say "unless some serious frame work is done first." I don't have to look in a hooker's mouth to know getting a beej from her is probably a bad idea.

Every one I've seen has had the frame boxed and the crossmembers replaced with custom units. That goes for the 4BT as well as the 6-cylinder conversions I've seen. All the ones I've seen have also been undoubtedly cool rigs.

I don't mean to discourage the OP - I had a Cummins sitting in my shop intended for a swap. After figuring out what it would really take, however (and having a new family and priorities), I sold the engine. The tongue-in-cheek advice is: find a complete Dodge, pull the body off, and figure out how to put whatever other body you want swapped onto the Dodge chassis and drivetrain.

Hmmmmmm. I wonder how I can do that.

And where I can find a cheap donor truck with a Cummins.

But if I can't I'll just put in a 6.2 or 6.5 diesel

 

[campfire]

Hmmmmmm. I wonder how I can do that.

And where I can find a cheap donor truck with a Cummins.

But if I can't I'll just put in a 6.2 or 6.5 diesel

I see MightAsWell syndrome has set in....