Here's the deal: I'm putting a 4Bt into a '67 Dodge Town Wagon, with NV4500 and a Dana 60 HD rear [ribbed case] 4.1 gears, 2WD. Got some new front 1,500 lbs springs from Eaton, adding a '70 D-200 front axle, and will be adding in some leaves in the rear from a D-200 so it will be about 1 ton rating. A rebuilt steering box is on the way from Firm Feel, plus replace tie rods etc.

Stock 4BT is 105hp, and it's the same engine as the 12 valve 6BT, minus 2 cylinders. I've already gotten some good info here, but need to narrow it down on performance upgrades. Long hiway miles towing a 30' trailer [6-7K?] with truck itself weighing 4,500 lbs. and reliability a major point!

I'm figuring that I should be able to look at a healthy and reliable performance level for a 6BT and then do the same on the 4Bt. What maximum hp level is still very reliable in a 12 valve 6BT, and what does it take to get there?

Same VP44, so does it not work as hard in a 4BT, or is the reliability the same from 4BT to 6BT?

Want more injector, but are POD's overkill in my application, and what would be best? Should I look at a Walbro lift pump, or is that too much for a 4 banger?

I've read of the various freebie or cheap upgrades, as fuel pin, fuel plate, smoke screw etc. and this truck will have a 3" exhaust which should do for a 4BT. Any further recommendations really would help, THANKS!
JimmieD

 

I guess the first thing we need to know is what injection pump is on the engine. Inline pump like the P-pump or A-pump or a distributor pump like the Bosch VE or a CAV (similar to roosa master).

Then you can determine what tweaks to make and of course gauges will be necessary.

 

Convert it to a P-pump for sheir ease of modability haha. then run 215s or 300s no exhaust restriction, maybe a larger turbo, a bhaf...and have some fun!!!

Dom

 

Engine is currently installed in a P-30 stepvan so CPL tag is very hard to read for a bling old guy. Family #382, CPL #0858, and looks like it says Injector #3912468 [maybe 3912458, not sure]. Another number says Engine [can't read the rest] 44557437. Another space says Pm 0.60. That's all the data I can get wihout pulling engine, and not quite ready yet....

 

Anybody know if this 4BT has the KDP, or is that only a 6BT problem?

 

Most likely it's a VE44 mechanical rotary injection pump, not the electrical VP44. If that's the case, you should be able to do any mod that would be done to a 6BT to it.
KDP: when you get the engine out, it won't hurt to remove the timing cover to inspect the kdp, tap it, tighten all the other accessible bolts, some remove, clean, then loctite them. Then replace the front and rear main seals. It's easier to do them out of chassis than in.

I would think at 12k pounds it would be a dog. Are you sure you can't get a 6bt in the Wagon? Whatever mods you do to it, you'd be watching your pyro while towing. Even stock I bet it would be somewhat hot.

Is the engine intercooled or non? For towing, I would definately want an intercooler. I think 4bt owners upgrade to a hy35, with 9 or 12 cm housings.

 

The truck alone weighs about 4,500 and I hear guys on this forum saying their Cummins 4X's are up to 7,500 lb. Dividing their 7,500 by 6, multiplying times 4, I seem to be about 500 lbs under their weight, and at 105 hp I would be equal to a 157 hp 6Bt in a 7,500 lb truck.

The engine supposedly only has 48K on it. Are front and rear mains a weak point? I guess if it's got the KDP it should also get a tab with the Loctite?

I think you're right that it's VE44, not VP44.

Don't know which turbo it has but yes, the HY35 was suggested before.

I just don't want to do more harm than good on this as it's a long term driver for me. That's why I'm asking a second time, just to be sure of good safe upgrades. Thanks for the tips!

JimmieD

 

Only the 4 BTA's would be aftercooled.....BT series is turbo without aftercooling. I don't see why an aftercooler couldn't be installed, though.

It is either a P pump or a VE....either one will provide a healthy dose of additional fueling. I have a come across a few swapped in 4 BTA's that have reliably cranked out 250 hp with a 9 cm HY35.

 

1st gen (which are VE pump equipped) 4x's are only around 6,000-6,500lbs. 2x's are 5k-5,500lbs. 157hp in a 7.5k truck = . Then less cubes for the medium duty workload. The weight difference isn't that much between a 4b and 6b. Yeah you can add injectors, turbo and mods, but you're still only at 3.9 liters and it will be working hard to keep things cool, cooling system, egt's etc. I could be way off, but if I was looking for a tow rig, I wouldn't use a 4b. A toy or wheeler yes. I knew a guy that installed a 4bta in his old model 1 ton dually- a 7,500lb truck, and he hated it. A dog, no power, etc. He eventually found a 6bt to put in its place.
Not really, but they sure are easier to change out of chassis. If they are both bone dry and show no crud buildup, then leave them alone. But if you remove the front timing cover to inspect bolts and kdp, you will need to install a new front crank seal anyways. If the crank has any wear or grooves, then a wear sleeve along with new seal will be in order.

Just off the top of my head, if I wanted a reliable 4bt, a low pressure piston lift pump (that us 1st genners are upgrading to from the diaphram lift pump) 13-18psi idle vs. 3-5psi idle, more reliable, less likely to fail etc, an upgrade turbo and housing, maybe a set of Bosch 190 injectors or if you have a non-intercooled engine, the stock injectors are already bigger, I'd keep them- possibly have them reworked, calibrated etc. Intercooler or aftercooler to keep things cool and added performance. Governor spring inside the injection pump to allow more fueling up to 3200rpm. Intake and exhaust upgrades. You should read up in the 1st gen forum, since that is what you have basically.

 

Is the HY35 a stock Cummins item, or could you suggest what they came on or where to get one? Thanks.

Yes, the stock hp rating for Marine 4BT's is 250 horsepower. These may be 4BTA, don't know for sure. Haven't been able to find out what they do to get those numbers, and of course they have LOTS of cold water available for cooling....

 

Bingo! The marine engines can achieve their ratings because they can cool the coolant, combustion air and oil with basically an infinite supply of cooling medium.

Rusty

 

[QUOTE=JimmieD]Is the HY35 a stock Cummins item, or could you suggest what they came on or where to get one? Thanks.QUOTE]

2000 and later automatic equipped rams have the HY-35. Should be easy to find since most guys in search of more power ditch these.

I have been contemplating a 4BT into my 1979 Cherokee. I would get the aforementioned turbo, add an aftercooler, check for the KDP, and if turning up the pump does not provide the required power, then go for some injectors. That said, I do not plan to tow. Like the others have said, you may not be satisfied with the power output. You may need to rethink your repower and look at the six cylinder.

 

Thanks for the info and tips! I'm hoping that with my 4.1 gears, NV4500, 4,500 lbs truck and trying to keep the trailer fairly light that it will be okay. I'm not in any hurry when I travel so shoving it down in 4th, 3rd or 2nd, whatever, is just fine. Though they're a little low on h.p. in stock form the 4BT torque numbers are similar to a 318-360 so it should be able to do the job. Mild tweaks will quickly bump the torque up to nearly big block specs. I'll just have to see how it goes because I want that 4 cylinder economy more than 6 cylinder grunt! Thanks....

 

I had a 4BT in an old bread truck turned up. I put a pyro on it first then added fuel to 1100 *. This truck would out run a 400 sb chevy. The chevy had an auto, the 4bt was a 465 4 speed!! It did this with twice the fuel mileage too.
It will get the job done for you if you tune it right.

Loaded the bread truck was at 11,000 pounds.

 

Talk about telling a guy what he wants to hear!!!

That's just about the way I had it figured, J-Fox. With the proper gearing anything is possible and they're a torque monster compared to a gas engine. Like you said on mileage, and even this stock 18 foot breadvan got killer mileage the few trips I've driven it. I'm not looking to go fast or tow at 75 mph, so I figured it should do the job. THANKS AGAIN!