4bt swap 3/4 ton rig

Yay!Gurrr

Better Faster Stronger
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I posted on Pbb but know there is a lot of good local tech out there... Im forming an 'exploratory committee' simply to evaluate this as an option...

Whats a used 4bt sell for ?
weight ?
operating rpm range?

would it make a good 2wd 3/4 tow rig to pull a single car trailer ?

from reading it seems it is limited (with basic mods) to ~150 hp and ~300 torque.. That seems like it would be almost perfect for a smaller tow rig.. It would be replacing a 454 so weight would be similer.. It would definitly fit... I've found a 4bt swap yahoo groups site with lots of good info and pics, a few even in similer chevy trucks..

Just looking for feed back ?



a few nice pics of a 91 chevy swap.. (not mine)

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My understanding is that they range in price from $500-3500 depending on when, where, and shape. Operating range is right around 2k like other diesels. If you could get a good enough deal on one it would be a worthwhile swap, but I would rather get a 12v cummins. the 4bt does really good in a jeep though.
 
I've seen a few in early Bronco's. The perform well in the smaller rig. I had a chance to buy an 2wd early 70's Ford F250 crew cab. Pull the bad 390 and drop in a 4BT. I think it would have been a good tow rig. Just short on time, space, and extra cash...
 
If you can get a more complete part number I can give ya specific pricing info new. (the 4BT is a style there are ~ 20 different 4bt engines)

A RECON (which is a cummins remanufactured product complete with same warranty etc.) 4BT-DR112AGRX List price is 4222.50 meaning we could probably source one ~ 3200-3500...

A 4BTA core charge is 1950, so 1000 for a rebuildable core would be a good deal if you wanted to go the RECON route...

PM me if you need more specific info ;)
 
Holy crap that would be slow..
 
I had been thinking about puting one in a Grand Waggy and using it as a DD
Yep I think it would be fine for a trail rig lot of people use them and cool in a DD but for a tow rig I think it would be a little slow and under powered. For a tow rig like you are talking I would go for a 6bt 12V.
Also look at a 5-6 speed stick. Just going off the 96 ctd with a auto.... It pulled like a dog and did not like the hills with an auto but I have run a few with the 5 speed and they do fine.
I think the 4bt was fine for what they wanted to do in a bread van and hauling chips. Those vans are not at the top of the list in weight plus they never towed. We had one for catering and on 440 it was all it could do to keep up, think most of that was gears- not setup for the highway.
Jon
 
Hey Mike!

First, my choices for your situation if it were me, ranked in my order of preference (which you didn't ask for so just ignore) :)
1) Keep your U-Haul truck!!! :lol:
2) If you definitely want the Chevy, keep the existing 454 that's in it
3) Rebuild the existing 454 in the Chevy if it needs it.

With that said, I love 12V Cummins engines for the simplicity (no electronics), good power, and good reliability.

But a 454 is also good. The one in my rollback has been great. Only complaint is the fuel mileage (of course). For comparison, the 6bt (lightly modified) in my 79 K30 has as much power as my 454, but gets better mileage, and cruises steadily at a lower RPM (yes, quieter than *my* 454).

If you are thinking the 4bt will have 150hp/300tq, I would compare it to the 6.2L in my 1990 Burb. The stock C-code 6.2L (has EGR, less power than J-code) has 145hp/250tq. Here are my experiences:

weight of Burb: 6000 lbs (scaled)
4WD 1/2-ton
3.42 gears
TH700R4
235/75/15 (28.8-inch) street tires
redline (governed) 3600 rpm

The Burb does fine daily driving, but would ideally have 3.73 gears instead of 3.42. It is BY NO MEANS fast at all. But I think I'm a slow driver. I run 10mph over the speed limit, but I don't accelerate fast.

I have towed some with the Burb. A stock 350 would out-pull it easily (I am comparing to my stock 1990 K5 with TBI 350 - 200hp/300tq). But it does get the job done around here. I would never plan to tow thru western NC in my Burb in current form - it would SUCK on the big hills.

The most I ever pulled with the Burb was 6500lbs (my TJ on my trailer) to Uwharrie. The steep (but not too long) hills near Uwharrie had it dropping to 45mph, but was I having cooling issues (clutch fan was bad) so I couldn't keep the pedal down. Towing on I-40 it never dropped below 55mph on any hill, and could hold 65 on most. As a comparison, with my TBI 350, I could leave it in drive and maintain 65 on the hills.

When towing, I just leave the Burb in Drive and don't use OD at all. I run about 65mph but have the RPM to do more. That's one issue I'm glad you're looking at with the 4bt - usable (and reliable/sustainable) RPM range.

I think *most* people would NOT be happy towing with my 6.2 Burb. I was OK with it, but was planning to get a little more power (intake and exhaust) and adding a little more gear to make it work. But now I have my K30 with 6bt, so the Burb never tows over 3k.

From the 6.2L I get an avg 18.5mpg empty and a low of 12mpg pure towing when I towed the TJ to Uwharrie (other towing has been 14-16mpg). I have heard on coloradok5.com of someone with a 4bt in a Blazer getting over 25mpg empty.

So your 4bt may have 50 more lb-ft of torque than my 6.2L, and you can install a spring in the inj pump to give you 3000 or 3200 rpm. I think it would work, and if you are like me, you might be happy with it. Compare it to my experience above - hopefully with the extra torque and a little more gear the 4bt would work for you. But remember that a stock 350 TBI will be equal or better in power and have a greater RPM range.

Would I put a 4bt in my rollback or K30? No, it would not pull the kind of weight I put on them (sometimes 20k GCVW). But what would I put in my Burb if the 6.2L ever died? 4bt all the way. More power than the 6.2L and better mpg.

Keep us updated on what you decide!!!
 
Someone on Pirate mentioned the Cummins shaking you to death and being noisy. I don't think it would. My 6bt is fine, and it quieter when at a steady RPM than my 454, because I have to turn more RPMs in the 454 to maintain the same speed. Accelerating the 6bt is equal or louder to the 454, but I have no muffler on the 6bt, and I love the way it sounds. :driver:

Also, I am sure your front end would have no trouble with the weight of a 4bt, since it is already handling the 454.
 
Thanks for the good info richard... I read a good deal yesterday and i think this engine would be a super daily driver (DD) engine.

I plan to clean of the current engine (454) check compression, etc. and tow with it as is to establish some base line for the truck/mpg/performance.

The reason I keep indicating a 350 over the 454 is I have one waiting for me for cheep. Its a 93 HD350 (4bolt fordged crank etc) I know from towing with the 350 in the white chevy even the whiped 350 w/ 190k was capable of getting 10mpg and holding 65 on the highway, even hills with droping out of OD and running some RPMs, Im sure a fresh engine would do better.. Same truck/engine got 17mpg on the highway (empty) doing 70 upto NY and back.. This is acceptable to me as far as MPG goes..

I still need to sell the camper before i do anything... So you may very well see me driving it around in the spring :)

Thans guys
 
Mike explain why you are wanting the 4bt pver a 6bt. Is it the weight factor, or the fuel mileage factor or what? It just seems to me like there is a good possiblility of the 4bt not living up to your towing needs, where as you know the 6bt would. I would hate to invest a lot of time and money into a project that might dissapoint the first time you hook a trailer to it. Just my 2 cents.

BTW i happen to know someone with a 6bt and a nv4500 that is just sitting around taking up space.
 
My thinking was that we all know how the 6bt can pull a 50' trailer with 10 jeeps on it, doing 80 mph up black mountain. My purpose for asking about the 4bt was to see what it was capable of. As i said at the very begining i was evaluating its potential.. I'm not sure im up for a 6bt swap at this time :)
 
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