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I am considering a Cummins 4BT (2nd generation) repower on my truck in the sig below because I want to have a more reliable and economical engine once I am done. I lean heavily toward the 4BT for several reasons: availability of engines, parts, conversion kits, knowledge base, ease of conversion (in my case), compatibility with current trans, etc. However, I have several questions about the 4BT - I have never seen or driven one. Please report as to whether the info I have gathered is accurate or not.
1) Noise and vibration. I have read several posts here and other forums that the 4BT is very noisy and has a lot of vibration (“will rattle your teeth out”).
2) I have read that the 4BTs after 93, 2nd generation, have the “internal balance option” so they have much less vibration.
3) I plan to rebuild the engine before installation and I have read that the 4BTs are expensive to rebuild.
4) Does the 4BT have cylinder liners?
 

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I know these things vibrate and are noisy but using a good rubber mounts and soundproofing material helps greatly according to others. I don't know about post '93 motors and dampeners. As far as rebuilding goes, if you have the shop manual it isn't hard ata all. One section is totally devoted to a step by step dismantling of the engine for rebuild. It even walks you through reassembly. Yea parts may be expensive, but at least you can do it yourself if you have confidence and some experience turining wrenches. As far as I know, the cylinders are sleeved (they have liners).
 

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1989 Jeep Wagoneer, 360v8, 727, stock for now,
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When you say 2nd gen I'm assumeing your talking about 94 and up with the P pump. These are no more or less in vibration or noisy than the first gen, VE pump engines. IF you want to know how they sound, open the hood of any Dodge CTD and just imagine it with 2 less cylinders. Take a ride in someone's 94 or later Dodge CTD, its quite inside. It aint rocket sicence to quite a Diesel, just add some noise dampening stuff.
AS far as rebuilding the 4B, the OEM parts are the best and the most expensive. Other parts for rebuilding are aviailabely. And no the Cummins B series is not a wet sleeve. After it has been bored out to max a (dry) sleeve can be installed to bring it back to a stock bore.
I've had my used 4BT engine in my Scout for 5 years and still running strong, after a life of pulling potato chips around (1988 build) . Rebuild it, maybe after another 100,000 miles. If its working don't fix it.
 

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I agree [again] with Scout 4BTA.

1) Noise and vibration. Yes, it's somewhat noisy but it depends on what vehicle it's going in, and as mentioned, what sound proofing is done. The vibration is there but mostly a shuddering at shutdown. It won't rattle your teeth out if it's installed correctly with the right mounts! My truck is not well insulated but you can have a normal conversation at any speed or rpm.

2) You can install a fluid damper and use the right motor mounts and have very little problem with vibration. I don't know anything about the 4BTs after 93, 2nd generation, with “internal balance option”.

3) I can't see any reason to rebuild the engine unless it's worn out. If it's under 150K miles you shouldn't have any problems. I expect mine to go at leaset 500K before needing a rebuild, if it would even need it then. There are in frame rebuild kits for $500, which is nothing but cheap.

I did a LOT of research before deciding, and there's nothing out there that begins to compare to a 4BT.
 

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When you say 2nd gen I'm assumeing your talking about 94 and up with the P pump. These are no more or less in vibration or noisy than the first gen, VE pump engines. IF you want to know how they sound, open the hood of any Dodge CTD and just imagine it with 2 less cylinders. Take a ride in someone's 94 or later Dodge CTD, its quite inside. It aint rocket sicence to quite a Diesel, just add some noise dampening stuff.
The last engine I pulled had a manufacturing date on the CPL tag of 1999. It was equipped with a Bosch VE rotary pump. It came with the standard rear sump automotive pan and there was no internal balancer. The term "second generation" may not always apply to the same years as those pertaining to the Dodge Cummins applications. Remember the industrial Cummins came with other pumps such as Lucas & Roosamaster DB and the pump used was usually determined by the engines application.
 

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same here, mine has a year of 1996 on it and it's got the VE pump.

Those 1/2 ton Diesels are pretty cool trucks, mainly because they are so rare and nothing like it's available from anyone else. I've seen a few go for good prices since i started my project, otherwise i probably would have jumped on it. A 6BT would be sweet in one of those too :D

Edit: how do you plan to get the electronics for the trans to work with the 4BT, install ALL of the sensors and stuff on the Cummins? I'd love to find one of those trucks with a 5speed.
 

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Those later model 4bt's are HAAARD to find. As far as benefits they arent worth the trouble looking either. Ive got a P7100 6bt that im working on to replace my VE motor. In a 6 cyl the increase in power capacity is substantial and perhaps worth the trouble, but in a 4bt its a waste. Your not looking at huge horsepower without just going crazy and risking the 4bts longevity. The ve pump motor is a proven success and Im happy with its simplicity and availability. NOW to clear up the previous statement, a 4bt does not have liners, nor does a 6bt for that matter. To rebuild a b series engine isnt that bad either. Its noisy and rough, but its music to my ears.
 

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Discussion Starter #8
Late Response

Sorry for the late response. I was on vacation and then got sick! And thanks all of you for your input - VERY helpful.

Diesel Durango,
I have not gotten into the details yet but, I was thinking/hoping that I would keep the current PCM (powertrain control module) which controls the engine and trans and connect a tack input from the 4BT. Again, just guessing at this point.
You have made me question whether I should replace the engine in this truck at all! It is rare, as a 1/2 ton diesel and 98 being the last year they were available - and it is working fine right now. The truck may be worth more keeping it stock than replacing the engine with a 4BT!
 

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My motor is a '97. It does not have a ballance shaft either.
I see no reason to rebuild one of these motors until it is time.
I have not driven one of the 4bt's in a conversion. I did drive the Frito truck home. It was noisy to the extent that I wish I would have had hearing protection along. After 10 hr driving I was nearly deaf, of course you are sitting right on top of the engine in a Frito truck. There is a little insulation right on top of the motor, but that's all! LOUD! I like the way they sound when listening to them idle. MUSIC!
Later Frito trucks with the 6.5 have the 4L60 or 4L80 transmissions. I think there is a stand alone computer box that controls this transmission in those trucks. If you got the 4bt from one truck and the 4L80 from another and then put the 2 pieces together you may have a real winner.
Hopefully anyone that is working on or planning to do one of these conversions has had some serious experience with autos/trucks before. It is not for a beginner. There will be major home fabrication needed. Just the physical size of the truck can create a major problem. I couldn't get it in my garage to do the work. It was too tall and too long. I had to disassemble in the driveway. I live in a subdivision, and am hated by my neighbors.
 

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Sorry for the late response. I was on vacation and then got sick! And thanks all of you for your input - VERY helpful.

Diesel Durango,
I have not gotten into the details yet but, I was thinking/hoping that I would keep the current PCM (powertrain control module) which controls the engine and trans and connect a tack input from the 4BT. Again, just guessing at this point.
You have made me question whether I should replace the engine in this truck at all! It is rare, as a 1/2 ton diesel and 98 being the last year they were available - and it is working fine right now. The truck may be worth more keeping it stock than replacing the engine with a 4BT!
since you have all the stuff and you know it works, it's just a matter of making it all work with the 4bt. I have no idea how hard this is, but so far i've found adapting things to work with stuff they weren't meant to can be a real pain. I don't know a whole lot about those 6.5's but don't they have some sort of electronic injection? If so that seems like it could be a problem to me. The pcm might not get all of the right signals if it isn't there...maybe?

you could always put an NV4500 in there too :grinpimp:
 
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