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Discussion Starter #1 (Edited)
Rather than wrecking anyone else's threads I will post my .02cents here....

--Not every vehicle was meant to have a 4BT, although almost everyone can fit it I would be concerned with weight. Dry the motor specs in around 750+ lbs, they were notorious for wearing out the P30 Chassis front ends due to weight. So a honda civic is not a good candidate for the swap. Know what your vehicle's front end is rated for weight wise and make the safe decision to beef up components or stay away from me on the road.

--Its a torquey rascal, It WILL tear up stock diesel app clutches, I've witnessed one motor eat 3 6.2L clutches ar 4000 mile intervals with correct installation due to the torque of the motor maxing out the dampener springs.

A $350 clutch set later its holding some of its balls.....I've also seen a driveline parking brake ripped to peices when it was accidentally left on and Jesse from High Angle wanted to see it because not even the Big block apps had done that.....and watched one bust rear spring pearch tack welds and roll the whole pumpkin over....Cummins sent out a service memo of updating and beefing up even the th400 for the 4BT app, its got a special deep transmission pan integrated into a lower bellhousing flywheel cover. The two options with the 4bt in the P30 vans was a SM465 and a TH400, run anything subpar and pay the price, A high HP tranny such as a built 700R4 will not likely stand the test of time to super low RPM high torque numbers. Even if it does will the housing last?

--The plus side of things are its extremely efficent, hard to overheat and extremely reliable.

--Its no speed demon, I have yet to see a 4BT run a 14 second quater mile but it can get out of its own way.

--Cost of the swap, be careful deals are out there but the overall upgrades and unforseen other costs, driveshafts, axles etc can easily put the swap near the $7-10K range. I have a total of 3K in mine so far
 

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Not sure I follow

Valid point regarding being safe with what you build. Make sure everything is supported..........
However, Ill counter with I dont see how a 740 pound motor is the "alleged" cause of front end failures. How can you blame the 3.9 when P30s could be had with 6.2 (1100 pounds) and 454s? I dont see the correlation rather a generalization. Far more 6.2 motors were put in the Cummins.

True the 4b is not for every vehicle.....still working on the 4b chopper:smokin: This is just a group of people who enjoy putting it in whatever is lying around. We think it is a good motor. Any forum will be jaded to whatever they are gathering about.

Anyway, thats all that came to mind........
my humle opinion

Id love to hear other peoples thought too!
 

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Yeah, it sounds like an isolated incident (front end failing) Aside from the weight of a 4b not even comming close to a 6.2 or BBC, there are far too many variables such as driver habits, proper freight loading, proper maintenance (thats usually the cause in any case).

For the 4B ripping apart 6.2 clutches, not sure what to make of that. Bad lot number, Im not going to make this personal and attack proper installation, second rate brand, etc. 6.2 clutches were not powerhouses and their clutch design may have reflected that???

A 6.2 was rated at peak power from GM at 3600 RPM and little peak power at that. I can see where a B motor makes its peak power say at 1800 RPM, the torque pours on hard and fast, not weak and gradual. To me the design of clutches would be so different, neither would work good or function in the other application.
 

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the big thing I think is cost.. I did the math on a land cruiser conversion lately.. Here is what I came up with in parts alone:

Spring Over conversion, necessary to clear front axle - $1500
NV4500, $1200-$1500
Bellhousing adapter for GM NV4500, $550
T case adapter, $600
Exhaust - $300
Radiator - $200
Misc parts, hoses, fluids etc, $500
Used hydroboost - $100
Driveshafts - $400
Steel for motor mounts/crossmember etc- $50

About $6G, before the cost of the 4BT...
 

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another thing to consider...

I have done some messing with an RPM calculator. I really really wish I could use 3.73 gears with my 35" tires (34.7).. I would be at 1800 at 70 mph, which I think is about perfect...

I have been trying to figure out why at highway speeds over 70 my mpg went way down. Because I have been using 4.1 gears instead.. Even with an overdrive at .73.

Here are fuel consumption data sheets...
http://autos.groups.yahoo.com/group/cummins4BT/files/


Here are transmission gear ratios:
http://www.garbee.net/~cabell/transmission.htm

Photos: 4BT and 4BTA consumption graphs, left and right, in order...
I found that the 4BTs more closely mirror the 4BT graph...
 

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conversion costs

No doubt conversoins are costly. I think most people get away with swaping motor mounts and using exsisting transmissions (GM, Chevy swaps). But I think this is where we oil burners come out ahead.

With the presumption that a correctly done conversion (More power is usually the key so cooling system, clearances, accessories, cross members, etc) addresses all areas. We get to reap the benefit of fuel milage! Really the costs are in the motor itself and adapters. At fuel prices right now, wont take long to get it back:smile:

Also service life of the motors is MUCH longer. Thats a factor too. I look at these swaps as investing. In the short term, you are behind. With time, the dividends are exponential!

More IMHO food for thought.

Ausitn
 

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Things to Consider

When I first started looking at a 4bt as a viable swap I was more concerned about performance than the cost or mechanics of making the motor work. Having most of my experience in gas engine performance, I was skeptical about developing the performance needed and preserving the reliability the 4bt is known for. That is until I took a stock CPL 858 and put it on the dyno.(see http://autos.groups.yahoo.com/group/cummins4BT/files/Dyno%20Results/ ) Prior to this dyno run I spent a considerable amount of time researching after coolers, injectors, turbo solutions, custom manifolds, and porting and polishing. My finding are the engines are very capable of being tuned to 250+ HP and 525+ lbs of torque. So IMHO put the time and money into accurate tuning results first, then when you have the results you like, decide if you have enough suspension, drive train, and brakes to control these little beasts.:grinpimp: :grinpimp:
 

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Discussion Starter #9
True the 4b is not for every vehicle.....still working on the 4b chopper:smokin: This is just a group of people who enjoy putting it in whatever is lying around. We think it is a good motor. Any forum will be jaded to whatever they are gathering about.
I'm in no way bashing the motor, it just is a factor unlike any other when dropped into any aftermarket app....its not just another motor its a factor to be designed around.

The P30 situation comes from a friend who used to work on frito lay trucks. The 350 trucks didnt have near the front end problems. He did however say he hadnt seen any head gasket problems, so its hard to actually overheat the motors regardless of idiot driving habits.
 

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You make a great point on your first post which I guess got lost in translation. In ANY swap, EVERYTHING needs to be accounted for for your and others safety, reliability, and enjoyment.

There are many who just slap stuff together "because" which I have personally seen almost costing lives:skull: Thats not the name of the game. Plan, build, show off, and enjoy
 

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When I first started looking at a 4bt as a viable swap I was more concerned about performance than the cost or mechanics of making the motor work. Having most of my experience in gas engine performance, I was skeptical about developing the performance needed and preserving the reliability the 4bt is known for. That is until I took a stock CPL 858 and put it on the dyno.(see http://autos.groups.yahoo.com/group/cummins4BT/files/Dyno%20Results/ ) Prior to this dyno run I spent a considerable amount of time researching after coolers, injectors, turbo solutions, custom manifolds, and porting and polishing. My finding are the engines are very capable of being tuned to 250+ HP and 525+ lbs of torque. So IMHO put the time and money into accurate tuning results first, then when you have the results you like, decide if you have enough suspension, drive train, and brakes to control these little beasts.:grinpimp: :grinpimp:
you are running 250hp and 525 tq in a cpl858? and thats reliable? what are you doing for inter/aftercooling, axles, etc????
 

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you are running 250hp and 525 tq in a cpl858? and thats reliable? what are you doing for inter/aftercooling, axles, etc????
No, my engine is not tuned to 250 and 525+. I was just commenting on the capabilities of a CPL 858 being tuned to those numbers. I'm currently tuned to 172hp and 426ft. lbs. of torque with reliable EGT, oil pressure and temp numbers, controllable boost, and water temps. All I was saying is based on the dyno numbers, the tuning adjustments getting to 250 and 525 is completely within reach. I'm currently running DynaTrac pro rock 60's with 4:10s. I would also say that to run at 250 and 525+ some form of aftercooling would be required help control EGT's.
 

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What did you do to get the 172/426 numbers? Just a pump adjustment or different turbo with air intercooler? I assume that is on stock injectors?
 

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What did you do to get the 172/426 numbers? Just a pump adjustment or different turbo with air intercooler? I assume that is on stock injectors?
Check out the "Engine Run Data Sheet" in the Dyno Results File. All tuning adjustments were done using stock injectors, turbo, and no after cooling.
 

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Check out the "Engine Run Data Sheet" in the Dyno Results File. All tuning adjustments were done using stock injectors, turbo, and no after cooling.
That is great information, somehow I missed it. 200-225/450-475 should be possible with a turbo and cooler with stock injectors. That finalized my transmission decision, it will not be an automatic, now I may have to reconsider the Ford 8.8" rear. :smokin:
 

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what are the egt's under full load?
how long have you run it this way?
is the yellow one where you currently have it set?
thats the equivelent of 270hp/650tq from a non inter/aftercooled 6bt with rotary pump.
The EGTs were a result of the engine being loaded by the dyno. How that works is, the dyno will accelerate the engine at 100 rpm (or wherever you choose to set it) per second while applying and measuring the load (torque). It is essentially full load based on the ability of the engine to hold the load without deceleration. The tuning results are directly from the dyno runs. The reason for averaging 3 dyno runs to compile a net result was to make sure the engine was operating at real temps. I was concerned about high egts. The yellow run was run at 300 rpm per second to observe turbo response. I then backed the tuning out a little and left it set with the "Blue" settings.
 

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This is totally awsome material. I don't think that you realise how much you have helped out the 4bt community. We all owe you a thanks for getting this info. The dyno results are exactly what we need, not some "oh do this and I 'think' you will have x-amount of power"
Next what we need is someone to do some of the same dyno tests and then try different turbo exhaust housing sizes. Then maybe even a different turbo. bounce
 

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I,VE seen alot of these engines with burnned pistons, and a whole bunch with the centers of the clutch disc ripped completely out not to mention double that with spring breakage in the disc . alot of folk say they make a bunch of horse power and torque but knowbody post any specifics such as fuel pump pressures, turbo, timming, piston compressions, injectors etc. part numbers . lets see some specifics. it takes the whole combination to make power & torque. if you change one component you have to change the others to match it.
just my opinion
bob
 
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