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rebuilding my 4bt

11K views 42 replies 11 participants last post by  ambulancechser 
#1 ·
I just took my 4bt down to the bare block so I could inspect everything and see what I have to work with.
Everything looks good, its front bearings were showing copper but the rest looked good. I think it started to lose oil pressure but it was cought in time befoer major damage was done. So new oil pump and a rebuild kit and should be good to go. The problem is they what the cpl # and the tag is missing. How do i find out what kit i need? what company to go with ? any help wolud be great thanks
 
#2 · (Edited)
... So new oil pump and a rebuild kit and should be good to go. The problem is they what the cpl # and the tag is missing. How do i find out what kit i need? what company to go with ?

You can try and google the part numbers you have on various parts and see if you can figure what they came with.

But before you order a kit have the bores looked at and measured. Even if the cilinders don't need to be rebored they'll need to be honed. The machine shop i took my block to cleaned, magna-fluxed and took all the measurements of the block for ~$70. it's probably a good idea to have them look at the head, it'll likely benefit from a valve job. Once you're there you may as well take the cam and crank with you and have them looked at.

What are you planing on getting out of the engine?
 
#3 ·
my buddy is bringing his miks over on monday to check every thing and was planing on having it honed.
i am planning about 300 hp. hopeing every thing is good i dont have a big budget for this project
 
#6 ·
You might be able to squeeze 200hp on a budget but definitely not 300.
Dave
 
#8 ·
i alredy have a 250hp pump that was just built and a hx35 so 300 hp wont be to hard. so most of my budget went to the pump. i am not trying to say i am going to cheap out on the motor build, i am going to do it right i only want to do it one time.
 
#10 ·
i am going to do it right i only want to do it one time.
There's no reason for you not having what you want. If you're not in a hurry you can put it together, money after all is just means to help you negotiate through life.

I'd spent whatever money you got on machining first. Decking and o-ringing the block, reconciling the rods haven't been mentioned here.

What do you need 300hp for anyway?
 
#11 ·
why I want 300hp is when I built my bronco it ended up with 100 hp and its boring to drive. i swore not to under power again. I dont have to have 300hp but it would definitely be alot of fun. i appreciate all the input from everyone but no one has answered my main ?. How do i get the right rebuild kit without the ID tag or do i not need any of that info? Thanks
 
#14 ·
If you have a 250 hp pump that sounds like a marine P pump. Not necessarily the ideal pump for a road engine.
What's so different about a marine p pump? Is it the governor?

And how does it get 250hp? Different fuel plate, plunger/spill port geometry or what?
 
#15 ·
You don't need anything special for a rebuild kit. Measure for bearing size and piston size. I'd put marine pistons in it. Now tell me more about your pump please. Also your hx35 won't like 300hp.
 
#17 ·
the pump was biult by columbis deisel in ohio for a guy that was going to put a 4bt in a s10 he lost intrust in the project and sold every thing. i got the pump with the recit for the biuld, call and spoke with the guy that biult the pump and it is set up for road use. i also compared it to the pump on my 6bt and the gov looked exactly the same. thanks for all the info
 
#18 · (Edited)
You may be able to trace the SN of the original pump if you still have it and find out the engine's ESN that way,
I think i remember a thread in which CrewCab59 gave someone their ESN after that member posted a pic of the pump tag.
 
#20 · (Edited)
i dont remember what the cc's are at and i think the gov is set to 3200 i was going to call them when i get closer to geting it together. we mesured every thing today rods,mains are ten under and look good.the motor has been gone throw befor. there are good part # on every thing so i should not have any trouble geting the right parts
 
#21 ·
i have my motor build mapped out at this point my plan is to balance the rotating assembly,stage 3 colt cam, arp head studs,p-pump,air dog lift pump, and a single turbo have not decided on one yet. going to order parts soon. would like input on my planned setup thanks for your input and experance
 
#23 ·
and a single turbo have not decided on one yet. going to order parts soon. would like input
Well i'm no expert but the experts are silent so here's my two pesos: The only single turbo that makes sense in my head in this set up would be a ball bearing turbo.

What injectors are you're planning for and what about pistons/rings?
 
#24 ·
i was looking at running 17 to one pistons and i thought all the rings are the same ? but i am new so i could be wrong

as far as "adreamsoreal" coment above 300 will be plenty i may have to work harder to get it. i hardly have room for the 4bt if i did the 6bt i would have to put cup holders on the rear valve cover cause it would be thru the dash. i have the 4b mocked in and it is thru the fire wall 2 inches
 
#25 ·
i was looking at running 17 to one pistons and i thought all the rings are the same ? but i am new so i could be wrong
Alright, i'm gonna tell you what i think and if i'm off base somebody please set me straight.

To get you 300hp you're going have to turn your engine more than twice as fast as the optimum rpm the engine was designed for and burn a lot of fuel to get there. That means tons of heat from burning and friction. Metal when heated expands. It's calculated into the design but you're changing it a lot and it's important that you take it into consideration.

I'm thinking pistons with thermal characteristics designed for that level of stress, low friction rings with appropriate thermal characteristics. i don't know if you can upgrade the piston cooling jets. I wonder what happens to the stock bearings at very high rpms. Do you need a better oil pump?

There's a shop near where i live that powder coats pistons to improve heat transfer and reduce friction, i don't know what that is worth though.

You got an engine that's got the potential to last a long time. It'd be foolish to wreck it by going cheep and/or abusing it just to get some kicks.

Hope that helps.
 
#32 ·
You're right, i was just trying to help OP realize how far from stock his his motor's gonna be. He's got a lot to learn but i like his attitude and think he deserves help.
 
#33 ·
iam in the same boat I cant find a serial number either,missing cpl tag,no numbers on the block other then 88058738 and that Im told by cummins is not it they said that no serial numbers evers started in 8 but I still wonder if its it any help would be great.....from my reading I see that you can search with the injection pump but I am missing that as well.....my motor is torn down completely so I may have to go of the pistons when I get my kit still need to get it to a machine shop though
sorry for hijack i should make a thread for this
 
#42 ·
I heard that you needed "special tools" to do a 4bt rebuild. Have you guys noticed any limitations to the average shadetree rebuilder?

:puke:
About the only special tooling (not expensive either) you might need is a dial bore guage,and a couple of regular dial guages and stands,a couple of good torque wrenches and some odd sized sockets for things like pump gear nuts,etc...i think thats the best part of a cummins build...you can tear one down and put one together again with new parts with about a dozen metric sockets, some extensions ,a handful of wrenches and a screwdriver or three.nothing out of the ordinary required.

and,as mentioned,a good machine shop...somebody that actually does machine work on diesels on a regular basis.this is really where the money goes.screw up the machine work and the rest is garbage.

be thankful it's not a cat...lol
 
#43 ·
it's just another form of ignition,with much heavier parts...find a manual for your engine and the rest is wrenching.
 
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