Building a big cam 3 400

On a side note, are you still participating in tractor pulls ? Would like to see any clips if you have a available…..

 

Have heard that they are stopping parts support for anything older than an N14 for the 855 line soon, they must not be wanting to import those anymore.

 

I put an injector in a Celect Plus N-14 little over a year ago, Cummins had to source it from the aftermarket. Ended up just getting one from guys in Massillon.

 

Yep, not much to show though, truck has reached a point where it is finding all the weak points.

 

A lot of good info on this thread... appreciate everyones input. We have 3- 855 cummins 400s. CPL on 2 of them are 625 and 449. We are rebuilding both engines. The 400 with the 625 cpl is running and the other 400 that is 449 cpl is not and will have to be out of frame from ground up. We just purchased it this weekend.. it was in a 359 Pete. So yesterday I took heads off expecting the worse but didnt look to bad... YET. So will be dropping oil pan to see what carnage there is down there. If ... (question mark) the block is good and zero cracks after someone magnaflux it. I would like to get some advice on what next. My thoughts were having it line bored first. Then if crank is good have it turned too ? When we bought truck the back follower box cover was off and could see damage on cam and a couple pushrods not in place. So assuming the block is good.. (im thinking not... fingers crossed) A new cam, cam bearings ect. So the best cam would be from a CPL 625 build .. correct ? Also what exhaust manifold is best for flow. By the way... this is build is for a working truck...359 pete... I would like to see a safe 600 hp. and not too much smoke.. lol. Except of course when you mash that accelerator to the floor ! Thanks for in advance for any help.

 

As far as line boring goes, I would check your clearances first. You may not need anything.

Same with the crankshaft. Unless you see that it has a problem that has to be cut, just send it out to be magnafluxed and if it's good they'll polish it.

More than anything, it's most likely you're going to need counterbores cut and probably will need some kind of block repair.

As far as reliability goes for a truck that runs every day, my own personal feeling is 500 horsepower is the cut off for longevity.

Up to about 500 horsepower if you're careful you can probably have a service life similar to a stock engine.

Beyond that, you always have to have the money and the time to get back into it when whatever happens happens, because it most likely will happen, and it will happen prematurely.

Check your camshaft numbers, but I'm pretty sure most of those camshafts of that era if not all of them were the same. The difference was the timing with the offset key, but you don't have to worry about that because they're all 400s that you have.

449 and 625 were similar engines. I think mostly the difference was in the fuel code and possibly injectors.

If you are building the engine and you seriously want 600 horsepower, I would call premco and he can tell you how to build that engine for what you need for him to give you 600 with the pump, injectors, and turbo.

If you want even more, he can tell you how to do that also.

He'll also tell you how to time it, which is usually an area of confusion when people are trying to build High horsepower.

Good luck.

 

Sounds good... That was my first order of business for Monday to call Premco. As far as push rods and Harmonic balancer... If push rods are straight and minimal wear on ends are they good to go or should i get all new ones. Same goes for Harmonic balancer... seems like i heard someone say to replace it ? Not really sure what goes bad in these but I would consider if need be. Thank you sir for the reply.

 

Roll push rods on concrete floor. If they don't wobble you're good.

Replace harmonic balancer.

 

roger that !

 

Drop your push rods from a couple inches on the floor. If they ring they are good, if a dull thud replace them, they are full of oil