Big Cam Cummins reliability

Yes, my Pistons were ordered for CPL 586, which is the 475hp engine. Throttle shaft is drilled out larger diameter, bigger gear pump, dual fuel line, plus a lot of other little things. The air to air helps keep my egt's down on harder pulls. I run a lot of I-77 from Charleston, WV on north. Very few times my trans comes out of OD with a 15613 trans and 3:70 Rockwells.

 

I used to run i77 in se-oh some pretty good hills around them parts.

 

That's a good looking setup,Oldskool. I always wondered how an old NTC would perform with an intercooler setup,vs. the old aftercooler. You've basically made a mechanical N-14,which in my opinion is the best way to go. The reliability of a N-14,without the ecm,sensors,600 miles of wiring,expensive injectors. Hard to beat an old simple PT pump.
One day my ECM gave up on my N-14,wouldn't start,expensive repair.Luckily it happened at home,where I could troubleshoot it,remove it,and send it out. If that had happened on the road,would have been the hook,and a real expensive nightmare.
A good friend used to have a small fleet of tanker yankers,about a dozen trucks of all breeds,mostly Cats. All his trucks would run,and I mean run. Everything turned up. He had a turned up mechanical N-14 in an old Freightliner,and the drivers would fight over who got to drive it,best running truck of the bunch.
To the op,I think you're doing the right thing. You do have to "drive" these old mechanical injection trucks,you'll learn what I mean by that,esp. no lugging. But the realiabilty,low cost of ownership,and if you have some mechanical aptitude,and can rebuild a Briggs+Stratton lawn mower engine,you can rebuild an NTC Cummins. Good luck.

 

Sure can't beat the price of a old BC Cummins engine. Cheaper than a Detroit and sure pulls better!

 

As far as how many miles you can get out of a rebuild, it really depends how well the engine is serviced and how well you take care of it and even how you drive it and if you have it turned up, and if it's ever gotten hot on you etcetera etcetera. There are a lot of factors that go into that.

They are not throw away engines or engines that had any kind of real problems that you had to rebuild them in a short order of time. The n14 is essentially the same engine although I think I read somewhere that the rod bearings and main bearings may be slightly larger, I'm not exactly sure but those engines go easily a million sometimes million and a half miles. I read somewhere on here that someone had one that went 1.9 million miles and he. is still running it. So I really would not be concerned about that. And don't worry about CPL numbers either. Just get a good Cummins big cam 350 or 400 and you're on your way. Like I said earlier just be careful with the big cam four because they had some problems with the low flow Cooling.

I would just make sure you have enough money put away that if you need a crate engine that you can buy it and just keep going. I myself avoid caterpillar because I just don't see the reason for spending that amount of money on an engine. I think those parts are outrageously expensive and you can rebuild that Cummins big cam multiple times for what it would cost you to do the caterpillar once.

My suggestion would be that if you want to turn it up maybe turn it up 10% and if you can fit it on your truck put a charge air cooler like old skooler kw did. Put a pyrometer on it and try to be gentle and use the power when you need it. But I have to tell you those engines really pull well.

As far as gearing goes a lot of guys have a lot of opinions on that. But generally speaking over-the-road trucks can have a higher gearing, which is a lower number, like say 3:36 or something like that. The old truck that I had with a big cam had 370 gears and it pulled really nicely with that. The new truck that I have has 390 gears and I like that gearing better. 390 gears with an overdrive transmission is a combination that I like. 411 rears are good also for Pulling but you will be turning a higher RPM at 65 or 70. On the road ranger website they have a calculator that you can figure what your highway speed and RPMs will be for a particular gearing with the direct transmission or Overdrive.

You're probably more or less going to be at the mercy of whatever rears that you find because you're looking for an older truck so you're going to have to find one that's in good shape that has a good engine that's not going to be too much work and you may have to just take what you find and update it at some point if you need to make a change.

Also, I think it's probably a rare Beast, but the early n14 s were actually mechanical engines.

What model truck are you looking for?

 

You will need a pyrometer with those things. If you have a decent 400 to begin with you should not have too much problem. DO NOT whatever you do get a 4. The coolant situation is a total failure waiting to happen because the engineers tried to make that liquid go slow and you don't have enough volume in the small hoses to cool worth a #### when things get really hot with it.

Do not put it on a tall set of gearing like a 10 speed road ranger. You will fall down on every little hill you try to climb shifting down several gears to keep it moving.

It is a good engine for what it is. I like them. But my personal choice would be the Detroit of the old style. Two stroke probably. No computer in sight for anything. Modern trucks cannot even be short a pint of coolant before tossing a code and shutting down or derate when the DEF or other BS modern emissions crap fillup with particulate. You can find that you can get a mechanical engine to do things for you when you take very good care of them when it's not feeling well and you are far from a source of a good mechanic that still understands how to fix those old things.

Fuel mileage? Forget it. They are generally one RPM engine and if your gearing is short enough in the rears combined with a short rockwell 9 or something like that she will do a better job staying at 1500 or so cruise on the little hills.

You also will find with the older 400 and similar engines from that era the RPM situation is totally different than modern trucks. You cannot lug down that cummins. Once you get below say 1400 she will not do well until you down shift and get it back closer to 1900 or a touch higher. 2300 I think was redline governor for them. 1500 to 1700 or so is a good range sweet spot. It will make good music cruising down the highway without working too hard at 70 or whatever. But that will be pretty close to being flat out unlike today's trucks where you can get em up to 120 if they were ungoverned at 2150.

The 350 mack from the early 90's CL and CH models will be it's closest competition in mountain country such as Altoona, Breezewood etc. It will do a better speed with the same load than the 400 will.

However back to the old detriots, there isnt anything you can do to them that will hurt them. As long you keep that Pyro below 1200 at all times. Depending on the metals even 1200 might be way too hot. 900 would be much much better. On the other hand if you had stronger metals you can take her to 1400 on the pyro for a few minutes. No more than that because that heat will transfer to the engine oil, which will thin out some, then get hot and then the coolant in your radiator starts to rise and get hot. And if you have a transmission that needs a fluid oil cooler that will also begin to get hot. Next thing you know everything is all hot and bothered not running too well because you pushed it too hard upgrade.

If you have a older engine with a big time Jacobs braking system on it and not some BS generic retarder or some other crappy imitation you will find you can stand on that good Jake all the way down the mountain all day long and not hurt anything at all. Keeping your brakes really cold in mountain work will pay for that nice big jacobs in no time.

Another wonderful thing about the older engines, let's say the water temp gauge is no longer accurate. You raise the cab or hood, find the sensor in the top of the block take that out, follow it straight to the water temp gauge on your dash, unscrew that out of there and drop a generic stewart warner style water gauge in there from Napa or some such with your own tools in a short time by yourself. There are many things with the older engines that don't need no stinking computer except what God gave you between your ears. working with them long enough you gain knowledge that most people today simply just wont have going through a regular trucking school or a mega with a modern computer crappy truck telling them to fix every little tiny nickypicky appointment time killing BS at the dealer no less with another big computer attached to it before anyone knows what's actually wrong with it.


You will want a box of spares. Clamps in particular. Your intercooler pulls in enormous amounts of air to feed your engine at a cool temperature for good strong power. If your clamp anywhere on that particular intake line got weak and it starts to suck outside air in compromising its entire intake your engine is going to pour inky black smoke for a mile behind you and cover your trailer in oily unburnt fuel and feel like a 10 horsepower garden lawn mower barely able to do anything. If you want to make life exciting with a problem like that, show up at a open DOT scale and cover them completely in a cloud. They hate that very much. So a batch of fresh strong clamps, fresh hoses and a few other spare parts and the necessary metric and USA measure ment tools to go with everything is quite good starting point to keep a older engine going. You will carry extra oil. You will carry extra coolant, you will carry a couple cans of ether and a few other things that engine will want to have TLC from you and do well.

They will run forever if you take gentle care and drive it correctly within a range it wants to be driven at. If you try to save fuel by lugging along at 1100 thinking you got the whole thing beat, you are pounding on the pistons with a sledge and eventually she will find something important to break on you. That music will go away and become noise of a expensive money consuming kind. That's what you get for lugging those things too hard too much too long.

 

How much did it cost to get your Cummins rebuilt?

My 3406e was turned up to 750 in a truck stop parking lot. I could go more, easily. If you want to compare Cummins engines to CAT engines you should specify engine models so we're talking apples to apples. Because comparing older mechanicals to newer electronic engines isn't even in the same league.

 

Gold kit costs 4k from CAT.

20R-0681: KIT ENG OVER | ALBAN TRACTOR COMPANY INC.

 

That 11k is for a complete big cam. Browsing complete engine prices....I saw 46k for a complete engine from Cat....yeah.... no thanks

 

I met up with @OLDSKOOLERnWV at a rest area on 77. I was driving a 17 W900 565 ISX 18 speed with 3.55 rears and low pro tires. That ol bucket of bolts passed me going up hill like I was tied to a #### post. Wasn't blowing no black smoke either. I aint no Cummins man but if i had one or wanted one I would #### sure pay attention to what that man has to say.