So I just rebuilt this engine from the block up. It is a cpl 531. I set the static timing at -.069". It has an oversized turbo on it though. (Ht60). I get 32 psi turbo boost at full load (110,000lbs). And I get 175psi fuel pressure. The truck originally had an ntc475 in it. I have a 15 speed overdrive with 3.55 diffs. I have great power in the bottom 13 gears, but once I hit 14th gear I start running out of power at 1700rpm (45mph). It takes a couple miles of flat ground to get up to 55 or 60. So my question is....is this all this engine should have for power or do I possibly have low power? Searching the internet says to maybe set the pump for a 625cpl engine. I can't really find anything on the 531 cpl. Maybe I'm expecting too much... I am still waiting for my new pyrometer gauge to show up. Will take for a test drive to see what temps as soon as I get it installed. Any input would be great thanks. Rod
I'm thinking you need to get the fuel pressure up around 205-210 PSI. that should wake up the boost to about 40PSI, But you are really going to want to watch the EGT's. Don't monkey with the throttle shaft screw, you're going to need to drop a few button sizes.
Well sort of-First off a RTO 15spd has a wide split in top hole and with 3.55 rears-she's pretty long legged. A better rear ratio with the 15 would be 3.90 rears pulling that kind of weight. The 531 is a good CPL and the 625 is also. But here is where you can get some power, Do you still have the NTC 475? The 475 has a pump with a 1" gear and bigger orifice injectors. Installed in a 400 with 14.1 compression it will give you basically an increase of hp to 444. Plus it will not have to high of rail pressure so the cam will live. The 400's used a pump with a 3/4" gear for reference. But you need the bigger injectors to keep the rail pressure around 200. The 475 pump and injectors should work well with the HT60 turbo Removing the white plastic ball on the end of the throttle shaft and turning the rail screw for more fuel will increase fuel but it will also make for a sluggish throttle response. One thing that is often over looked is having a pump shop double the setting on the anroid, it creates a little more smoke at the stack on shifts because it's not cutting the fuel back because of turbo lag.
Yes I still have the 475. It's in pieces on 4 pallets in the corner of the shop. The fuel pump was just rebuilt before it dropped a valve. It's a future project to rebuild but other projects seem to be more important.
Will the 475 injectors work with the 400 cam? The 475 injectors are fresh rebuilds sitting in a box in the corner of the shop as well. I thought the injectors were a longer stroke...
I don't remember if the 475 injectors had a longer stroke but you can check with a pump shop to find out. I use Wentland Diesel in Milton Freewater, Ore. Funny I was just talking to Loren Wentland today about 475 fuel parts in a 400. But I do know it was common to use the 475 pump with 400 injectors, I believe the pump is flowed to have a slightly lower rail pressure.
Well maybe once I get the new pyro installed it would be worth changing out the pumps then. Any idea what kind of fuel pressure I would see with stock injectors? The ht60 sure spools up at low rpm right now so I'm sure the engine would still burn clean with the larger pump.
My diesel shop here in Canada says he can easily reflow the injectors and turn up the pump with a higher torque curve if I want. I'm a bit confused on fuel pressure though. My 335 small cam is set at 167psi fuel pressure and the diesel shop says this 400 big cam stock fuel pressure is 158psi. Seems low to me. But he also tells me there is multiple fuel pump codes for the 531 cpl. Building the engine feels like the easy part at the moment. Ha
Cummins and there CPL codes for pump settings are all over the board. 158 is pretty standard for big cam fuel pressure, a few ran as high as 175 depending on other calibrations within the pump and injectors. The key part is having the injectors flowed to match the pump to keep the pressure on the lower side. Years ago I built a BCIII for my own truck and I used a KT450 pump with a 1" gear and the injectors were flowed using NTA420 injectors IIRC.
I've never monkeyed with a 475 but aren't they mvt. If the travel is the same they would be flowed for some good power. Your gonna want 230cc or so and at least 200psi of rail pressure. Id throw the pump and injectors from the 475 in and see what she dose. Years back I built a mechanical N14 that was supposed to lift the left front. Started at 230cc and 250 on the rail, no fun. Went to 255cc and it pulled wheelies!
Yes Doyle the 475 is variable time and twin turbo and those fuel parts will make 400 scoot. But one thing to consider for every 10% of over fuel for on pressure the load on the cam goes up 10%. So 200 psi is a good area to stay focused on .
When my 475 dropped the valve I was in a panic and bought this ntc 400 cpl531. The pump on the 400 was bad so i put the 475 pump on the 400. My pyro worked and egts were ok. I never had a boost or fuel pressure gauge installed then though. Within 5000 miles the piston sleeve bottom orings gave way and all my coolant dropped. The cam then welding to its bearings and spun in the block. So I found another block and rebuilt the 400 and the 400 fuel pump. This probably didnt have anything to do with the 475 pump on the 400 engine but it sure makes me cautious. So 200psi rail pressure should be max for decent engine life then?? Thanks for all the input. Keep it coming
Years ago I had a friend that ran a 5 button in the pump on his BCII, stock button was a #42-a #40 is 5% over. Cams lasted about 1 1/2 years max. The fuel pressure ran around 280. At 200 range you will be alright, but like most things it all depends on the right foot.
So i found out the 475 has a high lift cam with injectors that have a .266" stroke compared to the 400 with a regular cam with injector lift of .224". I don't want to do anything too crazy with this engine. I'm proud that I built it from the ground up and know how much time it took. I'll see how it performs hauling grain over the mountain next week before I touch the fuel any. I'm thinking the smartest thing to do if I did anything would be to reflow injectors 10-20% over to keep the fuel pressure well below 200... thoughts???
Correct.
when I first got my super B grain trailers, I pulled them with a 400 big cam in a 79 w/star-38rears, 15 direct and 4.88? gears. grossed out at 63500kg(139700lbs). surprisingly, it didn't do too bad. I think some of your problem is the 3.55 gears. in my opinion, 4.10 gears(24.5 rubber) would be a better ratio for a 15 over. those old engines didn't like to lug as much as the newer ones. mine had a sweet spot at 1900 when at full load.
You're absolutely right 56wrench. My gearing sure doesnt help. The original 475 twin turbo handled the load fine but with 75 less hp and 200lbft less torque now it sure shows itself. I dont need to break any speed records but I sure dont like driving with my foot mashed to the floor all the time either.
The wide splits in the 15 doesn't help, truthfully I think a 13 would be a better gear box, but I like those 15's too.
Yes, but unfortunately the 15 speed is still in really good shape. So I'm pretty sure it's not going to get changed out anytime soon. I do agree though. A 13 would be better
This engine is in the 1981 western star that I have as my avatar.
Couldn't you just turn up the aneroid setting? Many years ago I had Macks that took forever to get to highway speed. there just wasn't enough boost to trigger the pump to send more fuel. The fix back then was just disable it.
Well I just loaded up at my east farm and brought the grain home (12 miles). Very happy with how the stock engine performed. There isn't a nasty headwind today though. I also changed my shift rpm. I used to shift at about 2000. Today I ran to the high idle limit ( 2250ish). That made a huge difference on the next gear's power. Is 2250 too high to run the rpm? And I did some math and indont have 3.55 gears. I have 3.90s. I get to haul 90 miles over the mountain tomorrow. I think it'll do just fine.
On another note....my fuel pressure gauge needle vibrates about 5-10psi when at full power. Is this normal or is my fuel damper maybe faulty? Thanks
IMO 2250 is a bit high 2150 is a bit more in scope. The only fuel psi gauges that don't bounce are the high dollar liquid filled type. At least that's what I have found. And good on the 3.90 ratio.
Thanks for the input Truck Shop!
Well I got to use the truck. Made 7 loads in the last 3 days. The first 4 loads were without much wind and the truck performed very well. Was able to get up to 58mph and hold it there on the flat stretches quite easily. The hills, well I was down to 35mph making it work but it did what I asked. Those 2 days the truck averaged just over 5mpg. Yesterday there was a 35mph headwind and I couldn't hold 14th gear on the flats. Down in 13th doing 45-50mph. The hills I was only down a couple mph when I created them. The 90 mile trip took me an extra 10 minutes. No big deal. What surprised me though was when I fuelled up after 3 trips yesterday I was still just over 5mpg!! Weird.
Well I got my pyrometer installed sunday and took 2 more loads across the mountain. As hard as I could lug the truck I was showing about 800 on the cool side of the turbo. Flat out hard working with good truck rpm I would only get to 700F. So I'm very happy with that. I'd say there is room to add a bit more fuel safely. Don't you?
You could add some fuel, get it up around 900 to 950. Proper temp for fast roasting a chicken.
I just spent 8 hrs in my pickup truck driving today thinking about the western star. When I get a couple spare hrs I might just swap the fuel pump out for the 475 pump. I have all the working gauges now to not melt it down. If I pay close attention to the gauges what could it hurt??
Remember no side stepping it.
The 475 injectors will NOT work with the 400 cam! The 475 injector has .266" stroke the 40 injector has .228" stroke. Terry
Yes you are totally correct, 475 injectors with .266 stroke were MVT cams only. The CPL 676 BCIV had a higher lift cam but only on the exhaust.
Now after searching through four boxes of engine notes and odds and ends off and on for the last week I finally found what I was looking for. Below is a data plate I removed from a BCIII Full Flow Cooled engine that was run out of oil some years back. It's a factory Cummins BCIII rated at 450 HP @ 2100 RPM CPL #1193 Built in 1995. The tag is easy to read, here is your factory ticket for custom rated HP by Cummins in a BCIII. Although I see photo went sideways. These engines were rare birds.
I was the Cummins guy in a truck dealership from 1980 till 2004. I only ever saw one and it was in an American grapple yarder. The 475 and the 450 both used the high efficiency Air Research aftercooler.
And he has the 475 after cooler in his 475 parts pile. And this one the tag belongs to was used in a tub grinder.
Getting back to the 475TT. Could I build this with fixed time camshaft instead of the mvt and not smoke too much. Having trouble sourcing mvt parts. So everthing with cpl matching except the mvt. If so, what would I time the injectors at?
if you go to Cummins they can look up the timing code GU on that data plate that corresponds with the CPL of 1193. I saw that 450 run cold and hot and it never really smoked as bad cold as some other big cams.
Will that 1193 not be an STC engine?
If you look on the Cummins data plate above it says {T.S. Zero Lash=Top Stop injectors} No it's not STC. It's a fixed time BCIII
Do you have any idea if the 1193cpl has the high injector lift cam? GU shows -.107 setting and my 475MVT shows -.120 setting. So not far apart. My thinking is it could have the high lift cam
Some of the late BCIV,s and the NT 88 were set at 101 to 107 it does not use a MVT cam. Notice this engine was built by Cummins in 1995.
When the NTC 475 was in production the training instructor from Cummins told me that they were converting NTC 475 engines from MVT to fixed timed engines in the Surrey shop and that they worked very well. I can't remember what they were timed at.
Right on! That's what I need to hear. Maybe next winter I'll get enough time to build that engine. Here's another question...what about turbos on the 475? I've been quoted $3000CDN to rebuild the twins. Would I be able to put something else on there and get the same low end torque as the twins?
I think most of those fixed timed 475's were timed at .072. Most on the turbo end use a N14 turbo.
I think .072" would be too low I would guess between .090" .105". Taking into consideration the longer injector stroke. Stock timing was .060" advanced and .120" retarded.
The problem is which cam did they use and which injector. If they used the NT88 cam I could see it those were .101 IIRC. I called local Cummins with the CPL 1193 450 hp engine to see what part number was used in that engine and if it is the same as the NT88 cam. But the parts guy hasn't gotten back to me yet.
So regular cam followers and boxes would work with the MVT cam? There are a few high horsepower generators with this cam and fixed timing. So unless they are a special follower....I'd like to go to a wrecker and get 3 follower boxes if I knew foresure they'd work with the 3026972 camshaft.
That's why I contacted Cummins to find out which cam was used in the 450/475.
Interesting conversation, I own and am tuning up the same year western star with the same CPL Big Cam 400, and a 15 speed, 3:90 rears.
Finally-The camshaft used in that 450 HP CPL 1193 is part number 3801668-only four available in the U.S. for a mere $1,819.95. Which is a STC cam shaft used in the 444 and mechanical N14.
This is going to sound stupid, but Amazon has that camshaft listed for $650 delivered From G+T engine parts.
No that doesn't sound stupid, Ag KiTs, InterState McBee all have the same cam in that price range of $650, But I like to post oem price to jump start people, cause everyone's a Ebay Shopper. But I dare say the 650 dollar cam is you get what you pay for. I don't like changing cams but one time-one ping only.
Would the 1193 be considered a formula 450?
No-absolutely not. Cummins built the 450's for stationary use. And it had a revision using the same CPL. It does have lower press fit liners. And as said above it uses a high flow Air Research after cooler, although it looks the same as any other after cooler externally. Plus it used the same turbo as the Mechanical N14-444. I have Cummins looking up the injector number that was used. But this engine was never offered for on highway use.
I have the cam & gear & followers out of a 444 stashed not sure of the cam # at the moment. if someone needs the # for reference I will check it & post it
what are the formula engines about? My engine says formula on it and is a CPL 531, not sure what that means. D&W Clutch horsepower charts list a formula 450, would that be a precursor to the 444?
531 was just a standard BCIII 400, Formula engines IIRC were based in the BCIV's and most were 365 hp. The only horse power charts I tend to believe are genuine Cummins. Yeah Pete would you post the number on that cam and the cam followers please, besides the 3801668 cam there were four others used in STC engines 3044767, 3801951, 3053525 and 3025517. Plus the NT88 had three different STC cam numbers also. Also after coolers got swapped around and used after coolers that said Formula on them got installed on engines that were not Formulas. Some BCIII's did have the Formula insignia on the cooler but those were high CPL numbers. I had a 531.
I am not all knowing or seeing and never saw a 450 Big Cam tag. At one time I worked as a fleet mechanic and we received some training. The class was for the N14 that was about to come onto the market and a Cummins engineer was teaching the class. Anybody in front of a bunch of people can get slammed and some people were not very nice. The last group of trucks that came in were 315's replacing the older 350's , why? He explained how the 315 maintained 315 HP over a wide RPM range. The 350 would produce more horsepower but only in a narrow RPM range and then dropped below what the 315 would do. Dug through his stuff and put it on a projector. So the over all point was that the 315 formula would out preform the 350 because it maintained more horsepower over a broader RPM range. Better over all performance and fuel mileage. The RPM operating range was reduced over time. Higher gearing and lower engine RPM for better economy. That was the basis for the formula to my understanding. Lower RPM power and better mileage.
Yeah that's the one the 315, and it didn't prove out like Cummins thought. Truth was it turned out to be a gutless dog. I was thinking it was a 365 and I do remember some of those tagged as Formulas, and those weren't much either. C. R. England bought a bunch of those and couldn't keep them out of the shop.
If I remember correctly the Formula engine made peak horsepower at 1900 rpm instead of 2100 rpm.
I have heard that the 400's were a rugged engine, with a good bottom end, strong jake brake, and the good parts availability and price. However they are hard to start in the cold, and being fixed timed they smoke bad when started cold. I have heard this was cured in the 444 with STC, or MVT. Can those systems be adapted to 400 using 444, or n14 parts? 400's had a low compression ratio, did this carry on to the 444?
MVT was not all that clean, and at the cost to convert, one my as well buy a mechanical N14.
How did the mechanical N14 handle timing?
The mechanical N14 was a STC engine using a PT pump just like the 444. Mechanical N14's were only built for two years 92 thru 93.
How much basic difference is there in a mechanical N14, and a similar specced 855 N?
The N14 is STC the N855 isn't. https://www.cummins.com/engines/n855-ccec
N14 mechanical
The 444 were a problematic engine. They had injector problems and piston de-bond failures. The top two rings in the piston were in a steel insert cast into the piston. The insert would work loose and cause a piston failure debris would take out the turbo and go back into the intake and into the adjacent cylinder. The N14 mechanical had injector issues as well. The NTC400 was a reliable engine.
That's quite true about injector issues at the beginning, but by using OBC method and setting N14 injectors to 125 in-lbs, 444 at 105 in-lb and NT88 at 90 in lb most of those issues disappeared. As far as the 444 piston issues--Yeah that was a big one for Cummins. But the period from BCIV's to the NT88/444 was a bad time for Cummins. The BCIII were the best CPL's, the filthiest of the BC's was the BCII CPL 449 very EPA unfriendly. Funny thing is it's what powers my 60 Mack.
I rebuilt a lot of NTC400 Cummins 449 was my favorite CPL timed to .072" and 250 PSI fuel pressure they pulled good and lasted 10,000 hours if serviced properly. Oil changes every 200 hours.
449 is a good engine, I find it interesting you time to 72, I also timed them to 72 and the book says 65.
The original CPL manual that was printed when the 449 was new said to time it at .070. The later CPL manual was revised to .065. I suspect maybe to clean up the blue smoke at cold start a bit. Timing at .070 they pulled a little better at the low end.
the cam I have is a 3025518 looks to be the most versatile one they built. looking thru my cpl book it seems to show up everywhere. follower assb. are 3038969 if I read right . 3025517-475-could also use the 5518 I am told. with a bit of tweaking
Thanks petepilot!---As I suspected your 444 3025518 and both the 3025517 and 3801668 are all basically the same. Cummins used the 444 STC cam in the 450hp CPL 1193 engine.
I have another another big cam 3 here that I believe has the same cam
At least the 315 would continue to race the rabbit. Shop I was working at received one of the first 365s on the market. It always made it home but turned heads when it came in knocking and hammering sometimes. Then straight to Cummings. That lease truck ran off a customer. The later model 365s did much better but they are still STC. Not my first choice but I have seen some STCs that would really get it done.
When I tore down the 475 I found the camshaft part number 3021589....is that even the proper cam for that engine?
Best I can tell you is call Cummins with CPL and serial #