315 big cam in a m818

[powerhouseduece]

Well, it has began! My new project has started and I hope to have it at least running by this winter. As some of you know, I picked up a fairly clean M818 wo/w from a member, once I recive the bill of sale and all that good stuff, it is game on! I also picked up a used take out, its a NHC-315 big cam Formula with jakes and 9 speed road ranger that came out of a totaled truck. I really couldn't find anything bigger for the price I picked this combo up for, but I think its a good start. Also thanks POWERSMOKE18 for all the help on this and dealing with all my questions. Also markmontana for the awesome truck! Its a great truck, just needs one minor improvement!

I'm going to be leaving my other 818 on 1600's alone for now, the motor and trans only have 6k mi. on them, it's not time for him yet!

Plan is, after the motor is mocked up in the truck, send the pump and injector's out for a little treatment and finish all the little odds and ends. I'm aready on the hunt for a bigger turbo, just got to be in the right place at the right time! First thing I need to do is build a stand for the motor. This thing is HEAVY! VERY VERY heavy! Last thing I want is to be crushed by the motor I just got! I'm also looking for a large cradle for installing thease motors, there were a few that came up on GL a year ago but were just out of my reach. Also might need a new forklift after moving this pig of a motor, mine ain't liking life right now!

I have been really trying to read up on thease old motors and from what I found, the formula's were build as economy motors, governed at 1750 rpm unlike our 250's and 400's witch are set at 2100rpm.

My 4bt swap has been put on the back burner for now, ill probably get on that some time this winter, cant drive a 2wd in the snow anyway!

Here are some pics of the motor, trans, and a few shots of the victim.. I mean truck. I hope to update this as much as possible, but I only one man!

 

[wreckerman893]

Should be an easy swap but remember...you are still gearbound by the rears.....taller tires will help but you will never run with the big rigs out on the interstate.
I would consider a change to air brakes.....I think there is a kit to convert the 800 series over to air without swaping out the axles and diffs.

 

[powerhouseduece]

I might have a little trick for the speed, comes from some old tractor pulling tech. Im only looking for 60mph crusing speed and pulling another truck at the most with a set of 395's. Im just tired of hills!

 

[Westech]

The other BIG problem is the Sprag T case. How are you going to activate the sprags? The Stock trans has a selector rod that engages the the air valves to lock in the forward and reverse sprag. With a different trans how are you going to do that? If you use manual valves you could leave the T case in "N" while driving but if you lock in "F" and have to "R" you will have to manual switch the valves.... just seams like that is the big problem to me.

 

[WillWagner]

88NT...Good engine. Looks like it came out of a Volvo. If it were me, I'd get rid of the trans mounted rear engine mounts. It makes it a PITA to anything on the rear of the engine once it is in and when you go in or out, the engine needs to come up apx 2 inches before it come out. It wreaks havoc when trying to manuver the pig around the clutch linkage. "formula" just means it is governed at 1900 RPM for fleets. No need to spend money on a "bigger" turbo. The one on it will work just fine. I have seen that engine pump out well over 400 HP and keep the turbo that is correct for the CPL. The 315 can be made a 350 HP engine with just a pump cal and no other engine changes. One last tidbit, get rid of the low flow cooling. It is a junk system. I'll look through some notes I have and see what I can come up with. One way to convert it to standard cooling involved removing the restrictors under the water rail and the other there were no engine mods, I liked doing the later. Let me do some lookin'

 

[powerhouseduece]

Will, thanks for the good info, you might be getting a few PM's along the way! All I really want out of it is about 350-400hp. With a complete rebuild and some other mods, I heard I can get around 600hp. $10k later.... Once I get a good stand built for it ill fire it up make sure its good to go. I though about using the stock 5 speed but I figure it will not last very long, even towing a m105! lol

Westy, I'm thinking about a 900 series t case if I can get one cheap. I talked to a buddy of mine and we might be canging the gears in the T case so high range will not be 1:1, but overdriven. I have heard of 1 other person doing this, so I might give it a shot. When I get the motor in and running, Ill probably just run without ait to the t case and no fron driveshaft for a while. Need to do a little R&D before I figure out what to do there.

 

[powerhouseduece]

Another question for you Will, did a lot of the cummins motors come with 24v stuff on them? Like for the Jake switches, and the starter? I was wondering if I have to run a 12v and 24v eletrical system on the truck or if ill get away with my Headwizard 24-12 power inverter.

 

[Westech]

the 900 case is already a over drive case.

 

[cornrichard]

I rigged up a reverse light on my 817 by tapping an air switch into the reverse side of the sprag air shift. I think you could use the reverse light switch on your new transmission to run a couple of solenoid air valves. This would shift the sprag when you shifted to reverse. You might also think about the allison in those 915s. I talked to a guy who drove one recently and he seemed to like it.

 

[powerhouseduece]

The sprage is the least of my worries right now. Getting the truck running and driving in rear wheel drive is a good goal for me right now. If I need 6x6 i got another 818 with 1600's!

Any link to some info westy? Im still hunting around.

I almost had a good deal on a m915 motor and trans but the tan one at my shop is too clean to cut up!

 

[WillWagner]

You can buy 24vdc brake solenoids. The switches don't matter. They pull alot of amps. You'll need a 24vdc FSOV too. That's the only other 24 volt stuff you'll need