Increasing PT pressure

[Jakelc15]

102635 is a 0 button

 

[jarhead1086]

I had to make two tools to remove my PT. The upper rear bolt had a 7/16" 12 point, but I had to cut the open end off the wrench off to fit it. The lower rear was a 5/8" 6 point, but I needed a super short 12 point socket to get it in the pocket and get some rotation. I slotted the socket 1/4" deep by 3/8" wide and welded a bar of the same size in the slot. I will keep these in my truck's tool kit. I took my PT to a local shop to get it flow tested. I left a #20 and a #22 button with it. They called me back and said mine already had a #20 in it and I was running 180 psi. He stuck a #10 in it since that was the only thing he had lower than a 20 and it bumped up 40 psi. Not too healthy. He put the old #20 back in and turned it out 1/4 turn which equaled +15 psi which took my 180 to 195. Now I have a brand new #20 and a #22 button for Floridianson to experiment with. While taking things apart I noticed the rubber line from the filter to the pump looked as ugly as me so I had a new one made with heat shield. I also noticed that my fuel filter gasket was well damaged. Boyce is having some made and they will be in stock within the next few days. I could have been sucking air? I will report when I get it all back together.

 

[Jakelc15]

Any updates?
I ordered a couple of buttons to experiment with, should be here Monday. I hope to get started on my turbo install soon too.

I pulled a trailer last weekend with my wife's trailblazer on it. On a hill a few miles long my exhaust temp got up to 1100°
I'm hoping to see if changing the button will bring the pressure up at lower rpms than the screw does.
I'd like to see full fuel pressure before 2100 rpm

 

[jarhead1086]

After I put mine back together it was running way too hot. It would jump the EGT's to 1000 easily on a flat with no load while accelerating. I had to back out the screw on a few small iterations until I felt safer with the EGT's. I am hoping to get a turbo, 5 "exhaust, and the air filter from Those Military Guys. I wonder if I need a muffler if I route out the back? I am really only looking to lower EGT's with the turbo for the hills around here. Sorry, I don't have any new pressure #'s to share unless I bench test the PT.

 

[Jakelc15]

I wasn't planning on putting the muffler back after the turbo install. The turbo acts as a muffler and really shouldn't make it any louder.
You would probably be better off finding an air filter assembly off a big truck in a junk yard. The high flow replacement filter for our stock housing doesn't filter as well as stock. It was designed to be used with an inner filter on an engine the size of one of our cylinders.

 

[Jakelc15]

I just got the turbo install finished. Took it for a ride.
Still 200 psi at pt pump and about 12 psi boost. EGT's stay a lot colder. And I kept it in 5th on a hill I normally would have dropped to fourth on.

I replied in an old thread about retarding the timing a degree or two. Upping the fuel pressure advances the timing. Our engines are way more advanced than the bigger h.p. versions. Retarding the timing will also bring the EGT's down. But too much will make it smoke bad and hard starting.

My future plan is to send my injectors to Antrim diesel and have them opened up a little. That will drop the pt pressure down where I'd really like it to be.

Also the truck is much louder now but it only has a weed burner on it for now.

 

[wrenchturner6238]

Jakelc15 Which timing thread did you post to? I am about to add a turbo to my 250 but I had not planed to change timing right away unless After I thought i needed to.

 

[Jakelc15]

http://www.steelsoldiers.com/showthread.php?95070-NH-250-lifter-housing-shims

Changing the timing is not required.
I think it may make better power at a lower egt and make the engine last longer though.

 

[jarhead1086]

Thanks for sharing Jakelc15, much appreciated. Did you use 5" exhaust and an intercooler? I am saving for stainless while I fiddle with the cooling system. I am running my exhaust out back with a MBRP 9" diameter x 24" low restriction muffler likely over the rear axle. I have rivets where my engine data plate was, but no plate so I'm not sure of my timing settings. I have some serious hills here when added with altitude made it hard to hold 25-30 mph empty. Still almost hits 70 on the flats without high EGT's if you had to. I avoid pavement and try and stay slow on dirt where it belongs.

 

[wrenchturner6238]

Looks good jarhead1086! How well did the air to water after cooler fit into the cabs fire wall?

 

[jarhead1086]

Looks good jarhead1086! How well did the air to water after cooler fit into the cabs fire wall?

Not a fan of BFH adjustments. Luckily, if you only install the front 2 of 3 lower bolts it can be installed at an angle and rotated into position. I used some permatex gasket goop to stick the gaskets to the block to ease the wrestling match. I had to install the cooler fully assembled. All the holes needed re-tapped thanks to the powder coat people not masking the holes. The air compressor hose I bought was too stiff to make the corner without kinking so I need to get something more flexible.

 

[Jakelc15]

You 939 guys have a lot more room under the hood. I used the factory intake manifold. I wanted to keep my cold start.
Are you planning on bumping the pressure or changing the button? I have a couple of buttons to try out but haven't had a chance to do it.
I hope to get the stack on this week. Going 5" all the way.
I was able to flip the manifold and keep the coolant tank in the original location.

 

[wrenchturner6238]

The intake I have has a glow plug in it and i am thinking about trying to make it work to aid cold starting but i am going to add a block heater so the glow plug probably not needed

 

[Jakelc15]

I installed a block heater too. But sometimes I stay at work overnight and it makes it easier to start when it's 10° outside.

 

[R Racing]

Did you get the intake and exahust manifold from a donner engine?

 

[patracy]

I need to make up a gauge for mine. I was going to order one from surplus center, but not for $15 in shipping. Guess I'll check with the local hyd shop tomorrow.

 

[jarhead1086]

Did you get the intake and exahust manifold from a donner engine?

I got the intake from the junkyard and cleaned it and powder coated it. The cooler was brand new in a rebuild kit with all new gaskets. I tried without luck to get exhaust manifolds from the junkyard. They all had issues (cracks etc.) so I bought new aftermarket manifolds for 1/4 the price Cummins wanted. They came with new bolts and exhaust gaskets.

 

[R Racing]

I got the intake from the junkyard and cleaned it and powder coated it. The cooler was brand new in a rebuild kit with all new gaskets. I tried without luck to get exhaust manifolds from the junkyard. They all had issues (cracks etc.) so I bought new aftermarket manifolds for 1/4 the price Cummins wanted. They came with new bolts and exhaust gaskets.

I know there is at least 2 types of aftermarket exahust manifolds available. Do you remember which style you purchased?

Thank you !

 

[Jakelc15]

I got a used manifold but this is the same one but new.
http://www.agkits.com/cummins-nt855...ig-cam-i-ii-iii-exhaust-manifold-3801322.aspx

 

[jarhead1086]

I got a used manifold but this is the same one but new.
http://www.agkits.com/cummins-nt855...ig-cam-i-ii-iii-exhaust-manifold-3801322.aspx

That is about what I paid and I think this is the same kit. My local guy had this in stock. I had to install in one piece after carefully getting the bolt spacing right by tapping them into each other. Barely cleared at the front. Mine fit tighter due to the ceramic.