Turn up a Big Cam.

hemijosh426

hemijosh426

honey badger dont care
Recently acquired a 87 international S2574 with a Big Cam Cummins in it. Truck only has 57,000 miles on it and runs pretty good for sitting around so long. It has a 10 speed roadranger hi/lo airshift in it. Jake brake too.

Looking to make some decent power with it, and get some more rpms, not planning on over the road trucking, this one is just for play, and for pulling at the farm fairs.

I have read about the governor shims, and about the fuel buttons, but all of the threads I have read are not specific, and ask the same questions I have. If I have overlooked some threads, please feel free to post them here.

Can someone tell me about the fuel buttons, how to install them, and how they work, and same with governor shims.

I also would like to know safe rpm limits on this fairly stock motor, and egt limitations.

We took the muffler off and the stack now exits right above the cab, and we got rid of that air dam, and the truck will soon be flat black.

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The button is under the bell shaped cover on the back of the pump its been so long sense i messed with one that i [ think ] theres a snap ring that hold it in there. to ad rpm you need to ad some shims to the button pack. I would not go more than 2400rpm full load because if you back out at high rpm loaded strait on the jake its hard on push rods and cam!!! There is a screw that you can back out to increase fuel flow to the inj's in the center of the throttle shaft just pull the lead plug.Before you make any changes you should put a gauge on the pump[theres a port on the shut down solenoid] you need a gauge that goes to at least 350psi and check current pressure at full load then you will no how far you have changed things. Depending on what CPL it is the egt's are really dependent on the quality of the pistons and as i have had a few cummins i can tell you the standing joke about cummins is the pistons are made from recycled beer cans!!!
 
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I've heard of guys brazing or welding the recess in the button completely flat. Since that surface area is what moves the button under pressure, the less surface area the more pressure it takes to move the button = more pressure. And since the cummins is a PT system (pressure time) more pressure over less time = more power.

I'm not a guru but that's how I understand it anyways.
 
There is plenty that can be done, I would suggest injectors first, then tune the pump to match the injectors.
 
Button, button, who needs a button???


First you need to know which button is in the pump! It would also be nice to
know the rail pressure as per the CPL.

IF YOU can stand the pressure I can melt it down in a heart beat.

A flat (no dimple) is a 0 (zero) button. If you have a GOOD pump it will knock
about 375+ pounds on the rail. Normal rail is about 150 plus or minus based on
again the CPL#.


DO NOT WELD OR BRAZE A BUTTON.................PERIOD!! It is a precision machined piece.

There are a lot more to it than just changing the button............... I can show you a $15,000 piston using
a "0" button and a few other things.

On the trans, how about a RTOO 9513 or an RTOO 12513..........massive top end!


.
 
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"00" buttons are not offered by cummins anymore, welding works just fine, you just have to be careful about it. We have 4 pumps all running welded buttons all without problems. And yes a good pump with a 3/4" gear pump will get to 375psi, but to really open up a PT pump you need a 1 1/4" gear pump and a set of injectors to match.
 
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