big cam 400 cummins tricks

Cummins is a Pressure TIME fuel SYSTEM. Were the Pump flows FUEL at a SET PRESSURE up to a Governed Speed then pressure is removed to prevent an overrun. The INJECTORS ARE HOW THE FUEL IS METERED on the N14 Big and Small cam and IIRC ISX series. ONLY ON THE B series what you get in the Dodge and certain Case Tractors is the Fuel System setup different with a Metering pump. Now the Injectors are normally CLOSED unless it is TIME for them to INJECT FUEL into the Cylinder how the amount is Regulated is based off the size of the Injector tip cup and metering Orafice where the fuel flows into the injector. V8 as for you saying you can only get 650 HP from the pump BS. Cummins used the SAME pump for all the engines in their line until the 80's the Big INDUSTRIALS have the same PT pump and some of them are well over 2000 HP. How do I know this called worked on one in Tech School our Clledge had a Backup Genarator that used a Cummins for its power source rated for 2000HP and the pump seal failed. We in class REBUILT IT as a project. was fun putting that sucker on the BENCH for the flow test.

 

You don't understand how PT system works. Celect and ISX are different. PT injector fill port is always open, fuel amount is metered by the pressure, the more pressure the more it fills the injector and the more is injected to the cylinder. At low fuel pressure like idle the injector is almost empty and the injection starts very late. More fuel pressure and injector is filled more, now injection starts earlier and lasts longer. Injection ends always at the same time. That's why you must set timing differently for each configuration. Pressure on the injector cams is always about the same, it just lasts longer. Like someone earlier wrote, wear is always on the tip of the lobe, that's were idle injection is done. If it were because of higher fuel pressure it would be earlier on the lobe.

When I said fuel pump mods I didn't mean gear pump but the PT governor, and I meant you don't need to change any parts, except maybe fuelbutton, to get 650 hp. Stock gear pump is good for at least 1200 hp at higher rpm, you don't need that expensive 1 1/4" gear pump.

 

i still want to know where to set the distributor cap

 

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Looking to get 500 to 550 hp out of Cummins Big Cam 4,changing from STC to fixed time,any ideas on CPL # to use or injectors,turbo,and what it should be timed at. thanks in advance,any info is appreciated

 

What is your current CPL? I personally wouldn't changge from STC what you need to do is get them to flow more( I have a great company) then build it to CPL 821 or 1211 you need a dual fuel line kit a 4 series turbo because based on the CPL it might be already set to give you 550HP this is nuthn for these engines to put out! Pm if you need more info

 

Keep it STC, advance timing a little bit and turn out fuel screw or change button and you have 600+ hp. It should already have 4 series Holset, good for 900hp.