Cummins Big Cam 400

What is the cpl 676? Regardless they are pullers for sure. If the pump was calibrated to the highest torque rating and a different button put in the hp is hard to say. Even if it calibrated to factory specs and button changed its hard to say. Get a working pyro if you don't have one. When you get it in a hard pull get off the throttle some to give it some air you will feel what I'm talking about. Its easy to cook a manual motor if you haven't driven one much. The big cam is a good motor overall.

 

That's a great engine that you have there. I don't know what your hp is now, but it's not hard to get 450 to 500 hp from a stock engine. Being a big cam 4, You have the low flow cooling system and the mechanical variable timing.

Be extra diligent watching your temp gauge for overheating, and make certain that your mvt solenoid and cylinder are working properly, and that engine will run for a long time.

 

MVT on a big cam 4 is highly unlikely, it would most likely be a california certified engine if it has that, the only other engines that came with the MVT are the factory twin turbos, now if you had said step timing control then you might be correct as all STC engines are big cam 4s and after, but not all big cam 4s are STC.

I can't see a turned up low flow engine lasting very long being worked hard in the conditions of an oils field.

 

You can check on the side by the cam followers for the solenoid if it has mvt. If you have cooling problems from the low flow system, it can be changed over. Like I said, be extra diligent watching the temp gauge.

 

Turning the fuel down will help, but the low flow engines are notorious for overheating problems. The engine itself is basically the same as the other big cams. Google it and you can find out all that is involved with changing it over.

You may have a stuck thermostat if you are overheating and your heater is not working. When the engine is hot, check to see if both the upper and lower radiator hoses are hot (don't burn yourself). If one is hot and one is cold, coolant is not circulating.

Also check your.heater hoses. There should be a valve on one of them that allows the coolant to circulate through the heater core. If the hose is hot before the valve and not after, try to manually open it.

 

As stated by Fld look for a valve in the heater hoses, might start up on the right front corner and look for a valve that has been turned off, if my memory is right most were brass. Might check and make sure (while its cool) that you have enough coolant in the system.