Big Cam Cummins

Well as many times as I relied to threads about Cummins engines, I finally bought a truck that I had to work on the engine (nothing major) I bought a 89 Freightliner, Tri axle dump, about a month ago, with a Big Cam Cummins, jake brakes. I noticed the engine had a missing sound in the exhaust, I knew I had a problem with it when I bought it, so I got it at a good price. I worked the truck for about 3 weeks and I got tried of the noise, not smoking, not using oil, no base compression, just that missing noise. I checked it with the heat gun and #6 was 100 degrees lower than the other cylinders. So Im thinking Injector, I hope. Pulled the Jake and replaced the injector, better but not good enough. Pulled the back head, it appears that whoever ground the valves, really didnt seat them good and the #6 valves were blowing by, making that exhaust noise. Replaced the head with a rebuilt head, now good to go Word of advise to anyone that has to replace a head on a Big Cam Cummins, if it has Jake brakes, make sure the head is the correct one for your CPL #. A friend gave me a rebuilt head that was for a Big Cam, Just before I went to install it I noticed the surface on top of the head, that the rocker box sets on was different, so now I had to go get a head from Cummins $400. I havent really checked, but I think the head, that I got from my friend, was the old style head and not for a Jake brake I still like my Big Cam engines, easy to work on, compared to some. I hope this helps someone PS Ive got a head for sale, for Cummins LOL::Banghead