Long story short the 12 valve engine that we purchased for the Jeep wrangler is a dud! BUT we aren't giving up that easily. Lets go back to plan A and get the trusty 24 valve VP motor installed and get this thing driving!
Is there any possibility that your vacuum pump system on your 5.9 has a leak? The vacuum pump exhausts into the crankcase, adding to crankcase pressure if there is a vacuum leak anywhere. The leak could be in the vacuum line to the brake booster or in the booster itself. An accurate diagnosis can save hours and dollars.
So I am running hydro boost brakes so no vacuum is actually needed. I plugged off the vacuum line on the unit but thought there may still possibly be an internal leak so I swapped the pump out with a new one and still no luck. I am almost certain it was caused from a head gasket failure from the broken stud I had found.
@@Sawyer_Garrett Thank you for sharing more about your thorough diagnosis. Was the broken head stud near any of the pushrod voids, causing compression to leak into your crankcase? You are wise to have a stronger than stock suspension for your 5.9 Cummins JKU. I have one with the 3.9 4BT Cummins and a heavy-duty Dana 30 from Teraflex. With the 4BT outweighing the 3.8 V-6 by only 350 pounds and with a steel bumper with a winch, stock ball joints were shot after 10 months of paved street driving. I had Dynatrac field-rebuildable ball joints installed and so far, so good. I understand that your 5.9 Cummins can weigh 1,200 pounds.
@@edwardhawran9406 Yes it was. Between cylinders 5/6. The head gasket appeared to look unharmed but the broken stud is literally the only thing that I had noticed. I am not an engine builder nor have I had a lot of experience with failed engines so it’s very easily for me to be looking over something. That was just the obvious failed thing and after talking with my machine shop and a couple other guys that do have experience in building engines that’s sort of the same thing they had mentioned.
So here is a serious question for you, now that you have gone through the majority of the 12V & 24V of taking it in and out of the Jeep body and chassis. Do you think it would be easier to have kept the engine in the donor truck and just figure out a mounting solution for the Jeep body onto the trucks chassis?? Or would you do it all over again the same exact way of mounting the engine in the Jeeps chassis and body??
That’s a great question! If I had to start from scratch from what a know now I would still keep the same Jeep frame and do it the same as it currently is but without all the trial and errors 😂 I have a brand new 2 post lift I purchased a couple years ago but have not yet pulled a trigger on building a shop. Once it’s built and I have a lift I will just remove the tub and that will make life a lot easier.
