buddybamboo
New Member
I have just gone through my first major 3.7 problem. The jeep was running rough on start up. This evolved to the codes showing missing on #2 cylinder. This was the only symptom for a while. Later i found that it was using antifreeze somehow. The oil was normal. I found that after the car sat for a few weeks, it was worse. I came to believe that antifreeze was getting into #2 cylinder, The exhaust would smoke on startup, with antifreeze smell.
Later I thought I had better get busy on the problem. Removing the valve cover showed nothing. The engine was very clean. Later I decided to do a block test. It failed. I pulled the head. The #2 cylinder was down, and full of antifreeze. I started the project, after the car sat about 2 weeks. The plugs all looked normal. Changed the gasket, and it was missing on the #6 cylinder. Injector cable was loose. I let it warm up, and cool one cycle and top off antifreeze. It was running great. Decided to go for a short test drive. On the way back, the engine just quit. No noise or anything. Would crank, but not start. Towed it home. I found nothing obvious. Decided to remove the valve cover. Found that the crankshaft dowl pin was sheared off. The camshaft was setting in the no valves open mode. Noticed all of the rocker arms were off of the intake valves. decided the valves were stuck open. Discovered that all 3 intake valves were stuck (bent), and not seating fully. Their edge was hung up on the outside edge of the head. They all had hit the pistons, but only a small nick was on each piston.The engine has 90k miles, and there is virtually no wear. There was no damage in this area.
Two problems came up, the first was removing the valves. I made a homemade valve removal tool and it didn't work well. Did discover the valves could not be removed for the spring could not be pushed down far enough to remove the keepers.(valves stuck open a little). The next day I decided to fix the lifter. Since I had out the torch for welding the tool, I decided to heat the valve stem from my access through the intake manifold.
The plan was to melt the stem. As I was getting the first one hot enough, I heard a bang, and the torch went out. Apparently as the stem melted, the valve seated itself. The top of the valve was actually cool! I had nothing to loose, so I did the other two valves with the same result. Since I took care of my homemade valve tool, to my surprise the valves came out. The tool really looks ugly, but works great. Plan replacing the valves. See no other problems. I will be replaceing the camshaft dowl pin with a pin that is slightly larger. I will drill the hole slightly larger for a tight fit. I will adjust the fit on the sprocket. I always assumed that the pin was a tempered steel. It is not. It is a soft steel. Some of the remains looked like peanut butter. The pin that I use is good tempered steel. My observations are that the rockers should never be loose if the valves are seated, and the hydraulic dampers are working.
I will get it together after I get valves. I live on a rual island, and have to order them.
Later I thought I had better get busy on the problem. Removing the valve cover showed nothing. The engine was very clean. Later I decided to do a block test. It failed. I pulled the head. The #2 cylinder was down, and full of antifreeze. I started the project, after the car sat about 2 weeks. The plugs all looked normal. Changed the gasket, and it was missing on the #6 cylinder. Injector cable was loose. I let it warm up, and cool one cycle and top off antifreeze. It was running great. Decided to go for a short test drive. On the way back, the engine just quit. No noise or anything. Would crank, but not start. Towed it home. I found nothing obvious. Decided to remove the valve cover. Found that the crankshaft dowl pin was sheared off. The camshaft was setting in the no valves open mode. Noticed all of the rocker arms were off of the intake valves. decided the valves were stuck open. Discovered that all 3 intake valves were stuck (bent), and not seating fully. Their edge was hung up on the outside edge of the head. They all had hit the pistons, but only a small nick was on each piston.The engine has 90k miles, and there is virtually no wear. There was no damage in this area.
Two problems came up, the first was removing the valves. I made a homemade valve removal tool and it didn't work well. Did discover the valves could not be removed for the spring could not be pushed down far enough to remove the keepers.(valves stuck open a little). The next day I decided to fix the lifter. Since I had out the torch for welding the tool, I decided to heat the valve stem from my access through the intake manifold.
The plan was to melt the stem. As I was getting the first one hot enough, I heard a bang, and the torch went out. Apparently as the stem melted, the valve seated itself. The top of the valve was actually cool! I had nothing to loose, so I did the other two valves with the same result. Since I took care of my homemade valve tool, to my surprise the valves came out. The tool really looks ugly, but works great. Plan replacing the valves. See no other problems. I will be replaceing the camshaft dowl pin with a pin that is slightly larger. I will drill the hole slightly larger for a tight fit. I will adjust the fit on the sprocket. I always assumed that the pin was a tempered steel. It is not. It is a soft steel. Some of the remains looked like peanut butter. The pin that I use is good tempered steel. My observations are that the rockers should never be loose if the valves are seated, and the hydraulic dampers are working.
I will get it together after I get valves. I live on a rual island, and have to order them.
arty52:
