Build Thread Here we go again............
TnCJ
Senior Jeeper
- Posts
- 566
- Thanks
- 6
- Location
- South East Tennessee
- Vehicle(s)
- 1980 CJ 5, 4.2 engine, D30,AMC 20, T176, Dana 300, MC 2100 carburetor.
I've had a small "weird" noise coming from the front of my recently rebuilt engine. Just a "chunk chunk chunk" sound that was only noticeable at idle and only when the engine was warm.
Sooo, the paranoid person that I am and thanks to the internet I was concerned that it was a symptom of "cam walk" a condition where the cam is moving forward and hitting the timing chain cover. which over time can lead to failure of the cam.
Yesterday I decided it was time for exploratory surgery and to remove the timing chain cover and see what was going on in there. Not a real hard job but it does require taking the radiator off, removing the fan, harmonic ballancer, alternator and of course the timing chain cover.
All was going well until I got to the crank bolt, it broke free pretty easily but was tight all the way out. I knew that wasn't good but I was going to get it out no matter what. Seems my concerns were right, the bolt was stripped and the threads in the crank were pretty mangled. Off to town I go searching for the elusive 1/2 X 20 tap. Stopped at every parts store in town and finally had to buy a complete tap and die set just to get the 1/2 X 20. Got back home and finally got the tap started straight and slowly the process of straightening the buggered up threads. I'll have to say, that crankshaft is made of some very hard steel!!!
After I got that chore done I removed the timing chain cover fully expecting to see massive damage from the cam coming into contact with the cover or at least a loose timing chain that was slapping the cover. Not the case!! It was in pristine shape with nary a scratch, the timing chain was tight as well.
I did notice that the harmonic ballancer was not in great shape so I scrounged up the ballancer from the old engine. It looked to be in decent shape so I decided to use it.
Long story short, everything went back together fairly easy, filled the radiator back up and took a test drive. Got home and the mystery noise was still there but not as bad.
So moral of the story is..................a 40 year old Jeep gonna make some noise.
I'm going to drive it till it breaks.
Sooo, the paranoid person that I am and thanks to the internet I was concerned that it was a symptom of "cam walk" a condition where the cam is moving forward and hitting the timing chain cover. which over time can lead to failure of the cam.
Yesterday I decided it was time for exploratory surgery and to remove the timing chain cover and see what was going on in there. Not a real hard job but it does require taking the radiator off, removing the fan, harmonic ballancer, alternator and of course the timing chain cover.
All was going well until I got to the crank bolt, it broke free pretty easily but was tight all the way out. I knew that wasn't good but I was going to get it out no matter what. Seems my concerns were right, the bolt was stripped and the threads in the crank were pretty mangled. Off to town I go searching for the elusive 1/2 X 20 tap. Stopped at every parts store in town and finally had to buy a complete tap and die set just to get the 1/2 X 20. Got back home and finally got the tap started straight and slowly the process of straightening the buggered up threads. I'll have to say, that crankshaft is made of some very hard steel!!!
After I got that chore done I removed the timing chain cover fully expecting to see massive damage from the cam coming into contact with the cover or at least a loose timing chain that was slapping the cover. Not the case!! It was in pristine shape with nary a scratch, the timing chain was tight as well.
I did notice that the harmonic ballancer was not in great shape so I scrounged up the ballancer from the old engine. It looked to be in decent shape so I decided to use it.
Long story short, everything went back together fairly easy, filled the radiator back up and took a test drive. Got home and the mystery noise was still there but not as bad.
So moral of the story is..................a 40 year old Jeep gonna make some noise.
I'm going to drive it till it breaks.