I'm hoping to get some input here... This is what I'm working on:

2004 Durango 4.7, AT, 4x4

Some background information - I just rebuilt the engine. The block was checked, honed, new bearings, crank honed, new pistons, new oil pump, new timing kit, passenger side cylinder head is a re-man, driver side head was taken to machine shop for valve job and resurfacing, new radiator, new fan clutch, new t-stat, etc.

I installed engine and started it. The engine started right up and idled fine for about 20 minutes. I noticed the temp gauge climbing but not to redline (almost though). My thought was the system needed burped. I shut it down to let it cool and prepare to burp the cooling system. I restarted the engine and it ran for about two minutes then it died with a clunk sound. Would not restart.

Pulled plugs to find passenger side plugs are carbon fouled (not oil). Driver side clean.
Checked fuel pressure - good at 55psi.
Performed coolant system pressure test. It held 17psi for 10 mins - good.
Cylinder compression on passenger side cylinders - All between 175 - 180.
Cylinder compression on driver side cylinders - all 0psi!!!!

I pulled the valve cover on driver side. It threw one rocker arm. Timing chain is still intact, camshaft rotates, pistons are moving up and down. Still no pressure on driver side cylinder head.

I'm thinking head gasket but am still stumped.

Any ideas?

 

Update: I hooked my air compressor up to each cylinder on the driver side and all four held at approximately 100psi ( which is all my compressor is set at ). It seems that the cylinders just aren't making any compression.

I'm dumbfounded and my gauges are pretty accurate and consistent.

 

does it have a chain for each cyl head? i think so. check the chain setting. sounds like one of the chain is out of timing.

 

You are correct moe, it does have a chain for each head. I think you might very well be correct on timing issue. Looks like I'm going to have to pull the head either way. The camshaft lobe that threw the rocker arm is marred, rocker arm is bent, two other rocker arms seem to just be sitting in there without any tension/pressure.

 

Update :

I pulled the head. Conclusion is the camshaft dowel/pin sheared (not sure why) which threw it out of time. The pistons hit every intake valve causing bent valves and smashing valves into the head. Head is pretty much shot. Each piston top has a slight indention/scratch.

 

if the piston is not to bad you might be able to use it. try sanding dent a small amount and see what it looks like. sounds like more work than i would like to do. just be careful setting the sprockets. bad news on the damaged parts.

 

Thanks for the advice moe. Actually I did make an attempt to smooth out the piston heads. I used an aluminum ingot i had to "burnish" any rough spots. It seemed to work pretty good. I got a new re-man head installed. I still have to do the timing etc. .

After investigating this. Here is my opinion on what happened. When I removed the camshaft sprocket that sheared the pin it didn't take much torque at all to get the sprocket bolt out. I'm thinking the camshaft bolt didn't get torqued correctly. Here is why.. I've read on other places that when reusing a camshaft bolt, especially one that's been overheated that it can cause stretching of the bolt. Some after market camshaft makers require a new cam bolt and loctite when installing for that reason.

My theory is the bolt backed out some causing all of the force to be placed on the pin that sheared.