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Help! 4.0L V6 SOHC Timing chain

staples200

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I have a 2003 ford explorer that I believe has a timing chain failure. Before I knew anything about the issues with the vehicle, I could hear (What I know now was) the timing chain rattle. The vehicle just whimpered out on me one day on the highway over a year ago. I was pissed and just bought a jeep so I wouldn't have to deal with it. I have since rolled the jeep (...LOL) and am wanting to repair the Ford. Here is where I'm at....

I have both valve covers off, Cassettes on both banks seem to be in good condition, taught, with the tentioners and guides in good condition. I cracked the left bank valve cover right on the damn seal, cheap plastic piece of crap. Another 50 bucks added to the project.

When I turn the Balancer clockwise, both Cassettes seem to turn without problem.. It's a ***** to turn, takes all my strength though.. Not sure if thats normal.

After figuring out I had spark and fuel, I had a shop do a compression test last year after the engine failed.. And there were problems with the results, I planned on junking the vehicle and didn't even write down the results. I was sure I would find something wrong with one of the cassettes so I didn't bother going out and buying a new battery to be able to do a compression test before taking it all apart.

So my question is, Where do I go from here? Should I pull the timing cover, Just pull the whole engine? Set the damn thing on fire.. What is the quickest route to find the failed components from here?
 






If the rest of the truck is in good condition, you may want to just pick up a used motor with low milage. It sounds like timing chain skipped and you slapped a piston with the valves.

Turning the motor by hand should NOT take all your strength but should not be easy either.
 






pull the plugs

The cylinders walls may have rusted after a year of sitting. I suggest that you remove the spark plugs, add some oil into each cylinder and let it soak overnight. After a few rotations the crankshaft should become easier to rotate as the oil loosens the rust. If there is still mechanical resistance the pistons may be striking the valves.

It's too bad you didn't keep the compression results. Low compression on all cylinders on one bank usually means that bank's timing chain has slipped. Low compression on all cylinders may mean the primary (crankshaft to jackshaft) chain has slipped which is not common. Since you have the valve covers off it is easy to check the camshaft timing. When cylinder #1 is at TDC on the compression stroke both camshafts should have the timing slot below the axis of the camshaft and parallel to the head surface that mates with the valve cover.
cam1.jpg
 






silly question is the truck in neutral when spinning the crank.

if you are going to change timing chains the motor needs to come out.

better off getting a used motor I picked up a 2010 4.0 sohc ranger motor with 2000 miles on it for a 1000 bucks, I could not buy the parts to fix it cheaper than that.

and had it delivered to my house for 200 bucks. you gotta love the internet.
 






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