Terminal Timing Chain Disease

[wow97]

Hello everybody
i got the 4.0 ohv v-6 i want to see with valve cover off

 

[BubbaFL]

Well, I'm still at this.

Lost two 14mm sockets in the bottom of the bellhousing while disconnecting the flexplate from the torque converter.

Got one and a half exhaust downpipe bolts off, then my impact socket and wobble flew off and headed for parts unknown. Maybe it'll go smoother tomorrow!

 

[BubbaFL]

Happy New Year!

Happy New Year, Explorer Forum!

Today was out with the old - next year it's "in with the new"!

 

[BubbaFL]

If I had valvetrain or piston damage, it would be obvious and visible, right?

I pulled the heads off today, expecting to find carnage. I couldn't do a compression test on the left bank without a chain, and I was only getting about 30psi on the right bank.

Could this engine still be worth fixing?

(Click for big pics)

 

[2000StreetRod]

No collision evidence

From the photos I can't see any evidence of the valves striking the pistons and the valves appear to be seated. However, I'm concerned that you were only measuring 30 psi on the right bank which did not have any obvious timing chain issues. I wonder if the right camshaft sprocket retaining bolt or one of the jackshaft sprocket bolts came loose resulting in loss of camshaft timing.

As I stated before in a previous post, your engine may be usable.

 

[wow97]

Hello everybody
i got a 1997 ford explorer xl with 4.0 ohv v-6 i want to see want does ohv look like

 

[BubbaFL]

I suspect the jackshaft chain slipped a sprocket or two, causing the timing to be off.

Looking at the jackshaft chain, all of the "slack" was bunched up on one side of the chain, and that "slack" would work it's way around to the other side as I turned the crank.

I'll try to find a machine shop to take a look at the heads.

Any suggestions on cleaning out the crankcase? I pulled both oil pans, tons of plastic shrapnel in there. Can I rinse it out with water?

Also if you have suggestions on what else should be replaced while the engine is apart (aside from the obvious broken chain, guides, tensioners, etc.), I'd appreciate the guidance. I'm building a spreadsheet of parts and tools needed for the repair - I may give it a shot if it will cost much less than a V8 donor truck.

 

[waskly]

check connecting rod bearings and crank bearings.... you took it that far apart... might as well put a new lower end in. or just bearings.

 

[2000StreetRod]

Check for bent rods

I would check thoroughly for bent connecting rods although unlikely since the crankshaft rotates without binding. Was your oil pressure good when the engine was running? If it was low you should rebuild or replaced the oil pump. I would not spend any money on the engine until you get the heads checked for cracks and the valves and seats checked. I agree with waskly that you should check the main bearings and rod big end bearings. When I had my engine out to fix the cassettes at 150,000 my main bearings were in good shape and within tolerances. I wished that I had taken the time to check the big end bearings but I planned to rebuild the engine in the next year.

 

[BubbaFL]

Could you take a look at these pics of the bearings (rod bearing closest to the oil pump, and the main next to it) and let me know what you think?

The rod bearing cap "looks" scratched but feels perfectly smooth to the touch.