Terminal Timing Chain Disease

[BubbaFL]

Just thought I'd share the end-result of SOHC timing chain disease. Managed to get 160k out of her.

The first time she had the disease, the dealer replaced everything under factory warranty. Managed to get well over 100k miles out of her since then, and over 60k since the rattle came back.

RIP sweetheart
1997 - 11/14/2010

 

[my98nnj]

Interesting.

 

[swetrid]

Looks like cam sprocket bolt snapped off, seen it a few times.

 

[69Mach1]

Ouch! That looks rather catastrophic. The old six's you heard the ticking of the rocker arms. The SOHC six's you hear the ticking of the bomb waiting to go off.....

 

[BubbaFL]

I pulled the left side valve cover to take a look.

 

[2000StreetRod]

can't decipher photos

I can't tell what the first two photos are showing. Is that part of a timing chain guide assembly poking thru the valve cover? If so, the engine may not be destroyed, just the left guide assembly. The camshaft position nub indicates the #1 piston should be near TDC on the compression stroke.

 

[waskly]

looks like a connecting rod through the block, the first pic is the chain off the gear.

 

[BubbaFL]

First pic is the left cam chain hanging half off of the gear, second is a chunk of "something" that the chain grabbed and threw through the valve cover - I think part of one of the guides or tensioners. When I pulled the valve cover, the chain and metal junk fell down into the timing cover.

Is there any easy way to check for bent valves without replacing the timing chains / guides? Anybody see anything else "broken" in the third pic other than the missing chain etc.?

 

[waskly]

the pic of the thing through something is in the valve cover?

 

[BubbaFL]

Yeah, the second pic is a piece of something, and part of the left cam chain, sticking out through a hole in the valve cover.

 

[waskly]

still a very costly repair, since for something to fly out on a non clearance motor, valve / piston damage happens.

 

[2000StreetRod]

Oiler & valves

It appears that the tabs that hold the aft section of the oiler are broken and the oiler is laying in the head. The photo below shows the oiler in the normal position.

The green arrow identifies the nub for the camshaft position sensor.

The exhaust valves are the most likely to be damaged. Bent valves usually won't seat and hold compression. You can remove the camshaft, pressurize each cylinder with an air compressor hose connected to the spark plug hole with an adapter and listen for leaks. There is a risk of breaking the camshaft bearing caps when reinstalling the camshaft without the proper tools or being very careful. An alternative to removing the camshaft is to rotate it until both lobes for a cylinder are up meaning no valve depression. The crankshaft wil have to be rotated by hand when the camshaft is rotated to keep the pistons from striking the valves.

 

[BubbaFL]

Is there any way to remove the engine without rotating the crankshaft?

The left side timing chain is off (it was hanging on by one sprocket, and fell down inside when I removed the timing cover). Any ideas on how to get the engine out without causing further damage?

 

[2000StreetRod]

engine plus torque converter

If you can't rotate the flexplate to unfasten the torque converter then you'll have to remove the engine with the converter attached. If doing that, maintaining the alignment of the crankshaft axis with the transmission axis becomes more important. I suggest that you remove the motor mount plates attached to the block once you have the weight of the engine supported by the crane and the transmission firmly supported. You'll want the lift chains attached to the engine so the rear doesn't drop as it separates from the transmission shaft. Since the axis of the crankshaft and the transmission will be tilted up toward the front, you will have to raise the boom slightly as you move it forward (away from the transmission).

 

[wow97]

hello everybody
what does ohv motor look like with valve cover off

 

[BubbaFL]

Okay, I'm back at this project again (finally some decent warm weather here!).

Thought I'd share Bubba's Improvised Crankshaft Bolt Removal Tool - a big c clamp (from my brake job toolbox) and a piece of wood wedged against the frame hold the harmonic balancer, so I can attack the crank bolt with my breaker bar and a cheater.

 

[wow97]

does anybody have any pictures valve cover off on a 1997 ohv v-6 i have a rocker arm set-up i think 4.0ohv is cologne sohc v-6

 

[BubbaFL]

Got the timing cover off. As expected, chunks of blowed-up guides and cassettes everywhere.

(click for big pics)

 

[OneLever]

does anybody have any pictures valve cover off on a 1997 ohv v-6 i have a rocker arm set-up i think 4.0ohv is cologne sohc v-6

Please use the forum search function to find answers instead of hijacking existing threads. The very first link in that page gives you the pictures you're looking for.

Making good progress BubbaFL.

 

[BubbaFL]

Chain broke

Chain broke!