91 7.3L IDI: No Compression #3 Cylinder, Head Off

[vonTrapp]

Hi guys! Been awhile, but I've FINALLY chopped the frame in half, and managed to move the cab into the garage (the 400 foot long ex potato chip truck if you were wondering [img]/ubbthreads/images/graemlins/tongue.gif[/img])

Over the last week, I've been picking at the motor in the evenings, and finally managed to pull the head off of the passenger side. #3 cylinder had no compression previously, all others showed about 410PSI compression on 3 strokes...not bad! Head is off, no breaks in the HG, intake/exhaust valves removed on #3. This engine had previously had #3 exhaust pushrod jam up through the rocker. Replaced both and the injector, but still had no compression.

Anyways...I have some questions for the gurus here:

1) Exhaust valve guide has a rubber "seal" at the top held in place with a funky metal band. How the HECK do you get that clamp off?
2) Intake does NOT have this seal. Is it missing? [img]/ubbthreads/images/graemlins/confused.gif[/img]
3) Valves (so far) do not appear bent, and the seats look OK. I'll be reinstalling them temporarily, turning the head over, and putting some solvent around the valve seats to see if it leaks through.
4) Intake valve has some kind of orange plastic thingie inside the spring...it's broken. Exhaust valve does not have this. What the heck is this orange mystery?

5) Jumping ahead [img]/ubbthreads/images/graemlins/wink.gif[/img] I'm considering looking for a turbo for this truck (used). How does the turbo piping (exhaust work) with a trubo mounted on the top of a motor? Do both cylinder banks pipe to the turbo, or just one side? Any pictures or links?

Additional info: There were signs of something metal having broken off and bounced around the inside of the cylinder. No significant scoring on the walls, just a few nicks on the piston crown. Still checking to see if the valve guide(s) are broken. I also found traces of some metal shards underneath #3 exhaust spring. Glow plug looked fine, not broken.

Will also be testing for broken rings sometime this week (fitting temp metal plate over the cylinder, bolt it down with a crush ring, fill her with air and test for leakeage into crankcase).

Thanks guys...any help/advice is always appreciated!

[aaklingler]

1) don't know what the clamp is, i don't think it is supposed to be there.

2) yes, its missing, get exaust and intake valve seals and replace all of them.

3) whats the question???

4) could it be the valve seal.

5) i have a factory turbo, the pipe from the driver side goes under the motor and up to the passengerside manifold, there is a y and the pipe then goes up the back corner of the motor into the turbo, the down pipe goes down beside the up pipe.

The only thing that i can think of that would have been bouncing around inside the cylinder would be an old glow plug tip.

Have your springs pressure test and check the length of the stem sticking out of the head.

If your going to do your rings test do a couple other cylinders and not the back ones to give you a good comparison, these things leak like a sieve.

How are your lifters and cam on #3?

[vonTrapp]

Hi!

Well, the clamp is like nothing I've seen yet. It's flush to the seal, and I'm pretty sure it's factory. In fact, the rad hoses even had the staples in them, which surprised the heck out of me. Not much (if anything) has been done to the motor's guts.

Lifters for #3 look perfect. No flat spots, no signs of wear.

Have seen no signs of pinholing or of a hole in the piston.

How does the valve seal (black rubber seal fits on top of the stem guide) come off? Just pull it off?

Will advise when I get the cylinder leak test done this week.

And thank you for the info on the turbo. I've got my eye on a wrecked IDI (crank busted), but the turbo and exhaust should still be OK. [img]/ubbthreads/images/graemlins/wink.gif[/img]

[aaklingler]

your valve seals should just pull off.