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Discussion Starter · #1 ·
Greetings all, I am new to this forum and new to Isuzu.
I have a noise problem with my son's 2.6 Trooper. Bad noise coming apparently from the top end. Sounds like a socket in a tin can is being violently shaken. Narrowed noise to #4 cylinder. With the spark plug removed from the head, there is no noise. Re-install the plug, noise is back, which means that pressure is a factor. There is nothing loose in the cylinder, (I sent a camera in to have look see). I thinking maybe bad piston slap because the noise seems to be too high in the block to be a main or con bearing, and too high in tone as well. Perhaps one or both of the piston skirt extensions have been knocked off? There are no obvious scrape marks on the cylinder walls but there does seem to be some bright-ish marks in the walls at the very top of the stroke on oposite siddes of the cylinder.
Except for the old VW Bugs my mechanical experience has been limited to American machinery. I've been fiddeling with this for days and my boy need his ride.
Any suggestions please apart from "it's time for a re-build".
 

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I'll mention this only because it's not all that uncommon with the 2.6. Check crankshaft endplay as sometimes the thrust washers fall out allowing the crank to float back and forth and creating havoc. Even better drain the oil and remove the small oil pan looking for carnage. I know you've isolated it to number 4 cylinder but I'd still check the end play, if the thrust washers (or shims) have dropped out all other problems are secondary.
 

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Is it an automatic or 5spd?
If 5spd working the clutch, while in neutral,.will cause the clutch to push on the crank & you should hear a diff in the noise if its thrust washers. (not an end-all-be-all, but a quick noninvasive test)

If the noise goes away when you remove spark plug it could be valve related. Does the noise stop when you remove just the plug wire? (i.e. Take away strain of combustion)

If no foreign objects are in the cylinder the next option for top end is a bad valve or loose/broken fixture on the valvetrain. Pull the valve cover & have a peek, just don't get wrench happy, all the fasteners in there have low torque values & snap/strip easily.

~ psguardian
 

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Here's a link that will show the mentioned thrust shims. Also as you read through the thread Surfer Joe has some pictures of his old engine showing not only the thrust washers but a piece of piston skirt he found is his failed engine.
viewtopic.php?f=4&t=51731&start=25
 
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