2.9 Top End inspection / cleaning / rebuild

[eightynine4x4]

1989 V6 2.9 4x4 automatic

Finally getting a plan together to open up the top end and consider some possible rebuild or at least cleaning and inspection and gasket replacements.
I’ve already addressed a lot of peripherals to the engine in the last year or so, such as fuel/air/sensors/distribution/etc, so probably the issues that remain are due to the engine guts being out of shape or dirty.
The truck actually performs quite well most of the time. I only occasionally lose a cylinder for 10 seconds and it comes back with a little burst of throttle. But the primary issue is the noise.
Here is a 5 second video of the truck after going for a 10 minute spin.

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And here is a 5 second video of the truck immediately after startup. Clearly the RPMs are high but that’s just the engine doing it’s job. The ticking is much more pronounced though.

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The idle all performs as it should. Startup is reliable, however sometimes it is reluctant to catch. Starter is new. Battery is new and beefy.

Usually the sound completely goes away after a 15-20 minute moderate drive like 35 mph. Then it stays smooth and quiet with just an occasional light tick.

Obviously this sound could be called the classic ticking. I’m hesitant to conclude that the oil pump needs to be replaced or that the cam shaft is blocking oil, because so much of the time it sounds really quiet and smooth.

Others have suggested in this forum that it could be that the top end is gunked up and that openjng it up for cleaning might help a lot. So that’s where I’m at.. getting ready to open this up and figure out how to inspect.

 

[franklin2]

If you think it may be dirty lifters, before I tore it apart I would pour a can of Rislone in the oil and run it for a month. If it has dirty/sticky lifters, that stuff will fix it.

 

[eightynine4x4]

If you think it may be dirty lifters, before I tore it apart I would pour a can of Rislone in the oil and run it for a month. If it has dirty/sticky lifters, that stuff will fix it.

Thanks! Yeah I did that already a ways back. I do believe it helped actually. Rislone also quieted my motorcycle so i do like that stuff.
On the truck I also did a somewhat risky engine flush because i figured it was all or nothing here, and that seemed to help also. No signs of clumps came out, just black oil. Then I followed that with a few quick runs of oil just to get it flushed, and then installed a batch of Mobile 1 which i then learned performs very noisy in these 2.9's for some reason, so after a bit I switched to Rotella 15W-40 which has been sounding healthy and the engine is the quietest its ever been, and much of that is from the cleaning I'm sure. Also did a injector cleanout with a good quality type of rig that hangs from the hood. That made a noticeable improvement in drivetrain noise as well.
All in all it's performing decently enough to drive. When i got the ignition timing down it was a huge boost. I am running on 31x10.5's and even up super long moderately steep mountain hills i can accelerate and hang out at 45 mph. Before the cleaning and engine peripheral work I would bog down to like 20mph going up any significant hill.
I think i have to keep an eye on #1 and #2 spark plugs more than the others though. They get blacker than the other 4.

 

[franklin2]

A lot of people have injector problems when they get old with a lot of miles. My 2.9 had a rich idling problem and after messing with it for years, the injectors are the only thing left that I did not try/get checked. I did throw some off ebay in it, and I don't think they were any good either.

You could try some more snake oil and put some sea foam in the fuel and see if that clears out any sticky injector problems. Like the Rislone you have to put it in strong (whole can on a partial tank of fuel) and run it for awhile and be patient for it to work.