trying to diagnose knock in 6.2 build

[neo]

Hi all, I am back from an extended vacation courtesy of my lovely employer. "Light Travel" is not what you would think anymore.

Anyway, about the time I left, a year and a half ago, I had built a 6.2 for my wagoneer conversion. When I started it up from the begining, there was a "cam-timed" knock that reminded me of a bad injector. During the trouble shooting, I changed each one out to no avail. Also checked compression, but did not notice any significant difference.

Becuase I had reused the lifters and was concerned about them, I decided to pull the heads and look at the cam wear and lifters. I have only had the time to pull the d/s head and found the lifters and cam apear fine (so far) however, and here it the nitty gritty, cylinder 1 had a noticable build up the other three did not at the top near the fire-deck. It also had a very slight redish flakes in the combustion part of the head aroudn the valves. The other three bores were very clean, little to no soot at the top and uniform in color. I looked at the gasket and did not see anything, but around cylinder 1 compression ring the gasket pulled away from the ring, like it was not uniform. This was between the water jacket and the cylinder.

Now that I think about it, the engine also seemed to put off a little white smoke when it ran. :( What I am currently hypothesising is that the gasket never sealed properly right there, allowing a very small amount of antifreeze in the cylinder on suction stroke, then did not allow the full combustion of the charge, leading to the knock (or perhaps retarding the combustion) and allowing this black sooty build up aroudn the top of the cylinder. These were not FelPro gaskets, but will be replaced with FelPro.

Any thoughts, provoking or ridicule is apreciated.

Neo

[DmaxMaverick]

Your hypothesis sounds reasonable. I don't know of anyone here who doesn't recommend Fel-Pro head gaskets (with new bolts or studs), including me. Good luck!

[neo]

Thanks much on the perspective. I am going up today to replace the head gasket. The more i think about it, the more i believe this is spot on. Spoked with an old salt I work with this week and he indicated with his reasonably extensive diesel experinece, it is likely a head gasket. SO today, repalcement starts.
I purchased a felpro "blue streak" gasket after concluding that it apears there is one felpro offering for head gaskets for this engine. New felpro head bolts and some permatex thread sealant. Plant to clean it like crazy, then carefully put her back together. My fingers are crossed I do it right this time.
THe more I think about it, the more evidence I come up with indicating this is the root cause. My dad always claimed there was a misfire and there was steam coming out of the exhaust. I believe he was right on both accounts - yes, hard to admit, but he still knows more than I will ever aspire to know :o . It also seemed to always be low on coolant, belching some out the overflow. I suspect this was cylinder pressure escaping, dropping the pressure also hurting chnaces of combustion.
We shall see. I will repost (hopefully with pics.) thanks again!!
Neo
Hopefully be able to put fuel

[john8662]

you mentioned thread sealant? The new head bolts come with their special sealant on the threads and underneath the head of the bolt. No need to add anything else. Actually adding a wet sealant to the threads can squeeze off the threads and between the gasket. Guess what, yeah, leading to a leak. seen it happen. really really.

That's why on head studs I install them all dry if doing it in chassis, then pull them out one-by one, apply sealant (RTV only in my case) and send 'em back in the hole to be torqued. If engine is on the stand I'll install them all with sealant taking the time to wipe off any excess rtv that squeezed out then, carefully bringing down the gasket over the studs, then the final head. real pita. I really recommend bolts for most anything, seriously.

[neo]

Finally finished it this evening. She started up without much effort. No knock! She is idling a little rough, I suspect cause I had fIddled with the timing and it is likely off. Gonna set that back to zero in the mOrning. Have alot of work still to do, but a 6.2 banks td powered wagoneer is pretty cool in my redneck world! Super stoked to move past this part! Now, to get the DMV to pass me on the inspection! Thanks again for all the help!
Neo