Hey gang! Been a stranger lately, mostly due to a tremendous workload and a number of unforeseen catastrophes.

Some of you may remember that my 140K mile '86 blew a head gasket in an unusual manner in February. I got the engine out and the heads off right away, saw no major collateral damage but that's where it sat until last week.

I finally got back into it for a more complete teardown and discovered some new and mildly disappointing stuff.

-All eight glow plugs were fried... no clue why. It was starting fine.

-One prechamber cup fell out when I started cleaning the heads. I'll stake it back in, I guess.

-The valve seats & valve faces are in tough, tough shape... surprising considering I had the valves touched up in the late '90s when I replaced the original head gaskets. Not all that many miles ago (maybe 50K?)

-6 valve stem tips (both intake and exhaust) are galled and munged as badly as I've ever seen on an engine that has supposedly been well taken care of. Corresponding damage to rockers (not a big deal since I was going to update the rockers to 7.3 style). Now I know where that "tick" was coming from.

-Fair bit of what I read as embedded contamination in the bearings, both rods and mains, but especially the rods (the heavy load area.... top rod bearing and bottom main). Looks like it's been there a while, as it's partly worn away.

Anyway, the original plan was to do a performance rebuild. That idea faded away due to "circumstances" so I decided to just do the repair, add ARP studs, overhaul the turbo and "freshen up" the rest of an engine in what I thought was good condition. Looks like I have more freshening up than I planned for, more like an overhaul.

On the good side, the engine was squeaky clean inside and the bores are excellent and can be honed and reringed. Pistons are great. The crankshaft will polish up. Cam, lifters and timing gears are still optimal.

The two biggest surprises where the valve stem tips and bearings. Have always used good oil and filters and changed both dutifully (I've owned it since it was about a year old). When the engine was apart previously, I did my typical "sterile environment" routine and did a quick flushing out oil change after the work, so I doubt it came from me (though who knows).

The valve tips... no idea. They were ground by the shop doing the valve job to match the stem heights. Perhaps they ground too much off and got thru the hardening. I have yet to measure valve length.

I'll get around to pics in due course.

 

Sounds like you got your work cut out for ya. Keep us posted and post up some pics of those valves!

 

When you assemble your heads, use GM EOS. Dip the valve stems in it to lubricate them. The Dyno Lab that I worked in found that the heads assembled using the GM EOS would last about 50% longer (2200 hours with vs 1500 hourd without). The galling on the valve stem tips could be reduced by using Militec metal treatment. A drop or two between the rocker and valve stem should suffice. These items are pricey, but well worth the investment.

GM EOS $18.00 for about 6 oz.
Militec ~$35.00 for 16 oz.

 

This is what I fear about my "tick" that has developed.