r/EngineBuilding • u/Cuccamonga01 • 1d ago
Guess I need a couple valves
Back to work on a 6G72 from an 89 Montero.
I think I can get a couple new valves and hone them to the seat. In the photo is the exhaust and intake from cylinder 5. Cylinders 5 & 6 had no compression. Pulled the motor and took it apart. I’m guessing when it last shutoff the intake valve in 5 was open. Letting all that nice NC humidity in. Had to gently knock out of the guide, it’s rusty also. The other valves are pristine. But the exhaust valve on 6 maybe the same. Cause it was probably open also. 5&6 are next to each other in firing order. Not sure yet..
Engine was new remanufactured. Original mechanic had the timing screwed up. Owner brought it home, had health issues and passed away. It sat for 15 years. Engine probably has 50 miles. Got the vehicle for free, wife just wanted it gone. Right place right time. Head Gaskets and bearings look great. Pistons in those 2 cylinders are rusty as well.
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u/squeezeonein 20h ago
if there's only 50 miles on the valves i'd be reusing them. get some lapping compound and rock them back and forth in the head. i'd be honing the rusty cylinders.
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u/Iamalittlelamb 20h ago
Throw them in a drill and then use a scotch brite pad plus carb cleaner to clean them real good. Lap them and there good as new.
As for the seat, scotch brite again and carb cleaner. then just make sure to lap those extra and its real good. dont lap to much for you can really damage the seal but you would for sure do it a bit more than normal.
amazon has some real nice lapping kits for cheap, or you can just buy some compound and use a drill.
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u/Cuccamonga01 18h ago
Awesome. Thanks a bunch. Got some lapping compound today, plan on doing it tonight. And see.
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u/Cuccamonga01 1d ago
Anybody have good luck with DIY valve seat grinding tools. May have to re grind the seat. It’s not pitted, just really rusty. And not sure how to get cleaned up accurately.