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Very. The valve lash tends to tighten up over time and if not checked and adjusted at regular intervals this is the result.
I don't remember the maintenance schedule off the top of my head, but checking it every 30k, or once a year, and adjusting them to the looser side of the tolerance, is an easy way to prevent it.
Very. The valve lash tends to tighten up over time and if not checked and adjusted at regular intervals this is the result.
I don't remember the maintenance schedule off the top of my head, but checking it every 30k, or once a year, and adjusting them to the looser side of the tolerance, is an easy way to prevent it.
+1
Turns out maintenance is important. Who knew?
But also looks like that engine is burning a fair amount of oil. Carbon deposits from burning oil will also contribute to valve burning.
At this milage be sure to inspect valve guides for wear. They are probably shot and need replaced or you will be doing this again in 1000 miles.
Annndddd it looks like you have the wrong spark plugs installed, they should be flush with the combustion chamber. Or maybe that plug is just backed out.
Ah, this makes a lot of sense, no lash on the burned valve, took a couple turns to get any clearance. the other exhaust valve still had some lash. I thought the lack of clearance on the burned valve was due to the valve damage and sinking into the seat, but more likely it was just tight and burned.
speaking of the seat, it looks pretty good, not sure it needs to be cut.
at this point the head should go to the machine shop for a valve job, guides and guide seals. but the owner just wants the one valve replaced, so we'll see how long the fix holds.
the spark plug is backed out, hanging by a few threads.
on another note, I'll never understand why people run strait water. i guess they don't know how bad these things rust up. and changing that rear coolant pipe is very difficult with the head in place.
the nipple on the housing rotted from the inside and was pouring water.. Ugh.
on another note, I'll never understand why people run strait water. i guess they don't know how bad these things rust up. and changing that rear coolant pipe is very difficult with the head in place.
the nipple on the housing rotted from the inside and was pouring water.. Ugh.
Lol because the internet tells them it doesnt matter, or that Water Wetter is good enough.......
Fun Fact: During the three years after the US Govt. mandated 10% Ethanol content in street driven fuel, up from the previously mandated 5% Ethanol content, exhaust valve failure increased 96% across all US driven vehicles using 87 Octane fuel regularly.
Fun Fact: During the three years after the US Govt. mandated 10% Ethanol content in street driven fuel, up from the previously mandated 5% Ethanol content, exhaust valve failure increased 96% across all US driven vehicles using 87 Octane fuel regularly.
I think you are confused with the removal of lead from fuels. That DID cause valve seat issues for anything with soft seats.
I mean we did introduce ethanol into fuel right around the time these high strung solid lifter engines were getting up there in mileage and the general population wasn't exactly keeping up with maintenance. I could see how people would try to make that connection but it is not the ethanol killing valves, it is mostly lack of maintenance and some of the high mileage that is killing them.
update, guy wanted it fixed cheap as possible, just replaced the 1 exhaust valve. the seat was still good(enough). lapped the valve in with some grinding compound and put back together. JB weld on the rotten cooling pipe, adjusted all the valves to correct setting and..
it runs like new. even the AC is cold. no warranty given, the owner is happy.
Re: 200k B20 motor, burnt exhaust valve common?
