404 Deere Headgasket
Blew the headgasket in my 4630 today. Was just bringing it to the shop to give it a once over. Had to drive it a couple miles so it was up to temp and I had to idle back on a slight hill to pass a car. When I throttled back up, it let loose. It literally blew the fire ring on #1 cylinder out the front between the head head and block. No warning signs, was running like a top last fall and is still right on the money coolant wise.
Tractor has been turned up to about 180 at some point in it's life. Supposedly has 11,000 hours (I suspect less, if anything) and has never been touched. I suspect the head must be warped pretty bad for it to completely blow the gasket out in an instant under minimal load. Either that, or could a liner be cavitated and it suddenly failed and let a shot of water in? Is cavitation a known problem on these engines?
Anyway, a few questions for those of you who know these 404's (1977 model):
Should I get new head bolts? I have read that they were upgraded at some point, but I couldn't tell if '77 would be upgraded already or not.
I am planning on having the head planed and will touch up the valves myself. What should I shoot for on valve protrusion? Top of spec or can I go a little more for more compression (better starting)?
Any other suggestions while I have the head off? (Will probably roll bearings while it's in the shop, not that they have anything to do with the head).
From what I've gathered from other new JD equipment and what seems to be a huge concern is "How big is the fridge" and does it keep your wobbly pops cold enough ??
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Thats all Deere has left to make the machine flawless.