Ever see this before?

John B.

Well-known Member
Went to use my pressure washer that's powered by a Honda engine. While it was running it made a weird noise and stopped. There was no
compression after that. I looked for oil running on the ground and didn't see any. Didn't see any holes in the block either. I pulled
the valve cover off. Found the intake valve dropped in on top of the piston. The piston pushed it back up thru a new hole in the head.
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Saw a Honda 3 or 3.5 horse on an airless sprayer, owner didn't fog it or drain it or anything, old gas glued the intake into the guide. I was able to remove the carb and spray both ends of the valve with carb cleaner, worked it back and forth, oiled it and started it up. Came back the next day but this time it had compression; owner had neglected to fuel it. Wasn't it John Wayne that said "you can't fix stupid"?
 
Neighbor had the same engine off a pressure washer on a mini bike punched the valve up thru like that. In his case I didn't blame the engine more his modifications to the governor!
 
I dropped a valve on a 59 Ford 2 ton grain truck 292 Y block. I was on my way back to the farm, and I had a feeling I knew it had dropped a valve, but it was running on 7 really well. I figured it was as damaged as it could get, and that it had not actually blown up. So for 6 miles I kept the RPM at medium engine speeds ~2500 to 3000 by ear. I pulled into the side yard, put it in 4th gear and shut it off while dumping the clutch. This gambit paid off by stopping the engine crisply. The first valve cover I pulled off was the drivers side. Bingo. Spring, retainer and one keeper were accounted for, the valve stem was down in the guide about 1/2". The design of the engine has the valves perpendicular to the flat topped pistons. I put a pencil into the guide and turned the fan. That dang pencil moved upward!! I turned some more and the stem came out a half inch. I towed the truck over to the air compressor, and used a compression tester adapter to fill the cylinder with 100psi (in gear, shaft Ebrake on and blocked wheels). I pulled up on the valve and it slammed into the seat and held. Whew. I found a new set of keepers and reassembled the spring and retainer. I adjusted the valves on that side just to be reasonable. I hit the key and it ran perfectly. We kept the truck for several more years and it never had any issues. My dad was happy. Jim
 
Did that with a 427 Chevy while making a round on a drag strip. Red line was maybe 7,400 RPMs with valve stud girdles, roller rockers, triple valve springs, balancing, and all of the good stuff. A valve floated near red line and a 12.5:1 piston dome slapped it so hard that it put a hole in the piston and went through the combustion chamber in the L-88 aluminum head. Scrap.

I've experienced it before, weak or failed valve spring(s) at high RPM.

Mark
 

I had that happen on a Farmall H. Replaced the valve keeper and all was well. I have to say though that the piston and the valve fighting to occupy the same space does create a very interesting sound.
 
Yup!

My brother gave me a nearly new 3.5kw generator that had suddenly lost all compression. The engine was a 196 cc OHV Honda clone. Turned out the tip had broken off the intake valve. But the valve had not dropped in enough to hit/damage the piston.

Replacing the busted valve with a genuine Honda replacement valve got it running again. Not long afteward generator ran non-stop for 5+ days during an extended outage with no issues.
 
Happened to me on a MT JD -- was sitting ideling while I shut the pasture gate. Valve dropped down. When Fred Mason got the head off, the valve was sitting on top of the piston, stem was ,bent in a S shape. Put a new valve, valve spring, head gasket, valve cover gasket on it and went back to mowing hay.
 

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