VES Guillotine Preventive Engine Destruction Issue

[whoisthatguy]

I noticed that the very tip of a VES guillotine started to gouge into the piston, that resulted in some serious piston damage. So in my rebuild, I ground about a dimes thickness worth of metal off of the tip edge of the blade that is closest to the piston wall. Not a common problem but well worth the effort to prevent a failure.

 

[BeartoothBaron]

I read somewhere that valve to piston contact tends to happen on high-mile motors because the stop in the head for the valve wears over time. It's a fairly tight clearance; not sure why it couldn't be more, but it is what it is. I wonder if it's the kind of thing you could catch in time - you'd think you'd see the flat of the valve that faces the piston start to scuff before anything major happens, assuming you checked it often enough. I suppose the best thing would be if you could somehow weld up the stop and then machine it back to spec, but that's way outside anything I, or most mechanics could do. I can't see any reason grinding a bit off the end of the valve would be a problem - good suggestion.

 

[whoisthatguy]

After checking my other VES sleds, I found another VES guillotine with shiny surfaces near the pointed tips, from where it was working on causing me a sudden engine failure. So 30% of the VES engine cylinders that I have, have enough slop in the VES guillotine to cause damage to the pistons and rings, leading to a sudden engine failure and possible survival hike out to civilization.

 

[retiredpop]

I don't see any reason why it would harm anything by grinding off the tips. It doesn't look to be a critical area of the exhaust valve.