Valves bent??

[ryanhood1983]

If the valves hit the piston are they junk? they look ok, and it sure looks like the intake valves hit the piston.. any way to tell without removing them from the head?


http://i251.photobucket.com/albums/gg318/ryanhood1983/Mobile%20Uploads/083109_182700.jpg

http://i251.photobucket.com/albums/gg318/ryanhood1983/Mobile%20Uploads/083109_182701.jpg

[250x_kyle]

if they hit the piston its almost guarnteed they are bent.

[mcgrath]

Yeah, they will almost definately be bent if they hit. You will probably be able to see light through the valve port if they are bent because they wont close all the way. Intake valves are cheaper then exhaust atleast. If thats a score mark on the piston in the picture they will be bent.

[ryanhood1983]

I popped the valves out today, they appear fine. I been checking everything over, rocker arms and stuff. all looks good. I did scratch the piston some how when I installed it, right in the middle there. looks like the valves hit just hard enough to leave carbon on the shiny piston.

[racerdad88]

If the valve is hitting the piston, there is a problem somewhere - What comp. ratio is it? If 11:1 or higher, timing off or incorrectly adjusted valves will cause it to hit the piston!!!

[ryanhood1983]

it is 11:1 wiseco. checked everything before I started it after the rebuild. when I started it up it was making a terrible sound, a thread on the next page called 'new top end whats wrong' is exactly the sound its making. ive ajusted and re adjusted the valves on compression stroke of course. looked for unusual wear or scuffs from the timing chain. Even took the clutch cover off looking for a clue. Now ive taken it down the the bottom end. Checked ring gap, pulled the valves, and waiting for a new timing chain now. The jug looked great, no scuffs from the piston slapping it or anything. I didnt run the cylinder base gasket... maybe that has something to do with it??

[mcgrath]

You didnt run the cyl base gasket? What does that mean?

[racerdad88]

Originally posted by mcgrath
You didnt run the cyl base gasket? What does that mean?

If that is what I think it means, that is probably the problem - The gaskets are calculated in to the total height needed to the valves to clear the piston, especially when you start running higher compression pisotns - Also check the timing chain tensioner - Mine was worn out and causing excessive noise!!!

[ryanhood1983]

I believe i had the timing way off when I started it the first time. Thats probably why it left the marks. installed a new timing chain and the engine noise is gone now. runs great, without the base gasket

[ryanhood1983]

just use a sealer at the clyinder base instead of the gasket. supposed to bump compression ratio a bit. Found the info on this site somewhere..

[mcgrath]

I wouldnt use goop instead of a gasket. Unless you like leaky gaskets. Its up to you ,its just a reliability issue. I would use a base gasket and get a thinner head gasket. I know everybody likes doing performance upgrades and I have done them for years too, but now Im more into reliability and I still never get passed on the trail anyway. To each their own.

[TRXRacer1]

I like base gaskets myself but I wouldn't use sealer. Ryan is right though, you can pass on the base gasket and easily still be leak free.