need a little help...
 

I freshened up my stocker engine last week and made three runs on it since it was freshened up. I keep loosing valve lash on the intake valves only. It's loosing .020" each pass. Its like the valves are sucking up into the head. What causes this? Everything was the same except for the new valves(intakes) and a thinner head gasket.I checked the valve to piston clearance when i put it together and it was over .100"
The engine now has 240 psi of cranking compression but it runs slower. Any suggestions?

Re: need a little help...
 

Check your cam . This happened to my engine and the cam lobes were wiping out.

Re: need a little help...
 

Yep, it looks like the lobes are gone in a couple of cylinders.

Re: need a little help...
 

Flat Cam...

Re: need a little help...
 

Well I got the engine all apart today. The cam is ok. The intake valves are tuliped, sucked up into the intake ports. I am going to try to post a pic. Any ideas why? The old valves I had in it never did that. I ran them for two years.

Re: need a little help...
 

Which brand of valves? Manley, SI, Ferrea,...????

Re: need a little help...
 

too much timing or lean?

Re: need a little help...
 

TW,

Something is causing the valves to get extremely hot. It could be anything in the combustion process. I have also seen it in marine engines when water gets into the cylinders through the exhaust but I doubt this would be the case here. Did you change anything during your "freshen up" that could keep the valves from dissipating heat ? Like a much narrower valve seat than you had before ? Anything else change in your combination ? Not enough timing can be just as bad as too much. Vacuum leak ?

Just thinking out loud :)

Re: need a little help...
 

If the valves were sinking in the head wouldnt the lash get tighter not looser?

Re: need a little help...
 

Yes the valve lash would go to zero.
After, i put new rings, bearing and gaskets thats when the problem occurred. I use a .070 wide valve seat width. But the old valves were the same way. I changed to a thinner head gasket to try and get a llittle more compression.
I had always used manley valves in the past. Never had a problem with them. These valves were a no name brand.
I am thinking that I am running to lean, the exhaust gas temperature is 1400 deg. in high gear. I run 32 degrees total timing, that seems to be the limit with my combination. It runs slower e.t and mph with more timing.