No compression in #4 clyinder.
01-08-2007, 02:54 PM
#1
No compression in #4 clyinder.
Drained the oil, no mixture at all...... clean oil. Stuck valve? My computer is down, and I'm at a friends, so I wont be able to respond for a while, but I'd love to hear suggestions before I take the head off........
01-08-2007, 05:18 PM
#5
Rennlist Member
If compression is fine on all other clylinders you most likely have a burned exhaust valve. I burned out #4 exhaust valve a couple summers ago and when it happened the car acted like it had a fouled spark plug. Got home and through a compression tester on it and the needle never even moved.
I just bought one new Ex valve and had a fresh 5-angle valve job and O-ringing done here locally at a machine shop. Put new seals and guides in as well.
Had the exhaust manifold Swain coated as well while it was out.
I just bought one new Ex valve and had a fresh 5-angle valve job and O-ringing done here locally at a machine shop. Put new seals and guides in as well.
Had the exhaust manifold Swain coated as well while it was out.
01-08-2007, 05:42 PM
#6
Rennlist Member
+1 burnt exhaust valve on #4. Happened to me as well at the end of 2005.
Don't know about other experiences but I lost a sizable chunk of the valve. Enough to make me pull the turbo to check for damage.
Turbo was fine, as some people predicted it would be. So get the head rebuilt and you should be good to go.
Don't know about other experiences but I lost a sizable chunk of the valve. Enough to make me pull the turbo to check for damage.
Turbo was fine, as some people predicted it would be. So get the head rebuilt and you should be good to go.
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01-08-2007, 10:48 PM
#9
Rennlist Member
A burnt valve is caused by a combination of high EGTs (we all have that problem!!) and some thing that gives it a starting point. A small carbon particle lodged between the valve face and seat will prevent the valve from completely sealing and then you have extremely hot gases leaking through at very high speeds and pressures….very much like an acetylene cutting torch. The back side of the valve will look like it was cut with a torch.
Chris White
Chris White
https://rennlist.com/forums/showthre...valve+Callaway
01-09-2007, 12:03 AM
#12
Rennlist Member
Originally Posted by Charlie944
Here is the link to my #4 Ex vavle thread
https://rennlist.com/forums/showthre...valve+Callaway
https://rennlist.com/forums/showthre...valve+Callaway
01-09-2007, 01:22 AM
#14
Three Wheelin'
I think its caused by crap chips and too much boost. When you crank it up to 20 psi with stock everything, it starts detonating, the KLR retards timing, and combustion is still happening during the exhaust stroke, leading to the burnt valves.
01-09-2007, 02:23 AM
#15
Rennlist Member
Originally Posted by mark944turbo
I think its caused by crap chips and too much boost. When you crank it up to 20 psi with stock everything, it starts detonating, the KLR retards timing, and combustion is still happening during the exhaust stroke, leading to the burnt valves.