

| Subject: | Bent Valve Part II |
| From: | James Wagner |
| Date: | Sun, 9 Aug 1998 18:30:59 -0400 |
Thanks to those who sent me advice on the first part of my stuck intake valve episode. Now I've removed the head and can see that the valve and head did make contact, though only very slightly. There is a small scuff mark on the piston (shiny aluminum in the sea of carbon) and no mark on the valve. In order to get the van the one mile back to my drive way, I took out the push rod to the stuck valve, and ran on three cylinders. I though the van would just be a bit low on power and vibrate a lot, but it ran horribly. It idled great and ran OK up to about 1800 rpm, but above that it shuddered and stumbled. I suppose it was a lack of exhaust back pressure, otherwise I'd think the cylinders would be pretty independent of one another. Anyway, there was about an ounce of oil in the cylinder with the stuck intake valve (which I forced closed before I attempted to run on three cylinders. I also disconnected the fuel injector wire). But otherwise it looks fine. No scuff marks on the cylinder. I guess I should have disconnected the exhaust valve also, since the oil probably was just sucked up into the cylinder since the intake valve was not opening to reduce the vacuum in the cylinder. At this point I think I will try an old cylinder head and see if the cylinder runs makes adequate compression. I am still trying to determine what happened. I had replaced both heads and driven less than 100 miles the previous week with only a short episode of clanking sounds coming from the engine. I immediately checked all the valves and the compression in the cylinders and everything checked out ok. After driving it a bit more the sound disappeared. After a week of not driving the van, I started it, and went about a mile down a flat road to a stop design. The engine just died. When I tried to start it, the clanking sound was back. I check the valves and found the #4 intake push rod longed between the rocker and the cylinder head wall. The rocker was not contacting the valve and the valve was stuck in the open position. When I removed the push rod, I found it bent. Now that the head is off and I can't get the lifter out. The push rod seems to have dented the wall of the cylinder the lifter slides in. I think I'll hone the cylinder with a brake cylinder hone. If anyone has any advice please let me know. My advice is pay very close to those valves when replacing the heads. I think I had a small window to avoid this problem, but I guess I needed to test the valves for smooth movement. Thanks, -- James Wagner PS Anyone know why disconnecting one cylinder makes the whole engine run so poorly as opposed to just less power and more vibration.
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