My woes... valve?
Thread Starter
|
Elder User
Joined: Jun 2006
Posts: 654
Likes: 0
My woes... valve?
Truck stopped runnin in Nov, finally started diag'ing her, found the cam sprocket broken.
I replaced the timing set today.
Before she died, I had tested 3 cylindars for compression (I was lazy)
5-6-7
90-90-120
I know I need rings, thats in the future.
Today, I tested 5-6-7-8 I will do 1-2-3-4 after I eat/shower.
Got 90-90-120-0
When I turned the crank by hand, with the chain off to align them, did I bend my valves? Is there anyway I can find out if I have a bad valve without tearing a head of?
I need the truck to move under it's own power for a cheap as possible. It won't be driven, but it must move around the driveway. Once I can do that, I can beg funding for a rebuild from my girlfriend I hope. But first I'll have to demonstrate hope...
I replaced the timing set today.
Before she died, I had tested 3 cylindars for compression (I was lazy)
5-6-7
90-90-120
I know I need rings, thats in the future.
Today, I tested 5-6-7-8 I will do 1-2-3-4 after I eat/shower.
Got 90-90-120-0
When I turned the crank by hand, with the chain off to align them, did I bend my valves? Is there anyway I can find out if I have a bad valve without tearing a head of?
I need the truck to move under it's own power for a cheap as possible. It won't be driven, but it must move around the driveway. Once I can do that, I can beg funding for a rebuild from my girlfriend I hope. But first I'll have to demonstrate hope...
Posting Guru
Joined: Mar 2006
Posts: 1,526
Likes: 2
From: fargo, nd
you only have one cylinder that has enough compression to run. the ones at 90 would be probably bad rings, the one with no compression would either be a bad/bent valve or you blew your head gasket or broke a piston. my uncle did an experiment on a 390 one time... the experiment was to see how many cylinders could be not working and have the engine still run... he was able to get it to run on 1 cylinder in the end... so if you just need it up and down the driveway you should be able to start it as long as its carbed, but i wouldnt try to drive it that way.
Postmaster
Joined: Mar 2001
Posts: 4,968
Likes: 3
From: So Cal
You could pull the valve covers to check for broken or bent valves. Also look for broken rockers and missing or damaged pushrods.
As a an emergency bandaid, you could remove the push rods to the dead cylinder. Do this only if the valves are seated and have their springs etc. You don't want a valve hanging down in the cylinder.
While you are at it take a look at the valve guides to see if you cracked any.
If it isn't a dead vavle then you probably have a hole in the piston.
Good Luck,
Jim Henderson
As a an emergency bandaid, you could remove the push rods to the dead cylinder. Do this only if the valves are seated and have their springs etc. You don't want a valve hanging down in the cylinder.
While you are at it take a look at the valve guides to see if you cracked any.
If it isn't a dead vavle then you probably have a hole in the piston.
Good Luck,
Jim Henderson
Hotshot
Joined: Dec 2003
Posts: 18,423
Likes: 9
From: iowa
jim you don't want to remove the pushrods, you can push the lifters out of the bore far enough to open up the oil gallery and dump all your oil preasure thus not providing enough to keep the crankshaft alive (especially critical on the drivers side as it feeds the mains)
Postmaster
Joined: Mar 2001
Posts: 4,968
Likes: 3
From: So Cal
Originally Posted by monsterbaby
jim you don't want to remove the pushrods, you can push the lifters out of the bore far enough to open up the oil gallery and dump all your oil preasure thus not providing enough to keep the crankshaft alive (especially critical on the drivers side as it feeds the mains)
I remember way back the lifters on one of my engines was hard to remove seems like a slight ridge at the bottom of the lfters made it hard to remove a few, engine had normal wear and I was just modding it. Can't count on this tho.
Still a risky thing.
Without removing the rods, I don't think you can prevent the valves from moving unless they are already bent.
Bandaids are always a problem,
Jim Henderson
Thread Starter
|
Elder User
Joined: Jun 2006
Posts: 654
Likes: 0
To update.
Left bank, 90-90-120-0
right bank, 90-90-90-90
I removed the rocker arms from #8, so in theory both valves should be closed. I then pumped air into the cylinder, and it flowed freely out the carb. So, #8 intake valve is out of comision.
When my timming gear skipped, the truck was running, but shaking pretty bad. The stud that held the aircleaner down broke, and we assumed it it fell out of the engine bay en-route home. (I wasn't there)
I'm assuming that the stud made it's way into #8, and is holding the intake valve open. When I pull my intake tomorow, I'll find out...
Left bank, 90-90-120-0
right bank, 90-90-90-90
I removed the rocker arms from #8, so in theory both valves should be closed. I then pumped air into the cylinder, and it flowed freely out the carb. So, #8 intake valve is out of comision.
When my timming gear skipped, the truck was running, but shaking pretty bad. The stud that held the aircleaner down broke, and we assumed it it fell out of the engine bay en-route home. (I wasn't there)
I'm assuming that the stud made it's way into #8, and is holding the intake valve open. When I pull my intake tomorow, I'll find out...
