swapping valve springs
02-26-2013, 06:11 PM
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swapping valve springs swapped valve springs on my 5.3 today. On one cylinder, i heard air getting pass the intake and exhaust valves
I sprayed brake parts cleaner into the intake and exhaust ports I could see the cleaner bubble around the edge of the valves. The valves didnt drop while i changed springs plus the crank was difficult to turn with the air hose pressurizing the cyl.
Can someone tell me what is going with my valves or head?
I sprayed brake parts cleaner into the intake and exhaust ports I could see the cleaner bubble around the edge of the valves. The valves didnt drop while i changed springs plus the crank was difficult to turn with the air hose pressurizing the cyl.
Can someone tell me what is going with my valves or head?
Last edited by slicpartna; 02-26-2013 at 06:39 PM.
02-27-2013, 08:44 AM
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None of this makes sense. Obviously, if you were changing out valve springs, the rocker arms and pushrods were removed. Thus, no lifter pressing on the pushrod, pushing on the valve.
Turning the crank would have no effect on valve movement with no pushrods/rockers in place. So, that wouldn't indicate bent valves.
You're filling the cylinder with pressured air that's pushing the piston down. Trying to turn the crank while it's pressurized just means you're fighting against that pressure to push the piston back up the cylinder. I'd think if you had a massive amount of leakage, it'd be simple to turn the crank as you'd be pushing air out of the cylinder, past the valves.
I think you simply may have carbon build up on the valves. Probably just need cleaned and/or a valve job or simply lapping. Nothing you said seems to indicate any mechanical carnage.
Turning the crank would have no effect on valve movement with no pushrods/rockers in place. So, that wouldn't indicate bent valves.
You're filling the cylinder with pressured air that's pushing the piston down. Trying to turn the crank while it's pressurized just means you're fighting against that pressure to push the piston back up the cylinder. I'd think if you had a massive amount of leakage, it'd be simple to turn the crank as you'd be pushing air out of the cylinder, past the valves.
I think you simply may have carbon build up on the valves. Probably just need cleaned and/or a valve job or simply lapping. Nothing you said seems to indicate any mechanical carnage.
02-27-2013, 11:10 AM
#5
None of this makes sense. Obviously, if you were changing out valve springs, the rocker arms and pushrods were removed. Thus, no lifter pressing on the pushrod, pushing on the valve.
Turning the crank would have no effect on valve movement with no pushrods/rockers in place. So, that wouldn't indicate bent valves.
You're filling the cylinder with pressured air that's pushing the piston down. Trying to turn the crank while it's pressurized just means you're fighting against that pressure to push the piston back up the cylinder. I'd think if you had a massive amount of leakage, it'd be simple to turn the crank as you'd be pushing air out of the cylinder, past the valves.
I think you simply may have carbon build up on the valves. Probably just need cleaned and/or a valve job or simply lapping. Nothing you said seems to indicate any mechanical carnage.
Turning the crank would have no effect on valve movement with no pushrods/rockers in place. So, that wouldn't indicate bent valves.
You're filling the cylinder with pressured air that's pushing the piston down. Trying to turn the crank while it's pressurized just means you're fighting against that pressure to push the piston back up the cylinder. I'd think if you had a massive amount of leakage, it'd be simple to turn the crank as you'd be pushing air out of the cylinder, past the valves.
I think you simply may have carbon build up on the valves. Probably just need cleaned and/or a valve job or simply lapping. Nothing you said seems to indicate any mechanical carnage.
02-27-2013, 12:41 PM
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At this point spring pressure would be holding the valves shut. Unless something is between the seat and the valve (carbon) it would mean the valve job is suspect
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02-27-2013, 04:12 PM
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None of this makes sense. Obviously, if you were changing out valve springs, the rocker arms and pushrods were removed. Thus, no lifter pressing on the pushrod, pushing on the valve.
Turning the crank would have no effect on valve movement with no pushrods/rockers in place. So, that wouldn't indicate bent valves.
You're filling the cylinder with pressured air that's pushing the piston down. Trying to turn the crank while it's pressurized just means you're fighting against that pressure to push the piston back up the cylinder. I'd think if you had a massive amount of leakage, it'd be simple to turn the crank as you'd be pushing air out of the cylinder, past the valves.
I think you simply may have carbon build up on the valves. Probably just need cleaned and/or a valve job or simply lapping. Nothing you said seems to indicate any mechanical carnage.
Turning the crank would have no effect on valve movement with no pushrods/rockers in place. So, that wouldn't indicate bent valves.
You're filling the cylinder with pressured air that's pushing the piston down. Trying to turn the crank while it's pressurized just means you're fighting against that pressure to push the piston back up the cylinder. I'd think if you had a massive amount of leakage, it'd be simple to turn the crank as you'd be pushing air out of the cylinder, past the valves.
I think you simply may have carbon build up on the valves. Probably just need cleaned and/or a valve job or simply lapping. Nothing you said seems to indicate any mechanical carnage.
i have the engine out
would suggest removing the heads of of the block to clean the valves?
thanks
02-27-2013, 04:12 PM
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None of this makes sense. Obviously, if you were changing out valve springs, the rocker arms and pushrods were removed. Thus, no lifter pressing on the pushrod, pushing on the valve.
Turning the crank would have no effect on valve movement with no pushrods/rockers in place. So, that wouldn't indicate bent valves.
You're filling the cylinder with pressured air that's pushing the piston down. Trying to turn the crank while it's pressurized just means you're fighting against that pressure to push the piston back up the cylinder. I'd think if you had a massive amount of leakage, it'd be simple to turn the crank as you'd be pushing air out of the cylinder, past the valves.
I think you simply may have carbon build up on the valves. Probably just need cleaned and/or a valve job or simply lapping. Nothing you said seems to indicate any mechanical carnage.
Turning the crank would have no effect on valve movement with no pushrods/rockers in place. So, that wouldn't indicate bent valves.
You're filling the cylinder with pressured air that's pushing the piston down. Trying to turn the crank while it's pressurized just means you're fighting against that pressure to push the piston back up the cylinder. I'd think if you had a massive amount of leakage, it'd be simple to turn the crank as you'd be pushing air out of the cylinder, past the valves.
I think you simply may have carbon build up on the valves. Probably just need cleaned and/or a valve job or simply lapping. Nothing you said seems to indicate any mechanical carnage.
i have the engine out
would you suggest removing the heads off of the block to clean the valves?
thanks
Last edited by slicpartna; 02-27-2013 at 07:06 PM.
02-28-2013, 07:22 AM
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Yes, pull the heads off for cleaning.
You're going to need to take the springs back off and pull the valves out to clean them. The part you're going to want to clean is the tops of the valves where they seat against the head. If you take all the valves out at once, make sure to mark them somehow or lay them out they way they cam out so you can put them back in the same place.
Like Tainted mentioned, oven cleaner will work or some foaming engine degreaser. Spray it on and let it soak for awhile. Some 00 steel wool works or a stiff plastic brush. You don't want to use a really stiff wire brush and mar up the sealing surface of the valve. Same approach goes with cleaning the head itself and the valve seat area.
If you're going through all this trouble, you might as well get some valve lapping compound and lap the valves a bit before final reassembly. Should make sure you get a really good seal. You can find a valve lapping kit at Advance or Autozone. Probably overkill, but while you have the heads off it's cheap and easy to do.
You're going to need to take the springs back off and pull the valves out to clean them. The part you're going to want to clean is the tops of the valves where they seat against the head. If you take all the valves out at once, make sure to mark them somehow or lay them out they way they cam out so you can put them back in the same place.
Like Tainted mentioned, oven cleaner will work or some foaming engine degreaser. Spray it on and let it soak for awhile. Some 00 steel wool works or a stiff plastic brush. You don't want to use a really stiff wire brush and mar up the sealing surface of the valve. Same approach goes with cleaning the head itself and the valve seat area.
If you're going through all this trouble, you might as well get some valve lapping compound and lap the valves a bit before final reassembly. Should make sure you get a really good seal. You can find a valve lapping kit at Advance or Autozone. Probably overkill, but while you have the heads off it's cheap and easy to do.
