Stuck Open Intake Valve
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Cross-Country
Joined: Apr 2020
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Stuck Open Intake Valve
Recently Started to mess with an ‘84 f150 that has been sitting for about 15 years. I got it to actually turn over an run for a few seconds the other day after throwing a new non feedback carb and an HEI distributor on it. I continued messing with it and ultimately discovered that my cylinder 3 intake valve is open and will not close (I can visually see it through the spark plug hole) I’ve tried cranking the engine half way around to make sure it’s not moving at all, and it is staying open at all times. My initial thought is that it’s a broken valve spring, but after thinking about it after little while longer I’m wondering if maybe this valve was in the open position while this truck sat for years, and the lifter is now stuck in the open position, therefore holding the valve open.
I’m familiar with these engines and have totally rebuilt one in the past, just trying to get some others’ thoughts as I’m currently having to work on this truck outside in the woods and don’t want to do that any longer than I have to. Just want to get it running so I can drive it to my house and work on it in the garage
I’m familiar with these engines and have totally rebuilt one in the past, just trying to get some others’ thoughts as I’m currently having to work on this truck outside in the woods and don’t want to do that any longer than I have to. Just want to get it running so I can drive it to my house and work on it in the garage
Lead Driver
Joined: Jun 2013
Posts: 5,654
Likes: 1,158
From: Tolland, CT
How far is it to where you want it ?
You might want to at least pull the valve cover and look.
When it runs, does it seem like that one stuck valve is the only issue ? If so, drive to the home. How does the oil look ? is there water in the oil ?
If you've rebuilt one, think about it, I'm sure you'll figure out how safe it to drive it a short distance.
Maybe add a oil additive to help free up the lifter ?
You might want to at least pull the valve cover and look.
When it runs, does it seem like that one stuck valve is the only issue ? If so, drive to the home. How does the oil look ? is there water in the oil ?
If you've rebuilt one, think about it, I'm sure you'll figure out how safe it to drive it a short distance.
Maybe add a oil additive to help free up the lifter ?
Thread Starter
|
Cross-Country
Joined: Apr 2020
Posts: 78
Likes: 9
How far is it to where you want it ?
You might want to at least pull the valve cover and look.
When it runs, does it seem like that one stuck valve is the only issue ? If so, drive to the home. How does the oil look ? is there water in the oil ?
If you've rebuilt one, think about it, I'm sure you'll figure out how safe it to drive it a short distance.
Maybe add a oil additive to help free up the lifter ?
You might want to at least pull the valve cover and look.
When it runs, does it seem like that one stuck valve is the only issue ? If so, drive to the home. How does the oil look ? is there water in the oil ?
If you've rebuilt one, think about it, I'm sure you'll figure out how safe it to drive it a short distance.
Maybe add a oil additive to help free up the lifter ?
Cargo Master
Joined: Sep 2006
Posts: 2,120
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From: Evansville, Indiana
I did this successfully on Cadillac decades ago.
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Cross-Country
Joined: Apr 2020
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Once you remove the valve cover, remove the rocker arm and then use a brass drift and hammer to lightly tap at the stuck valve. Tap progressively harder if it doesn't pop loose easily. No brass tool? Use a piece of wood.
I did this successfully on Cadillac decades ago.
I did this successfully on Cadillac decades ago.
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Cross-Country
Joined: Apr 2020
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I ended up getting over to the truck and pulled the valve cover off the engine. When I did this, it revealed that I in fact did not have a broken valve spring. I then proceeded to remove the rocker arm from that valve after that I tapped on it with a hammer a few times and the spring was simply compressing, but not returning to its original position. I then sprayed, penetrating fluid into the valve, stem and continued hammering. Eventually, the spring compressed enough that I hit it with a hammer one last time and the valve popped right back to where it is supposed to be. I repeated this process a few times before whatever crap was in the valve guide freed up. Problem solved thanks everyone
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From: Virginia
You may want to get a can of rislone and pour it into the oil once you get it going. It's a very high detergent that can help loosen things up, it's great for ticking lifters. Run the engine on a regular basis for a few months with this stuff in it, and it can help clean things up.
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From: Angier, NC
Good to hear you got the valve unstuck.
It would have been nice if we knew what motor you have but as a guess it is a 300 six cylinder because on the non-feed back carb.
If you thought it was a stuck lifter, unlikely, you could have pulled the side cover to check lifters and push rods.
Dave ----
It would have been nice if we knew what motor you have but as a guess it is a 300 six cylinder because on the non-feed back carb.
If you thought it was a stuck lifter, unlikely, you could have pulled the side cover to check lifters and push rods.
Dave ----
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Cross-Country
Joined: Apr 2020
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Good to hear you got the valve unstuck.
It would have been nice if we knew what motor you have but as a guess it is a 300 six cylinder because on the non-feed back carb.
If you thought it was a stuck lifter, unlikely, you could have pulled the side cover to check lifters and push rods.
Dave ----
It would have been nice if we knew what motor you have but as a guess it is a 300 six cylinder because on the non-feed back carb.
If you thought it was a stuck lifter, unlikely, you could have pulled the side cover to check lifters and push rods.
Dave ----
The rislone is a great suggestion. Hoping to rebuild this engine ultimately, but want to do everything I can in the meantime
Mountain Pass
Joined: Aug 2018
Posts: 125
Likes: 30
From: Livermore, CO
I worked in an automotive machine shop for over 30 years and very seldom ever saw stuck valves. I got a free motorhome with a 460 engine that had set for about 10 years. I got it running and soon started sticking intake valves and bending push rods. It's the old nasty gas in the tank that does this, turns to varnish is what used to be said.
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