stuck valve advice

1959 - 1978, M151, M151A1, M151A2, Technical questions and discussions, regarding anything related to the M151.
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M151A2_mutt
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stuck valve advice

Post by M151A2_mutt » Fri Feb 24, 2017 11:43 am

I sent my M151A2 gas tank off to be restored, got the tank back about 5 months later and installed it. Started it up and noticed a rough idle. I then pulled the head cover off and found a bent pushrod on cylinder #3. In the process of replacing the pushrod and setting the valve clearances I found that cylinder #3 intake valve is stuck closed. While rotating the engine by hand when the time comes for intake valve on cylinder #3 to open I feel resistance and began to see the pushrod bind. I used some penetrating oil around the valve in hopes of unsticking it. With the rocker armed moved out the way the valve will not move even with a tap from a rubber mallet. My next step is too remove the head and repair what is needed. Before I remove the head does anyone have any advice on how to free up that valve.

thanks
Rich


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Re: stuck valve advice

Post by Rickf » Fri Feb 24, 2017 1:02 pm

The valve is most likely stuck due to varnish from old gas. I usually pour a little Marvel Mystery oil on the valve stem a couple times a day for a few days and once in a while give it a couple taps with a brass hammer. Don't rush it but it usually breaks free in a couple days. If it does not there may be more to the problem and head removal may be required but I would try this first. A rubber mallet is going to be too soft, if you do not have a brass hammer use a regular hammer and a piece of wood against the valve.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

M151A2_mutt
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Re: stuck valve advice

Post by M151A2_mutt » Fri Feb 24, 2017 3:47 pm

Thanks Rick, All it needed was a harder tap with a hammer and piece of wood. It took a few cycles of tapping it down and letting it slowly spring back up to closed position before it functioned normally. While it was slowly closing again I looked in the combustion chamber through the spark plug hole and saw lots of black gunk on the valve. What do you think about pouring some sea foam into the intake manifold to clean the valves?

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Re: stuck valve advice

Post by Rickf » Fri Feb 24, 2017 4:07 pm

I don't have a lot of personal experience with Seafoam but it can't hurt. What I would do is once you get it running be sure to run the Marvel or Seafoam in the gas and at least with the Marvel run a quart of it in the oil in place of a quart of oil. I don't know if Seafoam works that way or not.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

M151A2_mutt
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Re: stuck valve advice

Post by M151A2_mutt » Fri Feb 24, 2017 4:54 pm

Thank you, I will give the marvel a try

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Kurt Lesser
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Re: stuck valve advice

Post by Kurt Lesser » Tue Feb 28, 2017 6:49 am

Marvel mystery oil is great stuff for freeing up stuck parts and I use it all the time. I had an M37 once that I added one of those wonder additives and to promptly stuck 4 valves. Marvel was recommended and within 15 minutes all of the valves were merrily cycling again. It's the only additive I believe in now. I've never used the Seafoam but its supposed to be another good product. All of these engine additives have really benefited from modern chemistry but we tend to stick with what we know. Another great product is Kroil. Its an exceptionally good penetrating oil for loosening up frozen parts and rust welded nuts and bolts. If you don't want to use the old hot wrench on it give Kroil a try first.

Kurt
Kurt Lesser
US Navy, 1969-1975
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Rickf
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Re: stuck valve advice

Post by Rickf » Tue Feb 28, 2017 8:50 am

I remember Kroil was around back in the 60's and probably much further back than that in industry. A friends dad used to bring it home from the plant and it was SO much better than Liquid Wrench which was the gold standard at the time.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

M151A2_mutt
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Re: stuck valve advice

Post by M151A2_mutt » Sat Mar 04, 2017 6:15 pm

I have used Kroil many times on rusted bolts etc. Always works great. Rick the marvel loosened up the valve quite nicely after a few days. The mutt has been running great. I also decided to give seafoam a try today. I peaked at the valves through the spark plug hole with a flashlight before and after the seafood treatment and noticed a considerable amount of carbon deposits removed. Obviously I turned the engine over by hand to position the valve in the open position so I could see them. Thank you all for the advice.

Rich

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Re: stuck valve advice

Post by Rickf » Sun Mar 05, 2017 5:46 am

Good to hear a report on the seafood :lol: :lol: :lol: :lol: (Seafoam). I always like first hand reports so I can either pass them along or use them myself in the future. I have a Mustang GT with the spark plugs that have a bad habit of breaking off in the head due to carbon deposits. I am going to do the Seafoam bit on that vehicle and hope it saves me some headaches.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

M151A2_mutt
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Re: stuck valve advice

Post by M151A2_mutt » Sun Mar 05, 2017 6:44 am

My computers darn spelling autocorrect feature always does more bad then good haha :lol: . I'm sure the seafoam will help your mustang out. On my mutt I simply removed an intake manifold plug and ran a tube from there to the bottle of seafoam. I let the engine suck about half the bottle up. I set the engine idle higher then usual until all the white smoke cleared. Tons of white smoke will come out the exhaust so do it before the neighbors wake up haha


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