Sticking valves

RalphG

RalphG

Well-known member
Remember those two sticking valves on my 39 Deluxe, as seen in the video of starting it up? I had them un-stuck and running on all 8. I went to start it this morning after sitting in the shop for probaby 3 weeks and number one exhaust valve stuck open again. I don't suppose there is any easy fix for this other than running the engine more frequently. Or else try and leave the engine so that number one cylinder has both valves in closed position.
Anybody else find this to be a common problem on flatheads?
 
I dunno, but I watched your resto video's and when you said you did a mediocre job of sanding the car I laughed out loud!

I think more regular usage and maybe some MMO or similar in the fuel and down the carb can only help.

Other than that, for the sake of a pair of head gaskets and an intake gasket why not pull the heads and manifold and pull all the valves and give em all a clean up and a very gentle lap in.

Mart.
 
Mart said:
I dunno, but I watched your resto video's and when you said you did a mediocre job of sanding the car I laughed out loud!

I think more regular usage and maybe some MMO or similar in the fuel and down the carb can only help.

Other than that, for the sake of a pair of head gaskets and an intake gasket why not pull the heads and manifold and pull all the valves and give em all a clean up and a very gentle lap in.

Mart.
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I have to admit the wedding photographer must have used some special magic to make even my rough old paint job look pretty good in the photos. Trust me, it is rough, but for now it protects the surface and looks ok.
Actually that engine was apart in the late seventies and had quite a bit of work done to the top end. I can't recall all the details now but think the valves would have received attention at that time. No doubt sitting for almost 30 years without running might have something to do with the sticking valve problem. I have sprayed some penetrating oil down the valve stem and leaving it to soak for a while.
 

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RalphG said:
Remember those two sticking valves on my 39 Deluxe, as seen in the video of starting it up? I had them un-stuck and running on all 8. I went to start it this morning after sitting in the shop for probaby 3 weeks and number one exhaust valve stuck open again. I don't suppose there is any easy fix for this other than running the engine more frequently. Or else try and leave the engine so that number one cylinder has both valves in closed position.
Anybody else find this to be a common problem on flatheads?
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Hi Ralph, don't let anyone say this is not normally an issue, it most definitely is an issue!

I've had "first-hand" experience with this problem, '49 Ford, 239" P/U, and in the end the only way to totally avoid it is to have the guides lined with bronze liners. After I rebuilt my own truck I never had a single valve "stick" after that. It could sit for a year and it would be fine.

There a few options that MAY help some, knurling being one, but in the end the bronze eliminates it altogether. Whether you choose "spiraled" or "plain" liners, it will be a permanent cure.

Thanks, Gary in N.Y.

P.S. I've done hundreds of the guides, literally, in my lifetime and have never had a "hanger" with the liners! I still sell a bunch of these during the course of a year! Most are done on an "R&R" basis, customer sends in the old guides we make them new and send them back!
 

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Valves stick due to several causes. The shaft of the valve becomes carbon coated from failure of the head to seal against the seat. The valve chamber may be full of sludge from the use of non detergent oil, or failure to change oil frequently. One or more valve springs may be weakened or broken. The lifter may be sticking. We used to scoop black sludge out of the valve chamber by the handful. The only permanent "fix" is to pull the heads and the intake manifold and remove the valve & guide assembly for inspection, and to be sure the seats are not worn out. We replace all springs, as well, because they do wear out and lose tension, and tend to take a "set" from sitting compressed for long periods.
 
I all ways polish the valve stems and guide bores before I put the valve assembly back together, takes a little more time but solves most valve sticking problem
 
Well it is running fine tonight and the valve is opening and closing as it should.. after soaking all afternoon with penetrating oil . I really don't want to open this engine up unless I have to so for now I'll keep trying the penetrating oil treatment and hope it cleans up the valve stem over time. Still need to do the 30 year oil change but I didn't run it long enough to get the engine hot. Only ten degrees here today. :(
 
I believe that a knurled valve guide will do the job at a very small cost. I did this to all my engines as I felt the guides hold lubrication with a tight fit. (.0005/.001") AND WILL LAST FOREVER.
 
I had sticking valves in my 239 1950 F-1, when i switched to a synthetic oil the problem went away even though the truck sits for months at a time. Pete
 
Prior to my purchase, my '47 sat in a barn for a year and a half. When I started running the engine the valves didn't stick but I could tell the engine was tight and it sounded like I had a piston knock. I started using 10W-30 in the engine and MMO in the gas. The engine has "relaxed" and I'm quite pleased with how it sounds and turns now. The 10W-30 oil still provides very good oil pressure and doesn't burn-off. As others have said, the best thing is to drive these engines frequently, get then good and hot, and keep changing the oil.
 
J Franklin said:
Change that oil NOW!
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OK. It is on my "to do list" for tomorrow. The old oil is 10w-30 and I will be replacing it with the same brand and weight as it is what I use in most of my vehicles. Oil pressure is good on this old flathead.
 
Got the same problem with mine but it is a rebuilt motor with new valves and guides. Started it up 2 weeks ago and ran it up To temperature and it ran fine. Started it up today and it had 3 exhaust valves stuck. Pulled off the intake and it bent the guide clips. Having just fetched up I am going to try to get enough penetrating oil in the to free them up and install new clips. The motor has only a few hours on it so I am a bit baffled. The only thing I do different is run 100 octane low lead gas that I get at the local airport. Would that make them stick?
 
If they stuck tight enough to bend the clips, they need to be removed and get proper stem to valve clearance. I would check them all. Sounds like whoever did the build has them way too tight.
 
Peterooster said:
I had sticking valves in my 239 1950 F-1, when i switched to a synthetic oil the problem went away even though the truck sits for months at a time. Pete
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Pete may be on to something here. I had a case of 20W/50 Mobil 1 left over from my racing days. I decided to use it in my '51 so as not to waste it. It has worked great for the last 10-12 years (good oil pressure and no more leaks than usual). Over this period of time, the car has set for a year or two a couple of times, and I've never had a problem with sticking valves. Coincidence? I can't say for sure, but I'll keep on using it
 
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