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Re: Houston we have a problem

PostPosted: Fri Jul 24, 2020 11:06 am
by hattrick4467
I believe the valve is loosened up but I need to confirm that it will not stick on full range movement. Otherwise I will be looking for another push rod!

Re: Houston we have a problem

PostPosted: Fri Jul 24, 2020 2:11 pm
by nikkinutshop
Hammering the valve down into the cylinder may be the worst advice.
My first attempt would be to try and get some oil around the valve stem at the top of the guide. Then tap on the valve stem with a brass hammer. Unless the valve is really stuck, the spring should return the valve to closed. The valve may need a little extra encouragement with an attempt to turn the valve. Vise Grip may work.
I have a modified sparkplug that I have adapted a MILTON "M" air fitting to. I have used shop air to hold a valve up. If you do this, make sure the truck is in neutral. The air pressure may kick the engine over and launch the truck. I know a guy who was pinched between his workbench and the truck.
I don't recommend straightening bent pushrods, but it may be possible as a temporary fix until a replacement can be found. Pushrods are the weakest link in the upper valvetrain. Pushrods transfer and redirect the upward motion of the lifters, which goes in one direction, to the rocker arms which move in another direction. Consequently, they are subjected to bending forces as the load and engine speed increases.

Re: Houston we have a problem

PostPosted: Fri Jul 24, 2020 3:17 pm
by Sokan
Push rods are available new, Melling MPR-205. There are several on ebay and Rock Auto claims to have them.

Re: Houston we have a problem

PostPosted: Sat Jul 25, 2020 10:07 am
by bedrockjon
my dad bought a 1941 Cadillac from his neighbor, I helped him get it going,

it had 3 valves stuck open, 2 on one bank and 1 on other bank,

did like Nikki said soaked stems with penetrating oil, tapped them lightly, 2 popped free 3rd one was stubborn, we used vice grips with a piece of thick leather to grab the head and slowly wiggle it a little until it freed up, changed the oil and was good to go,

until he rear ended a Mercedes on the Pasadena freeway, that beautiful grill got destroyed.

was a flathead motor so a little easier to deal with

Re: Houston we have a problem

PostPosted: Thu Aug 06, 2020 7:54 am
by hattrick4467
So just an update on my valve issue. I was able to take a brass punch and tap the valve down without taking the spring off and it was just stuck down. Nothing I tried would pull the valve back up but after about a week with kroil, prybars and finally a tie rod end removal tool I was able to pull the valve up and slowly work it back and forth. I was then able to adjust this valve and have 120+ lbs of compression. Truck now idles at 800-850 rpms but is running super rich at the moment. I guess after sitting for 20+ years I should let it run a bit and then go through a due a little tuning.

Thanks for everyone's advise on this.

Mike

Re: Houston we have a problem

PostPosted: Fri Aug 07, 2020 9:20 am
by Buzzman72
That compression number is encouraging. Glad to hear you're making progress!

Re: Houston we have a problem

PostPosted: Fri Aug 07, 2020 1:43 pm
by hattrick4467
So I went out last night and started the truck. Ran fine but seemed to be idling too slow and running rich. Found that odd after it sat and idles the day before for 10 or 15 minutes. Played with the timing a bit so that is closer. I am beginning to wonder if I put the rod in the correct hole for the accelerator pump on the holly carb as it has two slots. The carb idle screw does not seem to adjust and the carb was cleaner than a whistle with all passages open. Not a carb expert and there are variations of that cab so maybe I got something back together not quite right. The fuel bowl does not empty now so that is a bonus. On a positive note I did drive the truck around the field a time or two just to check things out. Had a couple too many wobbly pops to be on the road itself.

Have a good weekend.

Re: Houston we have a problem

PostPosted: Sat Aug 08, 2020 6:34 am
by nrowles
Sokan wrote:Push rods are available new, Melling MPR-205. There are several on ebay and Rock Auto claims to have them.


FYI I bought push rods on Rock Auto and made the rookie mistake to not compare before installing. When tightening down the rocker assembly one of the rocker arms snapped. The new ones bought off Rock Auto were 1/2" longer. I did confirm the box had the correct part #. Not sure if that mistake was across the board or what happened but if buying them make sure to compare closely.