Sticky valves

I got the flatty six running in the '47 Dodge sedan a while back, and it got to the point that a couple valves would stick. It would run really rough with some clatter for a few minutes when holding the RPM up, then just clear up and run smooth as silk - Until it sat long enough to cool off. Then it would do it again.

I tried several methods of de-carboning the valves with no luck.

So I got the idea of pouring oil into the carb until it killed the engine, then let it sit for about a week. worked great for quite a while just starting the engine and running it in the shop without driving.

Now it's doing it again. This time I'm getting an intake valve hanging up, and blowing fuel out of the carb.

I just did the oil thing again with a little fuel system cleaner mixed in.

What have you guys experienced in this area?

 

how about value cleaning system. Never used them, BUT i here good things.

 

Years ago were I worked we had Thermo-King refrigerators w/ air cooled 2 cyl flathead Onan engines. After not running all winter. These would have stuck valves, too. If they didn't get going in a couple of minutes of running, they weren't going to fix themselves.

The only sure cure was to take the tappet covers off and spray WD on the valve stems and work them up and down with a screwdriver beyond what the cam would normally move them. I don't know if it was varnish or rust, but after a few minutes of movement they would be fine. I think it was always intake valves. And we never had to go further than this to free them up.

Frank

 

There use to be a product called upper lube, we used in the Mobil Station where I worked in the late 60's. Don't know if it's still around but we use to pour it down the carb with the engine at a fast idle. Worked good.

 

A friend of mine says to pour a cup or kerosene down the carb (slowly) as it is running. Never done it, but he swears by it.

 

My tranny builder buddy just now told me to pour trans fluid down it LOL

May work, it's high detergent. He also said he had a buddy years ago that poured diesel down it.

Odd thing to me is that it went away for so long, then came back. I did drive the car for the first time the other day though.

 

Try a product called "Seafoam",and do the same saturation trick,as in pour in the carburetor to thoroughly soak every thing,and use the last bit in the can to "kill the engine".

Try running it again in a couple of days.

 

Sea Foam should get it. If you want something less harsh, Marvel Mystery Oil in the oil and the gas should help.

 

i have heard of doing this..buy some marvel mistery oil..put some in your gas tank some in your crankcase and run it for a while and see if this loosens up the sticky..if not you may be at the pint where you need to take them out aand clean them up good and put new guides in.. remember those engines like Lead..that helped lube the guides..they may be scored or have buld up on them