Sticking valves - cleaning them

Last fall before I put my 1928 Graham-Paige away the valves started sticking (when you would let off the gas pedal it would start missing). If you revved it up the problem went away. Drove the car into the garage and checked the gas apparently it had been sitting to long because it did not smell right. Well now it is almost Spring and I need to fix the problem. It is an "L" head engine so I can remove the side valve covers to see the valves operating. I am assuming I have varnish in the guides, old gas (I am building a house myself so she has been just sitting in the garage the last two years, I was driving her to the new house).

The plan...

1. Dump the garbage gas and replace with new.

2. Flush the lines, fuel pump, and clean the carb.

3. Add some mystery oil to the gas (to lube the valves).

4. Take some Sea Foam and spray it directly on the valve stems to remove the varnish, crank over the engine by hand, and repeat a few times.

5. Fire her up, put on a few miles and replace the crank case oil.

Am I missing anything? Still learning about the old girl, and want to keep her original.

Sounds like a good plan. But I'll add another tip. On a flathead engine, provided you can see (or locate) the valves through the sparkplug hole, you can squirt enough oil or other liquid on the top of an open valve that it will run over the edge and flow down the stem directly into the valve guide. I've seen posts on this forum about people claiming to have never had problems with old gas. My experience has been the opposite. You have to guard against the fuel breaking down. Be sure to add a fuel stabilizer to your tank whenever you fill up if there's any chance that you won't be driving the fuel off anytime soon.

I have been storing cars for the last 30 years without a problem. The new gas is just designed to be in a sealed container, as we all know our old cars have vented tanks. With the extremely high evaporation rate of the new fuels blends we are going to have more and more problems with carbureted, vented tank engines. Other than driving them a lot more, the only good answer I can see is draining the tank and running the carb dry. If you are looking at anything over 3 months you are looking at some serious clean up. I am planning on getting the non oxygenated fuel and adding Stable. Maybe that is just a new part of the hobby?

as mentioned above, I like to apply lubricant directly to the valve stem.

I'd remove the spark plugs, look into the combustion chamber, and see if the valves are visible.

If so, hand crack the engine until a valve is open, and using a penetrant oil with the red plastic spray wand, spray the valve stem.

Once you have done this on each valve, the valves should opperate normally.

GLong

My valves are pretty hard to see through the spark plug holes but I know where they are supposed to be so I can make a blind spray and be pretty confident it will get there. I am assuming you are suggesting Mystery oil or Sea Foam? Do you have a preference?

I would use carb cleaner if you are sure the sticking is caused by dried gasoline varnish. If you think it is due to lack of lubrication, meaning not enough engine oil is getting on the valve stems while running, then I'd use just about any penetrant: PB Blaster, Sea Foam, Liquid Wrench, Kroil etc.

I like the ATF/Acetone mix for almost everything, but needing an aerosol with a flexible wand to spray in the direction of the valves makes this penetrant difficult to use.

If you do a compression test first, you might find which cyliders do have sticking valves, and be able to concentrate on those cylinders..

GLong

I have good success using Seafoam in both the fuel system and the crankcase. My suggestion is run a high concenration in the fuel system in fresh gas until they free up and normal concentration in the engine oil. Add gas to the tank to the normal concentration once they free up. Kindly report back on what you did and what worked.

If you can get it running and even if it is running roughly, give it some revs and dribble MMO down the carb.

You will smoke the neighbors out and it will kill all the midges in the area but it will free the valves up. Then make sure you have added plenty of MMO in the gas and take it for a long ride. The problem will be solved.

If you can get it running and even if it is running roughly, give it some revs and dribble MMO down the carb.

You will smoke the neighbors out and it will kill all the midges in the area but it will free the valves up. Then make sure you have added plenty of MMO in the gas and take it for a long ride. The problem will be solved.

I like this suggestion. Reminds me of dumping top engine cleaner down the carb years ago to get the build up off the valves, etc. Great smoke screen.

Only one small problem... updraft carb, I will try to put it in though the vacuum line inlet.

That would work, or just take off the air cleaner and spray the carb cleaner in with an old spray bottle (ie: windex). I used to be able to put a whole can of Cleens through my carb and not waste any of it as long as the engine was running about half throttle and just pouring the stuff in front of the carb. Half throttle was enough of a draw to suck it right in.

Charging up the battery, snow finally melted yesterday. I think I am going to try the MMO through the carb and in the gas. I still need to drain the old gas and get fresh stuff, might pull the carb and clean it up while I am at it.

I don't think I would bother to drain the fuel unless it contains ethanol, in which case there could be a little water in the bottom. You can probably just pump that out with the starter after disconnecting the fuel line at the carb.

At about 1930 they probably had 45 to 65 octane fuel. What do you think the octane rating will be for 90 octane fuel after two years sitting? My side-valve 1930 Dodge 8 loves old fuel. It burns faster than modern high octane fuel and the car runs better. I have never had any problems starting the car after two or even four years sitting, once fuel reaches the carb. The only problem I have seen, other than sticking valves, is powdery white deposits in the carb after the old fuel has evaporated (tho not in the Dodge). This was in a mid-50s boat (one of those beautiful varnished wood, laid back gentleman boats) with a side-valve engine with up-draft carb. The carb needed a complete strip and clean before the engine would more than idle on the idle jet.

The previous owner of my car used to pretty-much stall it by squirting Shell Ensis into the carb when shutting it down for storage. No sticky valves then! Lots of smoke to annoy the neighbours though - do it on a windy day!

Alcohol in fuel absorbs water into the fuel, once the alcohol is saturated, then the water will settle on the bottom of the tank. What this means is that the fuel is full of absorbed water, and is BAD BAD BAD. Drain it. Don't complicate your running problem with probable bad gas/fuel. The fuel may or may not burn well enough to allow the engine to start, and surely will not be good enough to run the engine on while diagnosing another engine problem.

I would do a compression test first, to see if you actually DO have sticking valves.. If it was a random miss at idle speed, it could have been many other problems or issues. IE:, fuel, points, fouled spark plug, dirty idle circuit in carb, etc etc.

To be honest your description of how the engine was running/missing does not necessarily sound like a sticking valve, more like several other possible problems.. Did the low speed miss also include an additional tappet or lifter clatter/noise??

Only a compression test will tell if you have a valve or two stuck open... Or remove the valve cover and visually inspect for a very wide clearance.

GLong