IS IT A STICKY VALVE ?

[elmo]

if it is a sticky valve , it is usualy caused by a worn valve guide or weak valve spring or a combination of both , the cause is a build up of carbon in the worn guide . over the years , ive had plenty , my usual fix(i,ve never had to replace a guide ) is remove the head and them offending valve , run a chainsaw file through the guide , take xtra cair that you only remove the cabon build up ( it might seem a brutal solution to some but its worked for me for the last 30 plus years )  just make sure you start up and run your engine reguarly, i do it at least once a month

[Wm Steed]

Marvel Mystery oil is usually a sure cure for sticky valves... The flat head motors are very prone to sticky valves, especially if they have been sitting for several months/years.
I have followed the practice of poring MMO down the carb while the engine is running prior to putting the vehicle away for a prolonged period of time. If an engine is going to be out of service for an extended period of time I pore MMO down the carb until the upper portion of the engine is full. Over time much of the MMO will seep down the cylinders through the open valves, the valve that are tightly closed will also benefit from the MMO.  Of course if you fill the upper cylinders with MMO it is a good idea to remove the spark plugs and crank the engine over before you try to start the engine.
It is amazing how much rust will form on the cylinder walls and valve stems in an engine that sits for many years. The problem is even greater in areas that have high humidity.
I have a friend that has a '55 hemi, he had the engine completely rebuilt, started it and let it run for about 20 minutes. The engine was shut down and the head pipes plugged, then the car was sealed with tape... Eight years later after the body work was done the engine would not turn over, when the engine was opened up to see why it would not crank over, my friend found that the engine was all rusted up requiring a complete rebuild. Expensive lesson....Bill 

[plym_46]

Check the pivot pin on the fuel pump.  folks have noticed that some of the newer off shore products have suffer from and improperly straked piivot pin retention system.  It allows the pin to back out and the cam lever either runs at an angle runs off center or doesn. run on the cam at all.  A simple sheetmetal clamp can be fashioned to retai it after it has been put back in its proper position.

As for your brakes it is not uncommon for a piece of rust or debris to lodge itself in or over the pressure relief port in the MC. this prevents brake fluid to return or allows it to return slowly so the pressure from the pedal push stay retained in the wheel cylinders or line thus activating the brakes and or the brake lights.  Start by assuring this port in you MC reservoir is clear.

A sticky valves is usually accompainied by a misfire due to lack of compression, or back fires throughthe carb if its an intake or throughthe exhaust if its an exhaust valve.

A sheet of paper held vertically near the exhaust exit will react to a sticky exhaust valve by being sucked back toward the pipe as opposed to being blown away, as the piston on the intake will also suck air through the partially open exhaust valve.

[CHS]

you mentioned valve ease. I use Marvel Mystery Oil in my gas. It has been around forever. Just follow the ratio chart on back of the container. I put it in the tank just before fill-up. It is supposed to lubricate the upper cylinders. Since there is no longer lead in the gas, I was told it will help lubricate the valves. It is also supposed to help keep the fuel system clean.

[TodFitch]

Regarding the tap-tap sound: Might be a valve that did not have the jam nut properly tightened and is now out of adjustment. Might be the fuel pump (lever is actuated by the cam at the same rate as the valves are actuated). I hope it isn't a piston or bearing.

If it is a sticking valve, I believe the standard instructions that come with a vacuum gauge so the pattern of needle movements you might see for that condition.

[36 Ply]

52plym-

Congratulations on getting your Plymouth back on the road. If you have a spare switch, I would replace the stoplight switch with your spare. If it's the kind that threads into the master cylinder, possibly you could soak the one you're using now in some kind of solvent, then keep it for a spare.

Sorry, can't help with the sticky valve part of your question.

Good luck,
Pat O'Connor

[52plym]

Yesterday, after nearly 5 years and a lot of work, I finally took my '52 Blue Belvedere out on a shakedown cruise all over the State of Connecticut.  Went nearly 200 miles - ah, perfection.  The car purred like a kitten and seemed like 45 - 55 was it's sweet spot.  About 20 miles from home, while cruising along at about 45 - oil pressure about 55 - temp in the low end, the engine made a very loud tap tap tap sound.  I immediately turned off the ignition (tapping stopped), and pulled over to the side of the road.  Checked under the hood and could find nothing amiss.  I  re-started the engine and the tapping started again, almost sounded like the fan was hitting something.  I "goosed" the engine a couple of times, and the tap tap tap stopped....I drove on without any other problem.  Then it occurred to me that way back in the '50's, we used to put a product called Valve-Eeze down the caruretor in order to lubricate the valves.  Could this have been a sticky valve ?  If so, how do I prevent this from happening again ?

One other problem. My brake lights will stay on and I have to hit the brake pedal a couple of times to turn them off.  I have a spare switch.  Could the problem be a bad switch ?

Any help or suggestions would be appreciated.

Thanks