Valve Sticking?

Shadetree

Shadetree

Well-known member
My 8BA engine in my F1 probably has less than 300 miles since a complete overhaul. I didn't start it all winter long and this spring it has what sounds like a valve lifter needing adjusted. Last fall the noise was not there. I talked to an old Ford Flathead guy and he says it is not uncommon on a fresh overhaul for a valve to hang up slightly in the guide and then close making the clicking sound. It does have a slight flutter on the left side exhaust pipe in time with the tapping. I can picture an exhaust valve doing this.

Last evening I had my wife crank the engine over with the ignition switch off while I poured about 8 ounces of Marvel Mystery Oil down the carburetor. I let it set overnight but it still clicks when I started it this morning.

Any thoughts on how to correct this short of removing the intake and head? Should I worry about running it like this?
 
Shadetree said:
My 8BA engine in my F1 probably has less than 300 miles since a complete overhaul. I didn't start it all winter long and this spring it has what sounds like a valve lifter needing adjusted. Last fall the noise was not there. I talked to an old Ford Flathead guy and he says it is not uncommon on a fresh overhaul for a valve to hang up slightly in the guide and then close making the clicking sound. It does have a slight flutter on the left side exhaust pipe in time with the tapping. I can picture an exhaust valve doing this.

Last evening I had my wife crank the engine over with the ignition switch off while I poured about 8 ounces of Marvel Mystery Oil down the carburetor. I let it set overnight but it still clicks when I started it this morning.

Any thoughts on how to correct this short of removing the intake and head? Should I worry about running it like this?
Click to expand...

I'm not sure this is your problem and I don't believe for a minute that it's common for a valve to "hang" on a fresh build, it's never happened here!!

Having said that I would strongly recommend, as I have in the past here, to ALL my Flathead customers to use "bronze-lined" guides. In all my years of machining and building these units I haven't had a single valve stick in the guide, ever!

You'll find this is a common occurrence when you start the ride only occasionally and make any short trips. The condensation built up inside doesn't get a chance to really burn off. This is also "tough" on the exhaust systems overall.

(Add) Good luck with the repair whatever it turns up, hope it's fairly easy??

Thanks, Gary in N.Y.

P.S. I'm aware of the initial expense of doing the bronze setup, but most guys buy new guides anyway on fresh builds. Not sure what new guides cost, maybe $90.00 or so and they are most likely Chinese now anyway, but even at near double the price to do the bronze ($160.00/10.00 ea.) you have a much better build overall. The moisture will not cling to the bronze material like the cast iron pieces! You'll "waste" that difference in gaskets alone if you need to go inside the unit later!
 
Last edited:
had four valves hanging up in an 8BA recently, pulled the plugs out and spray pumped MMO on the offending valves thru the spark plug holes and used a wood dowell to push the valve close, snapped closed a few times and then worked good. This engine sat up for atleast 8 years and after a little work is running great, sticking rings/valves will respond to MMO in the gas better than anything
 
Remove the air cleaner, start the engine and slowly drizzle MMO down both barrels of the carb for a few minutes keeping the engine running. Don't do it in the garage as there will be a lot of smoke. G.M.
 
I knurl the guides I use, then clean them out with solvent and a brush. This will keep a valve from sticking, and holds oil. I use positive type valve stem seals on the intake, this will help with oil consumption, and I believe it helps hold oil in the guide.
Karl
 
Excellent suggestions all! I will keep trying MMO (always try the easy things first) and if it doesn't work I'll pull the engine, take it apart and depending on what I find I'll go from there. I can't help but think it is a valve sticking after sitting all winter. It does not have a dead miss and it wouldn't `click' if it wasn't closing at all. Think about this: Let's say an exhaust valve is sticking as it closes about half way. As the piston comes up on the compression stroke, the rushing air is enough to push it closed, giving a loud `Click' as it closes. Does that sound logical?

Many thanks to those that responded!

My wife and I are heading for our 496th Fighter Interceptor Squadron Air Force Reunion in Myrtle Beach Monday. We have been doing this since 2003. The stories just get better with each reunion....
 
I would think the ticking is from the large gap between the lifter an the valve stem when the valve is stuck open.
 
pull the intake and see what ya see....a little easier than pulling the whole engine??....maybe look in thru the spark plug holes??....Mike
 
I would think the ticking is from the large gap between the lifter an the valve stem when the valve is stuck open. 40cpe

Since it doesn't seem to have a dead miss I wasn't thinking the valve was stuck open all of the time. A compression check would verify this and yes, the clicking could be the lifter hitting the valve stem. Makes sense. Thanks! And I hope you are correct!

Anyway it’s off to decorate the graves tomorrow and then my reunion Monday so it will have to be on the back burner for a week or so...
 
pull the intake and see what ya see....a little easier than pulling the whole engine??....maybe look in thru the spark plug holes??....Mike

Mike,
Unlike our `30's cars, the trucks have a deep engine cavity because of the high fenders so if I have to pull the head and the intake, in my opinion it would be easier just to pull the engine so I can get to everything. I have a topside creeper, but not sure it will work on this truck.

Thanks!
Bud
 
my engine is in a 51 F5, so I know what you mean--try the MMO, yes try easy things first the KIS principle
 
if you can figure out which valve is sticking, maybe squirt the MMO thru the spark plug hole??....get that blood rushing into your head as you hang upside down into the engine compartment....good luck....Mike
 
Last edited:
maybe a valve spring thats making that noise{broken} ive had that happen to me a couple of times
 
Pull the spark plugs and you will be able to see the exhaust valve. Crank the engine over and watch the movement of each valve. If one is sticking you might be able to see it. When the valve is down, carefully tap on the center of the valve to see if it moves any further.
 
I don't like the thought of a broken spring, but I will find the problem and share what I find. I know it is on the left bank and it is an exhaust valve. Thanks for all of the response and vast knowledge of this issue...
 
Many of the late replacement valves are stainless steel. This always leaves the possibility for problems when used with an iron guide. Aircraft engines and Lycoming engines in particular, had problems with galling of the guides many years ago when they tried and all stainless valve with an iron guide. The switched to a phosphor bronze guide and that stopped the galling but the guides wore too quickly. The went back to a sodium filled exhaust valve with corrosion resistant steel head and a ni-resist steel guide and those do pretty well. They still have a tensency to build carbon in the guide and now & then one will stick. They now have a high chrome guide that will maintain its bore diameter better under high temperature and hopefully will stop the related sticking problems. Time will tell.

I mention all this to give a other folks an idea about what goes on in the development of these systems and what kind of problems can be encountered in the quest for more reliability. Changes aren't always good. A steel stem with a corrosion resistant steel head is still the best valve for a flathead that uses an iron guide. If a person runs all stainless valves, they might consider a bronze/brass guide insert for the old iron guides. Knurling the iron guide on a stainless stem might just make it gall faster I don't know. Knurling was a way to increase the life of a guide back in the day but led to problems with oil consumption on intake valves of OHV engines that didn't have good seals for the stems. I don't know if that would affect a flathead or not since the oil has to be drawn against gravity into the cylinder during low pressure conditions of the intake stroke.

If you do a tear down & remove any valve assemblies, check all the parts for evidence of unusual wear and signs of carbon build up.
 
I guess that in AZ they are upside down- oh wait I thought it was in NZ- apparently they can't get flexiable nozzle pump spray guns in AZ
 
You must log in or register to reply here.
Back
Top