The Stovebolt Site Forums The Shop Area General Truck Talk Stuck valves Bent pushrods

I tried to fire up the old '51 1/2 ton this morning & I heard a helluva racket commin' from the ol' 216.
Pulled the valve cover & saw 3 intake valves sticking in their guides.
Pulled the rocker arms & found 3 bent pushrods.

I just did a valve job 3 years ago on this head.
& I installed hardened seats.

I use a fuel stabilizer in the gas all the time.

I got lucky & was able to free up all the sticky valves using carb cleaner & PB Blaster .
Didn't have to remove the head. Phew

Does anyone have suggestions on a fuel additive that will help keep the valves from stickin' in their guides ?

A few suggestions I have heard so far are:
Marvel Mystery oil.
A fuel lead substitute.
A small amount of diesel fuel.

I heard " Lucas " makes a top cylinder lubricant, but I dont know if it helps lubricate the valve guides or not.

Gonna drain the fuel & install a set of H.D. pushrods tomorrow, put it back together & start adjustin' the valves.

I think all the top oils help
But I've used Marvel for years

There's no real substute for using your truck more often

Nate put me on to Sea Foam...I think it works pretty good keeps everything clean I think that may help you at this point NAPA has it

The gas is changing so much last years wonderstof just doesn't work today

MT,I had the same thing happen to a 216 a few months after a valve job.The guides were even on the loose side too.My 3 other trucks with 235's,261's never have have a problem and they have tight guides and improved seals on them.
I'm thinking an additive in modern fuels mixes with the oil on the guide and makes a sticky mess?

We were talkin' about this on the VCCA site & some of the old timers over there said if the thing hasn't been run for awhile they wont even think of firin' up the motor until they pull the cover & beat on the rocker arms to loosen everything up.

There has got to be a better way.

I have never had this problem with my 235 & 261 equipped trucks.

How much MM should you mix to 5 gallons of fuel ?

Yeah, as you know,some guys on the GMC site were saying the same thing.It's a government plot to get rid of old trucks
Doesn't the MM oil have the suggested mixing ratio listed on the can?

Used to have an occasional stuck valve on my LeBlond engine. Started using Marvel Mystery oil in the gas and no problem since. This is an early (1934) 5 cylinder radial airplane engine. It does not have a full pressure oil system so the rocker arms and valve springs must be greased every 20 hours or sooner as needed. Most guys I know running old greaser radials in their airplanes are using an upper lube of some kind in their gas usually MM and it come in such a pretty can too. I have heard it said that the mystery is nobody knows if it works and the marvel is that they've already got your money. Weeds

had a motor that would run for a while then the ex vaulve would stick and it would die the jb weld in the gide was to tite added marvel oil to the gas no more sticking it dose work but it may varnish the gastank if it sets and gets old might use a boat motor fogger before letting it set

I recently read that "dribbling" transmission fluid through the carburetor until the motor starts to smoke effectively lubricates the motor...at that point, all critical areas should be lubricated. Just run the stuff out of the system in the Spring until the truck stops smoking.(I only read this article...i haven't tried it)

There are all kinds of oilers that fit on the firewall and drip oil into the manifold. All kinds of sizes
Marvel still sells one I think. They are adjustable and maybe better to use that mixin in the oil

How about if the engine hasn't been run for a while...loosen the spark plugs and turn it over by hand so as not to bang anything up? I would think that you'd feel somethin' if everything wasn't O.K..

I don't know if it would help valve guides or not but I have switched to Chevron Delo 400 15W-40 oil in my 261 stovebolt and noticed it has really cleaned out the sludge under the valve cover. It has also quieted down the rockers a lot and I have noticed less draft tube funk. I probably wouldn't run it without a filter because it could knock loose some sludge but I am really happy with it and the full flow filter. It only costs about 10-15 cents more a quart than Valvoline. It's certified for both gas and diesel engines.