Learn a lesson on bad gas

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67/6barracuda

67/6barracuda

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Put a rebuilt head on my car after sitting for 15yrs. Of coarse drained the gas as best I could. Put about five gallons of fresh fuel in it. Poured some fuel down the carb and fired it up. Started it let it run a few times. took it around the block three times and heard a metal clanging sound and it sputter. I pulled the valve cover and had a bent push rod. And all the intake valves are sticking. One is really bad, the one that bent the valve. So after all my work of trying to get this thing going. I might try putting a new push rod in and disconnecting the fuel line and starting it with fresh gas. This sucks.
 
It wasn't the gas. The valves were rusted in the guides and stuck.
 
sure, varnish turns into a hot glue on the intake valves. I just don't really want to pull the head back off after just getting it put back together. But chances are I'm going have to.
 
Sorry, didn't notice you put a rebuilt head on.
 
The valves were free moving prior to install. I was able to push down on all them. Now the are all sticking. I haven't even really drove the car. Did a cold adjustment .10 intake and .20 exhaust. Started it a few times let it warm up. Took it for a ride and that's when it all went south. It was something I did wrong . I'm well aware of that but I still think its from the gummed up varnish.
 
If it is sticky... Its varnish.....

Pull the tank.... Back flush the fuel line.... Blow it out with air.... New filter... Take the carb apart and clean it out....
I was able to free all the valves in the one I did with WD40.... However this engine did not bend any valves, but it did bend a bunch of push rods.... pull the intake and flush it... as long as the guides are not 2 tight you can get them freed up, if you dont want to pull the head....
What happens is when the varnish cools it gets rock hard between the valve stem and the guide....

Good luck...
 
67/6barracuda said:
sure, varnish turns into a hot glue on the intake valves. I just don't really want to pull the head back off after just getting it put back together. But chances are I'm going have to.
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I've yet to see it, I've seen cars running on so old of gas you can't stand around them because the varnish smell is so bad it will burn your eyes and it didn't bend valves
 
This was not caused by bad gas. You say "rebuilt head." This was likely caused by too tight valve guides, a pushrod that wasn't seated in the cups, valve adjustment, things of that nature. I doubt it was caused by "varnish". Lack of oil in the valve guides, maybe.
 
I tried to flat rate it.... It will just do it again... You have to clean the system complete..
Ask me how i know.... LOL
 
Pull one valve spring and pull the seal...You will see and feel... It sticky... Like molasses..
 
I agree it could be any combination of things but just the few intake valves are sticking. I was going to try replacing that push rod. disconnecting the fuel line from the intake on the fuel pump and running a hose into a gas container of fresh gas. chances are this won't help anything probably just bent the rod again. That one vale when push sticks open and slowly will return to its position. seems like a tight guide but it didn't do this before.
 
I wouldn’t have believed it to be true, but if you try to run bad gas the intake valves that are open when you stop the car can retain enough sticky varnish on them to cause them to not close immediately, then your push rod falls out of the debit that it is in and hangs up on something and bends.

It happened to me several time not only with my slant six, but later with a lawn mower I was trying to fix.

Clean the tank out as best you can, throw out the bad gas, add some seafoam and high test gas and you should be fine.
 
I ran some gas stored over a winter with a gas cap that didn't seal. Car ran like crap, barely idling. Pumped out the little bit in the tank, 5 gallons new stuff in, and it purred like a kitten. Some of the worst gas I've run, and no damage. Just my experience.
 
LocuMob said:
I ran some gas stored over a winter with a gas cap that didn't seal. Car ran like crap, barely idling. Pumped out the little bit in the tank, 5 gallons new stuff in, and it purred like a kitten. Some of the worst gas I've run, and no damage. Just my experience.
Click to expand...

I've run gas that was bearly a liquid before, car I purchased from salvage yard, trust me it wasn't bad gas, the exhaust would burn your eyes the smell of old gas was so bad

I would point to a very crappy rebuilt head, bad gas doe not go on the vavle seals, it goes into the combustion chamber, and burns; not well but it still burns
 
I worked at John deere dealership for 6 years and seen this on more than one piece of equipment. We usually were able to flush out all the old fuel put new fuel in with seafoam. then get it warmed up good at idle and then seafoam it through the carb and shut it off and let sit. After a while fire it up and watch the smoke roll!!! after that they were fine. ozz
 
bought a old motorhome that had been sitting for year....added gas to existing rotten gas...

don't remember if i bent pushrods...but the varnish gummed up the valves and it would not run...had to pull the heads off and get them dont...plus drop the tank and clean it out..
 
I had bad gas in my john deere lawn mower, 20hp ohv, it ran fine then the next time would not start. I pulled the valve covers and both intake pushrods had fallen off.
I put them back on and noticed that when I turned it over the intake valves were slow to close at first and then they got better. After new gas and seafoam they ran fine.

Same thing happened on my slant six.

Just because something didn't happen to you doesn't mean it can't happen. I guess it all depends on the tolerances of the valve guides and the strength of the valve springs.
 
I've seen both with old, bad gas: no problems, just a horrible stink, and then bad problems with sticky valves and a bent pushrod....in a 2.5L Jeep engine. Premium gas is supposedly not as bad to do this as modern regular low lead.
 
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