I have a chevy 216 that sat for a long time. LONG time. Maybe 30 years or so. Bone stock and had a new rebuild in the mid 1980's, but had very little mileage after the rebuild and then sat in a garage ever since. Put new gas in it, a battery, and it fired up. I drove it home (maybe 5-10 miles) and it smoked for a few minutes, sputtered a little, then started to run really smooth and quit smoking completely. Motor was quiet as a mouse. I added some sea foam to the oil and gas and let it idle for a bit. It sat for a couple weeks in my garage, then I drove it to my friends shop for storage and it started making noises in the top end after about 20 miles. Pulled the valve cover and saw that there were 2 pushrods just flopping around. Pulled the side cover and found there were actually 4 bent pushrods. Long story short, those 4 intake valves are really sticky. I can hit them with a hammer and they spring back just fine, but when turning the motor over they open and are very slow to close. I'm assuming this is causing the bent pushrods. Anyway, I would REALLY like to keep this motor as original as possible and not tear into it if I don't have to. Any ideas to possibly free up these valves? Or am I toast? Any help is appreciated. Thanks! Mac
make sure you have fresh gas,the old stale gas will cause them to gum up and stick,change the oil and put some marvel mystery oil in with the new oil,it will work wonders in these old motors.When you do get it to run and all the valves are working,run it for about a 50 mile trip to work it all in,when to motor gets warmed up and all the old stale gas is burned up it will come back,i also put a bit of the Marvel oil in the fuel,it acts as a fuel stabilizer too.Good Luck with this,i did the same thing on a Model A motor,after I was done it ran better then it ever did. Harvey
Thanks for the tip! Sounds like I'm on track then. I changed the oil, put MMO in the oil, sea foam in the new gas, but was worried about cranking it up again with these valves sticking like that. Think it will free up and run ok?
put MMO in the gas also. Start it up and just let it idle till it's warmed up then shut it off and let it sit for a couple days. Then do it again and shut it off. Then when it cools back down try the valves again and see if they are still slow to close.
The key to making sure they don't stick again. .. After adding the marvel to the oil..and fresh gas with marvel... Is drive it ...A lot..long Sunday drive..don't shut it off and let it cool down ... That's when the sticking happens. . Don't ask how I know... Some of us have to learn things the hard way ! Dave Posted using the Full Custom H.A.M.B. App!
I assume you replaced the bent pushrods, so I would give it a good run and hope for the perfect sewing machine sounding engine!
My father had a '50 Nash back in the day that a valve would stick once in a while. He would just pump a gallon of diesel in the 20 gallon gas tank then fill it with regular. In a couple of miles you could hear the knocking noise go away and the engine just smooth out. Yes it smoked a little but then a lot of cars smoked then.
Put a heavy dose of Sea Foam into a 5 gallon gas can, run a hose from can to carb. Allow it to idle 'till gas is gone. It took 20 gallon's of this combination before a 327 that sat 33 years straightened out. It does work. Good luck.
The last time I had a sticking valve, I put a quart of atf in the oil and ran it for about 20 min. After I changed the oil to get rid of the atf. Remember that atf is very high in detergent. Of course this was on an ot vehicle that my son was driving. Never had the problem again for the 2years or so that he drove it.
A fellow club member had this problem with a 235 and did this only used Sea Foam and I admit I was shocked it worked and still runs like a top today.
This is a breath of fresh air! Thanks folks. I just hope it doesn't bend another pushrod at startup...
Are you absolutely positive that it's a 216? They did make splash 235's up until 1953. Are the lifters solid or Hydraulic? If hydraulic, do the push rods have an X in the bottom where the rod meets the lifter?
We had an old 65 Pontiac that sat for several months after he bought a newer one. It would barely run. We added some Rislone and took it out for a spin on the beltway. It only took a couple of exits and it came back purring like a kitten. I don't put much stock in that mechanic in a can stuff but this cleared up the sticky valves in the Poncho.
Are you saying to let it idle until it burns 5 gallons of gas/seafoam mix? I think that would take a very very long time.
Well, it worked great. I was able to fire the car tonight and all valves are performing how they should. I couldn't run it long, only a minute or so, but I will run it on Thurs. Thanks everyone!
When we had sticky valves we would pour atf down the carb. While the engine was running, you will have to raise the idle on it up just enough to keep it running. It will smoke like crazy. I also used water the same way for carbon knocks, the water steam cleans the combustion chamber.
MMO in the oil and gas does the same thing without the smoke and the risk of breaking/bending internal components.
for us with the old welders that would sit for a year or too ( flathead powered or straights 6's) , we used to do a running diesel oil flush in the crankcase to remove any varnish on the upper stems on the guides and cleans the crud out of the bottom of the pan fill it like normal, throw a can of atf in it and swap on a new filter , just have to remember not to put any load on the motor while the diesel is in the crankcase , then after a draindown we would fill it with a detergent oil and pint of dextron atf , and run that for a period with a load on it then change out the oil . a high detergent gas will help too like BP gold , or mobils premium gas . often though if you run into a sticking valve it needs to checked as the guide might have a problem with it like carbon stuck between the valve stem and guide and if thats happening that means the guide is shot . .
Make sure you take it for a long drive,it is the little short trips with the bad gas that make these valves stick like they do.I would run some hi test in it too for the first trip or two.Might be a good idea to have a buddy follow you or leave word where you are heading in case the valves act up on the trip.Let us know the outcome of the drive. Harvey
The Jalopy Journal
