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Stuck intake valves, Why?

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bcliff

bcliff

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Junkpile B has been running good. I started it up Friday, it ran great. Tried to start it this afternoon, and it spins freely, like the spark plugs are out. I pulled the valve cover, and all four intake valves are stuck open. I have had a valve stick before, but not all four. I tried to pull them shut, but they won't budge. I figure the head is going to have to come off, but any ideas as to what is causing this will be appreciated. Possible cures without pulling the head would be good too. the engine sat for quite a few years without running, so maybe getting it out on the highway and "blowing the cobwebs out of it" is what it needs.
Thoughts??
Bruce
 
I would suspect I would pull the head and take a look. Worse case off to a head rebuilder.
 
Have you whacked the valves with a big rubber mallet? & does it look like the system is oiling them?
 
I had an MGB that had been sitting one time. The valves also stuck open. In my case, I was able to get them unstuck, but they stuck again. I did drive the car, it didn't help. I used all types of penetrating lubs, and the valves kept on sticking. You should have a complete head job at a machine shop if you want to do it right. Also, I would question the condition of the rest of the engine. I was unable to repair that MGB without removing the head. If you hammer the valves to try to free them up, be careful, because you may bend a valve, the pistons are down there you know. The problem is corrosion.
 
Their probably coated with gum or varnish, what ever you wish to call it and when heated up will turn to cement if its thick enough. Very common on antique cars that have set for many years. Pull the head, pull the valves and clean the whole mess up. It's not a hard job! It would also be a good time to have the head checked for cracks and valves reground, Afterward, do as Tony says and make sure their getting lubricated properly. JMHO. PJ
 
I'm thinking gunk is the problem too. The engine runs great and has good oil pressure. The donor car, a 74 GT is not a high mileage car.(Anyone need the body?). The valve cover has a layer of varnish inside. I think I read somewhere that this is common in in cars that have been run with paraffin based oils. The rockers are oiling well. New head gasket set is supposed to be here Wednesday. Looks like Tuesday will be disassemble and clean day. I'll get to have a look at the pistons and cylinder walls too. I don't expect any surprises, since the car was running when parked. I actually know the owner of the car and I know it is really true when he says that.
Bruce
 
On another note, this engine is a "get it running and drive it a while engine". It is out of a 74 (it is an 18V engine). The Junkpile B is a 69, and we have a proper 69 motor to rebuild properly, so it makes sense to put the money into the "69 engine.
Bruce
 
bcliff said:
the valve cover has a layer of varnish inside.
Bruce
Click to expand...

Speaking of valve covers. The valve cover is the coldest part on an engine and deposits will collect inside there before anywhere else. It is the greatest quick indicator of how an engine was maintained by it's previous owner. I always pull the valve cover or covers before buying an engine and look inside it. Sludge inside, they never changed the oil and that means crud in the oil galleys, bearings and everywhere imaginable. Clean valve cover, the PO took reasonable care of the engine and it has a better chance of being ok. It's just a rule of the thumb I use and it doesn't always work, but it helps.
 
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