After reading the post about the ATF fluid down the carb to free up a stuck valve, I wondered...How do you know when you have a stuck valve???? Does it smoke incessantly??? Chatter?? Run rough?? Just very curious, i don't think his is what is wrong with mine...just wondering
Thanks

 

59'er -

If any valve is stuck, the engine runs only on 7 cylinders, so it runs very rough. You can tell which cylinder has the problem by shorting out the plug wire to the block while it is running (or just pulling that plug wire). Shorting out the bad cylinder won't change how the engine runs. Shorting a good cylinder makes it run rougher. A compression test will also usually tell you which cylinder has the stuck valve.

If an intake is stuck open, it may also backfire up thru the carb. It depends on how open the valve is. A burned valve won't let the cylinder fire correctly because it can't hold compression, but it might not be open enough to get a backfire.

If an exhaust is stuck open, it just runs rough and you may see fire out the exhaust, depending on whether the exhaust is short enough to see it.

You can also have a valve stuck closed if the lifter is collapsed or a pushrod is badly bent. Then it just runs on 7.

Bottom line...it is an obvious problem. The usual drill is to check and make sure you have fuel and fire. If those check out, then a compression and/or leak-down test is in order.

The ATF trick is very useful to ensure that deposits on the valve don't start keeping it open so that it burns and becomes a much bigger problem.

 

I appreciate your input!! Cleared up some misconceptions I had. I think I will try the ATF sometime.

 

59er, I don't know which post you are referring to, but I remember one mentioning ATF in the oil to free up a stuck lifter. Did you see one that said to pour it down the carb? By the way, the way I knew to use it was the lour clicking that started one day. After about ten minutes with it running with the ATF in the oil, the clicking stopped and I changed the oil. Good luck, Jag

 

Jag, you say you added ATF to the engine oil for 10 minutes, then changed the oil. How much ATF did you add? ...Terry

 

It's an old mechanics' trick to add one quart. You don't drive it anywhere, you just let it run for a while until it goods good and hot. I had never heard of this until my mechanic friend told me that it might stop my sudden loud clacking noise. ATF is very high detergent, but is not made to handle the bearing loads in an engine. Good luck, Jag

 

Thanks Jag. I've often wondered if the stuff they sell as engine flush ($5-$10) is really a $2 bottle of ATF! ...Terry