No compression on #1 Piston

[Kelso]

I was having problems starting my 9n. Upon checking compression on #1 piston the reading was zero. When the engine runs now, i hear a noise on #1. My problem, how should I approach a solution for this problem. Not knowing what the problem is, I thought that taking the oil pan off might be the best approach to finding the problem. It could be a value problem though, couldn't it?
What are the possible problems causing this and how should I proceed in finding a fixing the problem. I know a little about overhauling engines but have only a little experience in this area. I appreciate any help you can give.

 

[Dan]

Most likely a stuck valve. Remove the front valve inspection cover and watch the valves as you turn the engine over. If one is stuck up, use an old toothbrush and some Marvels Mystery Oil and scrub the stem and pry it back down. This usually fixes the problem.

Dan

 

[JohnMD]

If what Dan says below does not fix the problem try doing a compression check again. Check #1 cyclinder and if it still reads 0 or real low add a teaspoon of oil and check it again. If the valves are not sticking the compression should come up some but if not much you could have broken rings. If all else fails it may be pull the engine time and rebuild.

 

[Ross Pugh(NC)]

I think Dan is son track with you problem. Zero compression almost has to be a valve not closing.

 

[Jerry/MT]

These old L head engines are prone to sticking valves. Open the side cover and crank the engine and you can probably verify the problem.

Repeated spraying a little brake cleaner spray on the valve stem followed by cranking the engine will help unstick the valve(s).

My old neighbor put a pint or two of automatic transmission fluid in a tankfull of gas on his 9N and claimed it prevented the problem.

 

[gahorN]

(quoted from post at 13:23:31 04/03/08) I was having problems starting my 9n. Upon checking compression on #1 piston the reading was zero. When the engine runs now, i hear a noise on #1. ....

What kind of noise? A knocking noise?

That's exactly what mine sounded like when the sleeve had shattered and dropped down into the oil sump.

Removing the sump is more work than removing the head and looking directly at the problem. Then if you see it's a valve you can unstick it. If you see it's a sleeve... then you're halfway towards fixing it. (Remove the oil sump and change out the sleeves, pistons/rings, conn-rod bearings and put it back together and put it to work. Don't forget to clean out the dried up carbon within the upper conn-rod bushings so they can get some oil pressure. Likely no need to re-bush.)

 

[souNdguy]

I agree with the others.. pull a valve cover for a looksee.. then go from there.. ( head next.. )

soundguy

 

[GB in MT.]

[b:c13793d9e5][i:c13793d9e5]
Kelso;
If you do find that the prob. is a stuck valve, try this system out. I has worked for others and myself. Works good too!!! 8)

HTH

Gary [/i:c13793d9e5][/b:c13793d9e5]

 

[Bob - MI]

Two issues: Stuck valve or hole in piston.

Pull the plug. Stick your air hose in the plug hole. Look for air coming out the crankcase breather (blown piston) or out the intake or exhaust (stuck valve).

 

[Kelso]

Thanks to all of you for your help. You were right, it was a value stuck in the open position. A little Mavel Mystery Oil did the trick. My 9n in running great now. Thanks again, I did not know what to do or where to start.

 

[GB in MT.]

[b:9d36fb86b7][i:9d36fb86b7]
Kelso;
Thanks for reporting back to let us know how it turned out. That also helps us help others with the same problems you had.
Glad yer 9N is running good again.
Copy and save the info I posted for ya. If this happens again, I would suggest you do ALL your valves with that info.

Gary [/i:9d36fb86b7][/b:9d36fb86b7]

 

[Kelso]

Thanks Gary, I have done just that( copy your reply)