Farmall M Engine Knocking

[cm9]

Hey everyone. I have a Farmall M with a loud knocking noise coming from the number 1 cylinder. Tractor will hardly move,misses and knocks loudly and is definately down on power. If the number one cylinder wire is unplugged the tractor runs without knocking albeit down a cylinder. There is also some oil blow by coming out of the air filter. Anyone have any suggestions? Thanks....

 

[MIKE R]

It sound like you have a sparkplug wire hooked up wrong which is causing big ignition advance in that cylinder. If it was a bearing or a wrist pin they wouldn't stop knocking when the plug was disconnected. It might be two of the 4 cylinder plugs are on the cylinder but only one is firing early enough to effect the engines sound and performance. Any other info on how this occurred. After changing plugs, working on distributor, ect.

 

[cm9]

My dad had the distributor cap off but that is it.

 

[MIKE R]

When it was off were the plug wires removed. If so there is a slight chance that one plug was put on the wrong plug at the distributor. I don't know the firing order but you might be able to take one plug out at a time and check to see if it is firing around top dead center on each cylinder. If two are out of time try switching them around and see if it makes a difference. Before you go pulling plug wires, label the order of which one goes were.

 

[cm9]

No the wires were not removed.

 

[Kiwi Farmall]

Go back to the basics and check the timing of the distributor ,check the cap has number one lead inline with the rotor when at TDC on cylinder number 1.Check plug gaps .It will something simple like that,as these are a basic system.Firng order will be 1-3-4-2 but I am not sure of the rotation.

 

[cm9]

Thanks I will give it a shot tomorrow.

 

[cm9]

Checked it out today. Started up no problem but was still knocking. We unplugged the number one wire and it went away. Plugged it back in and the knocking noise was still gone. It did come back after a few minutes. Going to change plugs, wires, cap,rotor, condenser and points tomorrow.......

 

[DJ54]

I'd suggest copper core wires.

 

[art]

Seen this before, yes number one has something wrong! To miss match plug wires or disconnect them will get rid of the noise because there is no load.

 

[cm9]

Changed everything out and it is running fine. Thanks everyone for your help.

 

[DJ54]

Hmmmm..., Re-read the last line... *There is also some oil blow by coming out of the air filter. Anyone have any suggestions?*

If there is oil blow by out of the air filter, sounds like a problem with the intake valve. Broken/weak valve spring..?? Valve sticking, or bent..?? I'd be pulling the valve cover before running any longer, before it possibly sucks a valve..!! Better safe, than sorry...!!

 

[MIKE R]

Hmmmm..., Re-read the last line... *There is also some oil blow by coming out of the air filter. Anyone have any suggestions?*

If there is oil blow by out of the air filter, sounds like a problem with the intake valve. Broken/weak valve spring..?? Valve sticking, or bent..?? I'd be pulling the valve cover before running any longer, before it possibly sucks a valve..!! Better safe, than sorry...!!

It still could be something with the timing. Fireing when the intake valve is open causing the oil. It was never said if the oil stoped coming out after the wires and stuff were changed.

 

[Soundguy]

compression test time.. and fire order check!

 

[Kiwi Farmall]

Changed everything out and it is running fine. Thanks everyone for your help.

Glad it was nothing major and back to normal

 

[Soundguy]

any details as to what you found?

 

[MIKE R]

any details as to what you found?

Still curious on what you found.