Ford 8N clacking

[Dukester]

I have been starting my 1949 8N up every weekend over the summer and fall when not using it and drive it around the yard. A few weekends ago when I ran it, it had a very loud CLACK CLACK CLACK from the engine - it is disturbingly loud. Clacking speed varies according to throttle up or down. Definitely rear of engine. Parked it for another week. Next weekend as a test I pulled each spark plug wire, one a time, just for a second while it was running. No change in the engine running on the first three plugs. On the fourth plug, closest to steering column, when I pulled that wire, the CLACK CLACK CLACK sound stopped completely, then restarted when the wire was connected.

I have had this tractor for going on 20 years and have done minor mechanical work like changing brakes, rebuilding steering column, rebuilding hydraulic pump but nothing engine-wise (don't know how but also never needed to!). Any idea what I might be looking at here? I am guessing I need to pull the engine cover off and look in and around #4 cylinder but I don't have a shop-full of appropriate tools to do a rebuild. I stopped at one small engine shop near the house and the guy said he quit working on old tractors a long time ago. I hope this one is not destined to be yard art!

Dukester

 

[old]

Good chance the rod bearing on that cylinder is going bad and if you keep running it you will have a hole in the side of the engine sooner or later

 

[Dukester]

Shoot!

 

[Roger in Iowa]

Is it possible the manifold gasket has failed and you are hearing exhaust from number four cylinder?

Easier to change than tearing down the engine.

 

[Dukester]

I don't think that is it as I don't hear it anywhere around the manifold when it is running. Is there a way to confirm this if this is what it is?

 

[old]

Drain the oil after you have run it for say 5 minutes. Watch for what looks like silver streaks in the oil. If you see silver in the oil very good chance you have a rod bearing and or other bearings going bad

 

[Dukester]

Ok thanks for this test.

 

[old]

You can also use a magnet in the oil you drain and see if it comes up with iron shavings

 

[showcrop]

8Ns are known for getting manifold leaks which get worse from moisture getting in between the gasket and the head or the gasket and the manifold. It is not uncommon for it to be mistaken for a much worse problem. Running it for short periods of time is very hard on it because the moisture of condensation doesn't get driven off. It lodges in the manifold-block interface keeping the gasket wet. Short run times, just as with any vehicle, is considered severe service, necessitating short service intervals.

 

[Dukester]

So if it is a leak around the manifold gasket it has to be around the #4 cylinder area. Is there a way to see or feel this clack where the manifold is?

 

[RobCons]

Use a wooden broom handle as a stethscope. Place one end on various spots of the engine and the other end on your ear. You will be able to hear the sound and locate it. Dont get the broom handle on something spinning.

 

[Hobo,NC]

Use at least 3ft of rubber hose I use 3/8" air line because I have plenty. A old piece of garden hose will work. Hold one end up to your ear and run the other around the exhaust. If it has a leak it will pin point it I guarantee.

This is my go to tool to find exhaust leaks : ) BTW it probably 8 to 10" long so the length does not mater.

 

[RobCons]

Hobo thanks for the tip. I didnt know about using a length of tube. I've got a JD 400 with an exhaust leak that I will use it on today. Cant hardly see the manifold due to the loader frame.

 

[Dukester]

If it turns out to be a bearing and not a manifold leak, I will have to take it to a repair shop to have it worked. I have the space but not the equipment and knowledge to work on the engine. While I have it in the shop and they are in there, should I have them do anything else?? I am guessing this is going to cost me more than the tractor resale value is, so at this point it is just for me to keep it running..

 

[old]

If you don't know how to rebuild and engine it is best to have someone who does do it for you

 

[Dukester]

That's the plan!

 

[showcrop]

(quoted from post at 08:00:34 12/10/21) If it turns out to be a bearing and not a manifold leak, I will have to take it to a repair shop to have it worked. I have the space but not the equipment and knowledge to work on the engine. While I have it in the shop and they are in there, should I have them do anything else?? I am guessing this is going to cost me more than the tractor resale value is, so at this point it is just for me to keep it running..

yes, conventional wisdom says to check the clutch disc and clutch release bearing closely, and to replace the transmission input shaft seal.

 

[old]

Of course if you where like me you could do most of it on your own but I have been rebuilding engines for decades

 

[Dukester]

Thanks

 

[Dukester]

You are right there!

 

[old]

First tractor engine I rebuilt was an early A/C B and I did it when I was home on leave from the Navy back when I was 18 or 19

 

[Dukester]

Did you learn how to do it all on your own? I never had anyone around that I could learn from, and why I am on this board, HA

 

[showcrop]

(quoted from post at 16:36:33 12/10/21) Did you learn how to do it all on your own? I never had anyone around that I could learn from, and why I am on this board, HA

The first engine that I rebuilt was a 5 HP Clinton on my father's walk behind garden tractor when I was 14. I don't remember how I knew what to do. Next was a 9.2 HP Rotax in my fathers Ski Doo. Then an outboard motor then an MG and on and on. Sure I made some mistakes but I learned from them and went on.

 

[old]

Yes I have learned how to fix engines etc. by the road of hard knocks. Back when I was around 10-12 my dad gave me a lawn mower to mess with. I took that thing apart many times and put it back together many times. Then as I got older I learn more like the Honda 50 motorcycle I had. I then went on to car/trucks and now tractors but I have been working on tractors since I was 18 or so

 

[Dukester]

Cool!

 

[Dukester]

Excellent! That's neat.

 

[old]

I have never taken so much as 1 hour of school on engines etc. but when I was in the Navy I took the CLEP test and scored very high on both of the mechanic's test as in 72 out of 75 correct answers