39 9n bad cam gear

IROCKWITHDIRT · May 30, 2011

So my 9N quit running last fall. No spark led me to discover distributor wasn't turning. Pulled apart to find pressed bakelite cam gear with missing teeth.

What are my options here? Guessing the path of least resistance will be to replace the cam and gear with a bolt on gear? Do I need to replace the tappets too?

How far do I need to tear things down to do a cam swap? Head off?

Thanks for any help, Kevin

wwildhorse2k · May 30, 2011

Hi Kevin,

Im in the process of doing a cam swap now. My overhaul was really fresh so your situation may be more involved than mine. I also have a one piece front seal so I had to drop the pan to get the timing cover off. I pulled the manifold and the lifter covers. I pulled the valve guide retainers and wired the lifters up to clear the cam. Pull the radiator and fan too. I would opt for the aluminum cam gear.

my $0.02

-- Mark

Jim in michigan · May 30, 2011

is there something wrong with the cam or justthe gear? You might be able to get the gear off without pulling it all out, not sure though, looks like the screw in the middle holds the gear on, I would have to check on mine to be sure.

Hobo,NC · May 30, 2011

They must be dieing,,, I have sold 2 bolt on cam set ups this year to replace the press fit,,, one guy was spose to bring me his old press on set up so I could play with it but he did not,,, I want one to play with so need to run him down...

If i were doing it the head and valves would come out,,, if it did not have adjustable lifters are one piece guides it would get'em...

IROCKWITHDIRT · May 30, 2011

Mine definitely reached the end of its 72yr lifespan. Crazy this is, look at it. Bakelite fell apart, but gears that are intact show NO WEAR.

Tractor could really use a rebuild, blowby and smokes under a heavy load. At the moment I have no garage so doing this all out in the open. Looking like my hopes of fixing her to just "get by" for now aren't looking too promising and she may be a yard ornament for a while.

Hobo,NC · May 30, 2011

(quoted from post at 01:15:31 05/31/11) Mine definitely reached the end of its 72yr lifespan. Crazy this is, look at it. Bakelite fell apart, but gears that are intact show NO WEAR.

Tractor could really use a rebuild, blowby and smokes under a heavy load. At the moment I have no garage so doing this all out in the open. Looking like my hopes of fixing her to just "get by" for now aren't looking too promising and she may be a yard ornament for a while.

I bet I could get it off and press a new gear on right were it sits.... I have done quite a few close to it on chebby 2.5's with the fiber gear with the engine set'n side ways FWD...

Ultradog MN · May 30, 2011

So you did the hard part already and have pulled the hood, radiator and timing cover.
Why not throw a new gear in it and put it back together?
A tractor that runs - even poorly and smokes will do you more good than a yard ornament will.
And if you happen to die suddenly the wife can advertise it as a tractor that runs but smokes for $1500 instead of a dead tractor for $500.
If you do rebuild it someday you will need a new timing gear anyway.
Good luck

36 Coupe · May 31, 2011

The gear has the same part number as Ford cars and trucks.Ive bought them from old Ford parts dealers for 8.00 when a tractor parts catalog was getting 49.00.On the V8s it was pull the cam and do the valves while it was apart.Would be easier to replace the press on gear .

IROCKWITHDIRT · May 31, 2011

Ok, my understanding was the 39-42 press on gear needed to be pressed on with a special indexing jig with the cam out since there were no splines or keyway for alignment. Believe me, I'm looking for an easy out here but didn't think it was that simple.

daz · May 31, 2011

Mine was a "40. I just pulled the old worn cam gear and knocked another one on. It lasted years and is still running. I did not pull the shaft. Just the gear off the front.

TheOldHokie · May 31, 2011

(quoted from post at 05:46:45 05/31/11) Ok, my understanding was the 39-42 press on gear needed to be pressed on with a special indexing jig with the cam out since there were no splines or keyway for alignment. Believe me, I'm looking for an easy out here but didn't think it was that simple.

Looking at your picture I see two indexing marks on the shaft and hub as well as a matching mark on the gear tooth.

TOH

rnorum · May 31, 2011

I think you could change the camgear. You could drill a hole in the rim to relieve the press fit pressure, get 2 large screwdrivers, put outward pressure and tap center of cam to get gear off.

First line up cam and crankgear (little circles)

When pushing on the new camgear, be sure not to pound out the rear camplug
If someone has done this, please advise.

36 Coupe · May 31, 2011

Theres a timing mark in your photos.

39 9n bad cam gear

IROCKWITHDIRT

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wwildhorse2k

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Jim in michigan

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Hobo,NC

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IROCKWITHDIRT

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36 Coupe

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