adjust cam timimg on JD B

[macandmall]

Can you move the cam on a JD B without removing the clutch and primary reduction cover? I want to advance the timing of my re-ground cam.

 

[48farmall]

Negatory, at least I couldn't on my unstyled. Have fun!

 

[macandmall]

That's what it seems like. With the left cam bearing out, I can move it away from the crank a little but not enough. The only way to get at the right cam bearing is to pull the clutch and the big primary reduction cover. Not what I want to do to my nice painted restoration.

 

[johndeereman]

I assume your just wanting to turn it one tooth? Can you unbolt the main bearing housing on the flywheel side and let the crank drop down some? Not sure if it would work just an idea

 

[Earl-IL]

Remove mag,remove crankcase cover ,remove gov oil line.Remove 2 bolts on front fan support raise gov housing about 3/8 in. Push in on cam it is spring loaded. If you still don't have enough clearance remove the left cam brg and inner race.If cam has never been out, make sure right side race comes back & doesn't hang up in housing.

 

[jd b puller]

Might be able to do that on a A or G, but Not on the B's. No spring and no bearing...

side Cover needs to come off. (and platform, brake, clutch, and possibly RH wheel)

 

[macandmall]

I have the gov off the left cam bearing out, I can get the tooth about half way out of mesh, but that is it. Not sure which direction you mean to "push in on cam. I removed the rocker form the head so the pushrods are not pushing on the lifters.seems like the oil pump gear is holding things up, and the right cam bearing, which is under the primary reduction cover.

 

[macandmall]

So the manual is correct. That is the procedure the manual says to do. Was hoping someone had found a shortcut after all these years.
Thanks,
Scott

 

[Mike N Mo]

Before you go to all the work advancing the cam, do you know where the timing is now, and where it's supposed to be (according to the intake centerline spec supplied by the manufacturer/cam grinder)? I'm not being judgemental here, nor do I know your skills in engine building, but you really need to know where it is now before you just shoot in the dark. Get a degree wheel and have fun. Mike

 

[Earl-IL]

Thanks for the correction . I assumed the "B" was the same. I should have read my manual.

 

[macandmall]

I didn't get any specs from the cam grinder. Up until now, I didn't know the timing might be off after the re-grind. I want to check the timing, but don't have a dial indicator. A pulling friend down the road might have one, but then it will be kind of a guess because the shop that ground the cam has a new owner, and he could only give me an educated guess as to what the intake timing might be. Right now, the exhaust valve is opening very close to the stock mark on the flywheel, and the new shop owner said it should be opening quite a bit sooner than stock, which leads me to think I should advance one tooth.

 

[macandmall]

I got a dial indicator and degree wheel. The centerline of the intake cam is 110 degrees. The new owner of the shop found some specs for a B grind the previous owner had, and thought it should be 105-110. I think part of my problem is my tires. Old style 12-38's. They are too tall and it's just geared too high with tall tires. It has a top speed of 18mph in 6th gear. A friend has some shorter 36" rims and tires I will try at our pull.

 

[macandmall]

I decided to take it apart anyway. I found that the cam timing was retarded. Intake center of lobe was at 110, now is 96. The exhaust valve was closing after the piston passed tdc, more than an inch down the bore, and the intake begins to open just as the exhaust closed. I advanced the cam 1 tooth, and now the exhaust closes right at tdc. The exhaust now begins to open before the piston reaches bdc, at least an inch to go in the bore, and the intake closes after the piston begins to move up the bore. I put it on my neighbors dyno today. I gained 5 hp after tuning it on the dyno today, it started at 20 today.It is still only making 25-26 hp, but it will lug a lot better. I noticed that right away when I drove it down the road. Starting from a stop in 6th gear is a breeze now. Before the adjustment, it was difficult to get going in 6th. Our local pull is Tuesday night, I am sure it will do better than it has in the past.

 

[macandmall]

Here it is pulling in 3500#. My Son recorded it on my phone, not very good quality video. It spun out at 255', right where most of the others stopped. The winner was an Oliver 70, went 263'. I'm very happy with the power now.
http://www.youtube.com/watch?v=DZ_1jAGU4t8&feature=youtu.be
Scott