Ironhead Oil seepage from acorn nut on Rocker Box

[rapierce]

Hey guys, I have oil seeping out of two of my acorn nuts one on the front cylinder and one on the rear. I would like to replace the o-rings, but when I try to remove them, the hex side comes off and the acorn nut just spins.

Is there a trick to getting the acorn nut off to replace the o-rings?

[sungod]

Originally Posted by rapierce

Hey guys, I have oil seeping out of two of my acorn nuts one on the front cylinder and one on the rear. I would like to replace the o-rings, but when I try to remove them, the hex side comes off and the acorn nut just spins.

Is there a trick to getting the acorn nut off to replace the o-rings?

You might try double nutting the shaft threads with a couple of thin (jam) nuts.

[JB in NC]

Your terminology is hard to follow.

If you mean the plugs on the right side of the rocker box are tight in the shafts, and you are spinning the shafts loose in the nuts on the left side:

First, tight plugs are a common problem, because they seem to tighten in service.

Second, you need to anchor the shaft firmly in the rocker box. Holding the right side plug, torque the left side nut to 40 ft.lb., for the solid chrome nuts found on your '80. (The thinner, earlier locking nuts, the ones with the red lights, can only take about 30 ft.lb.)

Third, go to the right side plug and spin it off with a rattle gun. It's often the ONLY way to get those plugs loose. Replace the o-ring (I personally like the 11118 quad seal in that particular location) and replace the plug, just snugging it in place, no heavy hand needed.

Jim

[rapierce]

Originally Posted by JB in NC

Your terminology is hard to follow.

If you mean the plugs on the right side of the rocker box are tight in the shafts, and you are spinning the shafts loose in the nuts on the left side:

First, tight plugs are a common problem, because they seem to tighten in service.

Second, you need to anchor the shaft firmly in the rocker box. Holding the right side plug, torque the left side nut to 40 ft.lb., for the solid chrome nuts found on your '80. (The thinner, earlier locking nuts, the ones with the red lights, can only take about 30 ft.lb.)

Third, go to the right side plug and spin it off with a rattle gun. It's often the ONLY way to get those plugs loose. Replace the o-ring (I personally like the 11118 quad seal in that particular location) and replace the plug, just snugging it in place, no heavy hand needed.

Jim

I think I understand what you're saying, but it's not the right side that is stuck it's the acorn nut on left side that I need to replace the o-ring, the "Plugs" on the right side are coming out quite easily.

[JB in NC]

OK, when I first read your post, that's what I thought you meant, but the above post in answer to your first kind of muddied my understanding.

There are no o-rings on the left side, the seal is just the thin, soft steel washer under the nut.

To tighten the left side nut, remove the plug on the right side. Put a 3/8 steel ball (oil pump checkball) in the opening, and follow with a 1/2-20 bolt tightened on the ball. All of this clean, of course, since this is part of your oiling system. Holding the shaft still with that 1/2" bolt. torque the left side nut to 30 - 40 ft.lb. as I said earlier. A light shock to the 1/2" bolt will break it loose, and you can remove the ball with a magnet. Assemble o-ring and plug, and you are done.

Jim

[rapierce]

Originally Posted by JB in NC

OK, when I first read your post, that's what I thought you meant, but the above post in answer to your first kind of muddied my understanding.

There are no o-rings on the left side, the seal is just the thin, soft steel washer under the nut.

To tighten the left side nut, remove the plug on the right side. Put a 3/8 steel ball (oil pump checkball) in the opening, and follow with a 1/2-20 bolt tightened on the ball. All of this clean, of course, since this is part of your oiling system. Holding the shaft still with that 1/2" bolt. torque the left side nut to 30 - 40 ft.lb. as I said earlier. A light shock to the 1/2" bolt will break it loose, and you can remove the ball with a magnet. Assemble o-ring and plug, and you are done.

Jim

Ok, I think I understand that. So there are just crush washers on the left side that seal it up?

[toodogs]

For the rocker shaft left side acorn nuts: Per FSM-M813 Service Bulletin the acorn nut torque is 15-20 foot pound.

There is a misprint in the 70-78 FSM 99484-78 where 60-65 foot pound torque is recommended.

[JB in NC]

Originally Posted by toodogs

For the rocker shaft left side acorn nuts: Per FSM-M813 Service Bulletin the acorn nut torque is 15-20 foot pound.

There is a misprint in the 70-78 FSM 99484-78 where 60-65 foot pound torque is recommended.

It's a 7/16 thread. 15 - 20 ft.lb. is laughable for that nut, I don't care what the service manual says. I can pretty much guarantee you that no motor left the factory with those nuts at that torque value. If the OP's shafts are leaking, then for sure they are not tight.

Jim

[toodogs]

Jim, the left nut seats a shoulder of the rocker shaft against pn 17451-57 spacer<hard washer> that seats against a mating shoulder in the rocker cover.

The left nut has nothing to do with compression of the o-ring that is under the right rocker shaft screw pn 17448-57 or 17448-71A <depending on model year>

[JB in NC]

Originally Posted by toodogs

Jim, the left nut seats a shoulder of the rocker shaft against pn 17451-57 spacer<hard washer> that seats against a mating shoulder in the rocker cover.

The left nut has nothing to do with compression of the o-ring that is under the right rocker shaft screw pn 17448-57 or 17448-71A <depending on model year>

Yes, but the OP's complaint is that the shafts are leaking on the left side, not at the o-rings. That was confusing to me at first as well.

Jim