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Vintage Sleds, Vintage snowmobiles => Vintage Tech Help => Topic started by: wankel303 on February 18, 2012, 11:15:22 AM
Title: JLO 292 - 1966 Scorpion - Clutch
Post by: wankel303 on February 18, 2012, 11:15:22 AM
I have a 292 JLO in the shop for crank seal replacement and an overall freshening up. This little popper is out of a 1966 Scorpion. As per usual, the primary clutch is being stubborn. These little JLOs have a 25mm taper and threaded crank as far as I know. Can someone confirm this for me? Paging JLOpower?
It doesn't appear that these clutches are the thread-on type but I want to make sure it's the usual pulling method before I continue to work on it. Can anyone tell me for certain?
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: JLOpower on February 18, 2012, 12:20:47 PM
The early JLO engines with the 25mm taper do pull in the same manner as the standard 30mm taper. Special care must be taken to ensure the puller slug is large enough to spread pressure evenly across the end of the crank. Do not use a socket as a slug.
The 25mm crank is easily IDed by the clutch retaining bolt. If it has female threads on the end of the bolt, that confirms your configuration. A standard 1/2" fine male threaded bolt was used on the 30mm tapered clutch.
While I am sort of unfamiliar with threaded clutches, every one I've ever encountered had a smaller cover bolt. My JLO books do not show a crank for a threaded clutch, but that does not mean they do not exist. JLO would adapt their engines for just about any specialized use.
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: wankel303 on February 18, 2012, 03:01:31 PM
This is a pretty strange set-up. There are 1/2-20 internal threads on the end of the stationary sheave as if to receive a clutch puller. I can also see the the threaded end of the crank ,and the dimple in the end of it, when I take a look down the hole in the stationary sheave. Where things get wierd is that there isn't the traditional "female threaded bolt" as you described retaining the clutch. It was only a 1/2-20 by 1" hex bolt threaded into the end of the stationary sheave. I don't know what is securing the stationary sheave to the crank. The internal diameter of the stationary sheave is only about 3/8" of an inch so the "female threaded bolt" you described would never fit. I gave it a rest for today to let it soack in some penetrant and I will take a nother look at it tomorrow night.
The 67 Scorpion Parts Diagram shows pretty much the same setup for the Mark II. The crank looks like a 25mm tapered with a threaded stub just like the L300 and L297 JLOs. It's on pages 5 and 6. You can see it here:
www.vintagesnow.com/Scorpion_files/1967%20Scorpion%20Parts%20Manual.pdf
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: JLOpower on February 18, 2012, 03:32:01 PM
I can't tell much from the manual. Sorry.
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: fp1967 on February 18, 2012, 04:07:25 PM
I had a JLO 252 or 292 that had a clutch on it as you describe. What I found was the hub of the clutch is machined with a taper and then threaded to fit the male threads on the end of the crankshaft. You have to unscrew it off of the crankshaft, but the problem is that the taper fit makes it pretty hard to turn. It is a weird set-up. I hope you understand my explanation. I think I might have that clutch laying around yet. If you want, I can take a picture of it. Just let me know.
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: Stigmen on February 18, 2012, 04:44:49 PM
I have a 66 that needed the clutch removed to do the crank seal. It was threaded. We took a giant pipe wrench, put a length of rope down the plug hole, secured the motor to the floor and jumped onto the wrench. It was going to break or come off. It POPPED loud. I thought for sure the crank busted but the clutch came off.
I did not split the cases to do the crank seals. I really don't remember how I did it since it was nearly 20 years ago. I still have the sled though.
Hope this helps.
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: JLOpower on February 18, 2012, 05:53:36 PM
Pictures would be appreciated. Never seen one as you described.
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: fp1967 on February 18, 2012, 07:24:04 PM
I will look for the clutch tomorrow. If I have it, I will see if I can get a good picture of inside the tapered bore.
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: Stigmen on February 19, 2012, 06:22:33 AM
I forget to mention you need to turn the clutch counter clockwise.
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: fp1967 on February 19, 2012, 09:51:41 AM
I took some pics inside the bore of the clutch, they didn't turn out the greatest. I tried a few different settings on my camera and this was the best that I could get.
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: wankel303 on February 19, 2012, 10:08:55 AM
This looks pretty close. So is the narrow part of the bore here where it is threaded? Is this a standard "right-hand" thread...i.e.."righty-tighty, lefty loosey"...?
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: JLOpower on February 19, 2012, 10:52:58 AM
Thank you for posting that.
A totally different set-up from the 25mm Polaris/Arctic/MF steel clutches I have seen.
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: fp1967 on February 19, 2012, 01:13:50 PM
Quote from: wankel303 on February 19, 2012, 10:08:55 AM
This looks pretty close. So is the narrow part of the bore here where it is threaded? Is this a standard "right-hand" thread...i.e.."righty-tighty, lefty loosey"...?
Yes on both questions. Once I got the clutch off, the crankshaft looked like all the other JLO 252 and 292 engines with the male threads at the end of the taper. If you are not familiar with what these crankshafts look like, I can take a picture of one and post it for you. Although I bet JLOpower probably has one on file that he could post.
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: JLOpower on February 19, 2012, 01:46:05 PM
Here's a photo of one that did not fare too well when the clutch was removed. You can see the threads are pretty rough.....
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: wankel303 on February 21, 2012, 10:26:48 AM
Well I had expected the worst last night and had everything prepared for a lengthy battle but within a couple of minutes, I had the clutch off and sitting on the garage floor. The little bugger spun right off with hardly even a grunt. I had thrown some heat at it the other day and it had been soaking for a good while so, I am certain that helped the removal.
Thanks for the help guys!
vintagesleds.com/bs/index.php/topic,66464.msg746728.html#msg746728
Title: JLO 292 - 1966 Scorpion - Clutch
Post by: wankel303 on February 18, 2012, 11:15:22 AM
I have a 292 JLO in the shop for crank seal replacement and an overall freshening up. This little popper is out of a 1966 Scorpion. As per usual, the primary clutch is being stubborn. These little JLOs have a 25mm taper and threaded crank as far as I know. Can someone confirm this for me? Paging JLOpower?
It doesn't appear that these clutches are the thread-on type but I want to make sure it's the usual pulling method before I continue to work on it. Can anyone tell me for certain?
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: JLOpower on February 18, 2012, 12:20:47 PM
The early JLO engines with the 25mm taper do pull in the same manner as the standard 30mm taper. Special care must be taken to ensure the puller slug is large enough to spread pressure evenly across the end of the crank. Do not use a socket as a slug.
The 25mm crank is easily IDed by the clutch retaining bolt. If it has female threads on the end of the bolt, that confirms your configuration. A standard 1/2" fine male threaded bolt was used on the 30mm tapered clutch.
While I am sort of unfamiliar with threaded clutches, every one I've ever encountered had a smaller cover bolt. My JLO books do not show a crank for a threaded clutch, but that does not mean they do not exist. JLO would adapt their engines for just about any specialized use.
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: wankel303 on February 18, 2012, 03:01:31 PM
This is a pretty strange set-up. There are 1/2-20 internal threads on the end of the stationary sheave as if to receive a clutch puller. I can also see the the threaded end of the crank ,and the dimple in the end of it, when I take a look down the hole in the stationary sheave. Where things get wierd is that there isn't the traditional "female threaded bolt" as you described retaining the clutch. It was only a 1/2-20 by 1" hex bolt threaded into the end of the stationary sheave. I don't know what is securing the stationary sheave to the crank. The internal diameter of the stationary sheave is only about 3/8" of an inch so the "female threaded bolt" you described would never fit. I gave it a rest for today to let it soack in some penetrant and I will take a nother look at it tomorrow night.
The 67 Scorpion Parts Diagram shows pretty much the same setup for the Mark II. The crank looks like a 25mm tapered with a threaded stub just like the L300 and L297 JLOs. It's on pages 5 and 6. You can see it here:
www.vintagesnow.com/Scorpion_files/1967%20Scorpion%20Parts%20Manual.pdf
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: JLOpower on February 18, 2012, 03:32:01 PM
I can't tell much from the manual. Sorry.
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: fp1967 on February 18, 2012, 04:07:25 PM
I had a JLO 252 or 292 that had a clutch on it as you describe. What I found was the hub of the clutch is machined with a taper and then threaded to fit the male threads on the end of the crankshaft. You have to unscrew it off of the crankshaft, but the problem is that the taper fit makes it pretty hard to turn. It is a weird set-up. I hope you understand my explanation. I think I might have that clutch laying around yet. If you want, I can take a picture of it. Just let me know.
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: Stigmen on February 18, 2012, 04:44:49 PM
I have a 66 that needed the clutch removed to do the crank seal. It was threaded. We took a giant pipe wrench, put a length of rope down the plug hole, secured the motor to the floor and jumped onto the wrench. It was going to break or come off. It POPPED loud. I thought for sure the crank busted but the clutch came off.
I did not split the cases to do the crank seals. I really don't remember how I did it since it was nearly 20 years ago. I still have the sled though.
Hope this helps.
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: JLOpower on February 18, 2012, 05:53:36 PM
Pictures would be appreciated. Never seen one as you described.
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: fp1967 on February 18, 2012, 07:24:04 PM
I will look for the clutch tomorrow. If I have it, I will see if I can get a good picture of inside the tapered bore.
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: Stigmen on February 19, 2012, 06:22:33 AM
I forget to mention you need to turn the clutch counter clockwise.
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: fp1967 on February 19, 2012, 09:51:41 AM
I took some pics inside the bore of the clutch, they didn't turn out the greatest. I tried a few different settings on my camera and this was the best that I could get.
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: wankel303 on February 19, 2012, 10:08:55 AM
This looks pretty close. So is the narrow part of the bore here where it is threaded? Is this a standard "right-hand" thread...i.e.."righty-tighty, lefty loosey"...?
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: JLOpower on February 19, 2012, 10:52:58 AM
Thank you for posting that.
A totally different set-up from the 25mm Polaris/Arctic/MF steel clutches I have seen.
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: fp1967 on February 19, 2012, 01:13:50 PM
Quote from: wankel303 on February 19, 2012, 10:08:55 AM
This looks pretty close. So is the narrow part of the bore here where it is threaded? Is this a standard "right-hand" thread...i.e.."righty-tighty, lefty loosey"...?
Yes on both questions. Once I got the clutch off, the crankshaft looked like all the other JLO 252 and 292 engines with the male threads at the end of the taper. If you are not familiar with what these crankshafts look like, I can take a picture of one and post it for you. Although I bet JLOpower probably has one on file that he could post.
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: JLOpower on February 19, 2012, 01:46:05 PM
Here's a photo of one that did not fare too well when the clutch was removed. You can see the threads are pretty rough.....
Title: Re: JLO 292 - 1966 Scorpion - Clutch
Post by: wankel303 on February 21, 2012, 10:26:48 AM
Well I had expected the worst last night and had everything prepared for a lengthy battle but within a couple of minutes, I had the clutch off and sitting on the garage floor. The little bugger spun right off with hardly even a grunt. I had thrown some heat at it the other day and it had been soaking for a good while so, I am certain that helped the removal.
Thanks for the help guys!
vintagesleds.com/bs/index.php/topic,66464.msg746728.html#msg746728