Clutch won't stay put!!

[YourCustomCart]

So I finished the engine rebuild in my 87 marathon a couple months ago. During the initial removal of the drive clutch from the crank snout, I damaged the threads inside the crank snout where the bolt goes to hold the clutch and pulley assembly on the crank. I ended up having to drill out the hole in the snout to tap the thread to 1/2-20 thread size. This was fairly easy to do. I bought a new high grade bolt in the new thread size that is the same length as the bolt that was originally in the crank snout for the clutch.

I spread a little anti-seize on the snout and slid the clutch/pulley assembly onto the crank. I put a lock washer and a flat washer and finally the plastic spacer on the new bolt and tightened it up to hold the clutch assembly to the snout.

After driving for about 20 minutes, the cart suddenly stopped moving forward but the engine continued to rev. I popped the seat cover and saw that the clutch assembly is spinning on the crank snout. So, I got the cart home and found that the new clutch bolt had backed out. I took the bolt out and thorougly cleaned the threads of both the bolt and crank. I checked to see just how far the bolt threading into the snout and found that the bolt was only screwing in about 1/2 inch. I Then applied blue loc-tite and retightened the bolt. I let the cart sit for 24 hours to allow the loc-tite to dry. After driving the cart again, the bolt backed out and the clutch slid off the snout again!

So now I'm wondering if the clutch/pulley assembly has to be pressed on? Should I try a longer bolt that will screw into the crank a little further? Red loc-tite? Please help. I'm disgusted that i've got this engine working so well and can't even drive my cart due to the clutch continuing to slide off the crank.

[BigCountry79]

does it not have a key way?

[YourCustomCart]

Nope. It's press fit.

[penn1]

Left hand thread be of any help?

[YourCustomCart]

Yeah, I imagine left hand thread would help, but theoriginal bolt wasn't left hand thread.

[Dave Box]

Well the original bolt didn't need Loctite and it is a right hand thread. Is it possible that the bolt is bottoming out in the hole giving the illusion that the clutch is on tight to the shaft when in effect it could go further onto the shaft and snug up more tightly?

Dave.

[YourCustomCart]

I just tried something and I will probably shoot myself in the foot by saying this, but it might just work. I went out and bout a 1/2-20 threaded rod and cut it down to 9 inches in length. Threaded that into the crank until it stopped. I got it as tight as usual could by hand, then screwed on nut with two flat washers and tightened it to the extreme. I screwed onanother nut to act as a lock nut and tightened that against the first nut. Took it out for a couple of minutes and so far so good. I guess I'll just leave it at that. What do you think?

[DOOmsman]

As long as it works?? Most threaded rods are at best grade 2 or 3!

I think Dave is right tho< did You use a plug or bottoming tap?

[YourCustomCart]

Hmm. Is it likely the threaded rod will break over time?

[DOOmsman]

Originally Posted by YourCustomCart

Hmm. Is it likely the threaded rod will break over time?

It may last forever, but you should understand that some
very funky vibrations occur in a spinning mass hung on the
end of the crankshaft. A clutch is a spinning time bomb, I
understand we don't spin our cart engines as fast as we spin
snowmobile. I shudder when people post videos of the
clutches and they are standing in line with them.