Loose Crank Pulley Nut

fivefix

fivefix

Member
I was on a club tour last Saturday and was enjoying a perfect Iowa fall tour. I am running water with a rust preventive additive and water wetter. I have a Vintage Precision thermostat gooseneck with the thermostat removed. My temperature for most of the day was running 150 degrees. A little cool I realize, but the weather turned form blazing hot to cool in Iowa within 1 week and I didn't get the thermostat reinstalled.

Shortly after lunch I glanced at my temperature gauge and was pushing 210 degrees. We pulled over and discovered my crank pulley nut had loosened allowing the pulley to slip off the crank key. The fan belt was barely turning so I had no water pump or alternator. Luckily I was 50 miles from home so I parked the car in a farmer's drive, jumped in another A to get home and got the car trailer.

The timing and crank gears were replaced with a Dan McEachern matching set this past winter so I only have driven 3,000 miles since the crank pulley nut was last tightened.

Is there a way to ensure the nut stays torqued? Does anyone use a star or lock washer? I hate to use Locktite.

Dave Fick
Muscatine, IA
 

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I agree with the Blue Loctite on the ratchet nut. Clean the threads of the nut and crank with brake cleaner prior to the Loctite.

FWIW: I had two ratchet nuts come loose on, about 130, engines I have built over the last 5 years. Both of them had metal timing gears installed...one from Dan and the other was an aluminum gear. One instance was my own, high revving engine and the other was on a Cragar overhead valve build used for hill climbs. The Cragar setup came loose twice. He used Blue Loctite the last time and it has held since. That's strange isn't it? It would be hard to believe the metal timing gear had anything to do with it.

Update: I use a cordless Dewalt Impact to spin the ratchet nut on and complete the initial seating and then check the torque. I finish, hand torque, to between 100# and 110#. Both slingers were in place and there was the normal amount of the pulley proud of the crankshaft to allow the ratchet nut to tighten against the pulley. One pulley was a standard cast spoked one piece and the other was a reduced diameter turned pulley supplied by Stipe Machine.
 
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Hey Dave,
I use same gears and a fine set they be:) !

Pay close attn. to what Mr. Brierley has written, IMO !
Also, you do not say if you torqued the BOLT and how much torque you used. At LEAST a 100 torque ! There is nothing wrong with using blue locktite for that application..IMO, that's what it is made for,eh ;)

BTW, I do not believe that there was any lock washer used there.
 
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The one comment about making sure you are torquing against the pulley and not the crank is important. Since you just replaced the gears is there any chance the slinger was left off of the crank? That keeps the pulley from going past the end of the crank.
 
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