Hi All, the problem I have just come across is not directly related to Jowett's but equally could be? It concerns a loose driving pulley on the nose of the crankshaft. The engine involved is a quite normal 'A' Series BMC engine, fitted in a Morris Minor. The front pulley arrangement could be any in-line engine. When attempting to time the ignition, this proved impossible, as the timing marks were jumping all over the place! Upon inspection, it was found that the front pulley was free to move, respective to the crankshaft, by about 15-20 degrees. The front nut was tight. Our suspesions are that the locating Woodruff key, or keyway, or prehaps both, are considerable worn? One. rather drastic, solution would be to drop some weld onto the joint between the front nut and the outer face of the belt pulley wheel? Hopefully thereby stopping any 'flutter'.
This situation could just also be found on Jowett's, but never in my experience. Perhaps Jowett engines are made of stronger stuff?
Any ideas?
All the best, David
Woodruff Key
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David Morris
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PJGD
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Re: Woodruff Key
It sounds as if the bolt (or nut) on the nose of the crankshaft is either bottoming out before the component stack (timing chain sprocket and crank pull etc) is clamped, or there is a washer missing that if in place would result in a clamp load.
If the engine has been running for any length of time with no clamp load, then it is very likely that the woodruff key is seriously worn (with little bits of metal now in the sump, or worse).
If the engine has been running for any length of time with no clamp load, then it is very likely that the woodruff key is seriously worn (with little bits of metal now in the sump, or worse).
Philip Dingle
aka, PJGD
aka, PJGD
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Keith Clements
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Re: Woodruff Key
Or it may be wissing a washer. Surely it should be tight even with a sloppy key or keyway.
skype = keithaclements ;
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David Morris
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Re: Woodruff Key
Thanks guys! The nut is dead tight, which, if it's missing a washer, might be why the previous owner tried to get the pulley to stay firm?
Many thanks for the help,
David
Many thanks for the help,
David
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RichardMc
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Re: Woodruff Key
A woodruff key is a locator and a safety mechanism should the bolt or nut fail, it is not a drive key, although a lot of people think it is because it looks like it should be.
The drive surface is the taper on the shaft and the taper in the pulley; the key is there to help you align them and save you if the bolt isn’t tight. If the pulley is loose on the shaft the problem is either the taper (worn, dirty, bashed up) or the bolt/nut isn’t tight. Nothing to do with the woodruff key. In your case it’s most probably a missing washer and the bolt is bottoming out or the pulley isn’t fully home, as others have mentioned.
You actually don’t even need the woodruff key and some engines don’t use them because the pocket it sits in can weaken the shaft but it would be a brave move to leave one out if it was designed to be there. Hope that helps.
The drive surface is the taper on the shaft and the taper in the pulley; the key is there to help you align them and save you if the bolt isn’t tight. If the pulley is loose on the shaft the problem is either the taper (worn, dirty, bashed up) or the bolt/nut isn’t tight. Nothing to do with the woodruff key. In your case it’s most probably a missing washer and the bolt is bottoming out or the pulley isn’t fully home, as others have mentioned.
You actually don’t even need the woodruff key and some engines don’t use them because the pocket it sits in can weaken the shaft but it would be a brave move to leave one out if it was designed to be there. Hope that helps.
Rich