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I have a 70's something spider block with locknuts on top of the main cap nuts 1-4. what's the torque setting for these?

Thanks for the help.
 

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I've never seen a torque figure, if you mean the stamped steel "pal" nuts. I just make them good and snug. I'd think any measurable torque would strip them.
Andrew
 

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Thanks for reply. Yep, the 'pal' nuts. Mine are hardened nuts in a stamped steel basket. Nuts in a basket!I was thinking about 10-14 lbs. 1/3 of the main cap nut spec... just don't want them coming off
 

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I can't imagine they'd help, if the main nut actually backed off. But who am I to second-guess Alfa. I know engine builders who say mild steel lock tabs, safety wire, cotter pins, all that is useless for something that's really under stress. If it's going to come undone, soft metal is not going to stop it.

I've built four engines in the last year, just got the pal nuts good and firmish tight with a socket and normal-length ratchet. No funny noises yet!

Andrew
 

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I can't imagine they'd help, if the main nut actually backed off. But who am I to second-guess Alfa. I know engine builders who say mild steel lock tabs, safety wire, cotter pins, all that is useless for something that's really under stress. If it's going to come undone, soft metal is not going to stop it.

I've built four engines in the last year, just got the pal nuts good and firmish tight with a socket and normal-length ratchet. No funny noises yet!

Andrew
the theory behind the jam nuts at the time was the natural resonant frequency of aluminum motors vs cast iron. the frequencies were believed to be such that at high revs the hardware would " buzz " and lose preload and ultimately get loose and fall off. the jam nuts changed the frequency of the assy and was , again , believed to eliminate the issue. i never saw the data but thats what i was told by an alfa engineer that i met at the 24hrs one year. its an odd mechanical equation when you start measuring prelaod and stretch on nut/stud assy and then put significant preload ON TOP of that nut with a second nut. what happens is that the threads under the second nut begin to absorb some of the preload from the threads under the first nut plus you have the frictional interface...
on the race motors i worried about the whole thing for all sorts of reasons not the least of which was the jam nuts falling off and getting loose in the bottom end so i used a better grade of nut that was thicker and loctited them.

like you say, the whole locktab thing is a bit wierd... you end up trying to achieve adequate preload on what is effectively a soft washer that will cold flow ... i throw them away at every opportunity and just use a proper washer and preload .
 

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I have a 70's something spider block with locknuts on top of the main cap nuts 1-4. what's the torque setting for these?

Thanks for the help.
From my experience, engines assembled by the factory all had the Pal nut's facets lined up with the nut below it. They weren't randomly put on askew. They are designed to slightly deform on the threaded part but not too much to lose their tensile strength. It's the flex of the thread chasers that hold them in place as you can imagine. One factory manual calls for 1.1-1.3 Kgm..(8-9.5 ft-lbs).or less than half of a spark plug.

If you tighten them just over finger tight and turn them with a socket between one and two flats to line them up perfectly you should be good to go. When they get to where they should be, you will feel that one more facet is too much. It's not a lot of torque, less than a spark plug if you know that feel. That is the method I use and seems to work ok. Hope that helps. let us know how that works out for you.
 
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