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MG MGB Technical - Pulley wheel bolt

Hello,

I have just fitted the flywheel pulley and securing bolt, but have noticed that the correct locking tab has a keyway in it. However this doesn't locate on anything as the keyway/spline is further back down the shaft. Is this normal?

Many thanks,
Alex Davies

Alex,

If you are working on the flywheel end (rear) of the engine, then ignore everything I'm saying, but I think you are working on the front end of the engine with the pulley/harmonic balancer.

If I remember right, and it's been about 4 years since I was in there myself, the lock tab only looks like it has a keyway cut in it. Actually the "keyway" is only cut into the lock tab to get a tang of metal to stick out behind the tab, which inserts into the keyway of the pulley. The idea is that that tang locks to the pulley to keep the tab from rotating so that it can do its job of locking.

So, if your lock tab does not still carry the metal with it that was cut to form the "keyway" I think it is defective. Again, I'm playing with 4-year old memory here, so check to see if this makes sense.

Charley
C R Huff

Alex i have never seen a crank pulley locktab with a keyway in it, are you sure you have the correct one,every crank pulley locktab i have ever used is just dished, with a hole in for the crank pulley bolt,if you look at the crank pulley itself, you will see that it has a half moon cut away in it (with the locktab fitted and the bolt in place this is hard to see this cutaway) the way this locktab works is: with the bolt tight you knock the locktab over into the half moon cut away in the crank pulley, and you bend it over opposite this onto the flat of the crank pulley bolt (use a pair of grips to bend it over),and thats it, good luck A.T
andy tilney

I have attached an image from a MGA but it shows what Andy is describing for the MGB.

Mick

M F Anderson

All of the ones I have used, perhaps six in the last ten years, have been as Charley describes. The inner circle, through which the harmonic balancer bolt inserts, has a cut, in two places, making a tab. The tab is bent backwards and fits into the hole in the harmonic balancer where it is cut to fit over the woodruff key on the front shaft of the crankshaft. The tab keeps the lock tab from rotating (in theory) and the outer section of the lock tab is bent over one flat on the bolt to hold it in place. A little blue Loctite on the threads of the nut is not a bad idea as the system is not as secure as the one that Mick shows in his illustration.

Les
Les Bengtson

I've seen a couple with the tab, but Mick and Andy are correct, the originals did not have this. In similar applications, I've seen the tab torn off by friction while tightening the big bolt, so my conclusion always was that the factory avoided this by deleting the tab and going to the trouble of machining the half-moon depression.

FRM
FR Millmore

This thread was discussed between 19/02/2011 and 20/02/2011

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