Forum

[Norm]

I'm not convinced the bobbins used in the twins seal too well in the worm and on measuring mine up the bobbin floats in and out of the nut by 5mm. I'm considering fitting a spring behind the bobbin to keep the bobbin in contact with the worm drive instaed of it floating about and hopefully sealing in the drive a bit better. Mine is reasonably ok but in a mates Inter the bobbin is quite loose which is a big concern. I have 2 new bobbins which fit better in the worm but won't fit in the nuts. Any thoughts about fitting a light spring in behind the bobbin to keep tension on the bobbin

[Mark M]

Won't a spring just wear it out quicker? I know that some people have had problems with these bobbins and returned to the quill type. If I recall correctly Hitchcocks actually advise checking the fit with this in mind. It's down to machining differences on the original engines apparently.
REgards, Mark

[another Allan]

Norm, if there is longitudinal movement of the bobbin and a spring is fitted behind it to close the gap between bobbin and oil pump drive, will that mean that there is a gap at the spring end of the bobbin which will allow loss of pressure from there? Following your recent post about these things, I did start to think that these bobbins are not such a brilliant idea after all, and as Mark says, it is probably necessary to do some machining to ensure the best fit possible. Maybe the recess for the threaded hole in the timing cover could be 'undercut' to allow the oil feed bolt to seat a little deeper and take-up any play.

[Norm]

Mark/Alan they are a pretty dodgy and I just had a couple arrive from MrH but they are different lengths which also gives me concern but the problem is I can't find the original quill bolts and MrH doesn't have any. I fitted one of the new ones and now it has blown the oil filter gasket, must be because of increased flow trying to go through the big ends and not bypassing the bobbin