Rocker spindle plates position

A query about the rocker spindle plates please.

I have some aftermarket aluminium spindle plates with a single tab to locate the rocker spindle. I know that on the rocker spindle the oil feed hole and flat face is positioned forwards on the exhausts and rearwards on the inlet side.

On the spindle plates that I have (I think from Norvil many years ago) the locating tab is not set at 90* to the mounting holes, but at an angle of about a 20 degree to a perpendicular line drawn between the mounting holes. This will therefore locate the spindle and the flat and oil feed hole, at an angle of approximately 20* either slightly up or down from a perpendicular line drawn from the mounting holes.



What is the proper orientation? I can't see anything in the workshop manual. Based on where the rocker sits for most of its time, excluding when it is operating, the lines that I have drawn on my head are I think going to keep the flat at near to 180* from the rocker oil feed hole, I think? The angle of the lines are slightly exaggerated. Does anybody know what is correct?

OEM one looks like 90 deg to me

Reggie said:

I can't see anything in the workshop manual.

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They are special parts intended to compensate for inaccurate oil feed drillings where the standard "90 degree" tabbed end plate would place the spindle slot in a position that would blank off the drilling.

Reggie said:

What is the proper orientation?

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With the tab on the side away from the oil feed drilling.

If, however, if the oil feed drillings in the head are positioned correctly then those plates are going to do the opposite and blank them off so could do more harm than good?

maylar said:

OEM one looks like 90 deg to me

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I'd just looked on the Andover site myself and saw this also just before you posted. Maybe that's the question answered? Mine are incorrectly manufactured when compared to the standard spec.

L.A.B. said:

With the tab on the side away from the oil feed drilling.

If, however, if the oil feed drillings in the head are positioned correctly then those plates are going to do the opposite and blank them off so could do more harm than good?

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Yes, I'd never thought about the shafts being set out of alignment blocking off some of the oil feed. I think that the slot in the rocker shaft is probably generous enough to barely make any difference. The only way to check this is to fit a shaft and see if there is any obstruction to the oil feed hole in the head. It looks as if I may be buying some more end plates.

Reggie said:

I think that the slot in the rocker shaft is probably generous enough to barely make any difference.

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Normally, it should be, and if partially blanked by the spindle then the oil feed can be opened up a little but this problem where the spindle almost blanks off the feed drilling has cropped up once or twice.

L.A.B. said:

Normally, it should be, and if partially blanked by the spindle then the oil feed can be opened up a little but this problem where the spindle almost blanks off the feed drilling has cropped up once or twice.

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Thanks for the info.