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Zetec Vernier
ian.stewart - 14/9/21 at 07:59 AM

I know its been asked before, BUT, Im looking for a Single Vernier for my ST170, Has anybody got a single one or a pair lurking somewhere unloved?

jollygreengiant - 15/9/21 at 08:16 AM

Excuse my apparent total ignorance, but, WHY and HOW would you have a venier cam shaft drive, on a camshaft drive that has NO camshaft location key/pin/peg/dowl on either the camshaft (front location) or the cam drive plate. Indeed it is fully floating and ONLY held in place by the clamping force applied by the retainer bolt. All cam drive timing is done by a location key in the back of the camshaft on the original Zetec engine (or the ones that I have worked on over the past nearly 30 years{ish}).
The logical scenario would be to vernier adjuster plates on the back end for a special engine, that dial the cam in then just tighten up the dive plates/wheels as per normal.

ian.stewart - 15/9/21 at 05:05 PM

quote:
Originally posted by jollygreengiant
Excuse my apparent total ignorance, but, WHY and HOW would you have a venier cam shaft drive, on a camshaft drive that has NO camshaft location key/pin/peg/dowl on either the camshaft (front location) or the cam drive plate. Indeed it is fully floating and ONLY held in place by the clamping force applied by the retainer bolt. All cam drive timing is done by a location key in the back of the camshaft on the original Zetec engine (or the ones that I have worked on over the past nearly 30 years{ish}).
The logical scenario would be to vernier adjuster plates on the back end for a special engine, that dial the cam in then just tighten up the dive plates/wheels as per normal.


ST170s have variable timing on the inlet only, the cams are indeed only clamped in position, the engine apparently responds well to giving the exhaust cam 6 degrees of retard, SO, the Idea is, set the vernier to 0, lock the cams in position with the bar at the back set the cams as usual, then set the vernier to -6 degs

[Edited on 15/9/21 by ian.stewart]