Hi all, i am in the process of assembling the primary drive on my Mk3 and I am struggling to to find the torque setting for the anti backfire nut. Is the breakaway setting of 50 lbs ft quoted in the manual also the torque setting of the nut? It seems rather a lot for a nut that size. I bought this as a "project" in a partially stripped state, yes, yes, I know! Any help here is greatly appreciated
Stewart Denton-Giles
I Removed the starter from…
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There is no torque setting…
There is no torque setting for the antibackfire nut, it is the breakaway torque you have to set the assembly to that means the antibackfire nut is just a means of adjustment. It is amazing how many people get this wrong.
Grip the antibackfire devices gear wheel in a vice using softjaws. Then turn the shaft (using a suitable tool, a splined thrustwasher welded to a socket is ideal) using a torque wrench. It is the torque the device releases at, is what should be 50 ftbs. I,ve come across quite a few devices that have had the adjuster nut wound down to 50 ftbs so rendering it effectively solid.
The difficulty arises when the adjuster nut has been removed, the action of the device operating when checking the 50 ftbs setting moves the adjuster nut on the thread, so next check results in a different torque reading.
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I Removed the starter from my Mk3 ages ago. However, I'm pretty sure the 50 lbs/ft load is pre-set when the nut runs up against the shoulder on the shaft. The nut will only require enough torque to keep it in place, and what that figure is I haven't a clue, but I'm sure if you put the thread data etc into a Google search for the torque range you might get a good answer. Other than that nip it down with a little thread lock.