Thread in twin carb manifold.

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nick rogers
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Thread in twin carb manifold.

Post by nick rogers »

We are having a discussion about the thread for the PCV spigot and servo one. A local engineering shop says 5/8" by 16tpi. But then added that it's the same as the crank bolt. On testing this, I tried a spigot into a crank and it only goes 2 turns at most. Any help appreciated.
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dklawson
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Re: Thread in twin carb manifold.

Post by dklawson »

The crank is a "Whitworth form" thread, 5/8-16. Form... not a true Whitworth size.

The manifold's servo connection should be the same as the oil pipe banjo bolt, 5/8-18. That's a "standard" but seldom used UNF thread. In addition to the oil feed pipe banjo you will also find this thread size used on the Smiths temperature sending units.
Doug L.
nick rogers
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Re: Thread in twin carb manifold.

Post by nick rogers »

Thanks, Doug. I remember that the temp sender fits the manifold, having seen them used as 'blanking plugs'. I also recall going to Home Depot on one of my visits to the USA and buying a tap for the crank very easily. Such a thing would be very difficult over here.
But you confirm that the 2 are not the same, as I seem to be finding. The engineering shop guy rarely works on anything BMC these days so I assume his memory is faulty.
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