small nit picky question

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seattle##gs

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Head steady. When I bolt up the triangle plates to the lord fittings they measure approx 2 3/4" from the inside of the plates. The box head steady itself measures 2 1/2" across which means the triangle plates are installed at an angle. does not seem to be optimum. Why?
My theory is that Norton used the same lord fittings as the muffs to save a few pennies. They had already made the head steady not realizing the mismatch and didn't care.
 
seattle##gs said:
When I bolt up the triangle plates to the lord fittings they measure approx 2 3/4" from the inside of the plates. The box head steady itself measures 2 1/2" across which means the triangle plates are installed at an angle. does not seem to be optimum. Why?
Click to expand...

When the lower triangular plate fasteners are tightened it should pull the triangular plates 'square' to the box section and slightly compress the rubber mounts.

seattle##gs said:
My theory is that Norton used the same lord fittings as the muffs to save a few pennies. They had already made the head steady not realizing the mismatch and didn't care.
Click to expand...


According to Norton Service Release N3/51, this preloading of the mounts seems to have been intentional, probably to limit the sideways movement of the head to reduce the engine 'rocking' from side to side.
 
seattle##gs said:
Head steady. When I bolt up the triangle plates to the lord fittings they measure approx 2 3/4" from the inside of the plates. The box head steady itself measures 2 1/2" across which means the triangle plates are installed at an angle. does not seem to be optimum. Why?
My theory is that Norton used the same lord fittings as the muffs to save a few pennies. They had already made the head steady not realizing the mismatch and didn't care.
Click to expand...

You're measurements confused me so I just checked on the 74 I'm building. My powder coated box is 2.514" wide and with the rubbers screwed all the way in, across them without the plates installed they measure 2.76". This means that the rubbers each compress about 1/8" when everything is tightened. The rubber buffers I'm using came from Andover Norton.
 
The preload is common in many applications. Don't fret it just enjoy the benefits.
 
OK. I guess it is intentional, it is a preload. I've noticed the gap over the years and always wondered about it.
 
seattle##gs said:
It seems awfully crude...
Click to expand...

If you think this is crude, try preloading a pair of taper roller main bearing inside the crankcase of a Velocette 500 it has to be .002 each side – the domestic oven was put to another use on this occasion – and wide open windows to get rid of the oily smell/pong that was left in the air.
 
seattle##gs said:
Head steady. When I bolt up the triangle plates to the lord fittings they measure approx 2 3/4" from the inside of the plates. The box head steady itself measures 2 1/2" across which means the triangle plates are installed at an angle. does not seem to be optimum. Why?
My theory is that Norton used the same lord fittings as the muffs to save a few pennies. They had already made the head steady not realizing the mismatch and didn't care.
Click to expand...

The problem is some suppliers perhaps most are selling car exhaust mounts. The original Norton rubber bobbins are narrower and not wasted.

Dave
 
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