Camshaft Bearings - Ruby  3-bearing engine

There are a number of differences between the 3 and 2 bearing engines, apart from the obvious!  The design of the camshaft centre bearing is a considerable improvement over the earlier roller race, and is a split bronze plain bearing located in the housing in the 3 bearing crankcase by a special set-bolt (i.e. one with a plain dowel pin at the end). 

Much easier to fit than an array of 14 rollers, but I spent over an hour trying to fit the split bearing by manipulating the  components on the camshaft into the appropriate hole in the crankcase, with my fingers in the limited space around the already fitted crank and the apertures for the tappets. Retreating to lick my wounds, I pondered how it was done at ‘The Austin’, where there must have been a simpler method.  

I slept on the problem, and decided to try another route – attach the bearing to the camshaft where it would normally sit, and since the front camshaft bearing hole is larger diameter than the middle bearing then lower the assembly carefully through the front bearing hole and as long as the locating holes in the front and centre bearings are lined up with the set-bolt holes in the crankcase everything would be fine………….but how to secure the bearing halves around the camshaft?  I considered various alternatives. 

Sticking the bearing halves to the camshaft journal with very thick grease or Vaseline and lowering the assembly into the crankcase. Holding the bearing halves together with a springy collar that could be unwrapped and retrieved, (probably how it was done on the assembly line at Longbridge). Tie-wrapping the halves in place and cutting the wrapping free. The method I decided on was to use a small rubber band which could be snapped and removed once the centre bearing halves were located, before final fitting. 

Ten minutes later, the camshaft assembly complete with bearings was secure in the crankcase (although the job took rather longer if the time taken to photograph the proceedings is taken into account) and the timing gears were correctly meshed.  

This article, written by Bob Kneale, originally appeared in CA7C Seven Focus April 2016, pp24-25