Sabre Tooth

So with only half a day to work on the Sabre last weekend I’ve only got a small amount of progress to report.

Basically, we got the engine  and diff fully aligned   this is always the critical issue because misalignment = chain jump or at very the least excessive chain wear. as usual it needs to be done in three planes.

Longitudinal alignment is done by dropping some thick wall Ali u shaped channel over the driver and driven sprockets and verifying the gaps

Relative axial alignment, is done by clamping a vertical straight edge  to each of the the sprockets and sighting across the gap to see if it tapers.   We also checked both the diff and driven sprocket with a digital inclinometer and they were found to be within 0.2 degrees of each other and vertical in the chassis.   Lastly we measured from the center line of the inlet cam to the main bulkhead to ensure the engine and crankshaft line was properly parallel to the transverse bulkhead.

When all three measurements were correct, we could start fabricating the mounts.  First job was to make some bucket bushes to fit the mounts on the block.  Firstly spin up a little top hat section to fit across the end of the tube we’re using then Tig weld it onto the tube.  Bolt this to the block.

Then make up the mounting tube to fit the mounts on the bulkhead.  These were fabricated for 1/2 bolts which are frankly massively heavy and vastly over specified. So I knocked up what were essentilly double ended bucket bushes, and some little top hats to fit the brackets, to convert to 8mm bolts.  All of which took ages… and to be honest I’m not very impressed with the result, as for some reason the 8mm holes up the middle of these components is rattling a little on that test bolt… which incidentally might be a little over long too. Tim also Kindly pointed out that it might well have been easier to fit 12mm bolts with a 6 or 8mm hole up the middle.

To be honest the whole set of engine mounts are turning into a bit of a nightmare.   The rear mounts are simply in free space, and difficult to triangulate  and the front mounts are a mess…. about the only thing that’s any good from this morning’s work is the bucket bushes on the block… Pah… I need to leave these alone for a while and look at them again with a fresh mind.  Chatting with Andy, he also suggests that before I complete the lower stays of the mounts I need to build the exhaust headers to make sure I have the routing right and its a lot easier  to do without the engine mounts in the way.  So  in time honoured fashion  I’m walking away from this job for a couple of days.

So on to an easier job.   The steering rack fits in the nicely made ally mounts, unfortunately the rack supplied was slightly undersized , and actually rotated in the mounts.  To  correct this I simply mounted the caps from the mounts in the lathe and span about 1,2mm off the mating faces.   This closed up the aperture, and when bolted up clamped the rack nicely in place, so at least some good progress to report today. Next step on the plan to a working steering system is to build my new quick rack into the fitted casing, as part of this I also need to fit some bronze bushes.

In the evenings, I’ve also mostly made up the clutch and throttle pedals.  These are made from the blanks I had laser cut in January, welded on to a centre spindle that I knocked up in the lathe.  The spindle is drilled to take some Oilite sintered bronze bushes and a 6mm spindle.

I’m not too pleased with these either.  the colour indicated that I over heated the steel…. Pah   Functionally they are fine…. just not made a well as I hoped