3 months later .....
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, 20th November 2009 at 16:12 (2795 Views)
It’s been a while since I posted any progress (3 months) – mainly due to there being very little! I appear to have been always ‘busy’ and away from the garage lately. Some shed time last weekend moved things along more.
I’ve had a set of brackets welded into the inner or the cone allowing me to drill and tap them so the end caps may be bolted in from the rear. I then bent and welded a bit of 5mm steel rod to the end cap forming a neat seal with the front cone, plus this will act as a base for the reverse cone to be welded to.
Next was to form a pair of reverse cones for the end caps. The hardest part of this was getting the size of the cone right. I’d used a few internet formulas but the cones never ended up the size/shape I wanted so I resorted to tried and true paper forming until I had the shape I wanted. There is a bag of cardboard rejects under the bench …… And a metal one after cutting it out, forming it and deciding it was not ‘right’.
The end cones were cut out of 1.5mm plate with my good old Black & Decker jigsaw, then carefully hand rolled over a piece of pipe. A quick zap with the welder to join them and I grabbed my trusty hammer and former to roll the edges over. These cones will be welded to the rod and everything ground down for a clean finish.
I’ve also welded a couple of threaded mounting tabs to the inlet end of the pipes so I can bolt on an alloy heat shield which hide the muffler mounting clamps. One heat shield is 90% finished (Mark II shield), the other a cardboard template ……
With the dollar up against the US I got on the net and shouted myself a set of stainless steel cores. These spunky units are 40% holes, weigh almost nothing and appear identical to the cores used by a couple of the big brand systems. It’s a shame no one will see them!
So I’m almost done. Hopefully some shed time this weekend will allow me to finish the end cones and the next pictures should be of at least one complete unit!
A quick weigh-in on the scales shows I’ve saved exactly 1 kg per muffler with the new ones – an added bonus.