The Heat Muff DL-05 came with very good instructions but the fit was not tight. I enlarged the end plate holes to #28 but still it rotated. I contacted the supplier (Rick Robbins) and he advised me to enlarge to no more than #27. It still rotated.
I was then advised to flute the inboard flange of the endplates to try and shrink the inside diameter. It appeared to work and the muff did not rotate. I then noticed that the rods/nuts were off set by about 30 degrees. I undid the nuts/clamps and starightened the rods and it still rotated. I reset back to the 30 degree offset and found it was secure so I left it at that. Looks like my number 1 pipe is slightly undersize at 1.735"
Post note 2013 at 48 hours - top end caps disappeared as rods sheared at SS nuts. Recommend to keep rods straight and not overtighten locknuts. Spoke to Rick and he suggested SS shim between inside of end plate and exhaust. I used the1/2" SS straps Vans supply for supporting 2" ducting as it was unused - 2" peice.
I have fitted an extra clamp at the bottom of the muff on the exhaust pipe - wire locked. Should the muff become lose the clamp will stop it slipping down the exhaust and interfering with the throttle arm.
It was suggested by another builder to put some steel wool inside the muff to improve the surface area contact with the heat/incoming air so I'll give that a try.
I also fitted a DL-04 90 degree elbow to the outlet to make the SCAT duct routing easier to clear the alternator cable.
Please note the first photo is only a temporary fit to be continued/
