Picking up from where I left Part 1 this next phase of the diff hanger fabrication is perhaps the most critical aspect as it involves mounting the hanger to the engine cradle perfectly in-line with the front engine sprocket.
I had figured out in my head that I would use some rose joints and an adjustable link bar as the upper mount. The link bar would allow me to shorten or lengthen mount which would effectively raise or lower the diff thus adjusting the tension of the chain.
The first job was making some tabs for the rose joint to attach to. I cut some 3mm flat-bar into 30mm lengths, clamped them together and drilled a 8mm hole using a drill press. The centre of the hanger was marked and the tabs were tacked so that the rose joint centre lined up with the hanger centre line.
I purchased some M10 rose joints from eBay (note. M10 is the thread size. The eyelet through hole is M8) a left-hand thread and right-hand thread. I also purchased some weld-in inserts, again left and right handed threads.
As pictured here I welded a nut between the two inserts. The theory being I could use a spanner to turn the link bar once fitted to the car however, this made the overall length of the link too long so I later ground the welds down and welded the two inserts together. I might make another one later with a slightly better design.
rear sprocket alignment & mounting
With the rose joint bolted to the diff hanger I needed to find a way to line the rear (big) sprocket up with the front sprocket. I checked the thickness of both sprockets with a vernier caliper finding that they were the same so mounting something straight to one side of the sprockets as a guide would result in them being in-line.
I grabbed a piece of wood and clamped it to the front sprocket. I then supported and clamped the rear sprocket to it also so I could tack the cradle rose joint tab to the cradle.
Everything lined up well and the rose joint has some adjustability in it so I can tweak the position for mis-alignment quite easily.
Checking driveshaft position
As I mentioned above, I made the link bar a little shorter by removing the nut I had previously tacked into place.
Next, I bolted up the subframe so that I could check the diff position and the driveshaft position. I used some steel tube that fitted the output covers quite well as a substitute for the driveshaft.
Overall the diff position is fairly good. It will need to be higher so that I have some adjustment on the upper rose joint link. I will achieve this but shortening the hanger bracket by 10-20mm.
The rear sprocket clearance on the subframe is good also. I cut the section out so I could have plenty of room during fabrication. I plan to add some steel back in to reduce the hole size and add some strength back in.