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I’ve been working on sound treatment on the Z and I’ve been planning from the start to hit the tail light area with sound absorbing foam. Reason is that due to the shape of the car, sound frequencies will accumulate there and project straight back out at the driver like a trumpet horn. Especially low level frequencies that contribute to droning. So I have cut out a piece of acoustic foam and stitched it onto the tail light cover panel with acoustically transparent fabric. The idea is that troublesome droning frequencies will be funneled down there by the shape of the cabin, pass through the fabric, and then get absorbed rather than project back out. I took it for a test run today and I swear it make a huge difference. Prior to adding the foam, the engine getting very woofy at around 4.5k rpm. Like it would go RrrraaaaaaaaaaWWWWHWHWHaaa. I know it’s not to do with the exhaust or engine cause the woofy sound isn’t there from the outside. Now with the foam it goes Rrraaaaaaaaaaaaaaa all the way up. Pics here of what I did, execution can be cleaner, I need to iron it and tighten it up but there it is.

weather will be good. I just saw a heap of trophies Gordon made for the day. (courtesy of GM push rods engine technolody)

With the head back at LCR, it needed to be assembled. 240Z's came with an oil 'spray bar' that bolts to the side of the camshaft towers, that sprays oil onto the camshaft lobes. This is a poor design as the tiny tube and orifices' can easily block up with gunk and worse, the bar itself can fracture over time & fall into the cambox... Nissan fixed this later in the bigger 2.8ltr engine (L28) with an internally oiled camshaft. Thankfully Les had enough junk L28 heads in stock, so the cam towers from one were used on the E31 head, as they are a direct swap. Because the top and bottom head faces had been decked, a set of cam tower shims were installed to bring the camshaft 'wipe' back into the correct geometry. Next a suitable camshaft was fitted. As the engine is relatively stock, we didn't want to go to wild. The grind is from Clive Cams, and is a direct copy of a Wade 733a. It's very very mild with just a tad more lift and duration over a stock grind cam. Unfortunately the original valve springs were worn out so a good set of used L28 valve springs were installed, along with new thicker lash pads/caps and refaced rockers. It was all reassembled, checked and pronounced good to go - it's almost a shame to put the tappet cover back on! The tappet cover was also given the Hydro-blast treatment.