2 September 2019

Actual Midlana content!

With the hillclimb coming up, there’s a few chores to take care of, with finally fabricating a replacement engine cover being the first. Longtime readers will recall that repositioning the intercooler to the top of the engine compartment meant that the previous nice clean engine cover no longer fit; believe me, I tried. The new cover is two-piece to surround the intercooler core, and to be removable. As mentioned before, the engine cover buys time by keeping flames out of the passenger compartment in the event of an engine bay fire.

I forgot that months (years?) ago, I’d starting taping paper templates to the back of the old engine cover to figure out sizing and where to separate the two, so starting with them saved some time. Anyway, it took me back me back in time to making the various aluminum panels on Midlana, which included relearning various fabrication tips, like “make sure to apply pressure to the¬†riveter away from the panel so that when the rivet stem snaps, the tool doesn’t leave a scratch.” Oops. The pictures pretty much step through the details.

I again want to mention how great yellow iridite (also known as “Bonderite” or “Alodine”) is on aluminum, as it’s an excellent way to prep for paint. The two part solution degreases, etches, and protects the metal (with no treatment, aluminum feels oily). Paint sticks way better with it, and best of all, it’s all done at room temperature and applied via either dipping or brushing the parts, then rinsed off with ordinary water.

The riveted-on green vent panel was removed from the old engine cover and reused. There is some concern that engine compartment cooling may be limited by now having both upper and lower covers. Also unclear is whether the right-hand side vent should be opened up. The left side was always open, originally for the side-mounted intercooler. The right vent was to feed air to an oil cooler, but was never implemented (the engine uses an oil-to-coolant heat exchanger instead). Anyway, easy enough to try it.

I chose to go with ordinary flat black paint instead of the metallic green, mostly because I’m lazy, and also because the dark green is so close to black that the two colors won’t jump out as an obvious mismatch. Still on the to-do list is painting the intercooler end tanks and side plates.

The weather this year is been surprisingly mild; we’ve only run the A/C a few times, so with it being September, there was some talk that SoCal might avoid the usual heat. Hah. The wise old farmer’s advice about, “the first week of September is always the hottest” has proven astonishingly accurate again. Right to the day, hot humid weather moved in and chased me out of the garage a bit early. Sweating is okay up to a point, but when I keep drinking liquids with no need to run to the house, that’s enough for the day.

In other news, parts for the electronic lead screw are showing up, but nothing much to show until more parts are here. Oh, and in other news, 7/8-8 left-hand Acme thread (a very odd thread!) was ordered to replace the worn cross feed screw in the lathe. Though the old lead screw hasn’t be removed yet, it’s clear that it’s worn because when backlash is set to “reasonable” in the middle of its travel, it binds up towards both ends. Backlash is a very subjective thing; some people are fine with a fair bit, and some are not. I’m somewhere in the middle.