An M.G. Locost Build
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September 5, 2016
Itís a Wrap

We are still greatly enjoying the amazing performance of our freshly rebuilt engine, and almost as much our ability to go from stoplight to stoplight without adding oil. We did change the oil and filter at around 500 miles, based on ancient break-in rules that suggest that after 500 miles the oil will be contaminated with tiny particles of piston rings. And actually, if we looked close enough, we think we could even see the tiny particles clinging to the dipstick. Or maybe not, but the oil was definitely starting to get a little hazy, so we're glad we changed it.

  Oil with tiny bits of piston rings
click to enlarge

Now that we're not buying oil every other day, we've switched from O'Reilly house brand 20W50 at $4/quart to expensive Valvoline VR1 racing oil. A total waste of money no doubt, but still way cheaper than the $20 a week we were spending on oil before the refresh. The best oil for an M.G. is a never-ending debate on the Internet, and whatever brand you use you're going to get flamed. The heart of the debate usually centers around zinc additives, a controversy having all the hallmarks of an Internet myth dating back to some GM cars of the sixties.

We're pretty sure we're using enough zinc. We have 1200 miles on the new engine, and it just keeps getting stronger. We actually started to wonder how such a small difference in the pistons could make such a huge difference in power. We estimated our compression ratio on paper went from 8:1 to 9:1, a 12% increase, but the increase in torque feels like more. A lot more. It didn't make sense. So we asked about it on the M.G. Experience website, and found out that the shallow dish pistons we bought are actually shallower than the old 8.8:1 shallow dish pistons.

So our compression ratio now is apparently more like 9.5:1, which is great but still doesn't explain why the new engine has so much more power. The best we can figure at this point is that our old engine was a lot worse off than we thought. You couldn't tell by looking, but the compression rings must've been as badly worn as the scrapers. Compression on that engine might've been as low as 7:1. We used to think it ran pretty well, but it's obvious now we were just being fooled by the car's light weight. The old engine was a dog.

New bonnet draped in 3M Scotchcal  
click to enlarge

With all of the miles we've been putting on the car lately, we got tired of looking at our bare aluminum hood a lot faster than we had originally anticipated. We still haven't decided which technology we're going to use to paint it yet, so as a temporary fix we wrapped the hood in vinyl, specifically 3M's Scotchcal automotive film in Dark Green. The same thing the racers use. At least some of them. Wrapping the hood turned out to be a fairly simple job, requiring only two pieces of vinyl and a single seam, along with a small selection of Band-Aids for the usual X-Acto cuts.

The vinyl film doesn't have the same high-gloss finish we've come to expect from paint, but at least it eliminated our least favorite automotive task, waiting for paint to dry. 3M's Dark Green is a shade darker than the Rustoleum Hunter Green on the rest of the car, and actually we like the 3M color a little betteróit makes the Hunter Green look kind of fadedóbut it's okay for now. We rushed the wrapping job in a few places, so it's not perfect, which gives us all the incentive we need to replace it soon. Or maybe not soon, but eventually.

  When finished, vinyl wrap looks similar to paint
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For now the hood looks okay in photographs, if you're really careful with the lighting and you take the picture from an angle low enough to get some reflection off the vinyl, simulating gloss. Black edging around the valve cover and carburetor holes gives the hood a more finished appearance, and as a bonus we filled in the yellow stripe, trimming it slightly for the engine cutout. We're not sure the stripe is 100% straight, or actually we are sure, but it still looks way better than the old stripe that went up and over the giant box of a hood scoop.

About that scoop. We've decided now that we're not totally against making a new scoop for the hood. The valve cover sticking up doesn't look so bad, but the tubes and pipes and cables that run across it look kind of industrial, i.e. the opposite of sleek. Of course the new scoop would have to be low and round and almost invisible, and we'd prefer it was made out of something other than fiberglass, like for example aluminum. As you might imagine, this isn't likely to happen in the near future. Or the far future. But we're not totally against it.

Unusual failure mode for a rocker switch  
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The weather has been hot for a while now, but our Locost cooling system has been up to the task, keeping the temperature gauge mostly steady and the coolant where it belongs, all very important for our new engine. The only casualty of the heat so far has been the fan switch, which crumbled one afternoon when we went to turn it off. We're not sure why, but possibly the plastic was weakened by sitting in the sun too long. The good news is, the switch failed in the ON position, so we still had a working fan while we waited for the new switch to arrive.

  Cockpit cover not wedged under a car
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In order to protect the new fan switch, and possibly other dashboard components as well, we started using the cockpit cover we made for the car last summer. Back then we were pretty excited about the cover, mostly because it actually fit the car, but also because it did a pretty nice job of keeping the interior from frying, so long as it wasn't too windy. If it was, the cover would blow off the car, and we'd generally find it lying nearby, possibly wedged under another car in the parking lot or more likely clinging desperately to one of the side mirrors.

Moderate breeze not visible in this photo  
click to enlarge

Part of the problem was that we never got around to attaching any hold-down straps to the cover. We'd just drape it over the roll bar and windshield, tuck the mirrors into the pockets, and hope for the best. Not too effective. We eventually ordered a length of elastic cloth that we could use for making straps, but by the time it arrived we had pretty much lost interest in searching for the cover in parking lots, and had stopped using it. Then the weather turned cool for the winter, and we relegated the cover to a cabinet in the garage, where we quickly forgot about it.

This year, in a rare act of imagination and foresight, or at least rare for us, we found the cover in the garage and sewed on elastic straps, one on each side. The straps hook under the rear fenders, using thin pieces of aluminum sewed into the straps and bent into the shape of hooks. While we were at it, we sewed the last of the raw edges, giving the cover a much more finished appearance. Not that it looks any better after these upgrades, but it stays on the car in a moderate breeze, which is all we ask.


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