With Wings As Eagles: Car/Mechanical Entries

The pressure's on

2011 September 26 09:37

Instead of flying, I stayed home yesterday, because I've been busy a lot lately and it was nice to have a day to work on the car.

Before driving, I did a bunch of stuff in the garage and adjustments to the engine. I have a relatively cleared work bench. I've collected together all the parts that I want to have in my spare set for long-distance driving, and all the VW tools are packed back in the tool box. I have a spare distributor which I was going to pre-time. My plan was I'd leave the distributor cap with the spark plug wires hooked up, and change out the rest of the distributor. However, it turns out that the notches in the distributor bodies are on different sides, so to do that I'd have to unplug all the spark plug wires, which is a pain, so I didn't bother. If I need to swap in the distributor, I'll have to statically time it, which will be fine.

I checked the valve clearances. Given my past problems with valves drifting, I was rather worried when cylinder #1 had much higher clearance than spec; it was like .014 inches rather than .006. The clearance getting larger is the natural way the engine wears, and is not indicative of a problem (clearance getting smaller is a big danger sign), so it's not catastrophic, bit a bit worrying since I just set them 600 miles ago when I assembled the engine. HOWEVER, cylinder #2 was similarly out of spec in the benign direction. Going to measure #3 (now on the opposite side of the engine), I've never hoped so much that a measurment would be out of spec. But cylinders #3 and #4 were similarly out, so I can only conclude that this is a symptom of the brand new pushrods settling in. I'll have to check it again in a thousand miles and hopefully it will remain stable.

I also wanted to run the engine for a while to get it to operating temp. I made sure the carb was adjusted properly. While I had the engine hot, I decided to spend some time and do an oil pressure test. When I re-built the top half of the engine, I replaced the oil pump because the old one was worn and had been put together by an idiot. I bought an entirely new pump, blueprinted the gears and body, sanded and polished the cover plate, and then installed it.

When I got the car, the oil light flickered at idle when the engine was hot. This is a sign that something in the oil system is worn; it's usually a combination of the main engine bearings wearing out and/or the oil pump. I did an oil pressure test; it was definitely out of spec. The test is:
30-weight oil, oil at 70 degrees C, 2500 rpm
new engine, oil pressure should be 42 psi; wear limit is 28 psi
Before the engine rebuild:
30-weight oil at 62 deg C, 2500 rpm, pressure was 18 psi
Since the rebuild, the oil light has never flickered at all, so I knew I had improved things drastically, but I didn't know how much. My test yesterday:
30-weight oil at 67 deg C, 2500 rpm, pressure was 42 psi
So it's well above wear limits, which is great, but it's nearly up to new spec. That's awesome! That long Monday Night Football game I spent sanding the (cast iron) cover plate until it was smooth was worth it!

I also drove the car yesterday to run errands. This was the first drive out of the driveway with the electronic ignition, which seems to be working stably. Yay!