Tuesday, July 24, 2007

Still at it

Parts, finally

It's about bloody time the new valve and the cam alignment tool arrived. Nice of them to turn up the week I have final exams from the Summer semester.

So far, reassembly has consisted of lapping the valves in. This is simple, mating up the valves and their seats, using some grinding compound to ensure a good seal between the two. This eliminates one potential source of compression loss (the other being the piston rings, and I'm not in the mood to haul the rest of the engine out for that anytime soon. Besides, compression test pressures are supposed to be 165 psi plus or minus ten. The good cylinders clocked in at 160 when I checked it out in the process of troubleshooting, which consisted of long periods of screaming and cursing in the driveway punctuated by moments of clarity in which I performed simple, sensible mechanical checks.

The neighbors think I'm batshit insane after my recent activities in the driveway, but at least I haven't had to shell out a few grand to have some mechanic make a mess of the repair.

Valve lapping is nice and easy. Once the valve is seated, with a liberal amount of compound applied to the seating surface, one only has to rotate it back and forth for a couple of minutes. The best way to do this is to attach a suction cup to the valve and run it between your hands as if trying to light a fire. I'm sure that some people just chuck the valve stem into a drill and let a drill do all the work, but I have more confidence in results achieved by hand. It's possible with power tools to wear down the seating surfaces too much.

I would post pictures, but Blogger isn't permitting uploads at the moment. Turds.

No comments: