Monday, May 26, 2008

Mechanical abuse

Or....how to waste about $600 in a week.

Recently, after having replaced the piston/liner/rod in my off-road buggy engine (OS.21VZB V-Spec), I went to the track to do a spot of tuning. After having some real trouble trying to get a consistent run out of it, I started to attack the track with a little too much enthusiasm (read: hitting all the jumps at full noise). At some point, most likely during one of the rather heavy landings, the air filter popped off the engine (that's bad, mmmkay?) and I did around 6 or so laps sucking all manner of dirt/grit into my nice new piston/liner :-( Scratch $125 worth of parts right there.

Not to be dissuaded from my current addiction to all things R/C, I put a new piston/liner/rod (which I had on hand for just such an occasion) in the engine and ran it in. Now, it should be noted at this point that it seemed to run faultlessly throughout the entire running in procedure. Revved out exceptionally well after run in and idled like a dream. All good, right? Wrong.

I put the car away until race day on Sunday, at which point I couldn't get it to run. It would start ok, but then wouldn't rev out. Then, after it got hot, it wouldn't idle. Then, it wouldn't start at all. So, after missing the start of my heat, I went back to my pits and pulled the engine out to have a closer look at it. After blowing it off with the compressor, I found a nice crack running along the entire bottom of the crankcase :-( That's also bad, mmmkay? Scratch another $125 worth of piston/liner/rod, plus a crankcase. Basically, that means a replacement engine, at around $400 or so.

Turns out when I replaced the first piston/liner/rod, I neglected to check the crank pin on the bottom end. A fellow racer gave me the tip after I displayed my newly destroyed crankcase to all and sundry in an attempt to share the grief. When I got it home, I stripped the engine down completely and checked the crank pin with another V-Spec engine I have. Sure enough, it's nowhere near the right size/shape anymore. Looks like it's been letting the bottom of the rod contact the case and....well....the rest is history :-(

Bugger.

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