Wednesday, May 7, 2014

Engine Woes (Whoas?)

Those of you who have following the blog for awhile knew that a big plan was that I was building up a proper race engine for this season.  Not to create a high-hp monster, but something that was tuned up nicely, perhaps getting a few more ponies to keep those damn SVs in sight.
After the long winter I had the engine complete.  Totally rebuilt from top to bottom, new lightened and balanced crank, new pistons and rings, refinished cylinders, and a ported and polished head.
Back in the bike and installed, I was running it though some gentle heat cycles in the weeks before the trip to MAM in order to get it ready for the track.  About 8 days before departure, after another heat cycle (never revving the bike past 6000 rpm), I decided I'd better take the machine for a short trip around the block.  Just exiting the driveway, the bike started to run very poorly, and seemed to act like it was running lean.  Wheeling it back in the barn, with just over a week before we were going to leave, I decided to put the stock engine back in, and figure out the problem with the engine later.  To be honest, I thought I had really screwed up somewhere, and made a mistake with assembling something.
I finally had a chance to look at what went wrong, and here is what I found...  by all accounts, I've dropped a valve.  One of the exhaust valves on the #1 cylinder is "stuck" open, which explains the lean condition the bike started to exhibit before I was able to shut it down.  Note as well the 2 divots near the stuck valve.  It appears pieces of the piston embedded themselves in the combustion chamber.

Another view -- note that the damaged combustion chamber is "cleaner" (less soot) than the undamaged one.  The droplets and moisture is coolant.  No failure, just leftover from the disassembly as I pulled the head off an immediately took the pic.

The other end -- the top of the stuck valve.  Nothing broken, but the valve collet retainer must have slipped out of the channel where it is normally retained...

When I removed the bucket, these two pieces were loose -- the spring retainer and the spring.  The valves are stock, and the springs are higher tension aftermarket to prevent float.  I guess I am glad that the failure doesn't appear to be my fault.  The engine was assembled correctly, the valve was just dodgy.  To his credit, Rick at RLR (who did the head work) emailed me and said he is sending me a new valve and new piston free of charge.  A fair deal, considering he really can't be responsible for a part failure either.  So, I'll be running a stock engine this year; 'ol faithful is back in the frame, running like a top.  I need to think on what to do next -- the head needs to be repaired, the piston replaced, and the rods inspected (doubtful they had any damage...)  Regardless, this is going on the backburner for awhile.  Good news is I'm off to Motorsports Park Hastings in a few weeks for another trackday just before the start of the MRA season.  Weather in Manitoba has been awful, so some warmer temps, good company, AND bikes is a great recipe for some fun!