Denny wrote:
: I have not used the flexible cutter you listed in the URL... I have
: reamed a number of valve guides over the years... My experience has
: been that you will find a combination of carbon / lead salt deposits
: and slight warpage (sometimes not so 'slight')... So, the straight
: reamer at the nominal 0.4985" size will do the best job... It will
: remove deposits and ream out the tight spots inside the bore...
: Your mechanic knows best, but my suggestion is to do it by hand with a
: Tee handle - and lots of muscle... The thought of using a drill motor
: may be attractive, but in less than experienced hands it can wreck the
: guide and then you will have to have the jug pulled and repaired...

Good to know. I will try to locate that sized reamer. I hope I can get the
stem out the bottom plug hole to clean it if it's gunked up.

: There is still nothing stopping you from first putting solvent down the
: guide bores, fresh oil, AVBLEND + MMO, and flying it... Less work and
: cost than reaming the guides and doesn't do anything that can't be
: undone...
: Local FBO and I did this to his rental Skyhawk recently when it
: suddenly stuck an exhaust valve and almost cost him a a 100 hour block
: rental from customer who needed to scout a number of factory sites
: across the southland over a 4 week time period, leaving the very next
: morning... This was big bucks down the drain if the airplane couldn't
: go the next morning...
: A large spray can of WD-40 (only thing we had on hand that night) and a
: quart of MMO in the oil saved him a valve job... The ol hawk came back
: still humming along... Old chinese adage, "Softly, softly, catchee
: monkey"..

My only thought on that is that it's an intermittent problem. Doesn't happen
repeatably, and when it does it happens to be right when there's no negotiation
allowed.... right after takeoff. Aside from a day/weekend worth of work, I'm thinking
that taking it out and cleaning it is the right way. There seems to be more than the
usual amount of OWT/circumstantial evidence supporting useage of MMO as preventative
measure. I'm generally skeptical of such snake oil, but I could see how it's possible
to help some.

-Cory

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* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
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