REFLECTOR: Engine troubles

[Glenn Babcock]

I had a similar problem, but with 2 out of 4 jugs.  After lots of screwing around I pulled the offending jugs and valves.  The valve seats were corroded.  

I'm an A&P and have rebuilt my share of engines, but like you I didn't have the right parts (and tools) to do the job.  I sent mine off to Don George (http://dongeorgeaircraft.com/) and he turned them around in a few days.  You can have just the valves done or get the complete job with honing, rings, etc.  I went with the complete job, about $400 a jug.  

He told me that it was moisture that caused this.  I highly recommend fabricating plugs for your cooling intakes, especially if you have downdraft cooling.  At rest the engine will hold some valves open, and moisture will gather on the seats.  Don is in Florida and they see this all the time.

Regards,
Glenn


On Mar 7, 2012, at 8:57 PM, Mike Dawson wrote:

> It is my understanding that you never perform a compression check on a cold motor.
> Make sure it is hot. Then try it.
> 
> Michael E Dawson
> ATCI CFII
> 
> 
> On Mar 7, 2012, at 5:32 PM, Geoff Gerhardt <geoff at thegerhardts.com> wrote:
> 
>> Some of you might remember a few weeks ago, after taking my first taxi I did a full run up and found my static was low.  After doing some troubleshooting, I found a couple issues - an intake leak and a faulty electronic ignition box.  My Light Speed ignition box is off to Klaus at Light Speed Engineering to be fixed.
>> 
>> During the process of checking the timing/ignition, I noticed that when I was trying to find #1 TDC by putting my thumb over the spark plug hole to check when it was on a compression stroke, I was not feeling much pressure.  So, I recently did a compression check.  The numbers were dismal. All were low: #1 - 10/80, #2 - 20/80, #3 - 24/80, #4 - 10/80.  All were leaking copiously past the intake valve.  Exhaust valves sounded tight, some leakage could be heard past the rings.  I took the intake pipe off #1 and put my fingers behind the valve and could feel the air rushing past.  Not sure why its so bad.  Looks like the guy who sold it to me (an A&P and Velocity owner) is either a terrible A&P or dishonest.
>> 
>> Can someone tell me my options?  My preference would be to rebuild it myself (I've rebuilt many engines, most recently a Porsche 911 - pretty similar!), so I'd look forward to it.  The drawback of that is time.  I could probably tear it down in day, but I suspect sending stuff out for inspection and acquiring all the necessary parts might take awhile.  What are my options for the cylinders?  Send the out for rebuild?  New?  How much $ are we talking?
>> 
>> The other option would be to send it to a rebuilder - definitely be more expensive, but do they have relatively quick turn around times?
>> 
>> Geoff
>> 
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