REFLECTOR: Engine troubles

[Mike Dawson]

I agree with Mark. If the bottom end is still in good shape, do a top overhaul.
Unfortunately, cylinder heads come in many forms. Factory new, used, ceramic, plated and fake!
Many can be rebuilt. I am a factory new kinda guy. Your mileage may differ.

Michael E Dawson
ATCI CFII


On Mar 7, 2012, at 6:05 PM, Geoff Gerhardt <geoff.gerhardt at gmail.com> wrote:

> 
> Mike: I did it both warm and cold earlier in the week with a different compression tester and got similar results.  Today, I did it cold with an aviation-spec compression tester.  While I agree that slightly different numbers could be had cold/warm - these are terrible numbers.
> 
> John: Yes, I agree - I can't understand how they could all be bad.  I took the valve cover off #1 just to check that at TDC, the lifter was not holding the valve up - there was a bit of play in the rocker indicating that both the intake and exhaust valves should have been fully seated and no force was being put on them by the lifters.
> 
> Geoff
> 
> On Wed, Mar 7, 2012 at 8:57 PM, Mike Dawson <medawson250 at yahoo.com> 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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