C90 wisdom needed

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ffg
Posts: 41
Joined: Sun Jan 27, 2008 8:43 pm

Post by ffg » Wed Jun 03, 2009 2:28 pm

Thank you all very much! Very helpful information!

Well, the news is not as bad as it might be.

We fitted a new oil filter and re-oiled. Ran up the engine to operating temp: the oil pressure fell ominously as before. Suddenly, after about 10 minutes, the oil pressure reading snapped back to the 'normal' range and stayed there! We are relieved! and suspect a sticking oil pressure release valve.

We then checked compressions and found two cylinders with almost no readable compression and one other slightly down.

A steady stream of air from the oil breather when testing the 2 defective cylinders, so we now plan a top overhaul of all cylinders, though we will be open to Geoff's suggestion about rings lining up - it was certainly a sudden event.
032561
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Colin Dix
Posts: 25
Joined: Wed Jun 25, 2008 9:46 am

Post by Colin Dix » Sat Jun 06, 2009 6:40 pm

David & I stripped the Cylinders off the engine this morning. All Pistons had rings stuck in the groove, some a bit, others completely stuck and not working. The bores looked in good condition. Were sending them to Ronaldson Airmotive for honing, and collect new pistons seals etc for the re-build.

The rings were stuck due to carbon build up, does anyone know what causes this? Are we using the wrong type of oil, maybe David can let us know the type,

BTW, we fitted a oil return kit recently, this amounts to 1/2" diameter tubing of around a meter long, angled up to the rear of the firewall, then dowd and out at the bottom of the cowl. We checked the pipe, and its clean inside with no sludge build up. Does anyone else have experience of this type of oil return kit?

Thanks

Colin
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tnowak
Posts: 506
Joined: Wed Jan 02, 2008 11:00 am

Post by tnowak » Mon Jun 08, 2009 8:05 am

A friend of mine with a C90 has the oil return arrangement you describe. Hasn't had any issues with it and works as advertised.
Tony Nowak
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Colin Dix
Posts: 25
Joined: Wed Jun 25, 2008 9:46 am

Post by Colin Dix » Mon Jun 08, 2009 8:25 am

Thanks Tony,

I'm pleased to hear that, I just wondered if the tube length increased the crank case pressure slighty and may have contributed to our problem.

Cheers,

Colin
tnowak wrote:A friend of mine with a C90 has the oil return arrangement you describe. Hasn't had any issues with it and works as advertised.
Tony Nowak
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Rob Swain
Posts: 393
Joined: Tue Jan 08, 2008 2:11 pm

Post by Rob Swain » Mon Jun 08, 2009 1:58 pm

mike newall wrote:The guys in the States [rebuild engines] all the time and provided you follow the manuals and get good supervision, there really isn't a big deal about it - only the ingrained British backward attitude to aviation.
Hear, hear!

Echoes my sentiments regarding the nonsense of being able to build a VW, almost making it up as you go along, but not being able to rebuild a Lyco or TCM which have definitive specifications and manuals to follow.
Rob Swain
If the good Lord had intended man to fly, He would have given him more money.
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Colin Dix
Posts: 25
Joined: Wed Jun 25, 2008 9:46 am

Post by Colin Dix » Sat Jun 13, 2009 8:48 pm

We stripped the engine last saturday, delivered the part to Ronaldson Airmotive on Sunday, collected the refurbished cylinders, new pistons, gudgen pins, gaskets wednesday, today we re-assembled the engine, it run up really good. We have had a 30 minute test flight, now were signed off and ready to fly again. Great job!

Thanks all for your help! Come and see us at the Croft Farm Air day next weekend!

P.S, Ronaldson Aviation are a really good company to deal with!


Rob Swain wrote:
mike newall wrote:The guys in the States [rebuild engines] all the time and provided you follow the manuals and get good supervision, there really isn't a big deal about it - only the ingrained British backward attitude to aviation.
Hear, hear!

Echoes my sentiments regarding the nonsense of being able to build a VW, almost making it up as you go along, but not being able to rebuild a Lyco or TCM which have definitive specifications and manuals to follow.
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David Hardaker
Posts: 70
Joined: Fri Jan 04, 2008 6:18 pm
Location: Yorkshire

C90

Post by David Hardaker » Sat Jun 13, 2009 10:33 pm

Colin
Now you know where the missing 150 rpm went from your static power check !
:D
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Colin Dix
Posts: 25
Joined: Wed Jun 25, 2008 9:46 am

Re: C90

Post by Colin Dix » Sat Jun 13, 2009 11:37 pm

For sure!


David Hardaker wrote:Colin
Now you know where the missing 150 rpm went from your static power check !
:D
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G.Dawes
Posts: 279
Joined: Wed Jan 02, 2008 11:00 am

Post by G.Dawes » Wed Jun 17, 2009 8:59 pm

:D
Glad it was OK but if you haven't already done it open the pressure relief valve and clean out the, muck, swarf or whatever, that might be there.
It may come back and frighten you again.
Cheers,
Graham
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Colin Dix
Posts: 25
Joined: Wed Jun 25, 2008 9:46 am

Post by Colin Dix » Wed Jun 17, 2009 9:12 pm

G.Dawes wrote::D
Glad it was OK but if you haven't already done it open the pressure relief valve and clean out the, muck, swarf or whatever, that might be there.
It may come back and frighten you again.
Cheers,
Graham
Thanks Graham, we will do that!

Cheers

colin
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