Today's Message Index:
----------------------
1. 12:35 PM - O-470 (BobbyPaulk@comcast.net)
2. 01:06 PM - Re: O-470 (FLYaDIVE)
3. 01:54 PM - Re: O-470 (Monty Barrett Sr)
Message 1
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A friend has an O-470-M on a Bearhawk and it has a oil consumption rate of a quart
per hour. It was worse than this before he honed the cylinders and installed
new rings. He also lapped the valves while it was down. He has 35 hrs. on the
new rings and still on mineral oil. Can anyone tell me what may be wrong or
what we can do to slow down the oil consumption.
Message 2
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Bobby:
Without seeing the engine and the cylinder bore I can only guess...
I'm guessing three (3) things;
1 - That the Cross-Hatch pattern in the cylinders are honed away.
2 - That he used the wrong Rings... Chrome Cylinders get steel rings.
Steel cylinders get chrome rings.
3 - Rings put in up-side down.
You can visually inspect with a bore scope for the hatch pattern.
Trying to figure out what rings were uses can only be done by reading the
paperwork for the order placed. And hopping that the correct rings were
supplied.
And if the rings were installed up-side down - - - Pull the cylinder off.
Barry
On Thu, May 3, 2012 at 3:35 PM, <BobbyPaulk@comcast.net> wrote:
> A friend has an O-470-M on a Bearhawk and it has a oil consumption rate of
> a quart per hour. It was worse than this before he honed the cylinders and
> installed new rings. He also lapped the valves while it was down. He has 35
> hrs. on the new rings and still on mineral oil. Can anyone tell me what may
> be wrong or what we can do to slow down the oil consumption.
>
> *
>
> *
>
>
Message 3
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If the top compression ring is upside down it won't go together. This
ring is 1/2 keystone ( tapered on one edge ). Bottom ring wide edge
faces up. Part numbers also go up. However, I have seen rings marked
wrong.
If chrome cylinders FLYaDIVE is correct. Never-Chrome on Chrome. IF
they are chrome they will not have a cross hatch.
If they are chrome they will either be fractured chrome ( channel chrome
) or " Cermi-Chrome ". They could also be Nickel-silicon ( Cermi-Nil
). The same statement about ring face material applies.
I would have a real good look at the pistons, particularly the ring
grooves. Rings have to seal there also. Cylinders can also get out of
round in the ring travel and also " washboard ". Caused from too much
heat and is usually the result of poor baffling.
Monty Barrett
Barrett Precision Engines, Inc.
-----Original Message-----
From: owner-continental-list-server@matronics.com
[mailto:owner-continental-list-server@matronics.com] On Behalf Of
FLYaDIVE
Sent: Thursday, May 03, 2012 3:06 PM
To: continental-list@matronics.com
Subject: Re: Continental-List: O-470
Bobby:
Without seeing the engine and the cylinder bore I can only
guess...
I'm guessing three (3) things;
1 - That the Cross-Hatch pattern in the cylinders are honed
away.
2 - That he used the wrong Rings... Chrome Cylinders get steel
rings. Steel cylinders get chrome rings.
3 - Rings put in up-side down.
You can visually inspect with a bore scope for the hatch
pattern.
Trying to figure out what rings were uses can only be done by
reading the paperwork for the order placed. And hopping that the correct
rings were supplied.
And if the rings were installed up-side down - - - Pull the
cylinder off.
Barry
On Thu, May 3, 2012 at 3:35 PM, <BobbyPaulk@comcast.net> wrote:
A friend has an O-470-M on a Bearhawk and it has a oil
consumption rate of a quart per hour. It was worse than this before he
honed the cylinders and installed new rings. He also lapped the valves
while it was down. He has 35 hrs. on the new rings and still on mineral
oil. Can anyone tell me what may be wrong or what we can do to slow down
the oil consumption.
st"
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