Bad cylinder

[Denny]

It turns out that the fouled plug I mentioned last week is oil
fouled... I suspect that the rings have gone... I will borescope the
cylinder for damage and check the seal on the intake valve stem, but I
suspect the worst... It is burning a quart every 1.5 hours, suddenly...

And the story gets complicated... The engine is roughly 1500 smoh...
The cylinders are old reruns... The case/crank is ~ 1958 manufacture
with nearly 6000 hours in the log book... It is unlikely that Lycoming
would take it for core credit... So the options are (in decreasing
cost):

Factory New (How much? I see, umm, let me get back to you on that.)

Factory rebuild - unlikely to get core credit, so total cost about $25k
+ labor

Field overhaul (my mechanic refuses to OH engines anymore so I will
have to ship)
~$9K base cost plus parts that won't make it - I'm guessing $15K +
If I remove the engine I will have the mount overhauled, new hoses,
etc...

TOH with 4 new Titan cylinders - ~$4K plus Shipping and Labor

1 new Titan cylinder - ~$1K plus S&L

Overhaul the cylinder - maybe $500 total...

Overhauling one cylinder gets you into RCR ( russian cylinder
roulette)...
Both the mechanic and I agree this is not the best route, but it is the
cheapest initially... He wants a factory reman to hang, of course...
The issue with changing out one cylinder is if one cylinder is gone at
1500 hours, how long before the next one, etc...

Doing a TOH at 1500 hours doesn't initially seem cost effective, but it
is where I am leaning... The bottoms on 320 150HP engines will, in my
experience, go lots longer than the 2000 hour recommended overhaul...
If I can get another 1000 hours out of the bottom (2500 total), which
is possible, both I and the airplane will likely be retired from flying
for other reasons...

decisions, decisions... daaayum...

denny

[[email protected]]

: Both the mechanic and I agree this is not the best route, but it is the
: cheapest initially... He wants a factory reman to hang, of course...
: The issue with changing out one cylinder is if one cylinder is gone at
: 1500 hours, how long before the next one, etc...

: Doing a TOH at 1500 hours doesn't initially seem cost effective, but it
: is where I am leaning... The bottoms on 320 150HP engines will, in my
: experience, go lots longer than the 2000 hour recommended overhaul...
: If I can get another 1000 hours out of the bottom (2500 total), which
: is possible, both I and the airplane will likely be retired from flying
: for other reasons...

: decisions, decisions... daaayum...

Your "broken ring" theory sounds likely. There are a few issues that may crop
up and modify the decision. What I would do is the following:

- Borescope all the other jugs and verify only one is burning lots of oil.
- Look *carefully* around the exhaust bosses and spark plug holes of all of the jugs.
- Pull off the oil filter/screen and take a look inside. See what you find, and how
much of it is aluminum/steel, etc.
- Rig up a jig for a dial indicator on the valve pushrods

If it's a 1500 hour engine, the bottom end should be in good shape still...
unless the cam's eaten itself (thus the dial indicator). If there's nothing in the
oil filter, even better indication that nothing bad is going on on the bottom end.
There may be some gunk for the jug that blew the ring.

What may have caused the ring to die? Low octane or lean mixture?

There's nothing inherently wrong with a jug going bad after awhile...
particularly heat-related cracks. That's no real reason to go down the slippery slope
of:
"If I overhaul/exhange one jug, should I do them all for a TOH?"
"If I'm going to overhaul, maybe I should buy new?"
"If I'm going to do a top overhaul, maybe I should split the cases and do the whole
thing?"

Pull off the bad jug, take a looksee (including the cam lobes you can see from
pulling off one jug). If it's just a blown ring and there's nothing visibly wrong
with the jug, put a set of rings on it, hone it, and throw it back together. You may
have to replace the piston.

In any event, I wouldn't let a cracked ring push you to an overhaul if
everything else is in good shape. Removing all four jugs is *almost* 4x the work of
removing just one. Splitting the case and doing the bottom is a LOT more work and
expense.

-Cory


--

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

[Mike Rapoport]

Mike Busch has an article on Avweb where he discusses this topic. His
conclusion seems to be to repair/replace only the affected cylinder. If you
repair the cylinder for $500, it only has to last a short while to be more
cost effective than the other options. The conclusion seems to be based on
the assumption that the failure of one cylinder does not indicate that the
others are about to fail..

Mike
MU-2

"Denny" > wrote in message
oups.com...
> It turns out that the fouled plug I mentioned last week is oil
> fouled... I suspect that the rings have gone... I will borescope the
> cylinder for damage and check the seal on the intake valve stem, but I
> suspect the worst... It is burning a quart every 1.5 hours, suddenly...
>
> And the story gets complicated... The engine is roughly 1500 smoh...
> The cylinders are old reruns... The case/crank is ~ 1958 manufacture
> with nearly 6000 hours in the log book... It is unlikely that Lycoming
> would take it for core credit... So the options are (in decreasing
> cost):
>
> Factory New (How much? I see, umm, let me get back to you on that.)
>
> Factory rebuild - unlikely to get core credit, so total cost about $25k
> + labor
>
> Field overhaul (my mechanic refuses to OH engines anymore so I will
> have to ship)
> ~$9K base cost plus parts that won't make it - I'm guessing $15K +
> If I remove the engine I will have the mount overhauled, new hoses,
> etc...
>
> TOH with 4 new Titan cylinders - ~$4K plus Shipping and Labor
>
> 1 new Titan cylinder - ~$1K plus S&L
>
> Overhaul the cylinder - maybe $500 total...
>
> Overhauling one cylinder gets you into RCR ( russian cylinder
> roulette)...
> Both the mechanic and I agree this is not the best route, but it is the
> cheapest initially... He wants a factory reman to hang, of course...
> The issue with changing out one cylinder is if one cylinder is gone at
> 1500 hours, how long before the next one, etc...
>
> Doing a TOH at 1500 hours doesn't initially seem cost effective, but it
> is where I am leaning... The bottoms on 320 150HP engines will, in my
> experience, go lots longer than the 2000 hour recommended overhaul...
> If I can get another 1000 hours out of the bottom (2500 total), which
> is possible, both I and the airplane will likely be retired from flying
> for other reasons...
>
> decisions, decisions... daaayum...
>
> denny
>

[Newps]

Mike Rapoport wrote:

> Mike Busch has an article on Avweb where he discusses this topic. His
> conclusion seems to be to repair/replace only the affected cylinder. If you
> repair the cylinder for $500, it only has to last a short while to be more
> cost effective than the other options. The conclusion seems to be based on
> the assumption that the failure of one cylinder does not indicate that the
> others are about to fail..

I have had cylinder problems too. Fix the bad one and fly.

[TripFarmer]

Personally I wouldn't play Russian Roulette. I wouldn't throw
money away with the TOH with 1500 SMOH and 6000 on the engine.
I did a TOH last year but I had 900 SMOH and 2900TT.


Trip

In article . com>, says...
>
>It turns out that the fouled plug I mentioned last week is oil
>fouled... I suspect that the rings have gone... I will borescope the
>cylinder for damage and check the seal on the intake valve stem, but I
>suspect the worst... It is burning a quart every 1.5 hours, suddenly...
>
>And the story gets complicated... The engine is roughly 1500 smoh...
>The cylinders are old reruns... The case/crank is ~ 1958 manufacture
>with nearly 6000 hours in the log book... It is unlikely that Lycoming
>would take it for core credit... So the options are (in decreasing
>cost):
>
>Factory New (How much? I see, umm, let me get back to you on that.)
>
>Factory rebuild - unlikely to get core credit, so total cost about $25k
>+ labor
>
>Field overhaul (my mechanic refuses to OH engines anymore so I will
>have to ship)
>~$9K base cost plus parts that won't make it - I'm guessing $15K +
>If I remove the engine I will have the mount overhauled, new hoses,
>etc...
>
>TOH with 4 new Titan cylinders - ~$4K plus Shipping and Labor
>
>1 new Titan cylinder - ~$1K plus S&L
>
>Overhaul the cylinder - maybe $500 total...
>
>Overhauling one cylinder gets you into RCR ( russian cylinder
>roulette)...
>Both the mechanic and I agree this is not the best route, but it is the
>cheapest initially... He wants a factory reman to hang, of course...
>The issue with changing out one cylinder is if one cylinder is gone at
>1500 hours, how long before the next one, etc...
>
>Doing a TOH at 1500 hours doesn't initially seem cost effective, but it
>is where I am leaning... The bottoms on 320 150HP engines will, in my
>experience, go lots longer than the 2000 hour recommended overhaul...
>If I can get another 1000 hours out of the bottom (2500 total), which
>is possible, both I and the airplane will likely be retired from flying
>for other reasons...
>
>decisions, decisions... daaayum...
>
>denny
>

[[email protected]]

TripFarmer > wrote:
: Personally I wouldn't play Russian Roulette. I wouldn't throw
: money away with the TOH with 1500 SMOH and 6000 on the engine.
: I did a TOH last year but I had 900 SMOH and 2900TT.

So you would overhaul then? I'd say take a look at the avweb article
mentioned a few posts back (I *knew* I'd read something to get that mindset). Figure
some economics assuming TBO:

1500 hours -> 2000 hours is 500 hours of "normal" service.
Swap rings in 1 jug: 3-5 hours of labor, $50 in parts minimum, $1500 maximum (if one
buys a new jug/piston)
Complete top: ^ multiplied by 4
Complete overhaul: $10-15k
500 hours @ $10/hour = $5k "left" in the engine.... definately worth a few jug swaps.

-Cory


--

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

[[email protected]]

This engine isn't too grand anyway you look at it. It is a great
example
of why one should go to the till once in awhile to get newer parts thru
a factory reman.

Another option: If there's nothing busted, just keep running it.
Check the
spec for oil consumption on the type certificate data sheet. If you
are under
it, you are OK.

You can put a lot of oil in for a cyl overhaul.

I had a 520 that was a quart in three then two for a long time. It was
a pig
but there wasn't really anything wrong with it.

Bill Hale

[Denny]

Just a follow up... The waters are getting murky...
Flew the plane to my mechanic... This gave us a hot engine for an
immediate compression check on the suspect cylinder.. 73/80...
No out of round cylinder here and no audible blow by in either the
exhaust or crankcase... hmmm...
Could be a broken oil ring but the replacement spark plug I put in
after finding the oil fouled plug, is clean and dry and firing just
fine after 3.5 hours of flight time... hmmm...
A check of the other 3 bottom plugs reveals them to be free of oil, but
two appear to be running lean and we suspect an air leak ... hmmm...
So, where's the oil going all of a sudden? WIth the other cowling off
I check the oil separator bottle... Almost empty... hmmm...
(I won't elaborate on the oil separator, it uses a quart Mason jar and
separates the oil mist from the crankcase and the wet vacuum pump -
unless you are really old you have never seen anything like it.)

So the brain storming started... the belief at this time is that:
1. a failed bottom plug oiled up because it was not firing
and was simply a coincidence, whilst
2. a new induction leak is causing the lean cylinders to burn oil
we suspect that the induction leak is in the oil pan

The plan at this point is to fly the plane at 23/24 on full rich and
measure the oil burn and fuel burn on each engine... Then fly it
leaned and recheck the oil burn and fuel burn on each engine.... This
is baseline info...
Once that is accomplished we will pull the bottom cowl (major job
involving disassembly of the air intake system, which is why it waits
on the flight test) then ground run it using a can of carb cleaner as a
probe to see if we can find a leak...

Good thing I own an airplane otherwise I would NEED a hobby to use up
all that excess time and money I have...

denny

[Orval Fairbairn]

In article . com>,
"Denny" > wrote:

> Just a follow up... The waters are getting murky...
> Flew the plane to my mechanic... This gave us a hot engine for an
> immediate compression check on the suspect cylinder.. 73/80...
> No out of round cylinder here and no audible blow by in either the
> exhaust or crankcase... hmmm...
> Could be a broken oil ring but the replacement spark plug I put in
> after finding the oil fouled plug, is clean and dry and firing just
> fine after 3.5 hours of flight time... hmmm...
> A check of the other 3 bottom plugs reveals them to be free of oil, but
> two appear to be running lean and we suspect an air leak ... hmmm...
> So, where's the oil going all of a sudden? WIth the other cowling off
> I check the oil separator bottle... Almost empty... hmmm...
> (I won't elaborate on the oil separator, it uses a quart Mason jar and
> separates the oil mist from the crankcase and the wet vacuum pump -
> unless you are really old you have never seen anything like it.)
>
> So the brain storming started... the belief at this time is that:
> 1. a failed bottom plug oiled up because it was not firing
> and was simply a coincidence, whilst
> 2. a new induction leak is causing the lean cylinders to burn oil
> we suspect that the induction leak is in the oil pan
>
> The plan at this point is to fly the plane at 23/24 on full rich and
> measure the oil burn and fuel burn on each engine... Then fly it
> leaned and recheck the oil burn and fuel burn on each engine.... This
> is baseline info...
> Once that is accomplished we will pull the bottom cowl (major job
> involving disassembly of the air intake system, which is why it waits
> on the flight test) then ground run it using a can of carb cleaner as a
> probe to see if we can find a leak...
>
> Good thing I own an airplane otherwise I would NEED a hobby to use up
> all that excess time and money I have...
>
> denny


There could be a reason for the bad plug. Pull the cowl and check the
"cigarette" leads at the plugs for crud, streaking, carbon. This
condition will cause misfiring and poor performance. You can pull the
cigarettes loose and clean the insides (and the insulation) with either
denatured alcohol or lacquer thinner.

[David Lesher]

"Denny" > writes:

>Once that is accomplished we will pull the bottom cowl (major job
>involving disassembly of the air intake system, which is why it waits
>on the flight test) then ground run it using a can of carb cleaner as a
>probe to see if we can find a leak...

On cars, a propane torch tank and head, sometimes with an added
hose, are used to find vacuum leaks... and it makes no mess.


--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

[Mike Noel]

You guys are braver than I am. No way I would stand just behind that
spinning prop spraying anything at the intake manifold.


"David Lesher" > wrote in message
...
> "Denny" > writes:
>
> >Once that is accomplished we will pull the bottom cowl (major job
> >involving disassembly of the air intake system, which is why it waits
> >on the flight test) then ground run it using a can of carb cleaner as a
> >probe to see if we can find a leak...
>
> On cars, a propane torch tank and head, sometimes with an added
> hose, are used to find vacuum leaks... and it makes no mess.
>
>
> --
> A host is a host from coast to
> & no one will talk to a host that's close........[v].(301) 56-LINUX
> Unless the host (that isn't close).........................pob 1433
> is busy, hung or dead....................................20915-1433

[Denny]

Good advice Orville, and the group should take notice...
In this case the cigarettes are clean, plug wires are the same age as
the plugs, just over 400 hours... I did say 500 hours in a previous
post but a look at the logs revised that (memory must be going - umm
what were we talking about?)...
After Steve the mechanic and I went over the engine I ran it at 75%
power and full rich on the way home... It ran like a little bear...
Dunno, it's got me puzzled...
I'm a bit of a fanatic on maintenance, which has me really PO'd at
this problem, *^&%#@$! mutter, mumble.... And the jury is still out
on the oil burn... I may yet be overhauling an engine (ugh)
Anyway, 16 Autolite Annie's are on the Brown Truck as I write this... I
did consider going to Platinum at twice the price, but decided that
changing out the plugs twice as often was the better choice... The
existing plugs will be shipped for reconditioning and stashed on the
shelf...
As long as I am pontificating on maintenance, a new battery is also on
the Brown truck... The one in the plane has two Michigan winters on
it.. It goes up on the bench on a trickle charger as a back up... I
do not have starting problems, even at zero degrees F...
And y'all are using AVBLEND every other oil change, right? Gotta keep
them Lycoming valves from sticking...
And, this next annual, the mags go out for rebuild (over 500 hours on
them this go around)... I do not have starting problems...

denny

[Montblack]

"Denny"
> And y'all are using AVBLEND every other oil change, right? Gotta keep
> them Lycoming valves from sticking...


Would half as much AVBLEND every oil change be akin to changing plugs twice
as often?

> I did consider going to Platinum at twice the price, but decided that
> changing out the plugs twice as often was the better choice...


Montblack

[Denny]

I suspect it would...
The annoying part was I quit using AVBLEND because I was using 15W50
which is spoz to have good stuff in it... Stuck a valve and went back
to AVBLEND...

On the other comment on propane, propane works but I can't see the
propane being sucked in, I can with carb cleaner...

On the prop - ya gotta chock the bird and be careful...

[Jay Masino]

Denny > wrote:
> I suspect it would...
> The annoying part was I quit using AVBLEND because I was using 15W50
> which is spoz to have good stuff in it... Stuck a valve and went back
> to AVBLEND...

Aeroshell 15w50 has the Lycoming anti-scuffing agent in it, not Avblend.

--- Jay



--
__!__
Jay and Teresa Masino ___(_)___
http://www2.ari.net/jmasino ! ! !
http://www.OceanCityAirport.com
http://www.oc-Adolfos.com

[Montblack]

("Jay Masino" wrote)
> Aeroshell 15w50 has the Lycoming anti-scuffing agent in it, not Avblend.


http://www.avblend.com/faq/faq.html

How does the Lycoming anti-scuffing agent work vs. Avblend?

What is a "National Aviation Parts Association" store equivilant for both?


Montblack

[David Lesher]

"Denny" > writes:

>On the other comment on propane, propane works but I can't see the
>propane being sucked in, I can with carb cleaner...

Ahh, it's not seeing....it's listening at idle. When you find a
vacuum leak with the propane probe, the engine suddenly runs
smoothly...

>On the prop - ya gotta chock the bird and be careful...

I do admit that blasted cooling fan out front make life a lot harder..

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

[Mike Rapoport]

"Denny" > wrote in message
oups.com...
> shelf...
> As long as I am pontificating on maintenance, a new battery is also on
> the Brown truck... The one in the plane has two Michigan winters on
> it.. It goes up on the bench on a trickle charger as a back up... >
> denny
>

The brown truck brought my new battery on Wednesday to replace the three
year old one. One can buy a lot of $130 batteries for the cost of having a
singel one flown into the Idaho backcountry!

Mike
MU-2
Helio Courier