Found Loose Cylinder Bolt

[Greg Hopp]

On preflight I noticed a little oil seeping around the bolt on the
pilot's front cylinder (Superior Milleniums). This is on a '67 C150
w/ the Continental O200. I grabbed the bolt and turned it @ 2 1/2
times until it was finger tight against the cylinder.

Partner and I have grounded the plane. The gents hanging out at the
FBO say, put a wrench on her and fly the darn thing. We'd prefer to
stay safe, legal and alive.

Anyone else experience this and what am I in for? Thanks folks.

Greg

[jls]

"Greg Hopp" > wrote in message
om...
> On preflight I noticed a little oil seeping around the bolt on the
> pilot's front cylinder (Superior Milleniums). This is on a '67 C150
> w/ the Continental O200. I grabbed the bolt and turned it @ 2 1/2
> times until it was finger tight against the cylinder.
>
> Partner and I have grounded the plane. The gents hanging out at the
> FBO say, put a wrench on her and fly the darn thing. We'd prefer to
> stay safe, legal and alive.
>
> Anyone else experience this and what am I in for? Thanks folks.
>
> Greg

Yeah, use a torque wrench and tighten it to its lower or middle torque limit
and go fly. Check the torque on the rest of the nuts too. You should be
tightening a nut instead of a bolt. There are two sets of torque values on
those nuts because they go on bolts (or studs) of two different diameters.
AN5 and AN6? You're probably going to have to use a special wrench for the
torque wrench to connect to, but there should be plenty of those around to
borrow. There are here.

[Jay Honeck]

> Partner and I have grounded the plane. The gents hanging out at the
> FBO say, put a wrench on her and fly the darn thing. We'd prefer to
> stay safe, legal and alive.
>
> Anyone else experience this and what am I in for? Thanks folks.

Were all the bolts lose, or just one?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Tina Marie]

In article >, Greg Hopp wrote:
> Partner and I have grounded the plane. The gents hanging out at the
> FBO say, put a wrench on her and fly the darn thing. We'd prefer to
> stay safe, legal and alive.

Don't just crank it down with a wrench! In general, every bolt connecting
everything to your engine has a proper torque. A lot of those torque settings
are way lower then you'd think, and you can overtorque things easily.

With that said, you have two choices here:

A) Put a torque wrench on it, tighten it and then fly it. Torque
settings are in the Lycoming Direct Drive Overhaul Manual (~$17 for a
reprint from Aircraft Spruce, or find the equivalent Continental
publication). Check it every few hours.

B) Take it to your A&P. He will pull out his torque wrench, his copy
of the Lycoming Direct Drive Overhaul Manual, tighen it, and tell you
to check it every few hours.

It's up to you.

Tina Marie
Tripacer N3653P
--
http://www.tripacerdriver.com "...One of the main causes
of the fall of the Roman Empire was that, lacking zero, they had no way
to indicate successful termination of their C programs." (Robert Firth)

[Ben Jackson]

In article >,
Greg Hopp > wrote:
>On preflight I noticed a little oil seeping around the bolt on the
>pilot's front cylinder (Superior Milleniums).

A guy across the hanger row from me lost a cylinder in flight on a
relatively new (60-70 hour) engine. Looking at the studs it appeared
that one bolt had been lose and backed off, allowing the other 3 to
shear off. I'd be looking at what kind of damage might have happened
to the adjacent studs while the bolt was loose.

--
Ben Jackson
>
http://www.ben.com/

[Dave Stadt]

"Ben Jackson" > wrote in message
news:jMcYb.46366$uV3.92300@attbi_s51...
> In article >,
> Greg Hopp > wrote:
> >On preflight I noticed a little oil seeping around the bolt on the
> >pilot's front cylinder (Superior Milleniums).
>
> A guy across the hanger row from me lost a cylinder in flight on a
> relatively new (60-70 hour) engine. Looking at the studs it appeared
> that one bolt had been lose and backed off, allowing the other 3 to
> shear off. I'd be looking at what kind of damage might have happened
> to the adjacent studs while the bolt was loose.

What kind of engine only has three studs/bolts holding the cylinder on?
OBTW nuts go on studs not bolts.

>
> --
> Ben Jackson
> >
> http://www.ben.com/

[jls]

"Dave Stadt" > wrote in message
...
>
> "Ben Jackson" > wrote in message
> news:jMcYb.46366$uV3.92300@attbi_s51...
> > In article >,
> > Greg Hopp > wrote:
> > >On preflight I noticed a little oil seeping around the bolt on the
> > >pilot's front cylinder (Superior Milleniums).
> >
> > A guy across the hanger row from me lost a cylinder in flight on a
> > relatively new (60-70 hour) engine. Looking at the studs it appeared
> > that one bolt had been lose and backed off, allowing the other 3 to
> > shear off. I'd be looking at what kind of damage might have happened
> > to the adjacent studs while the bolt was loose.
>
> What kind of engine only has three studs/bolts holding the cylinder on?
> OBTW nuts go on studs not bolts.

There would be six nuts holding each of four cylinders down on an O-200
Continental, the standard engine on a Cessna 150. IIRC, 2 are AN5 and 4
are AN6, i. e., the stud diameters are 5/16" and 3/8" respectively. I
watch my nuts, you should pardon the expression. They have anti-sabotage
paint on them and palnuts are even better. Torque is often not enough to
hold them from backing off, and they certainly do not have (and are not
supposed to have) lockwashers under them.

>
> >
> > --
> > Ben Jackson
> > >
> > http://www.ben.com/
>
>

[Orval Fairbairn]

In article >,
Tina Marie > wrote:

> In article >, Greg Hopp wrote:
> > Partner and I have grounded the plane. The gents hanging out at the
> > FBO say, put a wrench on her and fly the darn thing. We'd prefer to
> > stay safe, legal and alive.
>
> Don't just crank it down with a wrench! In general, every bolt connecting
> everything to your engine has a proper torque. A lot of those torque settings
> are way lower then you'd think, and you can overtorque things easily.
>
> With that said, you have two choices here:
>
> A) Put a torque wrench on it, tighten it and then fly it. Torque
> settings are in the Lycoming Direct Drive Overhaul Manual (~$17 for a
> reprint from Aircraft Spruce, or find the equivalent Continental
> publication). Check it every few hours.
>
> B) Take it to your A&P. He will pull out his torque wrench, his copy
> of the Lycoming Direct Drive Overhaul Manual, tighen it, and tell you
> to check it every few hours.
>
> It's up to you.
>
> Tina Marie
> Tripacer N3653P

According to my Lycomung Overhaul Manual, the cylinder torque settings
are:

1/2" base nuts: 600 in-lb (50 ft-lb)

3/8" base nuts: 300 in-lb (25 ft-lb)

Tightening sequence: (1/2" first)

On the O-235, tighten as if you have 1/2" bolts, too

1/2" 3/8"

4 1 4 1

3 2 3 2

[Paul Sengupta]

"Orval Fairbairn" > wrote in message
.
...
> Tightening sequence: (1/2" first)

This is something I was thinking of. What happens if one comes loose?
Should you just tighten it to thee correct torque, or should the others be
loosened then all tightened in sequence? Maybe even replacing the
gasket? (don't know about gaskets...I would only guess as to the
presence of one)

Paul

[Dennis O'Connor]

90% of engineering is common sense and only 10% is an incredibly complex
science... Luckily the first 90% is what keeps common machines running, and
that last 10% is reserved for machinery like the space shuttle, mars
explorer, etc..
denny
"
The gents hanging out at the
> > > FBO say, put a wrench on her and fly the darn thing.

[Greg Hopp]

"Jay Honeck" > wrote in message news:> Were all the bolts lose, or just one?

As for what we could visualize, just the one bolt appears loose. The
mechanic who installed the jugs has said: "I torqued them to
specification and have the paperwork to prove my wrench is correct."
He has advised us to tighten it up and see if will seat and stay
tight.

If not, the engine comes apart to helicoil the receiving end for the
thru bolt, is what I'm told.

Greg Hopp

[Greg Hopp]

Tina Marie > wrote in message >...
> With that said, you have two choices here:
>
> A) Put a torque wrench on it, tighten it and then fly it. Torque
> settings are in the Lycoming Direct Drive Overhaul Manual (~$17 for a
> reprint from Aircraft Spruce, or find the equivalent Continental
> publication). Check it every few hours.
>
> B) Take it to your A&P. He will pull out his torque wrench, his copy
> of the Lycoming Direct Drive Overhaul Manual, tighen it, and tell you
> to check it every few hours.
>
> It's up to you.
>
> Tina Marie
> Tripacer N3653P

The on-field mechanic says, from a liability standpoint, he's going to
crack and retorque each and every nut on all four jugs. 8-10 hrs
labor. Another (off field) mechanic says, if the nut won't tighten,
we're into a whole different issue wherein the case will need to be
split, sent out and the threads repaired (helicoil?) inside the case.
Now, what is otherwise a simple job costs a couple grand for the labor
alone.

Greg H.
Cols, OH

[Greg Hopp]

Orval Fairbairn wrote in message:
> According to my Lycomung Overhaul Manual, the cylinder torque settings
> are:

Thanks for your help Orval. We're going to the hangar tomorrow night
with a borrowed torque wrench for some testing.

Greg H.
Cols, OH

[Habah Fongoula]

The torque should have been checked after 25 or 50 hours. Your
mechanic should have specified this. Instead he throws meaningless
certifications at you. If he's studious enough to have his wrenches
checked, why didn't he tell you about retorquing, or even use a bit of
torque seal on the nuts? In any event, stop crying, have the cylinder
retorqued (all the nuts/bolts) use torque seal and have them rechecked
and torqued in 25 hours.

On 17 Feb 2004 07:10:45 -0800, (Greg Hopp) wrote:

>"Jay Honeck" > wrote in message news:> Were all the bolts lose, or just one?
>
>As for what we could visualize, just the one bolt appears loose. The
>mechanic who installed the jugs has said: "I torqued them to
>specification and have the paperwork to prove my wrench is correct."
>He has advised us to tighten it up and see if will seat and stay
>tight.
>
>If not, the engine comes apart to helicoil the receiving end for the
>thru bolt, is what I'm told.
>
>Greg Hopp

[Habah Fongoula]

On 17 Feb 2004 09:48:06 -0800, (Greg Hopp) wrote:

>The on-field mechanic says, from a liability standpoint, he's going to
>crack and retorque each and every nut on all four jugs. 8-10 hrs
>labor. Another (off field) mechanic says, if the nut won't tighten,
>we're into a whole different issue wherein the case will need to be
>split, sent out and the threads repaired (helicoil?) inside the case.
>Now, what is otherwise a simple job costs a couple grand for the labor
>alone.
>
>Greg H.
>Cols, OH

8 to 10 hours? Does this guy have only one eye and one hand. Ditch
this nit-wit, he's setting up to pay you off with your ow money.

1 - 2 hours to remove and reinstall cowl and baffling

1 - 2 hours to retorque all the nuts with coffee breaks

SHOP THIS WITH OTHER MECHANICS!

[Dan Thomas]

"Paul Sengupta" > wrote in message >...
> "Orval Fairbairn" > wrote in message
> .
> ..
> > Tightening sequence: (1/2" first)
>
> This is something I was thinking of. What happens if one comes loose?
> Should you just tighten it to thee correct torque, or should the others be
> loosened then all tightened in sequence? Maybe even replacing the
> gasket? (don't know about gaskets...I would only guess as to the
> presence of one)
>
> Paul


Some of those nuts are on studs that pass through the case to hold
it together and to keep the main bearings tight in their bores. A
loosened stud could allow the bearing to rotate a bit if it didn't
have a locating pin in it. Can't remember if the O-200 has one. I know
that the Lycs do. I've seen a centre main rotate in an O-200 while the
cylinders were off and someone rotated the prop. Everything jammed
real tight when we retorqued it.
Rotated bearings cut off their oil supply ports and don't last
long.

Dan

[Dan Thomas]

(Greg Hopp) wrote in message >...
> On preflight I noticed a little oil seeping around the bolt on the
> pilot's front cylinder...

What kind of oil does this pilot contain? Is it red?

Dan

[Greg Hopp]

"Paul Sengupta" wrote in
> Should you just tighten it to thee correct torque, or should the others be
> loosened then all tightened in sequence? Maybe even replacing the
> gasket?
> Paul

Paul:
The first mech. I talked to was adamant. It was his butt on the line
liability wise, and if I wanted him to do the job, he was going to
break all the nuts and retorque everything, estimating 8-10 hrs labor.
He also mentioned a "one time seal" that would then likely be a leak
candidate as a result, but he wasn't going to do it any other way.

Greg H.
Cols., OH
"First timer, always learning"

[Roy Smith]

In article >,
"Gene Kearns" > wrote:

> On 17 Feb 2004 18:02:35 -0800, (Greg Hopp) wrote:
>
> >"Paul Sengupta" wrote in
> >> Should you just tighten it to thee correct torque, or should the others be
> >> loosened then all tightened in sequence? Maybe even replacing the
> >> gasket?
> >> Paul
> >
> >Paul:
> >The first mech. I talked to was adamant. It was his butt on the line
> >liability wise, and if I wanted him to do the job, he was going to
> >break all the nuts and retorque everything, estimating 8-10 hrs labor.
> > He also mentioned a "one time seal" that would then likely be a leak
> >candidate as a result, but he wasn't going to do it any other way.
> >
> >Greg H.
> >Cols., OH
> >"First timer, always learning"
>
> Greg, the issue isn't with your mechanic's assessment of the work to
> be done. The real issue here is, does it take 2+ hours to torque a
> cylinder? I'm pretty meticulous, but 15 minutes a nut is quite a
> bit... over the top.
>
> There are issues here, however, where the prevailing torque of
> rotating the prop pre- and post- torque should be assessed, but
> still... 8-10 hours to accomplish this job in a thorough and
> professional manner is highway robbery....
>

I'm going to be a bit cynical here....

Was the guy with the 8-10 hour estimate the guy who last worked on the
plane? Maybe he was intentionally over-estimating in the hopes that you
would go find somebody else to do the work. Then the last person to
sign off on your engine would be somebody else and if something went
wrong he would be off the hook liability-wise.

[John]

Your first mechanic is an idiot but he is going to give you the shaft
for HIS error.
There is some difference in the break away torque of a bolt that has
sat with a preload on it and one that you are tightening to a
specified torque. It takes MORE torque than that specified to start
the nut turning if that nut has sat with a preload for more than a
second. You can be assured that if the nut turns when the specified
torque is applied then it is NOT torqued to the specified amount and
needs to be loosened and retorqued.

The most common cause of cylinder bolts getting loose is PAINT or dirt
under the cylinder flange.

These bolts are critical and must have the required torque.

If you loosen only one nut at a time you should not have to replace
the seal but if you loosen all of the nuts at the same time then there
is a good chance that it will leak because the cylinder will move.

On 17 Feb 2004 18:02:35 -0800, (Greg Hopp) wrote:

>"Paul Sengupta" wrote in
>> Should you just tighten it to thee correct torque, or should the others be
>> loosened then all tightened in sequence? Maybe even replacing the
>> gasket?
>> Paul
>
>Paul:
>The first mech. I talked to was adamant. It was his butt on the line
>liability wise, and if I wanted him to do the job, he was going to
>break all the nuts and retorque everything, estimating 8-10 hrs labor.
> He also mentioned a "one time seal" that would then likely be a leak
>candidate as a result, but he wasn't going to do it any other way.
>
>Greg H.
>Cols., OH
>"First timer, always learning"

[Greg Hopp]

(Dan Thomas) wrote in message > > On preflight I noticed a little oil seeping around the bolt on the
> > pilot's front cylinder...
>
> What kind of oil does this pilot contain? Is it red?
>
> Dan
Dan, not sure what you're getting at here...anyway, partner and I did
go out and lay a wrench on the offending bolt tonight. Just at this
time the on-field A&P showed up and together we tightened the nut
down, looking carefully to see of the bolt began to back out. It did
not. That's good news to us.

So, taking advice from here and elsewhere, we are going to test fly it
Saturday, check for proper torque, then go on a short hop, test again,
then keep an eye on it until we pull the cowling and check all the
nuts we can visualize.

Thanks for all the comments, the first year or so of ownership has
been very educational.

Best,

Greg Hopp
N4691X

[jls]

"Gene Kearns" > wrote in message
...
> On 18 Feb 2004 17:13:51 -0800, (Greg Hopp) wrote:
>
>
> >
> >So, taking advice from here and elsewhere, we are going to test fly it
> >Saturday, check for proper torque, then go on a short hop, test again,
> >then keep an eye on it until we pull the cowling and check all the
> >nuts we can visualize.
> >
>
> >Best,
> >
> >Greg Hopp
> >N4691X
>
> Greg, I'd suggest getting and using some torque putty. You can mark
> the nuts, studs, etc. with this and monitor conditions more easily.
>

Good idea. You can find it cheap from the suppliers. Preferred here is
orange paste, called Torque-Seal --- Anti-Sabotage Inspector's Lacquer.