Today's Message Index:
----------------------
1. 04:44 AM - Re: Re: Housai engine question: compression check (Greg Wrobel)
2. 04:55 AM - Re: Re: Housai engine question: compression check (Mark Pennington)
3. 07:17 AM - Re: Re: Housai engine question: compression check (Justin Drafts)
4. 02:02 PM - Re: Re: Housai engine question: compression check (Justin Drafts)
5. 06:53 PM - Re: Re: Housai engine question: compression check (Anthony Savarese)
6. 10:00 PM - Re: Re: Housai engine question: compression check (Walter Lannon)
Message 1
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| Subject: | Re: Housai engine question: compression check |
Sticking valves happen. We have all had them. The danger is when you let
them go you may eventually burn the valve and then you have another issue
to deal with. When you pull through in a perfect world you should not hear
any air coming from exhaust or carb. Sometimes a small amount may come
through and after a flight it should normally go away if not, then you need
to address it with a rubber mallet, or spinning the valve (lapping). We can
get into discussing Marvel Mystery Oil in the fuel and/or oil but that is
another bag of opinions
Greg "Clouddog" Wrobel
On Thu, Apr 29, 2021, 21:34 Justin Drafts <draftsjust417@gmail.com> wrote:
> Ok helpful gents and engine experts-
> A fruitful sunny day spent @ hangar with the suspect cylinders.
>
> Checked the small starting air valve: definitely in good working order and
> closing as appropriate.
>
> Pulling off rocker covers and watching the rocker arm and valve springs, I
> see there is
> no gap at TDC between the rocker arm and top of the spring /stem for
> cylinders #2 and #3.
>
> Just so I'm understanding valve lash / clearance correctly:
> - the 0.010-0.014" clearance mentioned is supposed to be here at the red
> circle in the
> attached pic, correct? (While the stem is at its highest point of
> travel/valve fully seated/TDC...)
> -adjusting this clearance/lash requires turning the large adjustment screw
> at the green arrow, correct?
>
> Based on the air I hear escaping the exhaust stack, I suspect the exhaust
> valves are sticking or
> otherwise remaining open.
>
> Not sure how I went from great compression #'s last year to 0/80 psi this
> year, but very little surprises
> me in maintenance anymore.
>
> Thoughts gents?
> Thanks- Justin
>
> On Thu, Apr 29, 2021 at 5:09 AM A. Dennis Savarese <
> dsavarese0812@bellsouth.net> wrote:
>
>> dsavarese0812@bellsouth.net>
>>
>> Also check the the air injector to make sure it is fully closed. It
>> too
>> has a very small valve inside of it about the size of a pencil eraser.
>> If the little valve spring is broken or the valve remains open, it will
>> of course affect the compression test.
>> Dennis
>>
>> A. Dennis Savarese
>> 334-546-8182
>> www.yak-52.com
>>
>> On 4/28/2021 11:58 PM, Justin Drafts wrote:
>> > Good evening all-
>> >
>> > A conundrum for you Housai engine experts; I need some advice to go fwd.
>> > Doing the compression check today, I hit a weird wall.
>> >
>> > With a partner I was checking cylinders starting with #1 at top, going
>> > CW when viewed from cockpit.
>> > All #'s were good (avg 75/80 psi), until I got the last cylinder, #2.
>> > We got 0 psi on the pressure gauge.
>> >
>> > Checking the pressure tester/gauges/fittings/hose, all are fine and
>> > perfectly functional.
>> >
>> > So we double checked the previous cylinder, which had just 10 min
>> > prior tested at 74/80 psi.... now it also
>> > showed 0/80 psi. ??
>> > No obvious air leaks from oil breather, carburetor, or exhaust stack;
>> > no oil evident at bases of the cylinders;
>> > the exhaust and intake stacks are good condition. I had flown the
>> > plane earlier in the day w/o any negative
>> > indications.
>> >
>> > Pulled the valve covers off to find the rocker arms, springs, etc in
>> > great condition, doing their job when we
>> > slowly turned the prop thru by hand.
>> >
>> > Stuck valves?
>> >
>> > We tried the "rope trick" to slip a nylon cord into the cylinder thru
>> > the open sparkplug hole, then gently run
>> > the piston up to TDC to try to reseat the possibly stuck-open valves.
>> > As yet, no help.
>> >
>> > Fishing for advice & thoughts... what are we missing?
>> > I've never seen a 0/80 psi reading... a bad piston ring or bad valve,
>> > should have SOME psi indication 30~60psi.
>> >
>> > Thoughts? Pointers?
>> > Thanks---
>> >
>> > Justin Drafts
>> > N280NC
>>
>>
>>
>> ==========
>> List" rel="noreferrer" target="_blank">
>> http://www.matronics.com/Navigator?Yak-List
>> ==========
>> FORUMS -
>> eferrer" target="_blank">http://forums.matronics.com
>> ==========
>> WIKI -
>> errer" target="_blank">http://wiki.matronics.com
>> ==========
>> b Site -
>> -Matt Dralle, List Admin.
>> rel="noreferrer" target="_blank">http://www.matronics.com/contribution
>> ==========
>>
>>
>>
>>
Message 2
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| Subject: | Re: Housai engine question: compression check |
Justin
You are right about adjusting the valves. You photo is accurate.
I would talk to someone at length about the step by step procedure if you
haven=99t done that yet. How you use the feeler gauge is important.
As
taught to me by others.
I would suggest fix the sticking valve before you adjust anything. I am
sure you are aware of that info.
And Yes. MMO is a very wide and varied discussion for sure. Me, I drink a
pint before every flight. LOL.
Mark
N621CJ.
On Fri, Apr 30, 2021 at 7:48 AM Greg Wrobel <clouddog22@gmail.com> wrote:
> Sticking valves happen. We have all had them. The danger is when you let
> them go you may eventually burn the valve and then you have another issue
> to deal with. When you pull through in a perfect world you should not hea
r
> any air coming from exhaust or carb. Sometimes a small amount may come
> through and after a flight it should normally go away if not, then you ne
ed
> to address it with a rubber mallet, or spinning the valve (lapping). We c
an
> get into discussing Marvel Mystery Oil in the fuel and/or oil but that is
> another bag of opinions
>
> Greg "Clouddog" Wrobel
>
> On Thu, Apr 29, 2021, 21:34 Justin Drafts <draftsjust417@gmail.com> wrote
:
>
>> Ok helpful gents and engine experts-
>> A fruitful sunny day spent @ hangar with the suspect cylinders.
>>
>> Checked the small starting air valve: definitely in good working order
>> and closing as appropriate.
>>
>> Pulling off rocker covers and watching the rocker arm and valve springs,
>> I see there is
>> no gap at TDC between the rocker arm and top of the spring /stem for
>> cylinders #2 and #3.
>>
>> Just so I'm understanding valve lash / clearance correctly:
>> - the 0.010-0.014" clearance mentioned is supposed to be here at the re
d
>> circle in the
>> attached pic, correct? (While the stem is at its highest point of
>> travel/valve fully seated/TDC...)
>> -adjusting this clearance/lash requires turning the large adjustment
>> screw at the green arrow, correct?
>>
>> Based on the air I hear escaping the exhaust stack, I suspect the exhaus
t
>> valves are sticking or
>> otherwise remaining open.
>>
>> Not sure how I went from great compression #'s last year to 0/80 psi thi
s
>> year, but very little surprises
>> me in maintenance anymore.
>>
>> Thoughts gents?
>> Thanks- Justin
>>
>> On Thu, Apr 29, 2021 at 5:09 AM A. Dennis Savarese <
>> dsavarese0812@bellsouth.net> wrote:
>>
>>> dsavarese0812@bellsouth.net>
>>>
>>> Also check the the air injector to make sure it is fully closed. It
>>> too
>>> has a very small valve inside of it about the size of a pencil eraser.
>>> If the little valve spring is broken or the valve remains open, it will
>>> of course affect the compression test.
>>> Dennis
>>>
>>> A. Dennis Savarese
>>> 334-546-8182
>>> www.yak-52.com
>>>
>>> On 4/28/2021 11:58 PM, Justin Drafts wrote:
>>> > Good evening all-
>>> >
>>> > A conundrum for you Housai engine experts; I need some advice to go
>>> fwd.
>>> > Doing the compression check today, I hit a weird wall.
>>> >
>>> > With a partner I was checking cylinders starting with #1 at top, goin
g
>>> > CW when viewed from cockpit.
>>> > All #'s were good (avg 75/80 psi), until I got the last cylinder, #2.
>>> > We got 0 psi on the pressure gauge.
>>> >
>>> > Checking the pressure tester/gauges/fittings/hose, all are fine and
>>> > perfectly functional.
>>> >
>>> > So we double checked the previous cylinder, which had just 10 min
>>> > prior tested at 74/80 psi.... now it also
>>> > showed 0/80 psi. ??
>>> > No obvious air leaks from oil breather, carburetor, or exhaust stack;
>>> > no oil evident at bases of the cylinders;
>>> > the exhaust and intake stacks are good condition. I had flown the
>>> > plane earlier in the day w/o any negative
>>> > indications.
>>> >
>>> > Pulled the valve covers off to find the rocker arms, springs, etc in
>>> > great condition, doing their job when we
>>> > slowly turned the prop thru by hand.
>>> >
>>> > Stuck valves?
>>> >
>>> > We tried the "rope trick" to slip a nylon cord into the cylinder thru
>>> > the open sparkplug hole, then gently run
>>> > the piston up to TDC to try to reseat the possibly stuck-open valves.
>>> > As yet, no help.
>>> >
>>> > Fishing for advice & thoughts... what are we missing?
>>> > I've never seen a 0/80 psi reading... a bad piston ring or bad valve,
>>> > should have SOME psi indication 30~60psi.
>>> >
>>> > Thoughts? Pointers?
>>> > Thanks---
>>> >
>>> > Justin Drafts
>>> > N280NC
>>>
>>>
>>>
>>> ==========
>>> List" rel="noreferrer" target="_blank">
>>> http://www.matronics.com/Navigator?Yak-List
>>> ==========
>>> FORUMS -
>>> eferrer" target="_blank">http://forums.matronics.com
>>> ==========
>>> WIKI -
>>> errer" target="_blank">http://wiki.matronics.com
>>> ==========
>>> b Site -
>>> -Matt Dralle, List Admin.
>>> rel="noreferrer" target="_blank">http://www.matronics.com/contribut
ion
>>> ==========
>>>
>>>
>>>
>>>
Message 3
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| Subject: | Re: Housai engine question: compression check |
All good info gents, thanks & very very much appreciated... stay tuned!
J
On Fri, Apr 30, 2021, 4:59 AM Mark Pennington <
pennington.construction.inc.1@gmail.com> wrote:
> Justin
>
> You are right about adjusting the valves. You photo is accurate.
> I would talk to someone at length about the step by step procedure if you
> haven=99t done that yet. How you use the feeler gauge is important
. As
> taught to me by others.
>
> I would suggest fix the sticking valve before you adjust anything. I am
> sure you are aware of that info.
>
> And Yes. MMO is a very wide and varied discussion for sure. Me, I drink
> a pint before every flight. LOL.
>
> Mark
> N621CJ.
>
> On Fri, Apr 30, 2021 at 7:48 AM Greg Wrobel <clouddog22@gmail.com> wrote:
>
>> Sticking valves happen. We have all had them. The danger is when you let
>> them go you may eventually burn the valve and then you have another issu
e
>> to deal with. When you pull through in a perfect world you should not he
ar
>> any air coming from exhaust or carb. Sometimes a small amount may come
>> through and after a flight it should normally go away if not, then you n
eed
>> to address it with a rubber mallet, or spinning the valve (lapping). We
can
>> get into discussing Marvel Mystery Oil in the fuel and/or oil but that i
s
>> another bag of opinions
>>
>> Greg "Clouddog" Wrobel
>>
>> On Thu, Apr 29, 2021, 21:34 Justin Drafts <draftsjust417@gmail.com>
>> wrote:
>>
>>> Ok helpful gents and engine experts-
>>> A fruitful sunny day spent @ hangar with the suspect cylinders.
>>>
>>> Checked the small starting air valve: definitely in good working order
>>> and closing as appropriate.
>>>
>>> Pulling off rocker covers and watching the rocker arm and valve springs
,
>>> I see there is
>>> no gap at TDC between the rocker arm and top of the spring /stem for
>>> cylinders #2 and #3.
>>>
>>> Just so I'm understanding valve lash / clearance correctly:
>>> - the 0.010-0.014" clearance mentioned is supposed to be here at the
>>> red circle in the
>>> attached pic, correct? (While the stem is at its highest point of
>>> travel/valve fully seated/TDC...)
>>> -adjusting this clearance/lash requires turning the large adjustment
>>> screw at the green arrow, correct?
>>>
>>> Based on the air I hear escaping the exhaust stack, I suspect the
>>> exhaust valves are sticking or
>>> otherwise remaining open.
>>>
>>> Not sure how I went from great compression #'s last year to 0/80 psi
>>> this year, but very little surprises
>>> me in maintenance anymore.
>>>
>>> Thoughts gents?
>>> Thanks- Justin
>>>
>>> On Thu, Apr 29, 2021 at 5:09 AM A. Dennis Savarese <
>>> dsavarese0812@bellsouth.net> wrote:
>>>
>>>> dsavarese0812@bellsouth.net>
>>>>
>>>> Also check the the air injector to make sure it is fully closed. It
>>>> too
>>>> has a very small valve inside of it about the size of a pencil eraser.
>>>> If the little valve spring is broken or the valve remains open, it wil
l
>>>> of course affect the compression test.
>>>> Dennis
>>>>
>>>> A. Dennis Savarese
>>>> 334-546-8182
>>>> www.yak-52.com
>>>>
>>>> On 4/28/2021 11:58 PM, Justin Drafts wrote:
>>>> > Good evening all-
>>>> >
>>>> > A conundrum for you Housai engine experts; I need some advice to go
>>>> fwd.
>>>> > Doing the compression check today, I hit a weird wall.
>>>> >
>>>> > With a partner I was checking cylinders starting with #1 at top,
>>>> going
>>>> > CW when viewed from cockpit.
>>>> > All #'s were good (avg 75/80 psi), until I got the last cylinder, #2
.
>>>> > We got 0 psi on the pressure gauge.
>>>> >
>>>> > Checking the pressure tester/gauges/fittings/hose, all are fine and
>>>> > perfectly functional.
>>>> >
>>>> > So we double checked the previous cylinder, which had just 10 min
>>>> > prior tested at 74/80 psi.... now it also
>>>> > showed 0/80 psi. ??
>>>> > No obvious air leaks from oil breather, carburetor, or exhaust stack
;
>>>> > no oil evident at bases of the cylinders;
>>>> > the exhaust and intake stacks are good condition. I had flown the
>>>> > plane earlier in the day w/o any negative
>>>> > indications.
>>>> >
>>>> > Pulled the valve covers off to find the rocker arms, springs, etc in
>>>> > great condition, doing their job when we
>>>> > slowly turned the prop thru by hand.
>>>> >
>>>> > Stuck valves?
>>>> >
>>>> > We tried the "rope trick" to slip a nylon cord into the cylinder thr
u
>>>> > the open sparkplug hole, then gently run
>>>> > the piston up to TDC to try to reseat the possibly stuck-open
>>>> valves.
>>>> > As yet, no help.
>>>> >
>>>> > Fishing for advice & thoughts... what are we missing?
>>>> > I've never seen a 0/80 psi reading... a bad piston ring or bad valve
,
>>>> > should have SOME psi indication 30~60psi.
>>>> >
>>>> > Thoughts? Pointers?
>>>> > Thanks---
>>>> >
>>>> > Justin Drafts
>>>> > N280NC
>>>>
>>>>
>>>>
>>>> ==========
>>>> List" rel="noreferrer" target="_blank">
>>>> http://www.matronics.com/Navigator?Yak-List
>>>> ==========
>>>> FORUMS -
>>>> eferrer" target="_blank">http://forums.matronics.com
>>>> ==========
>>>> WIKI -
>>>> errer" target="_blank">http://wiki.matronics.com
>>>> ==========
>>>> b Site -
>>>> -Matt Dralle, List Admin.
>>>> rel="noreferrer" target="_blank">http://www.matronics.com/contribu
tion
>>>> ==========
>>>>
>>>>
>>>>
>>>>
Message 4
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| Subject: | Re: Housai engine question: compression check |
Fast question... what's the req'd torque in the rocker arms' jam nuts ?
What # has everyone used?
Thanks again all--
Justin
On Fri, Apr 30, 2021, 7:16 AM Justin Drafts <draftsjust417@gmail.com> wrote
:
> All good info gents, thanks & very very much appreciated... stay tuned!
> J
>
> On Fri, Apr 30, 2021, 4:59 AM Mark Pennington <
> pennington.construction.inc.1@gmail.com> wrote:
>
>> Justin
>>
>> You are right about adjusting the valves. You photo is accurate.
>> I would talk to someone at length about the step by step procedure if yo
u
>> haven=99t done that yet. How you use the feeler gauge is importan
t. As
>> taught to me by others.
>>
>> I would suggest fix the sticking valve before you adjust anything. I am
>> sure you are aware of that info.
>>
>> And Yes. MMO is a very wide and varied discussion for sure. Me, I drin
k
>> a pint before every flight. LOL.
>>
>> Mark
>> N621CJ.
>>
>> On Fri, Apr 30, 2021 at 7:48 AM Greg Wrobel <clouddog22@gmail.com> wrote
:
>>
>>> Sticking valves happen. We have all had them. The danger is when you le
t
>>> them go you may eventually burn the valve and then you have another iss
ue
>>> to deal with. When you pull through in a perfect world you should not h
ear
>>> any air coming from exhaust or carb. Sometimes a small amount may come
>>> through and after a flight it should normally go away if not, then you
need
>>> to address it with a rubber mallet, or spinning the valve (lapping). We
can
>>> get into discussing Marvel Mystery Oil in the fuel and/or oil but that
is
>>> another bag of opinions
>>>
>>> Greg "Clouddog" Wrobel
>>>
>>> On Thu, Apr 29, 2021, 21:34 Justin Drafts <draftsjust417@gmail.com>
>>> wrote:
>>>
>>>> Ok helpful gents and engine experts-
>>>> A fruitful sunny day spent @ hangar with the suspect cylinders.
>>>>
>>>> Checked the small starting air valve: definitely in good working order
>>>> and closing as appropriate.
>>>>
>>>> Pulling off rocker covers and watching the rocker arm and valve
>>>> springs, I see there is
>>>> no gap at TDC between the rocker arm and top of the spring /stem for
>>>> cylinders #2 and #3.
>>>>
>>>> Just so I'm understanding valve lash / clearance correctly:
>>>> - the 0.010-0.014" clearance mentioned is supposed to be here at the
>>>> red circle in the
>>>> attached pic, correct? (While the stem is at its highest point of
>>>> travel/valve fully seated/TDC...)
>>>> -adjusting this clearance/lash requires turning the large adjustment
>>>> screw at the green arrow, correct?
>>>>
>>>> Based on the air I hear escaping the exhaust stack, I suspect the
>>>> exhaust valves are sticking or
>>>> otherwise remaining open.
>>>>
>>>> Not sure how I went from great compression #'s last year to 0/80 psi
>>>> this year, but very little surprises
>>>> me in maintenance anymore.
>>>>
>>>> Thoughts gents?
>>>> Thanks- Justin
>>>>
>>>> On Thu, Apr 29, 2021 at 5:09 AM A. Dennis Savarese <
>>>> dsavarese0812@bellsouth.net> wrote:
>>>>
>>>>> dsavarese0812@bellsouth.net>
>>>>>
>>>>> Also check the the air injector to make sure it is fully closed. It
>>>>> too
>>>>> has a very small valve inside of it about the size of a pencil
>>>>> eraser.
>>>>> If the little valve spring is broken or the valve remains open, it
>>>>> will
>>>>> of course affect the compression test.
>>>>> Dennis
>>>>>
>>>>> A. Dennis Savarese
>>>>> 334-546-8182
>>>>> www.yak-52.com
>>>>>
>>>>> On 4/28/2021 11:58 PM, Justin Drafts wrote:
>>>>> > Good evening all-
>>>>> >
>>>>> > A conundrum for you Housai engine experts; I need some advice to go
>>>>> fwd.
>>>>> > Doing the compression check today, I hit a weird wall.
>>>>> >
>>>>> > With a partner I was checking cylinders starting with #1 at top,
>>>>> going
>>>>> > CW when viewed from cockpit.
>>>>> > All #'s were good (avg 75/80 psi), until I got the last cylinder,
>>>>> #2.
>>>>> > We got 0 psi on the pressure gauge.
>>>>> >
>>>>> > Checking the pressure tester/gauges/fittings/hose, all are fine and
>>>>> > perfectly functional.
>>>>> >
>>>>> > So we double checked the previous cylinder, which had just 10 min
>>>>> > prior tested at 74/80 psi.... now it also
>>>>> > showed 0/80 psi. ??
>>>>> > No obvious air leaks from oil breather, carburetor, or exhaust
>>>>> stack;
>>>>> > no oil evident at bases of the cylinders;
>>>>> > the exhaust and intake stacks are good condition. I had flown the
>>>>> > plane earlier in the day w/o any negative
>>>>> > indications.
>>>>> >
>>>>> > Pulled the valve covers off to find the rocker arms, springs, etc i
n
>>>>> > great condition, doing their job when we
>>>>> > slowly turned the prop thru by hand.
>>>>> >
>>>>> > Stuck valves?
>>>>> >
>>>>> > We tried the "rope trick" to slip a nylon cord into the cylinder
>>>>> thru
>>>>> > the open sparkplug hole, then gently run
>>>>> > the piston up to TDC to try to reseat the possibly stuck-open
>>>>> valves.
>>>>> > As yet, no help.
>>>>> >
>>>>> > Fishing for advice & thoughts... what are we missing?
>>>>> > I've never seen a 0/80 psi reading... a bad piston ring or bad
>>>>> valve,
>>>>> > should have SOME psi indication 30~60psi.
>>>>> >
>>>>> > Thoughts? Pointers?
>>>>> > Thanks---
>>>>> >
>>>>> > Justin Drafts
>>>>> > N280NC
>>>>>
>>>>>
>>>>>
>>>>> ==========
>>>>> List" rel="noreferrer" target="_blank">
>>>>> http://www.matronics.com/Navigator?Yak-List
>>>>> ==========
>>>>> FORUMS -
>>>>> eferrer" target="_blank">http://forums.matronics.com
>>>>> ==========
>>>>> WIKI -
>>>>> errer" target="_blank">http://wiki.matronics.com
>>>>> ==========
>>>>> b Site -
>>>>> -Matt Dralle, List Admin.
>>>>> rel="noreferrer" target="_blank">http://www.matronics.com/contrib
ution
>>>>> ==========
>>>>>
>>>>>
>>>>>
>>>>>
Message 5
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| Subject: | Re: Housai engine question: compression check |
No torque spec that I=99m aware of. Tighten securely using proper 17 m
m socket wrench or a properly fitted box end wrench. Don=99t use an o
pen end wrench. Very likely you=99ll round off the corners of the hex n
ut.
Dennis .
Sent from my iPhone
> On Apr 30, 2021, at 5:04 PM, Justin Drafts <draftsjust417@gmail.com> wrote
:
>
> =EF=BB
> Fast question... what's the req'd torque in the rocker arms' jam nuts ?
> What # has everyone used?
>
> Thanks again all--
> Justin
>
>> On Fri, Apr 30, 2021, 7:16 AM Justin Drafts <draftsjust417@gmail.com> wro
te:
>> All good info gents, thanks & very very much appreciated... stay tuned!
>> J
>>
>>> On Fri, Apr 30, 2021, 4:59 AM Mark Pennington <pennington.construction.i
nc.1@gmail.com> wrote:
>>> Justin
>>>
>>> You are right about adjusting the valves. You photo is accurate.
>>> I would talk to someone at length about the step by step procedure if yo
u haven=99t done that yet. How you use the feeler gauge is important.
As taught to me by others.
>>>
>>> I would suggest fix the sticking valve before you adjust anything. I am
sure you are aware of that info.
>>>
>>> And Yes. MMO is a very wide and varied discussion for sure. Me, I drin
k a pint before every flight. LOL.
>>>
>>> Mark
>>> N621CJ.
>>>
>>>> On Fri, Apr 30, 2021 at 7:48 AM Greg Wrobel <clouddog22@gmail.com> wrot
e:
>>>> Sticking valves happen. We have all had them. The danger is when you le
t them go you may eventually burn the valve and then you have another issue t
o deal with. When you pull through in a perfect world you should not hear an
y air coming from exhaust or carb. Sometimes a small amount may come through
and after a flight it should normally go away if not, then you need to addr
ess it with a rubber mallet, or spinning the valve (lapping). We can get int
o discussing Marvel Mystery Oil in the fuel and/or oil but that is another b
ag of opinions
>>>>
>>>> Greg "Clouddog" Wrobel
>>>>
>>>>> On Thu, Apr 29, 2021, 21:34 Justin Drafts <draftsjust417@gmail.com> wr
ote:
>>>>> Ok helpful gents and engine experts-
>>>>> A fruitful sunny day spent @ hangar with the suspect cylinders.
>>>>>
>>>>> Checked the small starting air valve: definitely in good working order
and closing as appropriate.
>>>>>
>>>>> Pulling off rocker covers and watching the rocker arm and valve spring
s, I see there is
>>>>> no gap at TDC between the rocker arm and top of the spring /stem for c
ylinders #2 and #3.
>>>>>
>>>>> Just so I'm understanding valve lash / clearance correctly:
>>>>> - the 0.010-0.014" clearance mentioned is supposed to be here at the r
ed circle in the
>>>>> attached pic, correct? (While the stem is at its highest point of tra
vel/valve fully seated/TDC...)
>>>>> -adjusting this clearance/lash requires turning the large adjustment s
crew at the green arrow, correct?
>>>>>
>>>>> Based on the air I hear escaping the exhaust stack, I suspect the exha
ust valves are sticking or
>>>>> otherwise remaining open.
>>>>>
>>>>> Not sure how I went from great compression #'s last year to 0/80 psi t
his year, but very little surprises
>>>>> me in maintenance anymore.
>>>>>
>>>>> Thoughts gents?
>>>>> Thanks- Justin
>>>>>
>>>>>> On Thu, Apr 29, 2021 at 5:09 AM A. Dennis Savarese <dsavarese0812@bel
lsouth.net> wrote:
ellsouth.net>
>>>>>>
>>>>>> Also check the the air injector to make sure it is fully closed. It
>>>>>> too
>>>>>> has a very small valve inside of it about the size of a pencil eraser
.
>>>>>> If the little valve spring is broken or the valve remains open, it wi
ll
>>>>>> of course affect the compression test.
>>>>>> Dennis
>>>>>>
>>>>>> A. Dennis Savarese
>>>>>> 334-546-8182
>>>>>> www.yak-52.com
>>>>>>
>>>>>> On 4/28/2021 11:58 PM, Justin Drafts wrote:
>>>>>> > Good evening all-
>>>>>> >
>>>>>> > A conundrum for you Housai engine experts; I need some advice to go
fwd.
>>>>>> > Doing the compression check today, I hit a weird wall.
>>>>>> >
>>>>>> > With a partner I was checking cylinders starting with #1 at top, go
ing
>>>>>> > CW when viewed from cockpit.
>>>>>> > All #'s were good (avg 75/80 psi), until I got the last cylinder, #
2.
>>>>>> > We got 0 psi on the pressure gauge.
>>>>>> >
>>>>>> > Checking the pressure tester/gauges/fittings/hose, all are fine and
>>>>>> > perfectly functional.
>>>>>> >
>>>>>> > So we double checked the previous cylinder, which had just 10 min
>>>>>> > prior tested at 74/80 psi.... now it also
>>>>>> > showed 0/80 psi. ??
>>>>>> > No obvious air leaks from oil breather, carburetor, or exhaust stac
k;
>>>>>> > no oil evident at bases of the cylinders;
>>>>>> > the exhaust and intake stacks are good condition. I had flown the
>>>>>> > plane earlier in the day w/o any negative
>>>>>> > indications.
>>>>>> >
>>>>>> > Pulled the valve covers off to find the rocker arms, springs, etc i
n
>>>>>> > great condition, doing their job when we
>>>>>> > slowly turned the prop thru by hand.
>>>>>> >
>>>>>> > Stuck valves?
>>>>>> >
>>>>>> > We tried the "rope trick" to slip a nylon cord into the cylinder th
ru
>>>>>> > the open sparkplug hole, then gently run
>>>>>> > the piston up to TDC to try to reseat the possibly stuck-open valve
s.
>>>>>> > As yet, no help.
>>>>>> >
>>>>>> > Fishing for advice & thoughts... what are we missing?
>>>>>> > I've never seen a 0/80 psi reading... a bad piston ring or bad valv
e,
>>>>>> > should have SOME psi indication 30~60psi.
>>>>>> >
>>>>>> > Thoughts? Pointers?
>>>>>> > Thanks---
>>>>>> >
>>>>>> > Justin Drafts
>>>>>> > N280NC
>>>>>>
>>>>>>
>>>>>>
>>>>>> ==========
>>>>>> List" rel="noreferrer" target="_blank">http://www.matronics.com/N
avigator?Yak-List
>>>>>> ==========
>>>>>> FORUMS -
>>>>>> eferrer" target="_blank">http://forums.matronics.com
>>>>>> ==========
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>>>>>> errer" target="_blank">http://wiki.matronics.com
>>>>>> ==========
>>>>>> b Site -
>>>>>> -Matt Dralle, List Admin.
>>>>>> rel="noreferrer" target="_blank">http://www.matronics.com/contrib
ution
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>>>>>>
>>>>>>
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| Subject: | Re: Housai engine question: compression check |
Hi Justin;
I too have not seen a specific torque value for the rocker arm nuts.
However there are two special tools for this purpose. The wrench is an
open socket style with a fixed handle used in combination with a right
angle screw driver that is positioned through the open socket to hold
your adjustment position while tightening .
The operating word is as tight as you can get it with this wrench.
Re-check all clearances after tightening. Technically this whole
operation should be done four times. With the P &W R1340 that is a
must! due to something called a floating cam ring. These engines do not
have that problem but if you If you find any significant changes do it
again.
It is a straight forward operation for the intake valve but the engine
should be rotated slightly to provide clearance of the wrench for the
exhaust nut. This would apply for any socket type wrench. If that
clearance is not obtained there is a real possibility of damage to the
nut.
I expect you have noticed there is a light spring pressure that closes
up the valve clearance. At first glance one may think there is no
clearance. This spring is at the opposite end of the push rod and has
nothing to do with valve clearance in operation. It=99s purpose
is to keep the cam roller in constant rolling contact with the cam ring
to reduce wear. You can see this spring operation by pressing the nut
end of the rocker with your finger.
The feeler guage should be used at right angles across the width of the
rocker box. That will appear obvious since using in a fore & aft manner
will introduce interference and likely produce errors.
I have found over the years that the exhaust valves tend to tighten over
time and as a result I use 0.012=9D for the intake and
0.014=9D for the exhaust whether Huosai or M14P.
I will send you some photos of the proper tools tomorrow. Will need
your phone #. Mine is 250-485-8698.
Cheers;
Walt
From: Justin Drafts
Sent: Friday, April 30, 2021 2:01 PM
Subject: Re: Yak-List: Re: Housai engine question: compression check
Fast question... what's the req'd torque in the rocker arms' jam nuts ?
What # has everyone used?
Thanks again all--
Justin
On Fri, Apr 30, 2021, 7:16 AM Justin Drafts <draftsjust417@gmail.com>
wrote:
All good info gents, thanks & very very much appreciated... stay
tuned!
J
On Fri, Apr 30, 2021, 4:59 AM Mark Pennington
<pennington.construction.inc.1@gmail.com> wrote:
Justin
You are right about adjusting the valves. You photo is accurate.
I would talk to someone at length about the step by step procedure
if you haven=99t done that yet. How you use the feeler gauge is
important. As taught to me by others.
I would suggest fix the sticking valve before you adjust anything.
I am sure you are aware of that info.
And Yes. MMO is a very wide and varied discussion for sure. Me, I
drink a pint before every flight. LOL.
Mark
N621CJ.
On Fri, Apr 30, 2021 at 7:48 AM Greg Wrobel <clouddog22@gmail.com>
wrote:
Sticking valves happen. We have all had them. The danger is when
you let them go you may eventually burn the valve and then you have
another issue to deal with. When you pull through in a perfect world you
should not hear any air coming from exhaust or carb. Sometimes a small
amount may come through and after a flight it should normally go away if
not, then you need to address it with a rubber mallet, or spinning the
valve (lapping). We can get into discussing Marvel Mystery Oil in the
fuel and/or oil but that is another bag of opinions
Greg "Clouddog" Wrobel
On Thu, Apr 29, 2021, 21:34 Justin Drafts
<draftsjust417@gmail.com> wrote:
Ok helpful gents and engine experts-
A fruitful sunny day spent @ hangar with the suspect cylinders.
Checked the small starting air valve: definitely in good working
order and closing as appropriate.
Pulling off rocker covers and watching the rocker arm and valve
springs, I see there is
no gap at TDC between the rocker arm and top of the spring /stem
for cylinders #2 and #3.
Just so I'm understanding valve lash / clearance correctly:
- the 0.010-0.014" clearance mentioned is supposed to be here
at the red circle in the
attached pic, correct? (While the stem is at its highest point
of travel/valve fully seated/TDC...)
-adjusting this clearance/lash requires turning the large
adjustment screw at the green arrow, correct?
Based on the air I hear escaping the exhaust stack, I suspect
the exhaust valves are sticking or
otherwise remaining open.
Not sure how I went from great compression #'s last year to 0/80
psi this year, but very little surprises
me in maintenance anymore.
Thoughts gents?
Thanks- Justin
On Thu, Apr 29, 2021 at 5:09 AM A. Dennis Savarese
<dsavarese0812@bellsouth.net> wrote:
<dsavarese0812@bellsouth.net>
Also check the the air injector to make sure it is fully
closed. It
too
has a very small valve inside of it about the size of a pencil
eraser.
If the little valve spring is broken or the valve remains
open, it will
of course affect the compression test.
Dennis
A. Dennis Savarese
334-546-8182
www.yak-52.com
On 4/28/2021 11:58 PM, Justin Drafts wrote:
> Good evening all-
>
> A conundrum for you Housai engine experts; I need some
advice to go fwd.
> Doing the compression check today, I hit a weird wall.
>
> With a partner I was checking cylinders starting with #1 at
top, going
> CW when viewed from cockpit.
> All #'s were good (avg 75/80 psi), until I got the last
cylinder, #2.
> We got 0 psi on the pressure gauge.
>
> Checking the pressure tester/gauges/fittings/hose, all are
fine and
> perfectly functional.
>
> So we double checked the previous cylinder, which had just
10 min
> prior tested at 74/80 psi.... now it also
> showed 0/80 psi. ??
> No obvious air leaks from oil breather, carburetor, or
exhaust stack;
> no oil evident at bases of the cylinders;
> the exhaust and intake stacks are good condition. I had
flown the
> plane earlier in the day w/o any negative
> indications.
>
> Pulled the valve covers off to find the rocker arms,
springs, etc in
> great condition, doing their job when we
> slowly turned the prop thru by hand.
>
> Stuck valves?
>
> We tried the "rope trick" to slip a nylon cord into the
cylinder thru
> the open sparkplug hole, then gently run
> the piston up to TDC to try to reseat the possibly
stuck-open valves.
> As yet, no help.
>
> Fishing for advice & thoughts... what are we missing?
> I've never seen a 0/80 psi reading... a bad piston ring or
bad valve,
> should have SOME psi indication 30~60psi.
>
> Thoughts? Pointers?
> Thanks---
>
> Justin Drafts
> N280NC
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