Engine case sealer?

[bBob]

After splitting the engine cases, what is recommended for resealing them?

Thanks!

[Richard Lamb]

bBob wrote:

> After splitting the engine cases, what is recommended for resealing them?
>
> Thanks!
>
>

Silk thread - on old Continentals.

[Orval Fairbairn]

In article et>,
Richard Lamb > wrote:

> bBob wrote:
>
> > After splitting the engine cases, what is recommended for resealing them?
> >
> > Thanks!
> >
> >
>
> Silk thread - on old Continentals.

Make sure that you use *SILK* -- NOT nylon thread! Silk will compress,
while nylon will cause fretting. Your overhaul manual should tell you
how to do this.

Also, use some either Hylomar (blue) or the pink Continental sealant.

[bBob]

"Richard Lamb" > wrote in message
ink.net...
> bBob wrote:
>
> > After splitting the engine cases, what is recommended for resealing
them?
> >
> > Thanks!
> >
> >
>
> Silk thread - on old Continentals.

Thanks for the reply Richard.

I think I should have provided a few more details- we were in a rush
earlier.

I split the cases on a military aircraft gearbox for inspection. It appears
to be sealed with what we used to call 8802 (I think the proper title is
MIL-S-8802 sealant). This gearbox is for a non-aircraft project and is
exposed to high temperatures as it's nestled in the cheeks of a turbine
exhaust duct.

The lube oil supposedly reaches 180F but I think the housing may see 300F. I
think the case reaches pressures of 25 psi. The lube oil passages reach 120
psi.

I tried to locate 8802 or a substitute, without success. If you are not
familiar with 8802, when set it is like a grey colored 3M 5200 sealant. It's
a little tougher than Blue RTV.

What products should I be looking at to reseal this gearcase?

Thanks in advance.

[jerry wass]

There is a red sealant the auto atores are handling now that is even
approved by faa (so I waS told) it acts like an anaerobic sealer with
silicone rubber in it. forgot the number--in a red tube quite a bit
higher than the other types, but well worth it. Jerry


bBob wrote:
> "Richard Lamb" > wrote in message
> ink.net...
>
>>bBob wrote:
>>
>>
>>>After splitting the engine cases, what is recommended for resealing
>
> them?
>
>>>Thanks!
>>>
>>>
>>
>>Silk thread - on old Continentals.
>
>
> Thanks for the reply Richard.
>
> I think I should have provided a few more details- we were in a rush
> earlier.
>
> I split the cases on a military aircraft gearbox for inspection. It appears
> to be sealed with what we used to call 8802 (I think the proper title is
> MIL-S-8802 sealant). This gearbox is for a non-aircraft project and is
> exposed to high temperatures as it's nestled in the cheeks of a turbine
> exhaust duct.
>
> The lube oil supposedly reaches 180F but I think the housing may see 300F. I
> think the case reaches pressures of 25 psi. The lube oil passages reach 120
> psi.
>
> I tried to locate 8802 or a substitute, without success. If you are not
> familiar with 8802, when set it is like a grey colored 3M 5200 sealant. It's
> a little tougher than Blue RTV.
>
> What products should I be looking at to reseal this gearcase?
>
> Thanks in advance.
>
>
>

[bBob]

"jerry wass" > wrote in message
...
> There is a red sealant the auto atores are handling now that is even
> approved by faa (so I waS told) it acts like an anaerobic sealer with
> silicone rubber in it. forgot the number--in a red tube quite a bit
> higher than the other types, but well worth it. Jerry

Is it like the red sealant shown here?
http://tinyurl.com/znk34

[flybynightkarmarepair]

here is the now superceded Mil-Product spec for this stuff:
http://assist.daps.dla.mil/docimages/0000/74/12/7194.PD9
you want type II, Class C. Manganese cure, faying surface grade
polysulfide.

There is now an SAE spec for this stuff, SAE-AMS-8802

Pro-Seal, beloved (not!) of many RV builders is the same chemistry,
just thicker. You could use the class A stuff, and thin it with
Toluene.

Another poster mentioned what sounds to me like Loctite Gasket
Eliminator, good for up to 200 deg Celsius. That oughta do it, and
it's a whole lot easier to find than the polysulfide.

Volkswagen engine builders use Gascacinch, Yamabond, and some german
goo who's name escapes me at the moment to seal similar faying surfaces.

[bBob]

"flybynightkarmarepair" > wrote in message
ups.com...
> here is the now superceded Mil-Product spec for this stuff:
> http://assist.daps.dla.mil/docimages/0000/74/12/7194.PD9
> you want type II, Class C. Manganese cure, faying surface grade
> polysulfide.
>
> There is now an SAE spec for this stuff, SAE-AMS-8802
>
> Pro-Seal, beloved (not!) of many RV builders is the same chemistry,
> just thicker. You could use the class A stuff, and thin it with
> Toluene.
>
> Another poster mentioned what sounds to me like Loctite Gasket
> Eliminator, good for up to 200 deg Celsius. That oughta do it, and
> it's a whole lot easier to find than the polysulfide.
>
> Volkswagen engine builders use Gascacinch, Yamabond, and some german
> goo who's name escapes me at the moment to seal similar faying surfaces.

Thank you kind sir!

[Orval Fairbairn]

In article . net>,
Richard Lamb > wrote:

> Orval Fairbairn wrote:
>
> > In article et>,
> > Richard Lamb > wrote:
> >
> >
> >>bBob wrote:
> >>
> >>
> >>>After splitting the engine cases, what is recommended for resealing them?
> >>>
> >>>Thanks!
> >>>
> >>>
> >>
> >>Silk thread - on old Continentals.
> >
> >
> > Make sure that you use *SILK* -- NOT nylon thread! Silk will compress,
> > while nylon will cause fretting. Your overhaul manual should tell you
> > how to do this.
> >
> > Also, use some either Hylomar (blue) or the pink Continental sealant.
>
>
> Pink is for girls, Orval!

Or for Continentals!

[Orval Fairbairn]

In article om>,
"flybynightkarmarepair" > wrote:

> here is the now superceded Mil-Product spec for this stuff:
> http://assist.daps.dla.mil/docimages/0000/74/12/7194.PD9
> you want type II, Class C. Manganese cure, faying surface grade
> polysulfide.
>
> There is now an SAE spec for this stuff, SAE-AMS-8802
>
> Pro-Seal, beloved (not!) of many RV builders is the same chemistry,
> just thicker. You could use the class A stuff, and thin it with
> Toluene.
>
> Another poster mentioned what sounds to me like Loctite Gasket
> Eliminator, good for up to 200 deg Celsius. That oughta do it, and
> it's a whole lot easier to find than the polysulfide.
>
> Volkswagen engine builders use Gascacinch, Yamabond, and some german
> goo who's name escapes me at the moment to seal similar faying surfaces.


Do nor use RTV to seal crankcase halves! It allows minute movement and
will cause the mating surfaces to fret.

[Big John]

Richard

Arn't engines she's? Never heard anyone say 'he' quit.

Big John
`````````````````````````````````````````````````

On Thu, 23 Mar 2006 08:05:47 GMT, Richard Lamb
> wrote:

>Orval Fairbairn wrote:
>
>> In article et>,
>> Richard Lamb > wrote:
>>
>>
>>>bBob wrote:
>>>
>>>
>>>>After splitting the engine cases, what is recommended for resealing them?
>>>>
>>>>Thanks!
>>>>
>>>>
>>>
>>>Silk thread - on old Continentals.
>>
>>
>> Make sure that you use *SILK* -- NOT nylon thread! Silk will compress,
>> while nylon will cause fretting. Your overhaul manual should tell you
>> how to do this.
>>
>> Also, use some either Hylomar (blue) or the pink Continental sealant.
>
>
>Pink is for girls, Orval!

[jls]

"bBob" > wrote in message
news:eJnUf.10210$TK2.5516@trnddc07...
> After splitting the engine cases, what is recommended for resealing them?
>
> Thanks!

I split a case recently that was nice and dry on the outside. The previous
overhauler had placed two strands of silk thread on the parting flanges, one
strand on the inside of the fastener holes and one strand on the outside.

For the goo use Permatex Aviation Formagasket. I don't know if Hylomar is
legal or not but it's great stuff too. Thin it a little with acetone.

[jls]

"Orval Fairbairn" > wrote in message
...
> In article om>,
> "flybynightkarmarepair" > wrote:
>
> > here is the now superceded Mil-Product spec for this stuff:
> > http://assist.daps.dla.mil/docimages/0000/74/12/7194.PD9
> > you want type II, Class C. Manganese cure, faying surface grade
> > polysulfide.
> >
> > There is now an SAE spec for this stuff, SAE-AMS-8802
> >
> > Pro-Seal, beloved (not!) of many RV builders is the same chemistry,
> > just thicker. You could use the class A stuff, and thin it with
> > Toluene.
> >
> > Another poster mentioned what sounds to me like Loctite Gasket
> > Eliminator, good for up to 200 deg Celsius. That oughta do it, and
> > it's a whole lot easier to find than the polysulfide.
> >
> > Volkswagen engine builders use Gascacinch, Yamabond, and some german
> > goo who's name escapes me at the moment to seal similar faying surfaces.
>
>
> Do nor use RTV to seal crankcase halves! It allows minute movement and
> will cause the mating surfaces to fret.

According to the FAA an A&P in NC put a 6-cylinder Continental back together
with RTV silicone on the studs and under the cylinder flange nuts. The
engine later failed catastrophically in flight killing two in a Bonanza.
One of the cylinders had departed the crankcase, apparently because the nuts
backed off.

[Richard Lamb]

Big John wrote:
> Richard
>
> Arn't engines she's? Never heard anyone say 'he' quit.
>
> Big John
> `````````````````````````````````````````````````
>
Point taken...

The Bitch!

[Richard Lamb]

jls wrote:

> "Orval Fairbairn" > wrote in message
> ...
>

>>>Volkswagen engine builders use Gascacinch, Yamabond, and some german
>>>goo who's name escapes me at the moment to seal similar faying surfaces.
>>
>>
>>Do nor use RTV to seal crankcase halves! It allows minute movement and
>>will cause the mating surfaces to fret.
>
>
> According to the FAA an A&P in NC put a 6-cylinder Continental back together
> with RTV silicone on the studs and under the cylinder flange nuts. The
> engine later failed catastrophically in flight killing two in a Bonanza.
> One of the cylinders had departed the crankcase, apparently because the nuts
> backed off.
>
>

You know, this might address some of the VW problems as well.

[Cy Galley]

A good sealer is Loctite 515 or 518

"Richard Lamb" > wrote in message
ink.net...
> jls wrote:
>
>> "Orval Fairbairn" > wrote in message
>> ...
>>
>
>>>>Volkswagen engine builders use Gascacinch, Yamabond, and some german
>>>>goo who's name escapes me at the moment to seal similar faying surfaces.
>>>
>>>
>>>Do nor use RTV to seal crankcase halves! It allows minute movement and
>>>will cause the mating surfaces to fret.
>>
>>
>> According to the FAA an A&P in NC put a 6-cylinder Continental back
>> together
>> with RTV silicone on the studs and under the cylinder flange nuts. The
>> engine later failed catastrophically in flight killing two in a Bonanza.
>> One of the cylinders had departed the crankcase, apparently because the
>> nuts
>> backed off.
>>
>>
>
> You know, this might address some of the VW problems as well.
>
>
>
>
>

[[email protected]]

Richard Lamb wrote:
>> You know, this might address some of the VW problems as well.

---------------------------------------------------------------------------------------------------

Gee, you think so?

Hahahahahahahahahahahhh...

-R.S.Hoover

Who was shown the 'silk thread' trick by one of the German-trained
mechanics at Deet Eichel VW in Modesto, California more than fifty
years ago :-) (Volkswagen was one of the first manufacturers to use
gasket-less surfaces on mass-produced items.)

The silk thread trick is somethng all professional VW mechanics know
about - - and just another of the million things the shade-tree types
have never heard of.

Just make sure it sez 'pure silk.' And be careful not to use a thread
that is too large. Embrodery silk is a good source. It comes as a
kind of roving rather than twisted into a thread. Just cut a hank to
the required length then fan out one end and strip off a FEW strands --
that's all it takes.

Fly-tying thread is another good source and some find it easier to
handle. Some sewing threads are simply too thick -- they will emboss
themselves into the magnesium.

[Highflyer]

"bBob" > wrote in message
news:r5qUf.4989$hC.1856@trnddc08...
>
> "jerry wass" > wrote in message
> ...
>> There is a red sealant the auto atores are handling now that is even
>> approved by faa (so I waS told) it acts like an anaerobic sealer with
>> silicone rubber in it. forgot the number--in a red tube quite a bit
>> higher than the other types, but well worth it. Jerry
>
> Is it like the red sealant shown here?
> http://tinyurl.com/znk34
>
>

Be careful with sealants on aircraft engine cases. Continental specified a
single silk thread because it would compress to almost nothing and still
seal the case halves. Remember, with most aircraft engines the main
bearings are held by the two case halves. Anything that causes the seam to
widen at all reduces the crush on the main bearings and can contribute to
early bearing failure. If the case halves are true and they are properly
bolted up no sealant other than the single silk thread is required. Don't
mess up your main bearings trying to get the case to not leak a tiny
amount. It isn't worth it.

Highflyer
Highflight Aviation Services
Pinckneyville Airport ( PJY )

A reminder, the 11th annual rec.aviation flyin that started here many years
ago is coming up May 19, 20, and 21 at Pinckneyville. If you are planning
to come please let Mary know at so that she can make sure
to have enough steaks on hand to dinner. :-)

[bBob]

"Cy Galley" > wrote in message
news:v1JUf.841915$x96.640552@attbi_s72...
> A good sealer is Loctite 515 or 518

Agreed. The specs look perfect for what I need.

I just snagged a couple 50 ml tubes of 515, so I'll use that.

Thanks again for all the inputs.

[Richard Lamb]

wrote:

> Richard Lamb wrote:
>
>>>You know, this might address some of the VW problems as well.
>
>
> ---------------------------------------------------------------------------------------------------
>
> Gee, you think so?
>
> Hahahahahahahahahahahhh...
>
> -R.S.Hoover
>
Stop drooling, Bob.



I was just thinking that the silk thread idea isn't mentioned in
the "How to build an inexpensive aero engine" book, nor does GP or
Revmaster mention it.

Or have I lost that cell already?


Richard

[Peter Dohm]

> I was just thinking that the silk thread idea isn't mentioned in
> the "How to build an inexpensive aero engine" book, nor does GP or
> Revmaster mention it.
>
> Or have I lost that cell already?

I dunno. It was in all of the do-it-yourself VW manuals "back in the day"
and genereally mentioned #50 as the thread size. I had presumed that #50
was a fairly stout thread, however a post by Highflyer in this conversation
leads me to wonder and a breif www search was less than informative...

Peter

[jls]

"Highflyer" > wrote in message
...
>
> "bBob" > wrote in message
> news:r5qUf.4989$hC.1856@trnddc08...
> >
> > "jerry wass" > wrote in message
> > ...
> >> There is a red sealant the auto atores are handling now that is even
> >> approved by faa (so I waS told) it acts like an anaerobic sealer with
> >> silicone rubber in it. forgot the number--in a red tube quite a bit
> >> higher than the other types, but well worth it. Jerry
> >
> > Is it like the red sealant shown here?
> > http://tinyurl.com/znk34
> >
> >
>
> Be careful with sealants on aircraft engine cases. Continental specified
a
> single silk thread because it would compress to almost nothing and still
> seal the case halves. Remember, with most aircraft engines the main
> bearings are held by the two case halves. Anything that causes the seam
to
> widen at all reduces the crush on the main bearings and can contribute to
> early bearing failure. If the case halves are true and they are properly
> bolted up no sealant other than the single silk thread is required. Don't
> mess up your main bearings trying to get the case to not leak a tiny
> amount. It isn't worth it.
>
> Highflyer
> Highflight Aviation Services
> Pinckneyville Airport ( PJY )
>
> A reminder, the 11th annual rec.aviation flyin that started here many
years
> ago is coming up May 19, 20, and 21 at Pinckneyville. If you are planning
> to come please let Mary know at so that she can make sure
> to have enough steaks on hand to dinner. :-)
>
That being said, my learned friend, I notice that in TCM's IO-360 overhaul
manual, section 72-60-02(G) the following:

Spread a thin continuous film of No. 3 Aviation Permatex on the left
crankcase parting flange. ... Lay lengths of No. 50 silk thread on parting
flange. Thread should be on inside of bolt holes but never on the flange
edge. ... Stand No. 1, 3, and 5 rods upright. Being sure that thrust
washers have been installed and are properly seated, carefully lower the
right crankcase onto the left crankcase. (close quote)

Not that a silk thread by itself won't seal, but I have never seen case
halves put back together without sealant in addition to silk thread.

You could be reasonably sure of proper bearing crush by pre-assembling the
case halves over the crank and cam using plastigage. The crush on the
plastic thread flattens it out, giving you a clearance measurement in
thousandths.

One more caution: always check to see if service bulletins supersede
instructions in the overhaul manual.

[jerry wass]

Highflyer wrote:
> "bBob" > wrote in message
> news:r5qUf.4989$hC.1856@trnddc08...
>
>>"jerry wass" > wrote in message
...
>>
>>>There is a red sealant the auto atores are handling now that is even
>>>approved by faa (so I waS told) it acts like an anaerobic sealer with
>>>silicone rubber in it. forgot the number--in a red tube quite a bit
>>>higher than the other types, but well worth it. Jerry
>>
>>Is it like the red sealant shown here? NOPE--I'll go get the number & mail you back---JJW
>> http://tinyurl.com/znk34
>>
>>
>
>
> Be careful with sealants on aircraft engine cases. Continental specified a
> single silk thread because it would compress to almost nothing and still
> seal the case halves. Remember, with most aircraft engines the main
> bearings are held by the two case halves. Anything that causes the seam to
> widen at all reduces the crush on the main bearings and can contribute to
> early bearing failure. If the case halves are true and they are properly
> bolted up no sealant other than the single silk thread is required. Don't
> mess up your main bearings trying to get the case to not leak a tiny
> amount. It isn't worth it.
>
> Highflyer
> Highflight Aviation Services
> Pinckneyville Airport ( PJY )
>
> A reminder, the 11th annual rec.aviation flyin that started here many years
> ago is coming up May 19, 20, and 21 at Pinckneyville. If you are planning
> to come please let Mary know at so that she can make sure
> to have enough steaks on hand to dinner. :-)
>
>

[clare at snyder.on.ca]

On Fri, 24 Mar 2006 09:38:02 -0500, "Peter Dohm"
> wrote:

>> I was just thinking that the silk thread idea isn't mentioned in
>> the "How to build an inexpensive aero engine" book, nor does GP or
>> Revmaster mention it.
>>
>> Or have I lost that cell already?
>
>I dunno. It was in all of the do-it-yourself VW manuals "back in the day"
>and genereally mentioned #50 as the thread size. I had presumed that #50
>was a fairly stout thread, however a post by Highflyer in this conversation
>leads me to wonder and a breif www search was less than informative...
>
>Peter
>
Thread numbers, IITC, are like wire guages. A #10 is quite stout, and
a #36 is a typical machine sewing thread - with a #50 being quite
fine. If a sewing machine has ANY tension problems, you won't sew with
#50.Just what I remember from the sewing I did when I was a kid (my
mother was a very accomplished seamstress).

*** Free account sponsored by SecureIX.com ***
*** Encrypt your Internet usage with a free VPN account from http://www.SecureIX.com ***

[jerry wass]

jerry wass wrote:
> Highflyer wrote:
>
>> "bBob" > wrote in message
>> news:r5qUf.4989$hC.1856@trnddc08...
>>
>>> "jerry wass" > wrote in message
>>> ...
>>>
>>>> There is a red sealant the auto atores are handling now that is even
>>>> approved by faa (so I waS told) it acts like an anaerobic sealer with
>>>> silicone rubber in it. forgot the number--in a red tube quite a bit
>>>> higher than the other types, but well worth it. Jerry
>>>
Well, it used to be in a red tube, made by someone who got bought by
Permatex--now in blue tube--Still red sealant---NAME-Permatex
Anaroebic gasket maker--automotive grade--part # 51313
>>>
>>> Is it like the red sealant shown here? NOPE--I'll go get the number
>>> & mail you back---JJW
>>> http://tinyurl.com/znk34
>>>
>>>
>>
>>
>> Be careful with sealants on aircraft engine cases. Continental
>> specified a single silk thread because it would compress to almost
>> nothing and still seal the case halves. Remember, with most aircraft
>> engines the main bearings are held by the two case halves. Anything
>> that causes the seam to widen at all reduces the crush on the main
>> bearings and can contribute to early bearing failure. If the case
>> halves are true and they are properly bolted up no sealant other than
>> the single silk thread is required. Don't mess up your main bearings
>> trying to get the case to not leak a tiny amount. It isn't worth it.
>>
>> Highflyer
>> Highflight Aviation Services
>> Pinckneyville Airport ( PJY )
>>
>> A reminder, the 11th annual rec.aviation flyin that started here many
>> years ago is coming up May 19, 20, and 21 at Pinckneyville. If you
>> are planning to come please let Mary know at so that
>> she can make sure to have enough steaks on hand to dinner. :-)
>>
>>

[Peter Dohm]

> >> I was just thinking that the silk thread idea isn't mentioned in
> >> the "How to build an inexpensive aero engine" book, nor does GP or
> >> Revmaster mention it.
> >>
> >> Or have I lost that cell already?
> >
> >I dunno. It was in all of the do-it-yourself VW manuals "back in the
day"
> >and genereally mentioned #50 as the thread size. I had presumed that #50
> >was a fairly stout thread, however a post by Highflyer in this
conversation
> >leads me to wonder and a breif www search was less than informative...
> >
> >Peter
> >
> Thread numbers, IITC, are like wire guages. A #10 is quite stout, and
> a #36 is a typical machine sewing thread - with a #50 being quite
> fine. If a sewing machine has ANY tension problems, you won't sew with
> #50.Just what I remember from the sewing I did when I was a kid (my
> mother was a very accomplished seamstress).
>
Thanks, now I'll use the right stuff in the future.