Engine case sealer?

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

Thanks!

bBob wrote:

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

Thanks!



Silk thread - on old Continentals.

In article . net,
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.

"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.

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.

"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

"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. :-)

here is the now superceded Mil-Product spec for this stuff:
http://assist.daps.dla.mil/docimages...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.

"flybynightkarmarepair" wrote in message
ups.com...
here is the now superceded Mil-Product spec for this stuff:
http://assist.daps.dla.mil/docimages...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!

In article . com,
"flybynightkarmarepair" wrote:

here is the now superceded Mil-Product spec for this stuff:
http://assist.daps.dla.mil/docimages...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.