Engine case sealer?

Richard

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

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

Orval Fairbairn wrote:

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.


Pink is for girls, Orval!

"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.

"Orval Fairbairn" wrote in message
news
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here is the now superceded Mil-Product spec for this stuff: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.

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.

Big John wrote:
Richard

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

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

Point taken...

The Bitch!

jls wrote:

"Orval Fairbairn" wrote in message
news

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.

A good sealer is Loctite 515 or 518

"Richard Lamb" wrote in message
ink.net...
jls wrote:

"Orval Fairbairn" wrote in message
news

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.

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.

"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. :-)

"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.

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