Engine case sealer?

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

"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.

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. :-)

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 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. :-)

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.