crankcase joint seal

[DanH]

We must be careful saying "Permatex", a brand name with dozens of different sealing products. Need a product number.

You can't even be sure of product names. Some years back I bought some "Hylomar" at the auto parts store and it was not the classic blue gel. Had to order from an aircraft supply to get the real stuff.

[apkp777]

Permatex 3D aviation "form a gasket" is what AERO sent me and told me to use.

I can not find any POB #4 "Perfect Seal sealant". The lycoming OH manual says to use "a non-hardening sealant"? That leaves lots of choices.

SI 1125D says to use POB #4 or Loctite 515 or RTV 102 (White Silicone).

To the original post about the success of using RTV 102. I am not convinced that this is a good solution. I am all ears though. Right now I am planning to go with the Permatex 3D.

[Noah]

POB #4 "Perfect Seal sealant" is available. You can buy it from Mattituck, or search the archives, I recall somebody posting an internet source for it some months back.

[rivetshaver]

Thanks for the replies, It appears that no one has used rtv 102 during their engine build. It is quiet interesting the varied opinions and variations from specifically approved products and procedures. The concencus seems to be that the string and sealant method is the most widely used. I am leaning in that direction also. Now I need to find some string and POB sealant.

I am flattered to be called Dr. Targonski

[rocketbob]

Originally Posted by rivetshaver

The concencus seems to be that the string and sealant method is the most widely used. I am leaning in that direction also. Now I need to find some string and POB sealant.
i

...and its also worth noting that most case leaks happen with engines that use POB#4/string. On one engine certified engine I did recently I used two strands, POB #4 and did everything correct and it still ended up leaking.

[The Green Baron]

I intend to use Hylomar and 2 strings of silk thread as I have yet to hear anything bad about that combination. I like the fact that it allows you more time as it doesn't dry fast....or at all. Silk thread is available from Joanne Fabrics for just a few dollars. Hylomar is available on Amazon.com from various sources.

John

[az_gila]

Originally Posted by DanH

We must be careful saying "Permatex", a brand name with dozens of different sealing products. Need a product number.

You can't even be sure of product names. Some years back I bought some "Hylomar" at the auto parts store and it was not the classic blue gel. Had to order from an aircraft supply to get the real stuff.

...but the original stuff is Hylomar Universal Blue.

The Racing Formula is the same stuff with acetone as a solvent...

http://www.hylomar-usa.com/_resource.../products.html

It is also Permatex part # 85249.

http://www.permatex.com/products/Aut...ge_Sealant.htm

Interestingly enough, one of the main distributers for the Hylomar Blue Racing Formula is Harbor Freight --

http://www.harborfreightusa.com/usa/...bCategoryName=

Lots of Hylomar info and history at the links above.

http://www.hylomarblue.com/

Many part numbers and options so buy carefully, but this is the original Rolls-Royce developed non-hardening sealant.
Harbor Freight is a good source, but a local airpark resident found it was an on-line order only - maybe a store could special order it?

Your local Grainger store should be able to get the original Universal Blue stuff - imported from the UK according to their info page --

http://www.grainger.com/Grainger/items/2VUV1?Pid=search

[hgerhardt]

See post #2 of this thread: http://www.vansairforce.com/communit...ht=loctite+518

Don't use Loctite 515. It's not meant for aluminum. Loctite instead recommends 518, aluminum flange sealant.

I used 518 and fwiw, after 215 hours and 2 years, dry as the proverbial bone.

Heinrich Gerhardt
RV-6, flying

[chaskuss]

Originally Posted by az_gila

.snipped

The Racing Formula is the same stuff with acetone as a solvent...

http://www.hylomar-usa.com/_resource.../products.html

It is also Permatex part # 85249.

http://www.permatex.com/products/Aut...ge_Sealant.htm

snipped

Gil,
Wow! Great post with lots of good info on Hylomar. I'll add another. I've used both the original and the Permatex version listed above. Here is a link to the technical data sheet for the Permatex version found at your local auto parts store. See

http://www.permatex.com/documents/td...tive/85249.pdf

Charlie Kuss

[szicree]

I did the silk thread deal at Superior's build school once. It was no big deal at all. The actual mating was done on an engine stand with the crank standing upright. As I recall, we put a dowel through the wrist pin bore and used this to hold the first case half in place. It was easy, but I would want an extra pair of hands and a couple of dry runs before attempting it again. Also, I was told by the instructor that the silk thread provides a gasket of predictable thickness, leaving just the right amount of sealant.