[rebel-builders] Summary of front engine seal O-320 recipe

[Rick Harper]

Glad to help !

Biggus
----- Original Message -----
From: Garry Wright
To: rebel-builders@dcsol.com
Sent: Wednesday, May 16, 2007 12:00 AM
Subject: [rebel-builders] Summary of front engine seal O-320 recipe


Thanks Rick. By now I have a fair number of suggestions as to how to get
thru this. Mostly its clean it right, do it again, then seal it up with
a reliable bonding material, and wait until it cures.

Reliable bonding materials are:

The original Lycoming recommended goo.
Pliobond.
Loctite 515 combined with 7649 for surface prep.
Some others off this group recomend proseal which is plausible but
unconfirmed.

Cleaning fluids for the purpose are:
MEK
Acetone
Loctite 7649

Final ingredient - extreme diligence in cleaning it.

Thanks to all who made their recommendations.


Rick Harper wrote:

G'day Gaz , Wayne & Everyone .....

OK ...... I finally got to go flying today - and the air was like GLASS !!!

Flew down the coast to visit Jim Stonier (a fellow Rebel builder) - and landed on his !$#%&!# bumpy cross strip ... (I'll be using the loooooong / smoother one next time ! ...

Cruising along at 105 Knots in ULTRA smooth air was a HOOT

Once I get the new spats molded up & made - (along with the tailspring shroud I'm planning to make - and the tailwheel spat I just finished) I'm hoping to pick up a few more cruise knots as well !

I'm also just putting the finishing touches to my new three bladed / ground adjustable hub - which will take my new Ozzy made Carbon Fibre blades - (l....i...k....e...... Warp Drive ones - sorta - but with HUGE blade roots - ( so they won't give up the ghost - like my original WD ones did after 5 hours !!!) and 6" wide blade faces - just like a real Sensenich profile ...

but, I digress .................

Anyway - I got to look at the stuff I resealed my new Crankshaft front seal in with - (which hasn't leaked a drop since) ....

The 2 chemicals are both made by Loctite :

The sealant is Loctite 515 "Flange Sealant / Master Gasket"

The Accelerator is Loctite 7649 (which says it's a "Primer N replacement")

The destructions say to use the 7649 to wash & prepare both surfaces - and then wipe it all off

Then it says - once they are clean , to coat both parts again with the 7649 ....

Then to coat one part with the Loctite 515 - ( but to do BOTH parts if they have "rough surfaces")

Assemble & wait 30 minutes (at room temperature) for the 515 & Accelerant to do their stuff & cure - (longer in cold conditions)

Hope this help all you leaky front seal people !

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[Ken]

Yes BUT...
Anaerobic Loctite products generally need IRON present to setup up
properly. For use on aluminum you should still use the 7649 primer
unless you want to wait a week or more. Don't know if pure acetone is
as effective but I suspect it probably is. Easy to test by sticking two
scraps of aluminum together.
Ken

Garry Wright wrote:

I found out today that the Loctite 7649 is simply acetone in an aerosol
can. I also found out that my old AME uses MEK to clean, then applies
contact cement on both parts to set the seal in place. Lots of options.

Garry

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[Garry Wright]

You are correct Ken - as we have become accustomed - and as near as I
can tell. The can says acetone, 2-ethahexonic acid, organo-copper
compound, and triakylamonium carboxylate. That's a mouthful and close to
meaningless with my 45 year expired first year engineering chemistry.
(I'm a sparky) I know what acetone is but the other stuff is mystery
chemistry. The seal of course is surrounded by iron so may not need the
spray but will get it anyway. The can also says that spraying it on
leaves a residual of this stuff that is good for 30 days so the contents
hang around a while.

This has been an unexpectedly varied subject - thought it was very
simple when I started - but its kind of fun seeing what different people
use with good results. I ultimately bought into Rick's solution but it
is by some distance the most expensive. About $40C for the materials - I
would rather do that than risk having to do it again between here and
OSH this summer. : ) Also, having done it badly the first time, I really
don't want to repeat more than once.

Cheers

Garry

Ken wrote:

Yes BUT...
Anaerobic Loctite products generally need IRON present to setup up
properly. For use on aluminum you should still use the 7649 primer
unless you want to wait a week or more. Don't know if pure acetone is
as effective but I suspect it probably is. Easy to test by sticking two
scraps of aluminum together.
Ken

Garry Wright wrote:

I found out today that the Loctite 7649 is simply acetone in an aerosol
can. I also found out that my old AME uses MEK to clean, then applies
contact cement on both parts to set the seal in place. Lots of options.

Garry

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