Hi Mori, Did the photos come through ok I emailed to you on how I put on the 518?
It can be put on in a 1.5mm bead or screen printed on. For Triumph I used screen printing method using an acid brush from ace hardware. A thin coat on 1 side of case only.
I like to put it on the left case only. Then set right case on & bolt it starting with the 2 "screws" in the cyl. base, then outside the base as specified in work shop manual
. Using a rubber or plastic hammer tap case to level cly. base surface close as possible. The dowels are not perfect so that needs to be checked.
The lip on the left case tends to reduce squeeze out inside the motor. You can wipe squeeze out from the upper inner surface easily.
The beauty of the 518 or 515 type products is any squeeze out of sealant will dissolve in oil & not block any small oil passages. Also since 518 & 515 only harden in absence of air you don't need to rush application. You can take your time & apply neatly & evenly. If you make mistake, simply wipe off & go again.
Be ready with all case bolts. Once you place right case on, 518 starts curing rather quickly. Not too quick, but don't dally on assembly.
All of the "silicon" type sealants have the risk of squeeze out sluffing off into the oil & clogging passages or the oil pump. Even years later little bits can break off. I've seen this many times.
The '69 Bonnie had prior been assembled with red silicon. Little bits of silicon could be found in many places. Exhaust tappet feed was one of them.
Loctite 515 is similar to 518, but is much much stronger in the bond. Can be very hard to separate cases once cured. It does not leak. 515 is less forgiving of sticking to an oily surface. 518 will stick at least somewhat decent to an oily surface, but perfectly clean & dry is preferred. John's brother has been around 518 for some time in piston aircraft engine repair & 518 has proven durable & leak free.
Many manufactures use silicon due to it is cost effective, will seal non machined surfaces well & if applied to clean dry surface is very leak free. Bits of silicon in the oil has been an issue though. At Mercedes Benz there was so much problems with silicon blocking oil passages they have a week long class to train technicians on how to use it correctly.
Silicon on gaskets is a risky plan as it can allow gasket to "migrate" out. The gasket can split & slip out as the silicon does not glue it in place sufficiently. I've seen this many times. 3 Bond doesn't seem so bad on gaskets as it tends to harden after some days. 515 cures & holds gaskets & seals in place quite well. I have not used 518 on gaskets so I don't know what it will do. I've done a few experiments & it seems to hold ok, but not like 515.
515 used to install a seal where the hole is rough or damaged seems to work well, but the loctie acts as a lubricant & seal may want to pop out until sealant cures. In this case you must have some sort of way to hold seal in place like a large flat washer & bolt or something. Usually not a problem though.