Locktite or anti-seize

[BoatBuoy]

I am beginning re-assembly of a lot of the parts on a '56 30hp. Powerhead was good so I didn't have to take it apart. <br /><br />Now comes the dilemma I'm having on what to use locktite on and what to use anti-seize on. <br /><br />My experience ('57 35hp)is that big twins shake a lot and if the bolts are not tightened well, they come loose. Also, in my limited experience, I've pulled more than my share of threads out of aluminum trying to get bolts/screws tight enough to stay in.<br /><br />I'm doing the lower unit, re-installing elec. starter, recoil starter, carb, etc. Should I locktite everything?<br /><br />EDIT: fresh water use only

 

[WillyBWright]

Re: Locktite or anti-seize

Some general guidelines:<br />Red loctite on parts you never want to come apart again such as rod cap bolts.<br />Blue loctite on things things you might need to remove which will be most of the fasteners.<br />Antisieze on things that need to come apart readily like water pump screws.<br /><br />Don't use thread stuff or gasket sealer on fuel related parts like carbs except to mount them to the motor. Antisieze the head bolts cuz you should retorque them once you have a few hours on the powerhead. No gasket sealer on head gaskets. The main reason for gasket sealers is for reusing otherwise good gaskets, or when the surface is imperfect. Otherwise dry is best.<br /><br />Sometimes, grease is the best where O-rings are used. A good general purpose sealer for outboards is Liquid Permatex available in a bottle with a brush in the cap. Don't use Silicone.

 

[byacey]

Re: Locktite or anti-seize

Is silicon OK for around the spahgetti gasket on a lower end gear box, or is this best applied with permatex aviation gasket cement?

 

[Bill Mattor]

Re: Locktite or anti-seize

Finally a topic I know something about. WillyB is right on target with his advise.byacey, Don't use silicone or Permatex aviation, use permatex blue gasket sealer. It is similar to a silicone but has better sealing properties and is easily removed for repair or replacement work.<br />BoatBuoy<br />Antisieze for parts that are in the heat prone zone, blue locktite for lossening concerns, red only if your are sure you never ever need to remove that part.<br /> Also use the torker wrench when the spec's are available and you sould not need anythig else. I myself, ( when working on motorcycles) use lock washers on most all bolts and screws.<br /> For what its worth.

 

[funpilot]

Re: Locktite or anti-seize

Reduce torgue on items with antisieze. A good value is 20% less, or 80% of recommended torgue.<br /><br />funpilot

 

[Paul Moir]

Re: Locktite or anti-seize

I've had no problems at all using permatex aviation gasket cement (#3-H) on the spagetti seal. Silicone normally has poor resistance to the extreme pressure additives such as are used in hypoid gear oils (lower unit gears are hypoid cut). For that reason I've never experimented with it on lower units.<br /><br />Every nut and bolt - with very few exceptions - gets something. For things that tend to corrode & seize I use the permetex aviation stuff on the threads. If water can't get to it, it can't corrode. But I think you'd have the same effect with anti-seize. A word of warning though: don't use copper based anti-sieze. I use a lot of loctite blue. It helps seal out water too.<br /><br />As a side note, I've had great luck using Permatex Motoseal Grey for crankcase halves and other gasoline soaked areas. It's not RTV silicone based and works very well.

 

[Nos4r2]

Re: Locktite or anti-seize

Why not use copper based antisieze Paul? I've never had a problem with it but if there's something I should know then I'd appreciate the info.<br /><br />Cheers

 

[byacey]

Re: Locktite or anti-seize

I have some of this stuff that I was going to try on a head gasket: http://www.hylomar.co.uk/advancedformulation.htm <br />A friend of mine from Pratt and Whitney said this stuff works great, and it never hardens. from the data sheets it looks like it would be good for bolt thread anti-seize and gearbox sealing.

 

[Paul Moir]

Re: Locktite or anti-seize

Nos4r2, metallic copper can exacerbate galvanic corrosion in seawater exposed fasteners. It eats away at the aluminium.<br />Actually, there's lots of marine anti-siezes that contain copper since it works so well. They just throw in a pile of aluminium or zinc or something to sacrafice to the copper. They look black rather than the copper looking stuff you would spread on muffler parts, etc.<br /><br />I know some respected names here always use a sealer on their head gaskets. I pretty well never do myself and just rely on the sealant embedded in them. But I always check the heads for flatness and surface if they're not.

 

[Nos4r2]

Re: Locktite or anti-seize

Thanks Paul. Guess I'm gonna have to buy some proper stuff then <br /><br />Luckily I haven't used any on my current motor!