RTV for Cylinder block?

[jayjones72]

Any ideas on what RTV sealant to use for resealing my block after i reinstall the pistons? Are there different kinds, better brands, where to get? does it need to be Marine grade?
Thanks

 

[Frank Acampora]

Re: RTV for Cylinder block?

I have used almost everything with good results: Black RTV, Blue RTV, White RTV, The flanges are so wide that it really doesn't matter. Don't like Permatex though. HOWEVER: When rebuilding for another person I like to use the super expensive red anaerobic sealant that Evinrude uses. Locktite brand, I forget the number, 15 bucks for an 8 ounce tube but works really well.

 

[jayjones72]

Re: RTV for Cylinder block?

Thanks for the reply i was thinking on the black. It seemed a little expensive
like 24bucks for 13 oz I think from boat.net.
It's nice to know I have options.
Not sure if it would work but I have a whole tube of Hondabond I used for the oil pan on my acura it's really good stuff. May not be useful here just a thought.

 

[jason32038]

Re: RTV for Cylinder block?

Anything will work depending on how you use it. I like to use high tack rtv sealant on vehicles it works very well to hold gaskets in place when assembling. Are you trying to use rtv in place of the rubber crankcase gasket? If so i'd make your bead in the groove and let it dry completely...high tack will make it faster. When it's dry apply a small amount on the inside and outside of the bead and let it dry about 70% and reassemble block. If you dont let it dry somewhat it will force sealant inside and outside the block and won't create the best seal.

 

[jayjones72]

Re: RTV for Cylinder block?

Great advise.
I'm using it for the spacer plate from the block to the lower leg & for the crankcase around the groove and I think the book says around the crank bearings also. Maybe even some of the bolts.
I will get the block back next week from the machinist. (93 force 120)
This will be my first rebuild.
Tear down was pretty easy since I bought a complete parts motor for 200 bucks(91 force 120) and got to practice on it first so my motor was a snap.
If any one is interested i will try and get some pictures on here.