Thinking About Using Spray Sealer on a MHG?...Might Want to Read This
- Thread starter jdub
- Start date
JustAnotherVictim
Supramania Contributor
Making sure no one is confusing it with regular RTV. 
Plus I thought Orange RTV was orange not copper.....
Plus I thought Orange RTV was orange not copper.....
well, thats what I saw on Option though.. they put that orange RTV (might be a standard RTV for Nissans??.. i dunno) anywayz, Ive never done it and I would never do it either.
crazy Japanese dudes...
aite, peace.
crazy Japanese dudes...
aite, peace.
wanted to add an interesting note:
I received a new custom thickness hg from Cometic and EDIT: see note is post #46.
On two freshly machined surfaces (head is mirror, block is as smooth as his CBN cutter could get it) there should be no need for additional 'sealants' on the new HG, correct?
I received a new custom thickness hg from Cometic and EDIT: see note is post #46.
On two freshly machined surfaces (head is mirror, block is as smooth as his CBN cutter could get it) there should be no need for additional 'sealants' on the new HG, correct?
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That's interesting :icon_conf
You can go either way...copper spray is not going to hurt anything in this case and will fill any imperfections.
You can go either way...copper spray is not going to hurt anything in this case and will fill any imperfections.
check that-
After drilling out the front corner rivet, I wiped the area clean with brake cleaner and it smudged. The top layers have a hard and shiney dark grey coating that is smooth to the touch and shows finger prints. I assumed it was something inherant in the steel itself, but that corner that I wiped looks darker and has a very dull finish .
I guess I would have expected a viton (or any elastomer for that matter) coating to have more of a forgiving surface structure - My first assumption seems to be incorrect.
Edit made above...(post #44)
After drilling out the front corner rivet, I wiped the area clean with brake cleaner and it smudged. The top layers have a hard and shiney dark grey coating that is smooth to the touch and shows finger prints. I assumed it was something inherant in the steel itself, but that corner that I wiped looks darker and has a very dull finish .
I guess I would have expected a viton (or any elastomer for that matter) coating to have more of a forgiving surface structure - My first assumption seems to be incorrect.
Edit made above...(post #44)
John,
Curious as to your opinion on this stuff.
http://www.hylomar-usa.com/_resources/_pdf/Hylomar_Univ_Data.pdf
http://www.hylomar-usa.com/_resources/_html/products.html
Curious as to your opinion on this stuff.
http://www.hylomar-usa.com/_resources/_pdf/Hylomar_Univ_Data.pdf
http://www.hylomar-usa.com/_resources/_html/products.html
In terms of using it on a new MHG, I wouldn't...looking at the MSDS for the Hylomar products, they contain acetone and dichloromethane. Both are solvents, with acetone being a ketone that attacks viton...dichloromethane is basically paint stripper.
For use on a bare metal or composite HG, I don't have personal experience with the Hylomar products. The Advanced and Aerograde products have the highest temperature resistance (similar to copper spray)...I would choose the Advanced in a HG application.
For use on a bare metal or composite HG, I don't have personal experience with the Hylomar products. The Advanced and Aerograde products have the highest temperature resistance (similar to copper spray)...I would choose the Advanced in a HG application.
So does anyone have any opinions on what is superior for imperfect surfaces? Stripped viton+copper spray or only the factory viton?
Also, can anyone explain to me what exactly it is about the Cometic gasket compared to the HKS that allows it to have a surface finish of 50RA compared to 30RA? Is it the coating?
Also, can anyone explain to me what exactly it is about the Cometic gasket compared to the HKS that allows it to have a surface finish of 50RA compared to 30RA? Is it the coating?
For the best seal on the worst surface, I would use Hylomar Advanced with new Viton MHG. Hylomar Advanced has no solvents, is easy to use and re-use, and was developed by Rolls Royce to seal jet engines which must be serviced regularly.
I have been using it since it was known as Permatex Hylomar HPF back in the 80's and 90's. But apparently Permatex lost the distribution rights, so now it's like gold... $31.50 for a 3 oz. tube @ http://www.hylomar-usa.com/_resources/_html/order.html.
I always knew it was good stuff, my dad used it on his race engines, and even from NAPA it was over $7 for a 1 oz. tube! But $31.50 plus shipping? And a 3 oz. tube should last a lifetime. I'm still using the 1 oz. tube I bought in the 90's??!!
Next best IMHO would be a tossup between new Viton MHG vs. Copperspray on stripped MHG.
I have been using it since it was known as Permatex Hylomar HPF back in the 80's and 90's. But apparently Permatex lost the distribution rights, so now it's like gold... $31.50 for a 3 oz. tube @ http://www.hylomar-usa.com/_resources/_html/order.html.
I always knew it was good stuff, my dad used it on his race engines, and even from NAPA it was over $7 for a 1 oz. tube! But $31.50 plus shipping? And a 3 oz. tube should last a lifetime. I'm still using the 1 oz. tube I bought in the 90's??!!
Next best IMHO would be a tossup between new Viton MHG vs. Copperspray on stripped MHG.
everyone should be using the hks stopper.. it is the only metal gasket with a bead around the cyl. This gives the head and block something to bite into. It is the same type of gasket used on the mkiv and the reason you don't see them crying about a blown one. Pull the motor resurface the head and the block, then lap untill there are no finish marks. To spray it or not will not be the factor to blow the seal or not.
i know this has been asked but i am still not sure. Titan is a rebadged cometic, and so your saying it has the viton coating. when i look at my new titan mhg it looks like its just plain steel gasket. i expected the viton to actually look like a rubber coating but i cant tell. is it possible that its not coated?should i take a picture and post it?
