Gasket Sealant

[NickSR]

Hi Every one
I have an oil leak between the Rocker Box and Head on my Super Rocket, so when I was 19 I would have used Red Hermetite on the bases and paper gasket never had any problems, now 40 years later do we still do it this way or use silicone Instant Gasket?

Look forward to your comments.

Regards Nick
1962 Super Rocket
1954 C11G

[RichardL]

Nick,

Welcome to the forum. It would be great to see pictures of both your bikes, because we are hounds for such. I think silicone is not preferred for places like rocker covers (at least, not by me) because of the possibility of bits getting into the oil. There is a some discussion of this both ways, plus some other ideas, to be found under a different topic:

http://www.a7a10.net/forum/index.php?topic=501.0

I hope this helps, nevertheless, there are a lot of other eager helpers here.

Richard L.

[bsa-bill]

you could get (have'nt sen it lately) sealant that only sets in the absense of air, it is quite thin and disolves harmlessly in oil.
Personaly I use blue hylomar spread as thinly as possible on the gasket, just enough to form a very thin almost transparent film on the gasket, allow it to dry slightly before thightening down.
 this is just a personal view but I do like to make sure the escape route for oil and pressure in the rockers is clear, the exhaust rockers drain down through the barrels via a small tunnel cast into them (the barrels), this can get gummed up after time, make sure its clear and you wont have excess pressure in there to test your gaskets to much.

All the best - Bill

[Richard]

Hi
I use both red hermitite and hylomar  however I was plauged by this particular oil leak and found the ready made gaskets a bit thin on the front edge of the rear rocker box so I always make mine out of decent gasket paper using the rocker box as the pattern for the gasket. Also i believe that a certain amount of pressure is somehow built up in the rocker boxes when the engine is running and that seems to blow the gasket so since I fitted a breather pipe to the rear tappet cover I have not had another rocker box oil leak on my super Rocket to date.
Now there will be others that may dispute this but try it as making a gasket will cost nothing and getting a spare tappet cover is not a problem nor is fitting and old push bike inner tube valve stem (remove the valve) fitting a pipe to divert to the rear of the bike and try for yourselve.
You have nothing to lose and no damage to the engine will be caused by this.
Good luck with it
Richard

[shabashow]

Here's my comments on sealants from a previous thread.
I've found this stuff much easier to apply, both hylomar and hermatite are a pain to get even on a gasket, and they semm to harden up, so when you go to take the thing apart, half the gasket stays on one surface and half on the other.
John

 Re: my old dripper
« Reply #11 on: 14.12. 2008 13:43 » Quote Modify Remove 

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My local engieering company recommended a product called Curil made by a German company called elring, I believe.
It comes in two types - a hardening and a non-hardening formulation. He usually uses the hardening type, but I've opted for the non-hardening type - CurilK2.
I've tried hermatite and the blue stuff previously, but have always found that it make the gaskets stick the mating surfaces, so when I take bit off, some gasket stays on one side, and some on the other. AS well as that, it's a right palaver getting the surfaces coated evenly.
Since using this stuff, I haven't had any problems, and could even reuse the gasket, if no spare was available.
It's quite thin stuff, and I paint it on to the mating surfaces with a small paint brush, the size you'd use for doing plastic airplane models.
Touch wood - Haven't had any leaks from joints sealed with this stuff, so far,
John

[NickSR]

Hi Richard. L

Thank you for the welcome and the link, found it very helpfull, I will post photos as soon as I work out how to do it.

Regards
Nick
1962 Super Rocket
1954 C11G
Nottingham
England

[NickSR]

Hi Bill

Thank you for the advice, I will check the pressure escape route as suggested.

Regards
Nick
1962 Super Rocket
1954 C11G
Nottingham
England

[NickSR]

Hi Richard
Thank  you for your for your reply, I like the ideal of a vent in the rear rocker cover, its Newark Autojumble very soon should be able to get a spare one there.

Regards
Nick
1962 Super Rocket
1954 C11G
Nottingham
England

[NickSR]

Hi John
Thank you for reply and advice, sounds good to me.

Regards
Nick
1962 Super Rocket
1954 C11G
Nottingham
England