Rocker covers
Road Warrior
Joined: Dec 2015
Posts: 1,826
Likes: 1,046
From: Southwest Desert
Never use sealant on any gasket. Let the gasket do the work, or fix the issue. A temp fix would be okay I guess, but once you start the slippery slope of fixing thigs with silicone sealant and rubber bands...Well...Use James Gaskets, they are the best in the industry.
HDF Community Team
Joined: Dec 2005
Posts: 5,374
Likes: 2,570
From: NC USA
Good purchase in the nick of time. Congrats!
Seasoned HDF Member
Joined: May 2008
Posts: 21,026
Likes: 12,549
From: South Carolina
I use sealant on a lot of gaskets (Hylomar).
There are many applications where a sealant is not needed, but it just helps make the job easier, such as holding a gasket in place during assembly.
The Hylomar doesn`t harden, and when it is time to replace a gasket, it will not be stuck (embedded sometimes) in the aluminum.
Easy to say fix the issue, but a lot of the stuff some of us work on is impossible to find parts for.
Last edited by Dan89FLSTC; Jul 17, 2020 at 01:00 PM.
HDF Community Team
Joined: Dec 2005
Posts: 5,374
Likes: 2,570
From: NC USA
Two totally different animals.
Had a very bad (and very expensive) experience with Haylomar years ago, so I won't speak to that other than to say, it's thin stuff. Plain grease or RTV works as well for the few things I'd even consider it for. Just my opinion.
Aviation Permatex however, I can speak to. It's for putting things together that you hope and pray will never need to be disassembled again. Works great for sealing cork from gasoline (like a tank float) and is impervious to everything including steam. Only thing that will degrade or thin it before or after curing is denatured alcohol. If you glue your rocker covers down with that stuff, better than even chance you'll need a hammer, thin chisel and utility knife to even get them apart and you'll be cleaning for days to get it off the chrome parts.
Stick with clean and dry for the rocker cover rubbers. If you're using the old style (fiber) on the lower housing to head gaskets, then most anything is good. If they're the rubberized metal - dry only.
-----------------------------------
I'll stand by my recommendations on the rocker covers, but will offer this disclosure on Hylomar before too many get bent out of shape. This came up on here, 12-14 years ago and without the long story, I used a NAPA Hylomar brand in a tube and it's quite possible I got something mis-labeled or even a bad batch. It squeezed out and had the consistency of Prussian Blue Marking Compound. Thin, runny and barely stuck to anything... used it anyway on request of a customer and ended up splitting the cases (again) and having to re-seal the halves and the oil pump as well. Hot oil washed it out, best I could tell. Again, a lot of guys sing praises of it, but never again for me.
Had a very bad (and very expensive) experience with Haylomar years ago, so I won't speak to that other than to say, it's thin stuff. Plain grease or RTV works as well for the few things I'd even consider it for. Just my opinion.
Aviation Permatex however, I can speak to. It's for putting things together that you hope and pray will never need to be disassembled again. Works great for sealing cork from gasoline (like a tank float) and is impervious to everything including steam. Only thing that will degrade or thin it before or after curing is denatured alcohol. If you glue your rocker covers down with that stuff, better than even chance you'll need a hammer, thin chisel and utility knife to even get them apart and you'll be cleaning for days to get it off the chrome parts.
Stick with clean and dry for the rocker cover rubbers. If you're using the old style (fiber) on the lower housing to head gaskets, then most anything is good. If they're the rubberized metal - dry only.
-----------------------------------
I'll stand by my recommendations on the rocker covers, but will offer this disclosure on Hylomar before too many get bent out of shape. This came up on here, 12-14 years ago and without the long story, I used a NAPA Hylomar brand in a tube and it's quite possible I got something mis-labeled or even a bad batch. It squeezed out and had the consistency of Prussian Blue Marking Compound. Thin, runny and barely stuck to anything... used it anyway on request of a customer and ended up splitting the cases (again) and having to re-seal the halves and the oil pump as well. Hot oil washed it out, best I could tell. Again, a lot of guys sing praises of it, but never again for me.
Last edited by t150vej; Jul 21, 2020 at 01:27 PM. Reason: full disclosure
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Road Warrior
Joined: Aug 2005
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Road Warrior
Joined: Aug 2005
Posts: 1,949
Likes: 288
Just wanted to report back that I replaced the aftermarket rocker cover gasket with Harley OEM (updated version -92A) and took scoot for a 120 mile jaunt. No leaks! Thanks all for useful suggestions and advice.
Seasoned HDF Member
Joined: May 2008
Posts: 21,026
Likes: 12,549
From: South Carolina
Always let Hylomar dry for at least 15 minutes before assembling the parts.
The main reason I use it is that it holds the gasket in place, and even better, it makes the gasket much easier to remove vs installing a gasket dry.
As you say, it`s definitely not for sealing crankcases...
Last edited by Dan89FLSTC; Jul 24, 2020 at 12:12 PM.