Cometic HG design

Mike T

Well-Known Member
Joined
May 3, 2013
New motor is up and running with cometics and sure enough they are seeping a little oil. I put them on dry as suggested and took a lot of other steps that should have aided in sealing.

After looking at another cometic I noticed that the only critical sealing area without ribs/embossing was the areas exposed to oil.

In addition to the oil returns I believe the layers exposed in the lifter valley could seep too. Seems like at a minimum a circle embossed around the oil returns would greatly improve this problem or better yet ribs that run the entire length of the intake side blocking the oil returns and lifter valley.

Any thoughts?
 
The new Cometics are embossed at the oil returns. I always use a light smear of gasket maker there anyway. I stopped using copper spray when I noticed it runs out with the oil. The new ones have another coated layer between the bare layers if you have a thick gasket.
 
New cometics work better than orginals. I agree with guys above.
 
I wasn't aware that they updated the design. Interesting.

I've had excellent results installing them dry as cometic recommends, so I can't complain anyways.
 
The new Cometics are embossed at the oil returns. I always use a light smear of gasket maker there anyway. I stopped using copper spray when I noticed it runs out with the oil. The new ones have another coated layer between the bare layers if you have a thick gasket.
Was totally unaware of this...should have been a no brainier to do this a long time ago. Also makes me think the 1/2 price sale a while ago was to get rid of old inventory.
 
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what were they thinking? nothing between the layers. I guess their super flat, never run test engines surfaces were fine. lol
 
back in the day the dodge neon engine would burst the metal oil sealing ring on the composite hg . It was like the fire ring but with 70 psi oil pressure to it. It would crack and bleed oil like a mofo. The fix was these type of cometics. weird how some stuff fixes things and also makes something else worse.
 
Kinda sucks that my epiphanies usually come after everything is bolted together.
 
Think about the original design....all of the embossed areas would have to be totally compressed for the flat oil return areas to even have a chance at sealing.
 
The new Cometics are embossed at the oil returns.


Rob, how recent was the change? A friend has a newer set (last few months) and his were still the old design. He said they were packaged different than the old ones though.

If it's not too much trouble and you happen to have a newer one around could you post a picture?

Thanks,
Mike
 
I just installed the new set I had. I have 2 sets that are over 1 year old. I will look to see if they are the new style. I havent looked at them. They are spare sets for my engines. The set I just installed were from this year.
 
Dry installation and installation itself of MLS gaskets will continue to be a debate for years to come.

Mike, I have had great results with Hylomar between layers, even when reused. Cleanliness (oil free) combined with a light bead of solicone at the water ports on block and intake side, plus a healthy amount in the head/block/intake meeting corner is a must for leak free installation. Work the silicone into the corner with the rubber gasket, which some omit. I also add a light bead of silicone on the oil free surfaces of the top and bottom of the rubber gasket.

My motto is;
Better safe than sorry. Lol
 
Jerry, I did get the corners by the intake and that part seems good. It's not bad enough to leak on the ground but you can definitely see small wet trails here and there.
 
Jerry, I did get the corners by the intake and that part seems good. It's not bad enough to leak on the ground but you can definitely see small wet trails here and there.
As smart and detail oriented as you are, I figured you did. Was merely sharing the process I use. Let us know how you make out.
 
As smart and detail oriented as you are, I figured you did. Was merely sharing the process I use. Let us know how you make out.


Sure hope my response didn't sound bad Jerry that would never be my intention, you have always been helpful and I value your opinion.
Detail oriented I'll accept but the first part is a huge ? mark. Can't believe some of the DUMB mistakes I make:eek:
 
This set is dated 5/16
 

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This is strange......just took another look at photo of my friends gasket that was purchased a couple of months ago and no ribs on his.
Like I said earlier it came in a new style package though. Must be a mixture of product out there right now.
 
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