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Extreme Veteran
Posts: 398
 
Location: Milano, Italy | Hi everybody I am reassembling (for the hundredth time) my Poly heads (318) on the block, but I fear I have some minor irregularities on the surface of the block that could compromise my head gaskets sealing. Could it be a good idea to spray a light coat of aluminium paint on the block to help the gaskets sealing properties? |
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Board Moderator & Exner Expert 10K+
Posts: 13081
  
Location: Southern Sweden - Sturkö island | Use copper spray instead, there's an appropriate seal-helper here https://www.amazon.com/Permatex-80697-Gasket-Hi-Temp-Adhesive/dp/B00... |
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Exner Expert 10K+
Posts: 10033
Location: So. Cal | Use a wire wheel on a grinder to make sure you have the surface clear of any hard deposits. |
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Extreme Veteran
Posts: 398
Location: Milano, Italy | Of course I did that. Now it's superclean. |
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Extreme Veteran
Posts: 398
Location: Milano, Italy |
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Extreme Veteran
Posts: 398
Location: Milano, Italy | wizard - 2024-02-07 4:01 PM Use copper spray instead, there's an appropriate seal-helper here https://www.amazon.com/Permatex-80697-Gasket-Hi-Temp-Adhesive/dp/B00... Fact is, importing a good here in Spain ( I moved here since one year) it's quite a difficult affair. The spanish seem to enjoy the most crazy bureaucracy, making very hard to receive packages from any Country abroad, even Europeans.
So if I can use an aluminum spray can, I might be saved. |
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Expert 5K+ Passed away 30th Sept 2024. You will be missed Chuck!
Posts: 8954
Location: WHEELING,WV.>>>HOME OF WWVA | make sure the heads are super clean and use a good sealer. if the motor is running in the car, install new gaskets minimally tight. warm up
the motor and tighten again but don't force tighten. tops of gaskets aren't too important but the sawtooth is -----------------------------------later
and make sure the pans are clean and straight !! |
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Veteran
Posts: 146
Location: Denver, Colorado, USA | Lonesome Mopar, the answer to your question completely depends on the type of head gasket you are using. If you are using the most common A-block poly 318 gasket available, the FelPro 7734PT, you should never, ever use any type of sealant. The gasket is laminated with fiber layers embedded with sealing compound and is designed to be installed dry. Using sealant on this type of gasket can both impact the gasket's seating and actually cause leaks. The block deck and head surface should be bare steel free of all debris and wiped off with lacquer thinner or brake cleaner to remove any oil/residue before setting down the gasket.
If you are using a OEM-type steel gasket, the block deck, head surface, and gasket should be bare steel free of all debris and wiped off with lacquer thinner or brake cleaner to remove any oil/residue. Hang the gasket from a wire and spray both sides evenly with a complete coating of a copper-compound gasket sealer (I prefer the Permatex 80697 wizard mentioned). Some people use Permatex Indian Head shellac 20539, but the spray is much easier to apply and provides a great seal.
You should not any type of enamel spray paint. It is not designed to withstand the temperature and pressure, will burn to ash around the cylinders, and will not maintain the necessary bond to contain the combustion pressure. |
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Extreme Veteran
Posts: 398
Location: Milano, Italy | Great hint, thanks a lot. I will assemble them dry as you suggested. thanks again!!!!! |
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Expert
Posts: 3082
Location: N.W. Fla. | PolyJ - 2024-02-07 6:48 PM
If you are using a OEM-type steel gasket, the block deck, head surface, and gasket should be bare steel free of all debris and wiped off with lacquer thinner or brake cleaner to remove any oil/residue. Hang the gasket from a wire and spray both sides evenly with a complete coating of a copper-compound gasket sealer (I prefer the Permatex 80697 wizard mentioned). Some people use Permatex Indian Head shellac 20539, but the spray is much easier to apply and provides a great seal.
I've used aluminum paint on bare steel gaskets in my Hemi without any problems. However, when spraying I lay them flat, but off the surface using roofing nails to support them, for spraying. Hanging them can cause runs which caused leaks. |
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Expert
Posts: 3082
Location: N.W. Fla. | Forgot, What do you mean by "irregularities on the surface"?" |
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Veteran
Posts: 146
Location: Denver, Colorado, USA | Mopar1 - 2024-02-26 8:37 AM PolyJ - 2024-02-07 6:48 PM If you are using a OEM-type steel gasket, the block deck, head surface, and gasket should be bare steel free of all debris and wiped off with lacquer thinner or brake cleaner to remove any oil/residue. Hang the gasket from a wire and spray both sides evenly with a complete coating of a copper-compound gasket sealer (I prefer the Permatex 80697 wizard mentioned). Some people use Permatex Indian Head shellac 20539, but the spray is much easier to apply and provides a great seal. I've used aluminum paint on bare steel gaskets in my Hemi without any problems. However, when spraying I lay them flat, but off the surface using roofing nails to support them, for spraying. Hanging them can cause runs which caused leaks. Sometimes people get lucky using unorthodox materials, but enamel spray paint is not an appropriate head-gasket sealant. Since there are specific sealants formulated for steel head gaskets that cost about as much as a can of enamel spray paint, I see no reason to use enamel paint and take the risk of flooding an engine with coolant when the proper sealant has a far better track record at maintaining a strong seal.
As for runs when hanging the gaskets vertical for spraying the appropriate sealant, runs mean the user is applying the compound too thick too quickly. Repeated lighter fogged coats should be applied until full coverage, just like when painting any vertical surface such as a car's quarter panel. There's nothing wrong with laying the gaskets flat, and I'd recommend that if the user is prone to running paint, but hanging and spraying is much, much quicker and helps maintain a uniform thickness. |
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aluminium paint on the block under the head gasket
