I discovered Norton Service Release N3/68, Dated September 1973, in which the advice is to use "Loctite Plastic Gasket" when installing a copper head gasket. My query is this, what exactly is "Loctite Plastic Gasket" and is there a number so I can identify it. Thanks
Loctite Plastic Gasket
- Thread starter Changaroo
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Loctite 549 is possibly the modern equivalent, at £249 per 250ml I will not be buying any to find out. Is the service sheet referring to using this on the head gasket or replacing the barrel base gasket. For replacing the barrel base gasket then loctite 515/518 is the modern method.
Thanks kommando. The service sheet refers to using it on the head gasket. I will not be buying any Loctite 549 at that price either.
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Mick Hemmings used wellseal jointing compound on the flame ring type head gasket, in his video on Norton engine rebuilding. I don't see why it couldn't be used for the copper gasket as well.
I have used it with great success on the flame ring type. Coat both sides and leave it overnight to get tacky. Drop it on and torque it up.
rimmerbros.com
Cheers
Tom
I have used it with great success on the flame ring type. Coat both sides and leave it overnight to get tacky. Drop it on and torque it up.
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Tom
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The Ultimate Copper Head Gasket Sealant Comparison
PLIOBOND CONTACT CEMENT darkens & hardens at 450 to 500F and loses integrity at 500 but still stays in place and when its cooled it remains adhered to the metal. Stays adhered at 400 F.
jsmotorsport.com
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I use it almost everywhere. Have been for over 40 years on Panhead Hogs, SB Chevys, 3rd Gen Hemis and now my MK II Commando. Depending on the application, a light or heavy coat is applied and left to tack up before assembly. What I really like about it is the fact that when you dismantle the parts, the gaskets don't stick.
marshg246
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There may be no actual modern version. Back then, Locktite made sealers for companies: "Triumph Locktite" was different than Norton. For Norton Villiers, notice a primer and then the "Plastic Gasket" and obviously a British product since catalog is spelled "wrong" or is it spelt right 
I seen no requirement for sealer on copper head gaskets, but caution, they aren't supplied annealed and it is very important to anneal them. I would use CopperCoat on both sides just for insurance. On Triumphs, I've always used annealed copper with no sealer and have never had a leak.
I seen no requirement for sealer on copper head gaskets, but caution, they aren't supplied annealed and it is very important to anneal them. I would use CopperCoat on both sides just for insurance. On Triumphs, I've always used annealed copper with no sealer and have never had a leak.
The yaki
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I was advised by mick hemmings to use wellseal on all gasket surfaces. Trying to disassemble often resulted in having to remove the stuff with difficulty. Most gaskets I just use grease or in the case of a head, a new one every time. No problems as yet ! Roy.
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I had used Loctite plastic gasket for close to 50 years and used to get good results, I put my Mk3 together with 518 no gasket on the barrel as per manual [everything super clean] I now have a weep from the barrel joint just enough to be annoying, loctite is not what it used to be!
