Wildguzzi.com
General Category => General Discussion => Topic started by: leafman60 on April 12, 2019, 07:33:00 AM
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I am curious about the opinions from our august body of experienced mechanics regarding preparation of "paper" type engine gaskets for installation. We are talking about "paper" fiber type gaskets used for crankcase joining, cylinder base gaskets etc for engines like the venerable Guzzi motors. Cylinder head gaskets, molded polymer gaskets, o-rings or gaskets with factory deposited sealing beads are not included.
Do you install such gaskets dry? Wipe them with motor oil? Wipe them with grease? Or, do you go beyond the cusp and spray or coat them with sure-nuff sealants like RTV, Hylomar, Hi Tack etc ????
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I'm old school I guess, maybe it's not good, but I kind of wet them with motor oil or 2-stroke oil, I just put some oil on my fingers and go over them, not soaking them necessarily. That's for the flatter paper type used for intakes and cylinder bases and if all the surfaces are perfect. For the puffy newer green gasket types for say valve covers or older asbestos types used for exhausts and such I put them on dry. I'm blending experiences here, not all based on Moto Guzzi engines. I'm referencing two-stroke engines as well.
Edit: At times I've had some issues with sealing, especially intake leaks on two-strokes, and I've resorted to this product instead of using oil on the paper gasket and I and I highly recommend it. It will definitely make a good seal. https://www.napaonline.com/en/p/BK_7651210
Other times I've also had some issue with buggered up surfaces on crankcases, and in those cases I've resorted to the red gummy type sealants in conjunction to the regular gasket. That's sloppy and I don't like it, but it has solved problems in my past life (teenager)
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I have had good luck with putting a real thin coat of Permatex black silicone on one part, then sticking the gasket to it. Then another real thin coat of the same stuff on the gasket.
YMMV.
Larry
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Grease of the type that just happens to be at arms length. Slight film is all you need.
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On pan and valve cover gaskets I use Never Seize on the side going to the case or head. DonG
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Grease of the type that just happens to be at arms length. Slight film is all you need.
^^^^ THIS ^^^^
:thumb:
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I brush both sides with a thin film of anti-seize paste.
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I had an old time Guzzi dealer tell me the way to prepare paper gaskets was to dampen them with water. I don't remember his name but it was when we took a KC10 tanker to the Dayton air show in the mid '80s. I've not tried it yet but he made sense and it may be right. I generally use oil or grease. I believe useing silicone gasket sealer is a maintenance error anyplace on a Guzzi. It's better used on implement gearboxes.
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Some of the paper gaskets like those in the rear diff cover need to be soaked in water to swell up so the cover can be installed with out tearing the dry gasket..
TOMB
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Thin film of grease.
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What I do or don't put on gaskets/gasket surfaces depends on where the gasket is located and the type of gasket. I can't think of any "paper" gaskets on early big block engines except perhaps the "distributor" on Tontis. The rest are a fiber of some sort or composite. Transmission and rear drive do have paper gaskets though.
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I LIGHTLY (like... the thinnest layer possible) grease one part surface of the two being joined, leaving the other dry. Place the gasket on the greased surface, then mate the parts.
I don't care if one side sticks... as long as the other doesn't. That's where tears happen.
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Some of the paper gaskets like those in the rear diff cover need to be soaked in water to swell up so the cover can be installed with out tearing the dry gasket..
TOMB
This. Another example is the endcase gasket for big block five speeds. I just drop them into warm water before installation and the small amount of expansionas the paper swells means the holes line up nicely.
With kingerlite type head and base gaskets I just install them dry.
Pete