Fleetwin Exhaust Plate

[PugetSoundBoater]

quote Chris_P:

PSB,

Sorry but you definitely NEED sealer on head gaskets. Perhaps you are referring to not needing to when installing a new style gasket with the sealer already built in? Regardless, extra sealer wont hurt anything.

I omitted that the newer head gaskets have the sealant applied when made.
Thanks for catching my oversight in my response and your clarification on this issue.

"Some people want to know how a watch works, others just want to know what time it is"
Robbie Robertson

[drifter]

I have a book published by Peter Hunn titled "The Classic Outboard Motor Handbook" – copyright 2003. On page 91 there are several photos of the cylinder head installation on a 1958 Johnson 10hp. Very clearly in the photo you can see that the mechanic is applying, in liberal amounts , the silver, gooey, Permatex Anti-Seize compound to the crankcase head surface. The heading with the photo states: "a gasket sealing lubricant is applied to water jacket and cylinder assembly surfaces".
Is there any instance where this might be a good practice or was this possibly a mistake in staging the photo situation?
Drifter

[garry-in-michigan]

There was never any mention of a sealer used on head gaskets in the 1950’s Service Manuals. What was stressed was to be sure all surfaces were clean and FLAT – and to ALWAYS use a new head gasket . . . 🙂

[amuller]

I don’t think sealers are of much value or normally needed with a new head gasket. But when reusing one I would probably use the "Aviation Permatex" or something similar. With the increasing cost and decreasing availability of head gaskets there is obviously more temptation to reuse them.

Agree with NOT using copper-filled antiseize on aluminum. The aluminum flavor is readily available but its hard to know if it has graphite or other electrochemically active components.

One thing to bear in mind is that anti-seizes, whether metal based or teflon based, have a low coefficient of friction and can easily lead to overtightened fasteners. There is not usually warning of this on the container. Maybe it’s safer to use the OMC gasket sealer or the Mercury equivalent on threads?

[PugetSoundBoater]

I have also thought about the real possibility of over torquing fasteners when using anti seize. So now only use it on Spark plugs.
As i understand ,torque values are for clean and dry threads. Most fastener torque values are listed in a range for example 50- 70 in. lbs. , so there is some leeway there.

"Some people want to know how a watch works, others just want to know what time it is"
Robbie Robertson

[chris-p]

Agree ensuring the threads are CLEAN on the head bolts, and the head and block are clean and true are very important. Seen so many put together with crud still on both I know that is not happening though. I run them on my deck to ensure straight and polished before installing a head gasket.

[bobw]

Agree with Chris on making sure head bolt threads are clean prior to installation to get a proper torque setting. I either wire brush any bolts I intend to re-use or just use new bolts. I also run a thread chaser (not a tap) down all bolt holes to clean them out. Amazing how much crap you can dig out of some head bolt and exhaust cover bolt holes.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

[Author]

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