Author Topic: Opinion on Crank Seals  (Read 519 times)

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mswyka

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Opinion on Crank Seals
« on: April 21, 2018, 02:37:57 PM »
NOS engine assembled, in storage for 35 years, never run.

Should the crank seals be changed?
Intruders:  1978, 1979, 1980, 1981 Custom
Invaders:  1979 340, 1980 440, 1980 440 TOC Custom
Projects:  1979 Invader 340, 1980 Invader 340, 1979 Intruder 440, 1982 Intruder 440, 1980 Drifter 340 F/C, 1972 Panther 303 ...

Interceptor398

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Re: Opinion on Crank Seals
« Reply #1 on: April 21, 2018, 02:53:21 PM »
Start with a leak down test, put some hours on it and test it again.  The rubber is still old rubber.

rminier

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Re: Opinion on Crank Seals
« Reply #2 on: April 22, 2018, 06:30:51 AM »
 I don't think I would trust them, even if they held with a leak down test. It wouldn't be a terrible job to just remove the bottom crankcase half and change them for the peace of mind.
75 SnoJet Astro SS, 79 Kawasaki Invader 440 (two of them), 81 Scorpion Sidewinder, 82 Blizzard 9500, 83 Yamaha Vmax 540, 97 MXZ 670....and holding...for now.

mswyka

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Re: Opinion on Crank Seals
« Reply #3 on: April 22, 2018, 12:52:35 PM »
Sounds like good counsel. 

But this made me ask myself another question regarding replacing crank seals.

What is the true age of the replacement crank seals that we are buying?  I like to think that they are new, but is it possible, in some instances that I could be buying 30 year old seals?
Intruders:  1978, 1979, 1980, 1981 Custom
Invaders:  1979 340, 1980 440, 1980 440 TOC Custom
Projects:  1979 Invader 340, 1980 Invader 340, 1979 Intruder 440, 1982 Intruder 440, 1980 Drifter 340 F/C, 1972 Panther 303 ...

rminier

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Re: Opinion on Crank Seals
« Reply #4 on: April 22, 2018, 06:21:05 PM »
 Good point. With most things related to vintage sleds I would prefer OEM stuff.....thing such as pistons, etc. But a rubber item is a whole different ball game. Even if they are sealed up in a plastic wrapper, they are nearly 40 years old
 I have had great luck with Winderosa gaskets and seal kits in all my sleds....literally all of my sleds listed below have Winderosa crank seals.
 But, I know some very knowledgeable people on here have had trouble with them, mainly with the head gaskets leaking.
I'm going with Winderosa seals on the new Invader that I picked up, but I may tear into it enough to look at the top end, then I would probably prefer OEM gaskets for the cylinder base and head gaskets.
75 SnoJet Astro SS, 79 Kawasaki Invader 440 (two of them), 81 Scorpion Sidewinder, 82 Blizzard 9500, 83 Yamaha Vmax 540, 97 MXZ 670....and holding...for now.

gixxer6

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Re: Opinion on Crank Seals
« Reply #5 on: April 23, 2018, 07:58:56 AM »
Which engine?  If it were a NOS 550, I would change them.  But if it were say, a Drifter motor  ;) , I would run it.  Two reasons, I believe the fanners are more forgiving than the ultra high performance liquid 550ís.  And itís relatively low risk, drifter parts are much easier/cheaper than 550 stuff. 

sprocket

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Re: Opinion on Crank Seals
« Reply #6 on: April 28, 2018, 07:00:17 AM »
I wouldn't be afraid of running seals that are 40yrs old as long you check them over.