Finally picked up a bunch of seals so I can get some Mac motors together. Instead of SKF, the local bearing house carried Timken. I know a lot of you mentioned picking up the SKF at Napa, and other places. Just curious what you paid for them.
Here are the numbers again just in case someone wants to jot them down for future use.
SKF TImken McCulloch Application
6763 474261 50663 All flywheel except Mc10
6816 471553 104432 49MC, 91MC, 92-93-101 pto Mc10 mag/pto
7414 254270 104128 Mc5-9, 49, 90-91 pto
I noticed all of these Timken seals are double lip, which I really like, especially for my old chainsaws. On the gear reduction models the pto seal is supposed to be installed backwards. With the double lip its not a concern. I never bought the SKF seals before, so someone please chime in if they are also double lip.
My original concerns on cross referencing these to SKF numbers showed the 6763 and 6816 were for a .688" shaft, while the crank is only 17mm or .669". Thats a huge difference when pressure and vacuum are in play on a rotating shaft. But these fit very well and have a good interference without too much drag.
Mac seals
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Terry Bentley
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Tom Smith
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Re: Mac seals
Terry, SKF seals are not double lip. Do you have a Timken seal reference number for the Mc-20 thru Mc-100 PTO double lip seal? Tom
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Terry Bentley
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Re: Mac seals
I dont have the SKF number and have not needed any large pto seals as of yet. There is one issue to these seals. The SKF and Timken seals for 203 bearing are for a .688" shaft, even tho the actual shaft diameter is .669". So the outer lip of seal is almost useless. The PTO seal for .750" shaft(needle bearing) is correct for the diameter and outer lip is functional. But either way the outer lip will retain grease to extend life of seal. I did cross some of the seals to correct diameter of shaft, but the OD had a slightly tighter interference fit. The metal case was also completely encapsulated in the nitrile rubber like all of the Jap, Rotax and other foreign motor seals. I have not acquired any to confirm they will work without any complications.
If the SKF # is 7829, I will see what is available, when I get to my other PC.
If the SKF # is 7829, I will see what is available, when I get to my other PC.