Valve seal Recommendation(s)

elefantrider

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Is anyone aware of a cutter to install these PC teflon spring seals onto factory guides? I have a low mile head which doesn't need new KW bronze guides.
 

cliffa

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Cliff,
That web link describes the seal material as "Solid White PC". My limited understanding is that Teflon is described as PTFE or similar. What is solid white PC?
chaztuna, apparently Teflon is a brand name of DuPont and is actually PTFE (PolyteTraFluoroEthylene)


This is the sales blurb from the KW website...

"SEAL STYLE 6​

KPMI® solid white PC Style valve stem seals are available for builders who prefer a PC Style seal. These seals incorporate a clasp around the body of the seal and a choker spring around the neck of the seal. KPMI® solid white “PC Style” seals are manufactured from PTFE. PTFE material does not have “memory” and therefore is subject to creep. Creep allows the seal to conform to mating surfaces. Also, fillers have been used to keep the material stable and to reduce friction. PTFE is known to retain its mechanical properties at temperatures as high as 500°F. The twin spring design provides continuous tension on the valve guide and the stem of the valve. When your build creates extreme conditions…arm it with KPMI® “PC Style” Valve Stem Seals!"


I think "Solid White" may be another product name.

If you are buying some, would you consider buying extra's and posting some to me? as KW quote $25 to send 4 seals to Switzerland which is bonkers.

Cheers,

cliffa.
 

cliffa

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Is anyone aware of a cutter to install these PC teflon spring seals onto factory guides? I have a low mile head which doesn't need new KW bronze guides.
As far as I'm aware the seals being discussed on this thread are a direct replacement for the factory seals, i.e. no cutter required.
 
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The stock type seals work fine as long as they have the springs. But most suppliers send them out without the springs. You can get them from Old Brits (insist on the springs). Other brands with the springs do not always fit - some are too tall and strike the spring retainer.
I had some stock ones with springs and they turned hard as rock after about 15,000 miles. Then the bike started using oil. Some of that riding was in very hot conditions. I replaced them again with stock ones, but I think the teflon ones would have been better. I will put teflon ones in the next time I have the head off.
 

cliffa

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PTFE ( Teflon ) is the way to go. I hope Andover realizes this one day and dumps rubber/plastic. Who's going to notice originality inside the engine ?
I sent a P.M. to Madnorton some time ago asking if AN could start stocking them. I was not worthy of an answer apparently. :(

I'll try ZFD instead.
 
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Time Warp

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Is anyone aware of a cutter to install these PC teflon spring seals onto factory guides? I have a low mile head which doesn't need new KW bronze guides.
I can't see why they would not be a direct fit with Kibblewhite, stock 750 and 850 having 0.500" OD guides at that location. (I just measured)
The relief at the guide top edge looks to be all but the same also.
 

Fast Eddie

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chaztuna, apparently Teflon is a brand name of DuPont and is actually PTFE (PolyteTraFluoroEthylene)


This is the sales blurb from the KW website...

"SEAL STYLE 6​

KPMI® solid white PC Style valve stem seals are available for builders who prefer a PC Style seal. These seals incorporate a clasp around the body of the seal and a choker spring around the neck of the seal. KPMI® solid white “PC Style” seals are manufactured from PTFE. PTFE material does not have “memory” and therefore is subject to creep. Creep allows the seal to conform to mating surfaces. Also, fillers have been used to keep the material stable and to reduce friction. PTFE is known to retain its mechanical properties at temperatures as high as 500°F. The twin spring design provides continuous tension on the valve guide and the stem of the valve. When your build creates extreme conditions…arm it with KPMI® “PC Style” Valve Stem Seals!"


I think "Solid White" may be another product name.

If you are buying some, would you consider buying extra's and posting some to me? as KW quote $25 to send 4 seals to Switzerland which is bonkers.

Cheers,

cliffa.
Ok, I’m gonna have to ask the dumb question here... what does PC in the name ‘PC style’ mean / stand for ?
 

cliffa

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I just did some investigation and found this on tinternet:

"PC is a brand name, it stands for Perfect Circle, which is a division of Dana Corporation. PC is a manufacturer of valve stem seals for OE as well as the aftermarket"

So does "PC Style" mean they are a copy?
 
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I was wondering the same thing. I cannot see any info. on the KW site.
Well working for Dana many years ago has its advantages.

PC is a brand name, it stands for Perfect Circle, which is a division of Dana Corporation. PC is a manufacturer of valve stem seals for OE as well as the aftermarket.

So PC style is a knock off of a seal made by Perfect Circle.
 

cliffa

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I'm learning so much today. "Positive" seals are fixed to the guide, and "Umbrella" are fixed to the valve stem.
 
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Also with a positive seal if the guide material is not self lubricating then it will fail as there will be not enough oil getting to the guide.
 

elefantrider

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Also with a positive seal if the guide material is not self lubricating then it will fail as there will be not enough oil getting to the guide.
Is that so? I have PC seals fixed to iron guides on automobile heads. Seem to work fine with stainless valves.
 
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Is that so?
Cast iron is self lubricating from the high carbon content, the Kibblewhite nickel aluminium bronze guides are also self lubricating, the ones to worry about are the plain bronze ones made down to a price. I hardly even run my lathe with coolant and the cast iron saddle runs over the cast iron bed dry as it was designed.
 
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Also with a positive seal if the guide material is not self lubricating then it will fail as there will be not enough oil getting to the guide.
IIRC some the PC type seals had a SMALL notch in it so it would give a little oil to the guide
 

cliffa

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Also with a positive seal if the guide material is not self lubricating then it will fail as there will be not enough oil getting to the guide.
I read that as well, and I also found this:

"There is some misinformation out there that teflon seals will dry up the guides/stems and cause galling. This is the case ONLY if the stem/guide clearance is too tight. If you look at a PC Teflon seal, the stem hole is very slightly chamfered, which draws an minute amount of oil each time the valve opens. Some competitive Teflon seals have a very sharp edge on the stem hole, therefore they do not meter oil as the PC seals do. "
 
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I'm wondering if the KW 71006 teflon seals are the same seal as Compcam and others. Compcam part 513-16

 
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