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Teflon Seals

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celticdodge

Posts: 139

Joined: Mon Mar 27, 2006 5:29 am

Location: USA

Post Wed Jan 27, 2010 6:07 pm

Teflon Seals

Anybody using Teflon Seals on their intake valve guides on flatheads?
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Frankenstein

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Posts: 1547

Joined: Thu Jun 27, 2002 12:01 am

Location: Interlaken, NY USA

Post Thu Jan 28, 2010 8:58 am

Re: Teflon Seals

No, not teflon ones, but am using stock shovelhead guide seals on both of my BT flatties. Have 2 seasons on them, seem to control oil just fine. Turned down the guides to take the seals, also shortened them slightly so they would bear on the constant diameter part of the stem.
DD
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wilko

Posts: 159

Joined: Fri Jan 15, 2010 7:36 pm

Post Thu Jan 28, 2010 4:31 pm

Re: Teflon Seals

I would imagine flatties would need all the oil mist they can get!!
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Frankenstein

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Posts: 1547

Joined: Thu Jun 27, 2002 12:01 am

Location: Interlaken, NY USA

Post Fri Jan 29, 2010 7:23 am

Re: Teflon Seals

Wilco, I only added the seals after I installed the sporty pump. I had a real problem with oil coming past the guides and coking up the combustion chamber. Likewise, the inlet port had an oil slick on its surfaces. Granted the guides were worn, and maybe just new guides might have been enough. But, I installed new guides with seals after a season of that mess. And all has been fine since.
DD
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celticdodge

Posts: 139

Joined: Mon Mar 27, 2006 5:29 am

Location: USA

Post Sat Jan 30, 2010 7:56 am

Re: Teflon Seals

Thanks for the comments guys.I wonder if the oil mist that was in the intake port was so bad that it caused any affect that altered the fuel and air ratio.Also,was the coking build up in the exhaust port so excessive to cause a lack of performance.My own initial observation on this subject was that an oil mist that somehow clung to the valves hanging upside down in the flatheads would really help extend the life of the motor and out weigh any insignificant oil vapors that were able to enter the intake and exhaust ports and that was probably the reason the factory never introduced the use of valve stem seals.Also,could it be that a modified crank venting system would have had some affect in limiting the amount of oil vapor that was escaping into the ports.Having said all this how can anyone dispute the success in stopping the oil from going into your ports after installing valve stem seals in your intakes,(I am not sure from reading your post but did you also install seals in your exhaust).Still after all this in the quest to make our motors better,I can't help but wondering ,should we all be using valve stem seals on both intake and exhaust or intake only.Thanks again. :D :D
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Frankenstein

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Posts: 1547

Joined: Thu Jun 27, 2002 12:01 am

Location: Interlaken, NY USA

Post Sat Jan 30, 2010 11:43 am

Re: Teflon Seals

CD, in stock configuration, I don't think whatever oil gets to the intake port is a problem. After the pump change, the carbon buildup was unacceptable, at least a mm or more everywhere in the combustion chamber. And only a couple hundred miles to the quart. Admittedly, the bores were out of tolerance also. But the final straw was the blue haze from the exhaust. I don't like a motor that smokes. Says bad things about the builder, I think. At least in my mind it was embarrassing :lol:
But, if we're talking about stock oil systems, probably seals aren't a necessity. I did intake and exhaust valves, by the way.
DD
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celticdodge

Posts: 139

Joined: Mon Mar 27, 2006 5:29 am

Location: USA

Post Sat Jan 30, 2010 12:31 pm

Re: Teflon Seals

OK,high oil consumption and blue smoke put me over the edge,Did you have to modify your valve guides or were you able to slip the seals on the valve stems,seems like the guides should be modified somehow to secure the valve stem seals on the end of the guide to get the maximum wiping of oil from the stems and to seal off the oil mist.Any pictures would be cool,Thanks . :D :D
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wilko

Posts: 159

Joined: Fri Jan 15, 2010 7:36 pm

Post Sat Jan 30, 2010 5:09 pm

Re: Teflon Seals

I suggest with a tight inlet and worn rings would certainly fill your intakes with carbon. But anyway the seals are there now so we wont know if there will be premature wear in the guides until a few thou miles down the track. Please report to us in the future.
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celticdodge

Posts: 139

Joined: Mon Mar 27, 2006 5:29 am

Location: USA

Post Sat Jan 30, 2010 6:15 pm

Re: Teflon Seals

Wilco,for clarity,do I understand your position in that you are you saying that you believe premature valve guide wear will ultimatly be the result of using valve guide stem seals? :D
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Sidewinder

Posts: 89

Joined: Tue Dec 25, 2007 4:04 pm

Location: Norway

Post Sun Jan 31, 2010 2:42 am

Re: Teflon Seals

I run a U 74" with stock lubrication and stock settings (late version pump). There is near to no oil consumtion and no smoke on engine braking. The intake guides is well lubricated and has acceptable wear. The exhaust seem som run more or less dry and have considerable wear for the miles covered.
Torstein
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Frankenstein

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Posts: 1547

Joined: Thu Jun 27, 2002 12:01 am

Location: Interlaken, NY USA

Post Sun Jan 31, 2010 8:53 am

Re: Teflon Seals

Look fellas, I should explain myself more clearly. I started out responding to the question had I used valve guide seals? Well, yes I have, and gave my results to date. BUT, I think my responses in this thread have been confusing.
First, as Sidewinder suggests, on a stock machine, every thing works fine in the intake department, and there's probably excessive wear, by modern standards at any rate, on the exhaust. And oil consumption is acceptable.
If you want to stay with the stock systems, every thing seems to balance out just fine, live with the system as designed, and live in bliss. :-)
But, I wanted to change things on my bikes, I just couldn't leave well enough alone. I was extremely frustrated with the short lifespan of these motors. After fighting it for 35 years of wearing out a top end in 10k miles or less, it just got to me. Besides, we all know I like to tinker. :twisted:
So, there's option one, leave it as the factory did it, and motor into the sunset. (As long as the sunset is less than 10,000 miles away!).
So, of course, when I start messing with things, I start running into problems. Which is what I proved when I started out with a half worn out motor, but one that was doing fine as far as leaking, oil consumption, power, etc. goes.
I changed the oil pump system, and then I had a host of other problems appear. Oil seals on the valve guides was one of the fixes to a problem I made. We'll see if that creates excessive wear problems in the future, don't know yet. I'm probably only at 3k miles on the first conversion at this point.
So, you can stay stock, enjoy the ride, and do a rebuild once and awhile. Or, totally change things around, enjoy the ride, and do less rebuilds.
One last thing. all this refers to the Big Twin 74 and 80 sidevalves. I don't know that the 45's have the same top end problems. I just haven't the knowledge.
Thanks for listening,
DD

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