Valve Stem Seal Selection, Design and Materials

[Indycars]

Before I can assemble my heads, I need to make a decision about Valve Stem Seals. Not wanting to take anything for granted, I wanted to know more about possible different designs and materials available.

A few things I learned about seals are:

1) There are basically two general designs, Oil Deflectors and Positive type seals. The umbrella or o-ring seal is a type of oil deflector and move with the valve stem, where a positive seal is stationary.

2) They are OIL METERING devices ! They precisely meter the amount of oil passing by the seal and therefore into the the valve guide. Although the requirements for each engine differ according to the design parameters and operating conditions, the oil metering rate is generally within the range 0.1 - 1.0 mg per valve per hour.They are not installed to completely stop the oil, since it's required for valve stem to valve guide lubrication.



3) They operate on the same principle as the main and rod bearings, the hydrodynamic lubrication principle. When conditions are right, there is no metal-to-metal contact. The seal, valve stem and valve guide are riding on a thin film of oil just like main bearings.



4) Depending on the application and the design of the seal, the material used may be nitrile, polyacrylate, fluoroelastomer (Viton), silicone, nylon or Teflon.


The component parts, that make up a seal are:


These links can it explain it much better than I can.

http://www.enginebuildermag.com/Article ... signs.aspx
http://www.hastingsmfg.com/ServiceTips/valve_seals.htm
http://www.skf.com/files/004641.pdf

A very technical article if you are interested.
http://file.seekpart.com/keywordpdf/201 ... 516501.pdf

 

[DorianL]

Re: Valve Stem Seal Selection – Design and Materials

Fascinating, Indy...

 

[grumpyvette]

Re: Valve Stem Seal Selection – Design and Materials

GREAT POST!
thanks for posting the links its sure to help!

BTW its a good idea to never install valves in valve guides dry, its best to coat the valve stem with a thin coating mix of moly assembly lube and marvel mystery oil in my experience so they have instant heat transfer and lubrication on engine start-up

the question of which is better, vitron or teflon comes up frequently with both having proponents, its been my experience that the care taken during the installation and selecting the correct size seals and lubing them as they are installed with valve seal lip protectors has a great deal of influence on how well either material will function,Ive used both and replaced hundreds of both types, the care taken during the installation seems to be more critical than the material they are made from, and neither material lasts for ever, you can assume they need replacing by 70k miles in most engines, if you see any exhaust smoke. Ive also seen several guys cut 1' sections of heat shrink tubing to shrink in place over the valve stem notches , oil the tubing after its shrunk, install the valve seals then just pull and discard the tubing, Ive tried that and it works great!



related threads

viewtopic.php?f=52&t=401&p=491&hilit=+valve+seals#p491

viewtopic.php?f=52&t=2091&p=5600&hilit=+valve+seals#p5600

viewtopic.php?f=44&t=1054&p=1990&hilit=+valve+seals#p1990

viewtopic.php?f=52&t=1053&p=1989&hilit=+valve+seals#p1989


viewtopic.php?f=52&t=4684&p=12683&hilit=valve+seals#p12683

viewtopic.php?f=52&t=4283&p=11290&hilit=valve+seals#p11290

 

[Indycars]

Re: Valve Stem Seal Selection – Design and Materials


From what I've read so far, it would appear that Teflon would be good for the exhaust valves with it's ability to withstand temperatures approaching 600 F. For intake valves, Viton seems to be better with it's greater flexabilty while still rated for 450 F.

Any opinions ???

 

[grumpyvette]

Re: Valve Stem Seal Selection – Design and Materials

I've used BOTH types on several engines, and viton alone on dozens I have yet to see any real noticeable difference.
ive ordered them from CRANE,CROWER and ISKY many times and had the local machine shop use several brands, but lately Ive been using the CRANE teflon in most builds, mostly because they are easy to find at local dealers and I've had zero issues using them

both JEGS and SUMMIT CARRY THOSE SO THEY ARE EASY TO GET, EVEN THE LOCAL AUTO PARTS STORE CARRY,S THEM
http://www.jegs.com/p/Crane-Cams/Crane- ... 6/10002/-1

http://www.summitracing.com/search/?key ... eals&dds=1

 

[Indycars]

Re: Valve Stem Seal Selection – Design and Materials


I wonder if all the seals are made by just a few companies and they are all about the same if we are comparing
similar materials. I checked the original Brodix seals and their OD is 0.670", so the Crane's should work fine with
my valve springs since their OD is 0.620".

You say they are available locally.....who caries them and are they under the Crane name ???

Is it necessary to have a tool similar to this for installation, kinda expensive at $218.00 ???

http://www.cylinderheadsupply.com/t200.html

 

[grumpyvette]

Re: Valve Stem Seal Selection – Design and Materials

they are commonly packaged on blister packs

 

[Indycars]

Re: Valve Stem Seal Selection – Design and Materials

I found this much more affordable tool for installing valve stem seals at $30.

How would you use this tool?
Install valve in head first, then using the tool install seal over the valve stem pressing into place on the guide ???

http://www.cylinderheadsupply.com/t3.html

Allows the seal to be driven squarely. Safely install .500", .531" & .562" Guide O.D. Seals. (11/32" & 3/8" Valve Stems)

 

[grumpyvette]

Re: Valve Stem Seal Selection – Design and Materials

the two striped things are plastic valve seal alignment guides that are temporarily placed over the top of the valve stem, then oiled lightly, they are placed over the valve keeper lock grooves to prevent the seals being damaged during the valve seal installation process.
during assembly, the upper valve guides machined, the valve springs seats and shims are measured, the proper valve spring seat and shims are installed, the valve stems are lubed then slipped into the heads extending the valve stem up thru the valve guide, the valve is held fully seated, the plastic valve seal alignment guides that are temporarily placed over the top of the valve stem, then oiled lightly, then the tool you posted is used to seat the valve seal , once thats done the valve spring and retainer and keepers are installed.
ID point out that youll need to measure the valve stem and the valve seals, and install them correctly, I have seen several cases where guys just either slid the valve thru the seal and damaged the lips on the seal or installed the wrong size seals or had the valve seals come off the machined valve guides, that were either machined incorrectly or the seals were installed incorrectly, in all cases excessive oil burning was a result

 

[Indycars]

Re: Valve Stem Seal Selection – Design and Materials


So the sleeves come with the seals ???

I can handle a $30 tool, it was the $200 tool that had me a first.

Thanks for the info !!!

 

[grumpyvette]

Re: Valve Stem Seal Selection – Design and Materials

So the sleeves come with the seals ???

I can handle a $30 tool, it was the $200 tool that had me a first.

Thanks for the info !!!

the sleeves USUALLY come with the seals, but if they don,t just use a section of plastic soda straw you get free at burger king or Mc donalds

you simply us a razor to cut the straw length wise on the end so its split about 1/2" into two equal haves, spray with wd40 and slide the valve seals on facing the correct direction, if the straws the same size or a bit smaller that the valve stem diam. it still works if its a bit too large it can,t be used in some cases, unless you slit and trim it to fit properly

Ive also seen several guys cut 1' sections of heat shrink tubing to shrink in place over the valve stem notches , oil the tubing after its shrunk, install the valve seals then just pull and discard the tubing, Ive tried that and it works great!

http://www.bc4x4.com/pr/2003/hypertherm/

 

[Indycars]

Re: Valve Stem Seal Selection – Design and Materials

I sent an email to Brodix asking "The valve stem seal number US VS529V.....what is the material ??? ", below is their reply.

RICK,

US SEAL COMPANY SEAL PART # US VS 529 V IS Tri-Fluoro-Viton in our Viton valve stem seals mixed with 5 percent Teflon. PLEASE LET ME KNOW IF YOU HAVE ANY FURTHER QUESTIONS.


THANK YOU,

MARK FRETZ
BRODIX INC.
(479) 394-1075 EXT 34
MARK@BRODIX.COM

I found the seal at the company website, but I can't confirm the materials at this time.
http://www.oilseal.com/v-high%20perfor.html



Just thought I would pass along this info.

 

[Indycars]

Re: Valve Stem Seal Selection – Design and Materials


Now I don't know what to believe ! I sent another email to the US Seal Inc and they say its Viton. See email conversation below.

Hello,

That particular seal is only available in the Viton Material.

Thank You
Sean
------------------------------------------------------------------------------------------------------------
From: rickmiller
Sent: Tuesday, August 23, 2011 12:34 PM
To: usseal
Subject: Materials used in VS-529 Valve Stem Seal

I can't tell from browsing your website what materials are used in the VS-529, could you please let me know.

Thanks!
Rick Miller