RE: RMIHR (Valve Seals)

[Darrel Kline <darrelk@domain.elided>]

>>Thanks to Eldon McFarling for showing me several different valve seal
>>options for the IH motors.
>
>Please, Darrel or Eldon, share this info with the rest of us.  My guides
>were knurled at rebuild time, and the truck blows a blue cloud at
>startup ever since.  I'd like to eliminate it!
>
>Allan Weidenheimer
>72 1210 Pickup
>

I hope this isn't copy righted. :-)  
Here's the first email Eldon sent me on this subject, I'll forward his
valve guide wear email also:

>From: <EldonMcf@domain.elided>
>Date: Fri, 5 Jun 1998 01:13:27 EDT
>To: darrelk@domain.elided
>Subject: Valve seals
>X-Mailer: AOL 4.0 for Windows 95 sub 170
>
>Darrel,
>
>    I may have missed some of the discussion on binderchat, so i am just
gonna
>ramble a bit here, just thinking out loud.
>
>   There are several types of valve seals used in various engines. There are
>o-ring types, shield types, umbrella types, and positive types.  O-ring seals
>are used from the factory on IH SV engines & 4-152, and 4-196 engines.  Other
>truck engines like the MVseries use shields that are umbrella shaped, made
>from hard plastic, and install in either the spring retainer, or valve
>rotator.  6.9 & 7.3L Diesel engines use a combination of shields on the
>exhaust valves, and all rubber positive type on the intake valves.  Other
>makes of engines like Chevy & Ford use rubber umbrella type seals. these are
>similar to the shields that IH engines use except they install on the valve
>stem.  The umbrella's, and shields just kind of redirect where the oil goes,
>and keep the oil from splashing on the valve stem
>
>
>   If you notice smoke after startup, or oil consumption, installing valve
>seals can help reduce, or eliminate the problem.  IH literature reccommends
>using positive type, rubber & teflon valve seals for both gas and Diesel
>engines. IH labratory testing indicates that oil consumption increases with
>increased valve stem-to-guide clearance.  IH testing also shows that from 22%
>to 60% of total oil consumption was through the valve guides. some
benefits of
>using positive valve seals are: stops exhaust smoking caused by oil loss
>through guides, eliminates excessive oil consumption through valve guides,
>eliminates coking of valves & ports.
>
>   My couple cents
>
>     I like the teflon & rubber positive valve seals, and have used them in
>many engines both gas & Diesel.  The teflon material has superior resistance
>to heat, and wear, so they give a long life without cracking, drying out, or
>leaking. For 6.9 & 7.3L Diesel engines I replace the factory all rubber seals
>with the teflon& rubber style.  I have had excellent results.  I use this
type
>of seal on most every cylinder head I have overhauled.  I do mostly Diesel
>engines, with some IH gas, and a little of everything else.
>
>    The part number for the Perfect Circle set for the 304 is VS-12. This set
>contains 16 seals number 1812. for the 304 machining of the valve guide od is
>neccessary for the seal to fit on.  The machining operation is simple, but
>requires a machining tool. the tool can be purchased for around $45, and
>requires a slow speed 1/2" drill.  Most automotive machine shops can also
>machine the guides at a minimal cost.  The Perfect Circle number for the
>machining tool is VST-1812.  Perfect Circle parts & tools are available from
>NAPA, as well as other jobbers.  TRW also supplies these seals & tool under
>part number VP-68 seal & VP-504 tool.  I believe Big A auto parts handles
TRW,
>as well as other jobbers.  I don't know about the quickie auto parts chain
>joints that seem to  be on every street corner, I don't deal with them very
>much.
>
>    So why does the set for a V-8 have 16 seals?  Because you use them on
both
>intake & exhaust valves. Since the intake stem is exposed to vacuum its easy
>to figger out how the oil is drawn around the stem into the cumbustion
>chamber, but what about the exhaust?  Well the exhaust is also exposed to
some
>vacuum. the flow of gasses through the exhaust port creates a vacuum around
>the exhaust valve stem, and also draws oil into the combustion chamber.
almost
>all gas engines I have done have gotten positive seals installed on both
>intake & exhaust.  Most Diesel's use seals on the intake only, but there are
>some exceptions. since the Diesels don't create vacuum in the intake, the oil
>is drawn in by the flow of air, similar to the exhaust on the gas engine.
>
>   So to install the teflon seals you would need to remove the heads, and
>macine the guides.  I measured a 345 intake guide, and a 6.9 rubber intake
>seal would fit without any machining.  this could be an option if you plan on
>installing the seals without removing the heads. Then you could use the chev,
>or ford rubber umbrella seals on the exhaust.  I didn't have a valve spring
>handy to make sure there was enough clearance for the all rubber positive
>seal, which is slightly larger od than the rubber/ teflon seal.  I have
plenty
>of these if you want to go that way.  The last option is the rubber umbrella
>seals.  these can be installed without removing the heads, or doing any
>machining.  this would be the least effective choice since the seal only
>partially controls the oil.  If you should use this type of seal make sure to
>get Hi-temp, or viton seals.  the  plain rubber ones don't take the heat too
>well, and so they don't last very long. BTW the intake & exhaust valve stems
>are the same diameter, but the tops of the guides are different OD's. The 392
>does have different sizes of stems for the intake, and exhaust valves.
>
>    Eldon McFarling
>    Ceresco, NE

Now tell me does Eldon know his engines, or what? You just can't get that
kind of information from a book. I met Eldon and his family at the RMIHR
and he's one great guy. He also made the Red Cone trail look easy with his
stock 1980 Diesel Scout II.

Darrel Kline
Colorado Springs, CO