[Fot] Valve guides

[Tim Murphy]

Thanks to all who responded to my questions regarding valve guides and
clearances.  I just realized that we had 17 race weekends on that cylinder
head!  I'm just learning at what point various things like valve grinds and
guide replacement should be done.  Based on what we're seeing so far, doing
the valves every 8 or 9 races should work for us.  We also had a hole burned
in the head gasket where the shroud was cut away around the inlet valve on
#2 cylinder.  So a new head gasket every 8 or 9 races should hopefully solve
that problem also.  The head gasket had 11 race weekends on it.

      The machinist has checked the ID of the guides and from what he has
told me so far we will replace all of the guides.  I'm going up to meet with
him later this week and we'll determine what else has to be done, such as
replace some of the valves that have worn stems.  We do have a spare stock
head with the stock valves and I'm thinking of maybe using some of those if
need be and they clean up okay.  Is there any benefit to using currently
available valves over the original Triumph valves?

      Now that I've got a machinist and shop who I trust and can work with,
doing the periodic renewing shouldn't be a problem.

 

Thanks again, the FOT is great!!

 

Tim Murphy

1961 TR4 #317

 

-----Original Message-----

From: Greg Solow [mailto:Gregmogdoc at surfnetusa.com]

Sent: Monday, April 02, 2012 8:11 PM

To: Tim Murphy; fot at autox.team.net

Cc: rpm724 at att.net; ryan.murphy at fdlco.wi.gov

Subject: Re: [Fot] TR4 valve guide clearance

 

For stock cast iron guides the clearances listed in the shop manual are
fine. .0015 to .002" inlet and ..002 to .0025" on the exhaust. The engine
should run ok with up to .0015" additional clearance on each valve.  The
problem that we have found with the iron guides is when using a high lift,
fast acting racing cam, with additional spring pressure, The guides tend to
wear very fast. We found up to .004" wear in 4 or 5 race weekends. Then the
valves stop sealing as well and the engine looses power.

    It does not sound like you have a setup that required a better quality
guide. Don't use valve stem seals and keep an eye on the wear as time
passes.

 


                                        Greg Solow