[Fot] valve spring pressure on TR4 race engine

[timmmurphh at gmail.com]

Thanks for all of your responses.  We are going to add 0.030 shim to give
1.625 in spring height with valve on seat for a spring pressure of 95 lbs.
At valve full open with .342 max cam lift and 1.5 rocker arm ratio with a
0.016 valve clearance setting (Kastner G3 cam) we should get about 244 lbs.
of spring pressure with the maximum valve lift of 0.497.  At least that is
what I calculated.

 

As a note, I did get some valve float at about 6200 to 6300 RPM at Elkhart
Lake last Fall with the 85 Lbs. of seat pressure when I went over our max
RPM of 6000 trying to get past a Volvo.

 

Tim Murphy

 

From: timmmurphh at gmail.com [mailto:timmmurphh at gmail.com] 
Sent: Tuesday, February 14, 2017 1:56 PM
To: fot at autox.team.net
Subject: valve spring pressure on TR4 race engine

 

I have 85 lbs. pressure on the intake valve with the valve closed and it
sits at a height of 1.655 inches.  At .400 lift, I have 190 lbs. of
pressure.  We only run to 6000 RPM with the gearing we have and the engine
we have.  The valve springs are double springs and the machine shop says
they are all about the same, very consistent.  What pressures would be
recommended?  The machine shop thinks these pressures are light for a 6000
RPM engine.  Any advice will be appreciated.  Thanks.

 

Tim Murphy

1961 TR4  #317 BRG

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