[Fot] TR4 Valve spring - pressure, assembled height, suppliers

[Greg Solow]

Richard,
    I presume that by "intake" you mean total valve lift.  .430" lift is 
quite a bit more than stock.  I would use bronze guides and would try to 
obtain exhaust valves that have hard chromed or "plasma coated" stems.  We 
use .0015" to .002"  valve stem to guide clearance on the inlets & .002" to 
.0025" on the exhausts. Valve spring pressure with the valves closed should 
be 85  to 90 psi. You need to make sure that the spring you use do not go 
into "coil bind" at full valve lift. With the valve fully open, you must be 
able to stick a .040" feeler gauge in between the coils of the spring.
    We still "grind" all of our valve seats, and then lap them with fine 
compound to make sure we have a good seal. I guess we are "old school".  We 
generally use seat widths of .040" on the exhaust & intake with hardened 
valve seats installed in the head in both intake and exhausts.  I like to 
use 4 or more angles on the valve seats, 15, 30, 45, 60, & 75 degrees nicely 
blended to form as much of a radius as possible.  The hardness of the seats 
prevents the seats from wearing or "pounding" and changing shape as the 
engine runs. The most critical area in a head's ports is the 1/4" or so as 
the seat "blends" into the "throat"  of the port.  That area critically 
effects the flow of the port and the valve seat. This is not to say that 
other areas of the ports are not important. But on an engine with a cam like 
yours, you could spend a  lot of money and time for very little effect. The 
hotter the engine is, the more important the overall flow of the head and 
manifolds becomes. On a full race engine, ie cam with over 295 degrees 
duration, compression over 12: 1 and a power band going up to 7,000 rpm, a 
lot of power can be picked up by working on the exhaust port flow of the 
TR-4 .
                                                                             
                Greg Solow