- May 28, 2003
I don't know fact certain the heads were cut deeper for the insulators. I am starting to measure the RH4 and RH10 heads VS 750 heads.@dynodave says it was a problem skimming the additional head material, but I've already forgotten whether he related that to the MkIII...
Curious of course why so many RH4 are cracked. Did the RH4 heads have a higher roof in the 32mm porting job compared to the "combat" 32mm port job? I have never seen a cracked 32mm port combat head? Did the 1/2" 750 guides VS the 3/4" 850 guides cause the RH4 cracking problem?
Inquiring minds want to know.
I only rebuilt 2 850 heads long ago, and one was for a combat cam and the other for a PW3 cam so, IF there were intake insulators they were definitely left out.
I have searched for "spring heating" among many other search wording, as I believe the springs heat them selves due to the steel flexing and the oil would end up cooling them . I read a lot of discussions though they discussion most of the time concentrates on head and exhaust port over heating the metal. The heat weakens the spring rate. Even a lot of discussion about slowly "aging" the new springs .
spring design wow!