Has anybody run the Crower offset trunion rockers with longer than stock valves?
#21
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I think its a little more than .050 if you measure with an indicator. yes, the thread pitch of the stud is .050 with 1 turn, but theres a little more to it. Not enough to matter though since pushrods come in .050 increments. I'd say going off your .050 assumption is good.
#25
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With a 7/16-20 stud @ the fulcrum point there is .050” drop per full turn. A 5/8 turn results in a .031” drop at the fulcrum with a resultant drop of .049” at the lifter with a 1.7 rocker ratio. I have seen, in most instances that preload figure will yield audible noise.
One full turn yields a .050” drop at the fulcrum with a resulting drop of .079” at the lifter. A three quarter to one full turn will place the plunger at the proper height to purge the chamber and eliminate any audible mechanical sound. This figure is marginally past the half way point of available lifter travel.
These figures are for iron/aluminum, and will be ~ ¼ turn less with iron/iron combinations.
Bob
#26
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One of my engines I went 1 full turn past 0 lash. The other engine, a buddy of mine adjusted the valves. I think he went about 5/8 turn. The engine with 1 full turn past 0 had much less audible roller noise. Heres a quote from bob m last year about the morels.
With a 7/16-20 stud @ the fulcrum point there is .050” drop per full turn. A 5/8 turn results in a .031” drop at the fulcrum with a resultant drop of .049” at the lifter with a 1.7 rocker ratio. I have seen, in most instances that preload figure will yield audible noise.
One full turn yields a .050” drop at the fulcrum with a resulting drop of .079” at the lifter. A three quarter to one full turn will place the plunger at the proper height to purge the chamber and eliminate any audible mechanical sound. This figure is marginally past the half way point of available lifter travel.
These figures are for iron/aluminum, and will be ~ ¼ turn less with iron/iron combinations.
Bob
With a 7/16-20 stud @ the fulcrum point there is .050” drop per full turn. A 5/8 turn results in a .031” drop at the fulcrum with a resultant drop of .049” at the lifter with a 1.7 rocker ratio. I have seen, in most instances that preload figure will yield audible noise.
One full turn yields a .050” drop at the fulcrum with a resulting drop of .079” at the lifter. A three quarter to one full turn will place the plunger at the proper height to purge the chamber and eliminate any audible mechanical sound. This figure is marginally past the half way point of available lifter travel.
These figures are for iron/aluminum, and will be ~ ¼ turn less with iron/iron combinations.
Bob
#27
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The noise I am talking about is really only noticeable at idle.
I have the 4603 style lifters. The noise from the engine that had 5/8 turn wasn't alarming. I just noticed that the other one was quieter.
Last edited by MILD THUNDER; 02-04-2014 at 11:16 PM.
#28
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20w50 Valvoline VR1 Synthetic. Im not calling you a liar. I am just stating what I, and many other people have noticed about the morels being quieter with a little more preload than recommended.
The noise I am talking about is really only noticeable at idle.
I have the 4603 style lifters. The noise from the engine that had 5/8 turn wasn't alarming. I just noticed that the other one was quieter.
The noise I am talking about is really only noticeable at idle.
I have the 4603 style lifters. The noise from the engine that had 5/8 turn wasn't alarming. I just noticed that the other one was quieter.
I do wonder though how much oil viscosity affects the lifters because the do recommend no more than 40wt...
#30
What kind of 30wt oil are you running? Full synthetic? Wondering what your oil temps and pressures are running at easy cruise, idle, and after an extended hard run. What are your bearing clearances? I'm thinking about running something lighter myself, but probably closer to 40wt, maybe closer to 15W40 or 20W40 if I can find it.