GOSFAST said:
You guys figure maybe "gravity" lets the lifter float back to the end of the cycle, along with the pushrod and rocker? One hyd. roller lifter weighs 140 grams, a mech. roller comes in at 116, this is with no link bars. There's really no issue with pushrod "deflection" in a retro-roller situation, as the pushrods are relatively short. We do use only 3/8" with "steel" valves, and some do see titanium (valves). And I myself don't consider 160+# on the seat and 400+# open @.740" lift a "mild" spring pressure. We have to use a number of offset intake rockers (on the SB's) to get a "flimsy" (.080") 5/16" pushrod to clear the intake ports (after we port them) on most of these aftermarket heads. There's a prep now for some dyno testing with a pump-gas 400SB (mech. roller) with 1.6 offsets x 7/16 intake rockers and adjustable plates. This unit would never take even a 3/8". Keep in mind, these are 740HP "maintence-free, pump gas, budget builds" on the BB's and 600HP on the 406's (mech. rollers) and zero issues. We've been able to deliver 540+ on a 406" SB 10:1 C.R. 93 octane platform with a retro-hydraulic. Thanks, Gary in N.Y.
P.S. Every unit we do is "hand-built". By this I mean we wouldnt need 400# springs on .580" lift cam, thereby making pushrod selection an individual choice. These are very easy HP numbers to achieve, up to this time, basically using a few hours of porting. We're starting to the attention of the local fire depts. about using these pump-gas units for their racing teams. Also while I'm here, you should do some homework as to the "NEW" bee-hive springs. We use to take them off 1954 Oldsmobile units and put the old "tried & true" dual springs on instead. Buick also used them in the 1980's on their 350's. "New", yea right!
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Gary,
"Us guys" have both built a few performance engines & from experience the most important weight is on the valve side.
And just to be clear, I cannot speak for Roger but I do my "homework" & I take nothing for granted.
From speaking with him & knowing a few of his acclompishments I have to assume he does too.
I know enough to ask questions of those I respect the opinion of & even some who I don't.
If I don't agree I want an explanation that makes sense to me.
Yes lifter & pushrod weight play a part but a little common sense will tell you that you have a hell of a lot more effective pressure on the pushrod side of the valvetrain.
As for your comment about 54 Olds springs this is about as absurd a comparison as I have seen as is the Buick one.
Do you really think the new generation of beehives have anything in common with what was made 50 years ago besides the basic shape?
Different material, different wire shape,,,, different spring,,
Besides, who said anything about beehives in this post anyway??
And I have never said they were a cure-all just posted the results & have personal knowledge of.
And if you think there is no deflection in a hyd roller setup or in most any other pushrod engine system & especially in a Rat apparently you have never seen a spintron test.
Don't believe it,, call your friends at Comp & ask what goes on regarding pushrods.
Tell the cup teams they don't need the pushrods they are using in small blocks.
Tell me why with no other changes in a back to back test an 18 degree small block with dead straight very short pushrods picks up 10+HP going from a very good 3/8 pushrod to a double taper 7/16" one.
& this is a pushrod that is only about 6.250" long,,,