grinder11

iTrader: (1)

I ran Smith Brothers oil restricted PRs for over 30,000 miles, had no issues at all. SB told me they simply press a short length of split pin/roll pin into 1 end of the PR, and that end is installed up, at the rocker arm end, NOT down at the lifter end.

Dian

on second thought, with the 1.1 restrictor in the rocker cup i dont need to worry much about whats "upstream". the small size never occured to me, probably because the passage is larger on the cup side.

astma, you probably know thats not how it works, if you think about it.

if anybody is wondering here the prices of pushrods (the three manufactures are pretty much the same):

11/32 x 120 $15/20
3/8 - 5/16 (dual-taper) x 95 $26/32

the first number being mantons non-heat-treated "3 series". the heat treat thing (4030) escapes me, as there is no functional advantage of higher hardeness/yield/ultimate strength in this case.

bending deflection:

5/16 x 80 x 7.400, 53g (stock): 110µ
3/8 - 5/16 x 80 x 7.400, 61g: 70µ
3/8 - 5/16 x 95 x 7525, 69g: 50µ

edit: as has been stated in a recent thread a 11/32 x 120 rod will have 28% less deflection at probably close to 80g.

G Atsma

Dian- Max flow on any circuit is only as good as the worst restriction. That IS how it works.
One restrictor hole per pushrod will restrict as much as a full lengh restriction.
Besides all this, you are overthinking his whole deal.

Dian

no sir and yes sir.

now consider this: at a 20° tilt the 1.5mm pushrod hole and the 1.8mm hole in the cup (the 1.1mm restrictor is on the other side) overlap only a bit, like 10% of the area. no idea how to calculate the average overlap, but fortunately the function will be strongly "exponential". the area proportion of cup restrictor (1.1mm) to cup hole (1.1mm) is 37% so in the end im confident this will not hinder flow through the restrictor.

edit: this is what yella has to say about the 1.1mm restrictor.

"The Ls1 Pushrod cup\rocker design -has been designed to function in a number of ways :

1) To maintain enough oil in the cup to maintain lubrication of pushrod to rocker interface during its motion

2) To provide an adequate amount of oil to the full compliment full caged roller bearings which it does

3) To provide measured oil supply to the roller tips via the duct design on the arm"

G Atsma

What are you really trying to achieve here?
The LS valvetrain is exceptionally well-engineered, with hundreds of thousands of them going multiple hundreds of thousands of miles in their lifetimes.
Many racers are pulling 600+HP with mostly or all stock valvetrain components.
How is yours different?

stockA4

please tell us how you're going to race This thing, some may appreciate all the "tech" that has come of this, especially what peace of mind cost these days but this ridiculous scrutiny of pushrods has gone way too far without a clear-cut goal in mind, nobody That's posting in here offering help or advice even knows what the hell the application is actually for.

You're basically asking for help with re-engineering the valve train for the stock RPM range It would make sense to know why before anyone else gets out their calculators and wastes any more of their own personal time on this thread.

Dian

i tought i would share what info i was able to extract from trevor manton:

1. they use the semi-spherical tips on all ls engines. my impression that 3/4 spheres are needed was wrong.

2. the tips are 8620, nitrided i assume and given a chemical/mechanical type of super finish (→ rem, isf) that results in an isotropic surface. then they put dimples in there, by laser would be my guess. these are about 10µ in size (1. pic). 2. pic shows how smooth the surface is in profile. this is at a 500-1000x magnification, i put a 30µ hair on the tip with the focus in between (3. pic). for comparison the original tip (4. pic) with some clearly unisotropic texture and the ground manton stem (5. pic). they have been using this finish for a long time and it seems superior to the smith tip that looks just like the original.

3. as to the size of the holes, trevor pointed out their smaller hole is chamfered. well, this is not really the case, there is a flat around it that will not make much difference in oil flow. so my conclusion is: the manton setup would work well with the stock rocker cup (larger hole), the yella restictor would work well with the stock push rod hole but both toghether might be too restrictive.

does anybody know, how dual-taper pushrods are made? are they somehow swaged from the larger stock?