Mike,
I read one of your posts, indicating that you do work with a spin tron machine.

I have a few questions.

How much dynamic valve lift increase have you seen by switching to 3/8" x .080" wall from 5/16" .080" in a 6200-6500rpms motor?

Dynamic; being under actual running/loaded and turning 6000+ rpms.

I understand the pushrods look like an S under serious conditions, a stiffer wall therefore making for more DYNAMIC lift, but how much is my question, thanks!


Second question, have you tried Super 7 degree locks/retainers, and are they prefered over a 10 degree lock in a Flat tappet, or street roller application, i'm using 7 degree locks now, but if i ever changed cams i'd probably look towards super 7 degree locks.

How far from coil bind do you set up your race/full effort street/strip springs?

Have you tried Lightweight solid F/T lifters (Comp sells them i believe) and has the rate of engine accelleration changed? Valve train dynamics changed?

The valve seats, have you found 45 degree seats to have an effect on valve train dynamics as comparied to 50 degree seats?

Have you found anything to comment on about the difference between silicon steel, and super clean silicon steel valve springs in a 6500rpms street/strip motor?

thanks, if you're wondering, these are just some of the things i ponder during the day :D

Brian,
Don't mean to butt in,but the lowdown that I get from the valvetrain people is pushrod dia is more effective for combatting valve float than a thicker wall thickness.
Also more weight on the lifter side is far less as critical as the valve side and also helps dampen valvetrain loft.
Hope this helps
Bob

bob, re-read it, i'm comparing 3/8 x .080 to 5/16" x .080".

Brian,
I read it 3/8 is better.
hope this helps.

Brian,

Please accept my appology for jumping in here as I cant offer anything but I do have a question related to yours....

This goes back to the old PolyDyne equation where there was an attempt to compensate for the deflections of the various valve train componuts when designing a lobe....

I doubt many still use the old PolyDyne equations in newer designs lobes but do any newer methods try to capitolize on these newer stiffer linkages and vastly superior valve springs of today VS yesterdays designs ? Is there enough of a change with these stiffer linkages / valve trains that a newer lobe design can be made specifically for these better valve trains ?..

In a way this does tie in with Brian's questions.
I hope Harold or any other cam expert can offer something here....

Thanks for letting me Butt in...

Originally posted by Motor Martyr:
Mike,
I read one of your posts, indicating that you do work with a spin tron machine.

I have a few questions.

How much dynamic valve lift increase have you seen by switching to 3/8" x .080" wall from 5/16" .080" in a 6200-6500rpms motor?

Dynamic; being under actual running/loaded and turning 6000+ rpms.

I understand the pushrods look like an S under serious conditions, a stiffer wall therefore making for more DYNAMIC lift, but how much is my question, thanks!


Second question, have you tried Super 7 degree locks/retainers, and are they prefered over a 10 degree lock in a Flat tappet, or street roller application, i'm using 7 degree locks now, but if i ever changed cams i'd probably look towards super 7 degree locks.

How far from coil bind do you set up your race/full effort street/strip springs?

Have you tried Lightweight solid F/T lifters (Comp sells them i believe) and has the rate of engine accelleration changed? Valve train dynamics changed?

The valve seats, have you found 45 degree seats to have an effect on valve train dynamics as comparied to 50 degree seats?

Have you found anything to comment on about the difference between silicon steel, and super clean silicon steel valve springs in a 6500rpms street/strip motor?

thanks, if you're wondering, these are just some of the things i ponder during the day :D ===
Brian,
Damn guy you ask questions that people write whole books on :D

Never said I did work with a SpinTron. I believe what I said was if you ever saw a SpinTron test you probably wouldn't want to build any more engines ;)

I have watched SpinTron tests & at one of the ATEC conferences about 4 or 5 years ago they had a seminar on valvetrain testing mostly relating to springs that had some outrageous videos of what springs do at different RPM's.
I believe it was hosted by Comp but not sure.

I cannot answer your question directly regarding the difference in pushrods but basically the push rods looked more like spaghetti than nice straight pieces of tubing & your "S" description is a pretty good one.
This BTW is much worse in a Rat due to the goofy pushrod angles.
As for lift loss it was more a question of valve train control than lift difference I think.
Consider the pushrod as a piece of spring steel complete with harmonics & resonant frequencies for a moment.
Now consider what happens when your spring goes through it's harmonics & dances clear off the head & retainer.
This is sorta what happens with pushrods only to a lesser extent.

I did a back to back (A B A) test on an 18 deg 332" small block on the dyno with a roller & there was a 10-12HP difference going from very good 3/8 x .080 wall pushrods to 7/16 double taper ones & these were pretty short pushrods.
Also, the torque curve lost most of the stupid little dips that you would normally attribute to spring surge.
But, this is also a 9500 RPM engine

I cannot see this being near the problem in a flat tappet deal with reasonable spring pressures but it would not surprise me to see in increase in power going from 5/15 to 3/8's pushrods with an aggressive cam in a 6500 type engine but I have not done any reliable tests like A B A under the same conditions so this is just an assumption.
I do a lot of restricted small block stuff that is 7000-7300RPM give or take & used both pushrods & have made pretty much the same power & reliability with either but sorry to say, no real good testing.

Retainers/Keepers:
I use Super 7 BeadLoc stuff almost exclusively on all the Titanium valve roller engines & standard Super 7 on Stainless & on some flat tappets I do.
I do not use or recommend 10 degree locks on hyd or flat tappet springs but they are fine on roller stuff with a lot of spring pressure to keep them together.
10 degree locks do not capture the valve as well as 7 degree ones & I along with some other endurance engine builders I know tend to stay with 7 degree locks on flat tappet cams.
I have never lost a valve due to locks with 7 degree stuff but I cannot say the same thing with 10 degree ones. :(

I personally feel the Super 7 is the best of both worlds. It gives you the surface area of the 10 degree ones & the clamping of the 7degree ones but don't feel they are necessary with most flat tappet stuff except for the higher RPM ones like 7500 up.
You have taken apart a lot of heads, have you ever noticed how easy 10 degree stuff comes apart?
And on lighter spring applications have you inspected the valve, lock, retainer close & seen signs of movement you didn't like? Usually worse with 10 degree assemblies.

Coil bind:
I have run the springs to .040 before but like more. For a number I'd like .080 or better.

Haven't seen any difference with the "light weight" lifters myself.

Seats:
Wouldn't think there would be any issues regarding valve train dynamics but you will lose a ton of flow at low lift.
I haven't played with 50 deg seats & my understanding is they need a lot of lift & work best with specific ports & chambers & are not a real good deal in regards to long term use.

I think seat angles are very head specific & I rely on the head people for recommendations in this area for most applications as I just do not have the time to do all the neat stuff I would like to like spend days on the bench & dyno.

Joe Mondello has done a lot of research in the seat angle area & you can post this question to him directly here:
http://www.bigmouthweb.com/g5-bin/client.cgi?G5genie=267

Last I talked to him he & the wife were headed to Hawaii for a vacation but may be back by now.

Springs:
No

Crap,,, that was long,,,

thanks mike! Guess like most things it comes down to individual application.

Brian,

No real hard data to give you, but from being in the pipe and tube sales business, I can tell you that given all things being equal as to weight for a particular length (say 6" for discussion sake), a cut pc. of tube and bar both weighing 50 grams, the hollow tube will be much stronger than the bar. If the overall wt of the cut pc is kept the same and the diameter increases, the wall thickness will be reduced. The practical applied limit for structural applications is about a 20% offset either way [increase diamter by 20%, decrease wall by 20%]. Obviously, the larger practical diameter is always best.