'06 Quicksilver Z06

The article says that the combo, Katech Torquer cam and PSI beehive springs, with REV solid exhaust valve, was tested to 7500 RPM.

TEST 5: Katech Torquer cam and PSI beehive springs, with REV solid exhaust valve
Intake valve: Not tested
Exhaust valve: 0.016-in. max bounce at 7,100 rpm; tested up to 7,500 rpm
Katech notes: This combination is not recommended, because valve bounce exceed the 0.15-inch threshold, although the PSI spring did control the REV valve better than did the dual spring.

Read more: http://www.superchevy.com/how-to/140...#ixzz3JxWC8TKt

7500 was the extent to which it was tested, and the maximum bounce observed of .016" came at 7100. That sounds to me like it was gotten back under control after 7100 RPM. At least between 7101 RPM and 7500 RPM.

But what about my other question Mark:

Would you happen to know if the same setup, Torquer cam, same beehive springs but instead with Ferrea hollow stemmed valves which are about 12g lighter than the SS valves used in that link you pointed me to, has ever been shown to demonstrate about the same amount of bounce as the setup in the Superchevy article showed, but at a lower RPM, and below the 7k redline and hence at an earlier onset?

Mark2009

First you should get some actual weights. Numbers I've seen show the REV at 100g on a scale and the Ferrea hollows at 85g.

Data I've seen indicate the Ferrea hollow is stable to 7700 RPM with the components you specify.

Mark2009

I believe that is a typo since it does not show up in the CF report:

Regardless, there is no related data above 7100. Presumed data is not real.

'06 Quicksilver Z06

Using those numbers, we're talking a 15g difference

The article indicates that the Rev valve was 98g.

I've seen in here the Ferrea hollow stem weighing in at 85g or 86g

I see.

So do you consider in excess of .015" of valve bounce to be the point at which a valve is out of control, as the article indicates?

Or put another way, are you saying that if a valve in a setup intended for this engine, reached in excess of .015" of valve bounce, prior to the 7K redline, that you would consider that "stable to 7700 RPM" if the testing went to 7700 RPM?

And also, does the "data" you mention above that you say that you've seen, does it indicate any instances of valve bounce in excess of .015" prior to the 7000 RPM redline? :

"Consideration for when a valve is out of control is subject to debate; however, 0.015-inch of bounce is the basis we use for our recommendations"

Read more: http://www.superchevy.com/how-to/140...#ixzz3Jxbsa2LD

"...valve bounce exceed the 0.015-inch threshold, although the PSI spring did control the REV valve better than did the dual spring..."

Read more: http://www.superchevy.com/how-to/140...#ixzz3JxbewrO0

From that, it seems that .015" is the "threshold" they're using.

No, I don't believe that it was a typo. Below is the response that I got.

That test was run with that particular setup twice. Once for the thread which you linked to, and again for the article in Superchevy.

So yes, they're saying that the Torquer cam, Rev SS valves, beehive springs setup was run to 7500 RPM.

The way that that the data is reported, is by indicating where maximum valve bounce occurred during the RPM range through which the entire test for a given setup was run. And by indicating if it came prior to redline as well.

And the maximum valve bounce, over the course of the 7500 RPM range during which the test was run, occurred at 7100RPM and was measured at .016".

TEST 5: Katech Torquer cam and PSI beehive springs, with REV solid exhaust valve
Intake valve: Not tested
Exhaust valve: 0.016-in. max bounce at 7,100 rpm; tested up to 7,500 rpm

Read more: http://www.superchevy.com/how-to/140...#ixzz3Jxdd0RF7

If bounce had exceeded .016" before 7500 RPM, then they would not have been able to state; "max bounce at 7,100 rpm; tested up to 7,500 rpm".

Mark2009

Only if it continues at or in excess of that rate as RPM increases.

What I said is:

Irrelevant. No data. No data. No data. No data. No data.

'06 Quicksilver Z06

So in the setup we're referring to with the Ferrea hollow stemmed valves, if valve bounce actually exceeded .015" and at multiple points in the RPM range and prior to redline, you consider that to be an "acceptable" result?

That's a bit different than the criteria used by the author and testers in the Superchevy article.

They recognize a threshold limit of .015" of valve bounce for maintaining control of a valve, and they make no allowance for exceeding that prior to redline.

I'm aware of what you said. But in order for you to say it, I'm starting to get the impression that such a statement would require you to go against the "threshold" that the Superchevy article and the thread you pointed to, state, and would require that you disregard instances of valve bounce at .015", or which would exceed .015", prior to the 7000 RPM redline.

And your argument as to the "relevancy" of the Superchevy author's statements regarding where maximum valve bounce occurred and to what degree, in addition to the maximum RPM tested, well we can let those reading their statements decide.

Mark2009

1. You're trying to put words into the mouths of others who are not here participating in order to create a false dichotomy. This is not logical debate.

2. Your argument is based on a reliance on statements you are trying to parse mightily to create inconsistencies instead of a technical understanding of the data.

Have a nice day

Mark2009

You have zero data to support your sound. Z.E.R.O.

ConfusedGarage

When I did my heads years ago I milled .030 over bumping me to like an 11.5-6ish with the Katech torquer cam on a 110 - all on 93 octane. I've run this combo for years with 20 degree day drives to work and 100 degree track days. I am very pleased with the results and wouldn't hesitate to do it again the same way. I run my car to 7200, I don't short shift it at all, but I stayed with a new version of the OEM exhaust valve - less weight.

'06 Quicksilver Z06

No, I'm using their words and prior stated positions, complete with links to the aforementioned and asking if you are of the opinion that valve bounce exceeding .015" on more than one occasion and prior to redline is a stable setup in your opinion.

There is no argument. I'm merely asking you if the setup Ferrea hollow stem valves, Torquer cam and beehive springs were to exceed .015" of valve bounce prior to redline, and on multiple occasions, if you would consider that a stable setup.

And if so, then how would that be any better than the same setup using solid stemmed SS Rev valves and beehive springs which shows no bounce in excess of .015" , the number given was .016", until after redline.
.

Thanks Mark. You have a nice day too.

Mark2009

Agreed. You have constructed a hypothetical which you think will fail.

On what exact occasions and to what extent? Perhaps you should draw a hypothetcal chart with data points so everyone can clearly see what you are conjuring.

'06 Quicksilver Z06

What hypothetical are you referring to?


Any "occasion" or "occasions" prior to redline, and to any extent beyond .015".

No need to draw a chart to ask you if "an instance" or "multiple instances" of .015" or more of valve bounce prior to the 7000 RPM redline, in a setup intended for use in the LS7, is acceptable to you.

You should be able to answer as to what you consider acceptable valve bounce to be.

And if you're fine with calling excess of .015" prior to redline "acceptable", well then you ought to be able to say yea or nay.

'06 Quicksilver Z06

Unless you're saying that their comment:

"Exhaust valve: 0.016-in. max bounce at 7,100 rpm, tested up to 7,500 rpm" is inaccurate, ....... well then you're batting a great big Z.E.R.O with your argument.

They just told you in the Superchevy article with regard to the test #5, that they tested to 7,500 rpm and that maximum bounce, which was .016", came at 7100 rpm during that test.

Now are you disputing that? Are you saying that the maximum was "more than that" in the RPM range that they state? Are you saying that you actually need to see the numbers up to 7500 RPM before you accept that? :

Mark2009

Your argument is insane... there is no data above 7100, but you find great comfort in that exact area.

You don't use lack of data to prove an engineering point

FNBADAZ06

OP....shave the heads

I run .030 with the first gen Katech 110 cam on 91 pump here in Arizona.
I even have given thought to milling a bit more and switching to the K501 cam.

I run OEM valves with the Katech supplied PSI springs and retainers.

Just make sure you check and order the appropriate pushrod length.

Mark2009

There is more than that to the equation. This has all been discussed before, so there is need to rehash it again. Go revisit the Spintron thread that got locked, many of your questions are addressed there.

'06 Quicksilver Z06

Amazing how you continue to try and dodge the question already asked of you which centers on what happens below redline.

Do you consider valve bounce at, or in excess of .015" prior to the 7000 RPM redline, and on multiple occasions prior to it, to be acceptable for a cylinder head setup intended for use in an LS7 with a stock redline?

A "yes" or "no" will do fine. :

AzDave47

Mark and Quick, enough already. Do you need adult supervision?

I'm fine with good info provided but not the back and forth bickering of "he said, he said".

'06 Quicksilver Z06

There's good info there Dave. You just have to look in the "back and forth" for it.

All this time, the general position among some of us, has been that: "all else equal, a lighter valve will give less valve bounce and hence more desirable results from a valve stability to redline standpoint, than a heavier/stronger valve".

Now, when the prospect of it coming to pass that this is possibly not always the case, and when one of the recently more popular flavor of the month valves might be involved, then every attempt is made to avoid discussing not only that, but any potential implications of that.

So anyone who took that position, might now have some 'splainin to do, if it turned out that way. And they don't want to explain because they can't.

If I'm being told or lead to believe, that an 84-85g hollow stemmed Ferrra valve with a Torquer cam and beehive springs should do better from a valve bounce perspective up to redline because "the valve being used is lighter", than a Torquer cam and beehive springs but with a solid stemmed 98g exhaust valve setup, well then the way I see it, it had better......because if it doesn't, well then what would be the point of using the hollow stemmed, air filled Ferrea valve in the first place? Especially when taking heat transfer capabilities into account.

In such a scenario and if this were the case, then not only would you not see any benefit whatsoever from a prevention of valve bounce below redline perspective, in fact it might even work to your detriment, but you would be taking on potential heat transfer issues to boot. And for what??? : Because someone insisted that because they are "lighter", then automatically they must be "better"????

That would not be good for those who have touted these valves over the solid SS valves for the longest now.

What happens to the "lighter valve is always better, all else equal" position, reinforced in here for a long time now, if this is the case?

That's right. It won't hold up.

And it may turn out that it was the efforts some of the more staunch believers in here in that position, that potentially end up actually undermining that position.

Take a look at Test #5 Dave. What do you see???

http://www.superchevy.com/how-to/140...#ixzz3JxWC8TKt

Ask Mark up front, have him answer with no BS, and no hemming and hawing, just straight up, if setup #5 did any better or worse below redline, and especially just prior to and AT redline, (and both you and Mark, can see how it did below redline here by looking at the peach colored line in the graph showing exhaust valve bounce), using the Ferrea valve in place of the Rev SS valve which was used in test #5 of the link I gave you just now.

You look at that peach colored line in the graph of the first post Dave, here and you don't see the "threshold figure" that everyone in here talks about since the spintron craze of .015" of valve bounce, until you cross over into 7100 RPM.

Ask him if the same is true with the same setup, but instead using Ferrea hollow stemmed valves, or if you would actually see of .015" of bounce before redline with such a setup using Ferrea hollow stem valves and using the same Torquer cam and beehive springs.

64drvr

I appreciate your guys info but what does this have to do with milling heads?