Example(s) of 50* seat reducing flow, but increasing power?

[GARY C]

Some of the old stuff I work on come with 30 deg seats on intake and exhaust... the same engines also came with 45's on both.

i always convert the double 30's to 45's and make more power. That's common knowledge that you hurt power with 30's

That's a real life low lift flow loss and a power gain

Except for in the article the 35 averaged about 6hp and tq over the 45 degree seat and the 50 was only 6 better than the 35, if my math was correct...so I guess more low lift flow and less low lift flow make more power than flo.

[twl]

My experience was on a 500cc single cylinder vintage motorcycle racer with wide valve angle hemi and 3.3" bore.
It came in with 45° seats, and we did a flow test.
After we changed it to 50° seats, it lost some flow below .400 lift, but gained a lot of flow from .400" - .600" lifts.

I considered his cam to seem long in my opinion, so I am not sure if the flow increase or the effective shortening of duration was the reason for the increase. Maybe both played a part.

But it picked up midrange and upper rpm tq, and picked up 3 hp at peak. I would only use it on higher lifting engines. For limited lift engines, I would stay with 45°. I never tried 35°.

[CGT]

Some observations from the magazine article (can't believe I'm doing this ). Especially after staring for hrs on end at vortec heads the last several weeks which were used in that test, also being around the dyno on engines pulled down that low quite a bit. I tend to disregard the first couple readings at the bottom of the pull, there can be some phuckery down there(not always). And there seems to be some of that in that test too.

Regarding this variation or that variation of each valve job. ALL of those valve jobs could be better I guarantee you that.. There is always mention of this top cut or that one. I can almost promise you that the 50° VJ wouldn't have likely even had a topcut, or barely one or an intermittent one at best, especially on that casting, especially after it was given a 15 degree top or whatever it was from the prior 35°VJ. And if it did, it would have had to be sunk ALOT to get there and then there would be a pretty good sized compression loss from that. ( 4cc's lost from doing that on project dale budget vortec) And yet the same trend still shined through in that simple test.... More VE, fatter torque curve.

I can't blame anyone for being critical or skeptical of someone else's tests or dyno's, I certainly am...hell im even skeptical of my own. But that simple(yet not perfect) test shows the same trends I've seen time and time again. And I have no interest in changing anyone's mind on this subject. I actually hope anyone I may compete against runs a 30° valve job, or makes it a mission to maximize flow at low valve lifts. ….that emoji is titled "razz"

[gmrocket]

Some of the old stuff I work on come with 30 deg seats on intake and exhaust... the same engines also came with 45's on both.

i always convert the double 30's to 45's and make more power. That's common knowledge that you hurt power with 30's

That's a real life low lift flow loss and a power gain

Except for in the article the 35 averaged about 6hp and tq over the 45 degree seat and the 50 was only 6 better than the 35, if my math was correct...so I guess more low lift flow and less low lift flow make more power than flo.

Next time I build a 360hp vortec headed low compression 455 I'll keep that in mind

[randy331]

There will be several who will say "you just didn't get the cam right for the increase in flow" and that will be from ones who have done no testing at all, and even some who never even build any engines at all and just spread info from forum to forum or have been to a seminar or read a book that says so, so it has to be fact that you can't have less flow but more power.

Seems my prediction is coming true.

Randy

[PRH]

Imo, if you take the results from the magazine test at face value, and assume the quality of the valve seat work was equal for all three tests....... you’d conclude that both the 35* and 50* angles make more power than a 45* will.

[GARY C]

Imo, if you take the results from the magazine test at face value, and assume the quality of the valve seat work was equal for all three tests....... you’d conclude that both the 35* and 50* angles make more power than a 45* will.

Yes and if they had only test the 45 and the 50 it would look like the 50 was good for 12 hp/tq. It's easy to draw the wrong conclusion a poorly conducted test.

A bad test can be worse than no test because it's hard to change the convinced mind.

[GARY C]

Some observations from the magazine article (can't believe I'm doing this ). Especially after staring for hrs on end at vortec heads the last several weeks which were used in that test, also being around the dyno on engines pulled down that low quite a bit. I tend to disregard the first couple readings at the bottom of the pull, there can be some phuckery down there(not always). And there seems to be some of that in that test too.

Regarding this variation or that variation of each valve job. ALL of those valve jobs could be better I guarantee you that.. There is always mention of this top cut or that one. I can almost promise you that the 50° VJ wouldn't have likely even had a topcut, or barely one or an intermittent one at best, especially on that casting, especially after it was given a 15 degree top or whatever it was from the prior 35°VJ. And if it did, it would have had to be sunk ALOT to get there and then there would be a pretty good sized compression loss from that. ( 4cc's lost from doing that on project dale budget vortec) And yet the same trend still shined through in that simple test.... More VE, fatter torque curve.

I can't blame anyone for being critical or skeptical of someone else's tests or dyno's, I certainly am...hell im even skeptical of my own. But that simple(yet not perfect) test shows the same trends I've seen time and time again. And I have no interest in changing anyone's mind on this subject. I actually hope anyone I may compete against runs a 30° valve job, or makes it a mission to maximize flow at low valve lifts. ….that emoji is titled "razz"

If you sink a valve but mill for compression does it hurt power or flow or both?

I have heard you can't do it because of FLOWZ but if it makes the top cut chamber blend better it could be good for POWERZ.

[GARY C]

There will be several who will say "you just didn't get the cam right for the increase in flow" and that will be from ones who have done no testing at all, and even some who never even build any engines at all and just spread info from forum to forum or have been to a seminar or read a book that says so, so it has to be fact that you can't have less flow but more power.

Seems my prediction is coming true.

Randy

randy331... My opinion is, if you've found the cam that makes best average power in the intended rpm range, and lets say that cam has IVO of 25* BTDC and IVC of 45* the engine doesn't really want those events,

[ClassAct]

Some observations from the magazine article (can't believe I'm doing this ). Especially after staring for hrs on end at vortec heads the last several weeks which were used in that test, also being around the dyno on engines pulled down that low quite a bit. I tend to disregard the first couple readings at the bottom of the pull, there can be some phuckery down there(not always). And there seems to be some of that in that test too.

Regarding this variation or that variation of each valve job. ALL of those valve jobs could be better I guarantee you that.. There is always mention of this top cut or that one. I can almost promise you that the 50° VJ wouldn't have likely even had a topcut, or barely one or an intermittent one at best, especially on that casting, especially after it was given a 15 degree top or whatever it was from the prior 35°VJ. And if it did, it would have had to be sunk ALOT to get there and then there would be a pretty good sized compression loss from that. ( 4cc's lost from doing that on project dale budget vortec) And yet the same trend still shined through in that simple test.... More VE, fatter torque curve.

I can't blame anyone for being critical or skeptical of someone else's tests or dyno's, I certainly am...hell im even skeptical of my own. But that simple(yet not perfect) test shows the same trends I've seen time and time again. And I have no interest in changing anyone's mind on this subject. I actually hope anyone I may compete against runs a 30° valve job, or makes it a mission to maximize flow at low valve lifts. ….that emoji is titled "razz"

If you sink a valve but mill for compression does it hurt power or flow or both?

I have heard you can't do it because of FLOWZ but if it makes the top cut chamber blend better it could be good for POWERZ.

IMHO, getting the top cut in is not sinking the valve. The top cut is a big deal. I like a top cut a minimum of .060 wide and if I can get .100 I'm happy. If I can get a bit more than that I'll take it.

[randy331]

Imo, if you take the results from the magazine test at face value, and assume the quality of the valve seat work was equal for all three tests....... you’d conclude that both the 35* and 50* angles make more power than a 45* will.

I don't think one can, or should draw a lot of conclusions about ideal valve jobs from the test.
I talked to Daryl about that test before he did it, and gave him the angles I used on the EMC heads referenced in that article, but the heads on the EMC engine had Bowtie heads, not OE Vortecs. The chambers aren't the same, so not sure the valve job should be. He also mentioned budget, Hotrod just ain't gonna fund a long series of tests with cam changes etc for an article in a Mag, so he had to make do with what he had. OE heads and a cam he had.

Like CGT mentioned there are other variables not controlled. Compression etc.

But, the conclusion we should take from that test is, you can certainly manipulate the power/power curve by manipulating the window area the engine sees with seat angles, not just cams.

Daryl called back after the test and said he was surprised. Said he didn't think the power would change at all.

Nice to hear from some who have tried different seats, BUT,...I'm sure some of those that don't actually build engines will continue the, "but the cam, but the cam, the cam needed changed, you didn't get the cam right Bla Bla Bla Bla, trying to defend a position someone told them and never go out and build something and try some new things.

Randy

[ClassAct]

Imo, if you take the results from the magazine test at face value, and assume the quality of the valve seat work was equal for all three tests....... you’d conclude that both the 35* and 50* angles make more power than a 45* will.

I don't think one can, or should draw a lot of conclusions about ideal valve jobs from the test.
I talked to Daryl about that test before he did it, and gave him the angles I used on the EMC heads referenced in that article, but the heads on the EMC engine had Bowtie heads, not OE Vortecs. The chambers aren't the same, so not sure the valve job should be. He also mentioned budget, Hotrod just ain't gonna fund a long series of tests with cam changes etc for an article in a Mag, so he had to make do with what he had. OE heads and a cam he had.

Like CGT mentioned there are other variables not controlled. Compression etc.

But, the conclusion we should take from that test is, you can certainly manipulate the power/power curve by manipulating the window area the engine sees with seat angles, not just cams.

Daryl called back after the test and said he was surprised. Said he didn't think the power would change at all.

Nice to hear from some who have tried different seats, BUT,...I'm sure some of those that don't actually build engines will continue the, "but the cam, but the cam, the cam needed changed, you didn't get the cam right Bla Bla Bla Bla, trying to defend a position someone told them and never go out and build something and try some new things.

Randy

I'd like to add that after screwing with this for decades, I can say with pretty much total confidence if you are using a cam that is even close to what the engine wants, there is little gain in changing cams. Unless you are way off its just not a big deal. I can list the names of companies whose cams I've tested but it means nothing. I never buy cams off the shelf. I've used Isky cams that I bought after taking to Ron or Jamora that were every bit as good as anything else I put up against it. As long as you are competent to pick the timing events, or like me, you feel better talking with someone at the cam company of your choice you can't hardly make a cam mistake. Unless you lie to the guy on the other end of the phone.

About the only thing more expensive and time consuming than testing camshafts is testing oil and fuel. It costs a ton of money for very little reward, if you're not way off the mark to start with.

[GARY C]

Some observations from the magazine article (can't believe I'm doing this ). Especially after staring for hrs on end at vortec heads the last several weeks which were used in that test, also being around the dyno on engines pulled down that low quite a bit. I tend to disregard the first couple readings at the bottom of the pull, there can be some phuckery down there(not always). And there seems to be some of that in that test too.

Regarding this variation or that variation of each valve job. ALL of those valve jobs could be better I guarantee you that.. There is always mention of this top cut or that one. I can almost promise you that the 50° VJ wouldn't have likely even had a topcut, or barely one or an intermittent one at best, especially on that casting, especially after it was given a 15 degree top or whatever it was from the prior 35°VJ. And if it did, it would have had to be sunk ALOT to get there and then there would be a pretty good sized compression loss from that. ( 4cc's lost from doing that on project dale budget vortec) And yet the same trend still shined through in that simple test.... More VE, fatter torque curve.

I can't blame anyone for being critical or skeptical of someone else's tests or dyno's, I certainly am...hell im even skeptical of my own. But that simple(yet not perfect) test shows the same trends I've seen time and time again. And I have no interest in changing anyone's mind on this subject. I actually hope anyone I may compete against runs a 30° valve job, or makes it a mission to maximize flow at low valve lifts. ….that emoji is titled "razz"

If you sink a valve but mill for compression does it hurt power or flow or both?

I have heard you can't do it because of FLOWZ but if it makes the top cut chamber blend better it could be good for POWERZ.

IMHO, getting the top cut in is not sinking the valve. The top cut is a big deal. I like a top cut a minimum of .060 wide and if I can get .100 I'm happy. If I can get a bit more than that I'll take it.

This set I am playing with now looks like the top cut should blend well... or so I hope , little deeper and wider than most I have seen...

[ClassAct]

If you sink a valve but mill for compression does it hurt power or flow or both?

I have heard you can't do it because of FLOWZ but if it makes the top cut chamber blend better it could be good for POWERZ.

IMHO, getting the top cut in is not sinking the valve. The top cut is a big deal. I like a top cut a minimum of .060 wide and if I can get .100 I'm happy. If I can get a bit more than that I'll take it.

This set I am playing with now looks like the top cut should blend well... or so I hope , little deeper and wider than most I have seen...

I like that top cut.

[CGT]

Some observations from the magazine article (can't believe I'm doing this ). Especially after staring for hrs on end at vortec heads the last several weeks which were used in that test, also being around the dyno on engines pulled down that low quite a bit. I tend to disregard the first couple readings at the bottom of the pull, there can be some phuckery down there(not always). And there seems to be some of that in that test too.

Regarding this variation or that variation of each valve job. ALL of those valve jobs could be better I guarantee you that.. There is always mention of this top cut or that one. I can almost promise you that the 50° VJ wouldn't have likely even had a topcut, or barely one or an intermittent one at best, especially on that casting, especially after it was given a 15 degree top or whatever it was from the prior 35°VJ. And if it did, it would have had to be sunk ALOT to get there and then there would be a pretty good sized compression loss from that. ( 4cc's lost from doing that on project dale budget vortec) And yet the same trend still shined through in that simple test.... More VE, fatter torque curve.

I can't blame anyone for being critical or skeptical of someone else's tests or dyno's, I certainly am...hell im even skeptical of my own. But that simple(yet not perfect) test shows the same trends I've seen time and time again. And I have no interest in changing anyone's mind on this subject. I actually hope anyone I may compete against runs a 30° valve job, or makes it a mission to maximize flow at low valve lifts. ….that emoji is titled "razz"

If you sink a valve but mill for compression does it hurt power or flow or both?

I have heard you can't do it because of FLOWZ but if it makes the top cut chamber blend better it could be good for POWERZ.

IMHO, getting the top cut in is not sinking the valve. The top cut is a big deal. I like a top cut a minimum of .060 wide and if I can get .100 I'm happy. If I can get a bit more than that I'll take it.

I agree. The heads I mentioned in my post had a .100 wide top cut. MOST dont get done that way that I see and if you were your just doing a stock or mild build with these heads I don't know that I would either if you were trading compression for topcut on a 250hp deal. I get what your saying, I wont call it sunk, I'll just say I ended up with a lot more installed height .

I'd like to add that after screwing with this for decades, I can say with pretty much total confidence if you are using a cam that is even close to what the engine wants, there is little gain in changing cams.

So true, there are bits and pieces here and there, usually always come with a compromise of some sort. People that have "been there" tend to have this realization. But most people want to believe its magic or (VOODOO)