16V Valves....

[oldeskewltoy]

back in OST-033, oldeskewltoy Wrote:As to the Supertech valves..... that is a future flowbench project



But for now... that is still a future project

Its time to go back to the future......

For all but a few exceptions, all the heads I've ported have run stock Toyota valves. Stock Toyota intake valves came in at least 3 varieties(maybe more??), those with a blank face, those with a "4A" on them, and finally those with a small 4 point diamond on the face. There are slight differences in the stock intake valves, but essentially they are all the same shape.

A few heads ago, a respondent to my threads asked if I had run other valves, for he had success running performance based valves in his work. At the time, I was only aware of Supertech having performance based stock valves for the 4AG heads, since then I've found another company that sells performance 4AG valves in stock sizes, SI Valve. There may be other companies making performance 4AG valves in stock size, but I didn't find them.

I contacted both Supertech and SI and got a set of four from each. The Supertech came with the back cut, the SI valves were back cut by me.

So lets take a closer look.......






Exhaust valves too.....




And here are our test chambers/ports......

from another forum Wrote:I do the back cut and valve shank reduction (not quite as pretty on my old cutter)

I've been looking at valve equipment over the past year+, at this stage, new valve grinding equipment is $$$$, used is possible, but often the chucks are quite worn... learned that most good chucks are accurate to .001", but the 4AG, and many other "performance" based multi valve engines work best with chucks a bit more accurate - .0005"

This is pure speculation, but a few heads back I had to replace all the exhaust valves because they were off by more than .002"



I wonder if the machine that cut these had a "worn" chuck??????



For now... I'm sticking with having access to "L", and the local machine shop in town, they did the nice work on the 5MG guides....

since we are no longer moving south.... I'm looking at spending a few grand on extending the garage enough to have a dedicated space.

from another forum Wrote:I can not wait to see which valve form flows the best in a 4AG head at low and high lift. I'm surprised there isn't a back cut on the exhaust valves. I had alway assumed that the exhaust flowed better with a back cut.

I've asked about it from the porting specialist @ "L", he always shrugs his shoulders and tells me the proper bowl shape to the short radius is far more important then a back cut on the exhaust valves.....

As to flow... I'm anxious to see as well... I'm also interested if one is better for lower lift cams, while another is better for higher lift cams...


more to come.....

[Bean]

Looking forward to the results and good luck with the extension, hope it'll work out as planned or better

[oldeskewltoy]

The extension is some 6 months... maybe? Hope to afford to do it, but a few priorities before it

from another forum Wrote:For sure the short side radius has more influence on flow, then the back cut. I just recall reading an article about the effects of a 20* Vs a typical 30* back cut on the exhaust valve of a SB motor. Dave W

only partially done so far... but exhaust valve type seems to matter less then ported, or unported port....


A bit of understanding of how the FP2 flowbench I have, operates... It takes air samples every 2 seconds, these samples measure air in CFM (cubic feet per minute) The samples come out to the tenth, I take 18 to 20 samples per setting, from those 18 to 20 sample 6 are randomly taken to then average. This is how I get to post readings to the hundredth. For TRUE actuality readings, look @ the number and figure the high number was .5 higher, while the low number was .5 below. For example in the first readings below ".050" - 27.78 - - 38.96" 27.78 was actually 18 readings that ranged from 27.2 to 28.3.


Some numbers.........

Stock chamber w/stock ports, stock valves no back cut
..........Lift - Exhaust- -Intake

• .050" - 27.78 - - 38.96
• .100" - 61.81 - - 78.58
• .150" - 94.28 - - 116.58
• .200" - 109.44 - - 148.48
• .250" - 114.66 - - 167.41
• .300" - 116.40 - - 175.94
• .350" - 118.36 - - 179.08
  

Stock Chamber w/stock ports, SI valves
..........Lift - Exhaust- -Intake

• .050" - 28.22 - - 40.24
• .100" - 59.47 - - 80.65
• .150" - 93.47 - - 121.53
• .200" - 111.23 - - 150.81
• .250" - 116.23 - - 167.92
• .300" - 117.90 - - 175.35
• .350" - 119.62 - - 180.24
  

More to come........

[oldeskewltoy]

oldeskewltoy Wrote:Some numbers.........

Stock chamber w/stock ports, stock valves no back cut
..........Lift - Exhaust- -Intake

• .050" - 27.78 - - 38.96
• .100" - 61.81 - - 78.58
• .150" - 94.28 - - 116.58
• .200" - 109.44 - - 148.48
• .250" - 114.66 - - 167.41
• .300" - 116.40 - - 175.94
• .350" - 118.36 - - 179.08
  

Stock Chamber w/stock ports, SI valves
..........Lift - Exhaust- -Intake

• .050" - 28.22 - - 40.24
• .100" - 59.47 - - 80.65
• .150" - 93.47 - - 121.53
• .200" - 111.23 - - 150.81
• .250" - 116.23 - - 167.92
• .300" - 117.90 - - 175.35
• .350" - 119.62 - - 180.24
  

More to come........

adding.....

Stock Chamber w/stock ports Supertech valves
..........Lift - Exhaust- -Intake

• .050" - 27.50 - - 38.93
• .100" - 64.23 - - 80.18
• .150" - 94.12 - - 120.22
• .200" - 109.31 - - 150.00
• .250" - 114.77 - - 167.36
• .300" - 117.03 - - 174.54
• .350" - 118.05 - - 179.44
  

Ported results still to come.......

[Project D]

Funny how the SI exhaust valve flow @ low lift
   

[Dave W]

"Funny how the SI exhaust valve flow @ low lift"
[Yes| There is a slight drip but I would think the overlap area [.050" low lift] would still be excellent.
The SI intake valve is a clear winner on that side. It will be interesting to see what porting and deshrouding will do for the numbers.
Great info for establishing baselines.
Dave W

[Bean]

Hope the Supertech fair a bit better on the ported head, else I've bought the wrong valves...

[oldeskewltoy]

As to the importanace of flow @ .050... look where the piston is @ .050" of cam lift?? Then look where the intake cam and piston are from 20 degrees after top dead center to 20 degrees after bottom dead center......

I'm not saying the numbers @ .050" are not important, just less so than from 20 after to 20 after....

Bean Bandit Wrote:Hope the Supertech fair a bit better on the ported head, else I've bought the wrong valves...

seems to matter.... but as to how much?????


Ported head

Ported head w/ stock valves WITH back cut
..........Lift - Exhaust- -Intake

• .050" - 27.53 - - 36.92
• .100" - 59.83 - - 77.63
• .150" - 92.16 - - 118.17
• .200" - 115.31 - - 152.52
• .250" - 124.52 - - 178.75
• .300" - 128.77 - - 195.78
• .350" - 131.11 - - 202.29
  

Ported head w/SI Valves
..........Lift - Exhaust- -Intake

• .050" - 27.12 - - 37.42
• .100" - 57.10 - - 77.57
• .150" - 97.28 - - 116.61
• .200" - 116.28 - - 150.43
• .250" - 125.32 - - 176.62
• .300" - 128.87 - - 194.51
• .350" - 130.55 - - 202.30
  

Ported head w Supetech Valves
..........Lift - Exhaust- -Intake

• .050" - 28.35 - - 38.83
• .100" - 61.40 - - 78.72
• .150" - 91.94 - - 118.15
• .200" - 112.64 - - 151.93
• .250" - 122.72 - - 178.27
• .300" - 127.77 - - 195.50
• .350" - 130.33 - - 203.43
  

[Rascal21]

Interesting read! Thanks for putting your spare time into this

So the conclusion, speaking bang for buck, unless chasing for 100% perfection, SI/ST/Stock valves (with or without back cut) on ported or stock (more or less) head does not really matter a huge lot?
I mean, if it stood between affording head porting or postponing everything for a set of ST/SI valves in addition?

It would explain why a lot of aftermarket companies who are into retainers, springs and underbucket shim conversions does not offer valves.

[harkes]

So realistically there could be a whole 1-2 hp in choosing the right valves