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.....