ITR Intake Valve on the left
GS-R Intake Valve on the right

Notice the shape of the stem and the back of the valve. The ITR intake valves have been cut down at the stem and the back of the valve (aka the backcut) for better flow and lighter weight. Don't have a gram scale, so I can't give you the exact numbers.




[Modified by IN VTEC, 8:05 AM 7/25/2002]

 

hmm Looks like the GSR has more "surface area" than the R valve. Anyways thats good to know that they r different..

 

nice pictures. thanks for the information.

 

There's a couple other things that the pic doesn't show, but are nice to know.

1.) The dimple on the bottom of the ITR intake valve is smaller than the GS-R's, and increases the static CR by a teeny weeny bit.

2.) The valve is probably 1mm larger in diameter, and is slightly noticeable if you place the two valve faces up against each other.

I was looking up the valve seat info in the Service Manuals. I have a '97 ITR supplemental and my '95 Integra bible.

The stems are the same diameter, the stem installed heights are identical, and the stem-to-valve guide clearances are identical.

But, the ITR valve seat width is .85mm - 1.15mm. Intake and exhaust identical.
And, the GS-R valve seat width is 1.25mm - 1.55mm. Intake and exhaust identical.

I can't remember what my machine shop told me the rate was per valve seat recut, but it wasn't much....I think it totalled to be slightly more than $100 to do (8). Don't quote me on that.

THey put the head on the valve seat cutter machine bench with the combustion chamber facing upwards. They insert a dowel rod that carries the cutting stone backwards into the valve guide. This centers the cutting stone. They have a bunch of different cutting stones for different seat diameters and widths.

This machine shop is also installing my valve guides and seals, and doing block work. I'm tired of buying tools. I must've spent just as much on specialized measuring and removal/install tools as I did on the actual parts. Feeler gauges, universal dial gauge, cylinder bore dial gauge, and a micrometer are the essentials.

 

ITR cams & valvetrain

I was planning a rebuild at 100k, but it came a little earlier at 75k miles b/c of a mishap.....so why not go all the way?

 

just curious if it would one would be better off just purchasing ITR valves?? cuz u never know about resizing, they are never going to be 100% of the strength they used to be (if this makes sense).

 

The valves were never cut. The valve seen in the picture is an ITR intake valve. What Teken was referring to was the recutting of the valve seat to accomodate the larger and different shaped valve.