Gtr Shim And Valve Stem Diameter?

[StavrosRB2630]

Hi.

As per title really, does anyone know the diameter of the valve shims and valve stems?

Also does anyone know how far the valve stem protrudes above the collars?

Any help appreciated as ive no idea.

Cheers

Stav.

[The Dan]

Can you tell me why you need to know...it may help me to understand exactly what you are trying to achieve. I think I have all the necessary info on the puter but will have to dig it up.

[StavrosRB2630]

Basicly a cam manufacturer (im in the UK) are planning to re-grind my cams to a different spec, and rather than just use bigger shims as they thought would cause too much mechanical drag (or something!) they wanted to add something to the bottom of the buckets as well.

Must admit im not 100% what he meant as i was trying to hear him in a busy office.

If this dont make sence to anyone i may need to ring him back and get a more detailed explanation!

[StavrosRB2630]

Oh, by the way i meant COLLETS not Collars! Sorry.

[SteveL]

Basicly a cam manufacturer (im in the UK) are planning to re-grind my cams to a different spec, and rather than just use bigger shims as they thought would cause too much mechanical drag (or something!) they wanted to add something to the bottom of the buckets as well.

<{POST_SNAPBACK}>

Sounds like they want to make more $$ out of you for custom work. AFAIC the 'drag' will be more or less the same, but lift rates will change placing extra load on the springs. Don't understand why you would bother adding extra to the bottom of the buckets when increasing shim thickness has the same effect.

For an R32 GTR, valve stem diameter is 6mm for inlet and 7mm for ex., but there is a small tolerance, off course. I have some spare shims so will check diam for you.

[proengines]

The shims are 12.3mm diameter. The exhaust valve is nominal 7mm on the stem but is reduced down to 6mm from just below the collet area to the tip of the valve, so the caps and collets are the same on inlet and exhaust. It's around 1.9mm from the top of the collets to the tip of the valve.

Depending on the thickness of shim and bucket you require you could run a toyota solid bucket, as fitted to the late 2jz and 1zz engines. You can buy them in increments, I dont have the minimum or maximum thickness here though. They are the same diameter as a 26 bucket and you dont have to worry about shims at all. They are a little fiddly to set but once they are done you dont have to worry about them any more.

[StavrosRB2630]

SteveL- No, as they doing it all for free

There was a reason, but it was when they thought the shim was above the buckets, soon as realised the cam dont operate directly onto the shim it didnt matter.

Dont think it was drag, cant remember the exact reason, but either way its irrelivant when the shim is below the buckets.

Cheers for the measurments, just happened i got them off another source this morining actually anyhow, but thanks all the same