Valves

[alex h]

I'm under the impression that valves tend to rotate a bit whilst in use? Is that correct?
I ask as the 4-stroke tuning book I'm reading goes on about undercutting the valve stem on one side etc (which probably isn't applicable to modern valves and heads) but if you only cut one side won't the valve rotate anyway and make the effort a bit pointless?

[Nathan]

Yep, valves rotate.

[alex h]

Whilst I think about it...
1) What's the diameter of the exhaust and intake valves on the Supra?
2) Is it a pent roof combustion chamber?
3) If it is what is the valve angle?
4) Are the valves recessed or flush with the roof?
5) Is the stock valve seat multi angle or radius'd?
6) What is the tolerance of the valve guide and what material is it made from?
7) Are the pistons on the Supra flat top (with a small valve cutout), or known by another name?

[alex h]

Cheers nathan - still puzzled then at Mr. Bell's work on making the valves non-symmetrical

[Nathan]

Quote[/b] (alex h @ April 08 2004,09:48)]Whilst I think about it...
1) What's the diameter of the exhaust and intake valves on the Supra?
2) Is it a pent roof combustion chamber?
3) If it is what is the valve angle?
4) Are the valves recessed or flush with the roof?
5) Is the stock valve seat multi angle or radius'd?
6) What is the tolerance of the valve guide and what material is it made from?
7) Are the pistons on the Supra flat top (with a small valve cutout), or known by another name?
All the answers are on these premises but I've no idea when I'll have a spare hour or so to dig them out ... http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/sad.gif

[Nathan]

......but off the top of my head...

2. is 'yes'.
4. is 'flush'
7. is 'dished with cut-outs'

[Darren Blake]

Aren't there two types of valve collet: single groove (non rotating) and multi (usually three) groove (rotating)? Most engines use three groove these days.

I have a load of stuff on the base engine dimensions for the Supra too if Nathan can't find it.

[alex h]

Darren do you have that info then??

[Darren Blake]

Yeah. Its on a CD somewhere. I found it recently while looking for something else. I'll try to dig it out for you.

[alex h]

TIA - now get round to Ian's with that o'scope