valves query

[davidbuttigieg]

Tried to have a search on this but had no luck..

I know that the valves on a 1.8 are smaller then those on a 2.0 and that the ones on a 714 are bigger then those of a 700, but what are the actual sizes ? and what size are the biggest valves that can be machined to fit a 1.8 head ? 34mm ?

and the exhaust valves, are they all the same size ?

[Wobba]

Valver inlet 30.7mm
Willy inlet 31.7mm
Megane inlet 33mm

Exhaust ones are all the same.

You can get bigger valve conversions like 34mm. I have heard of 35mm but apparently it needs a lot of work to get it right (i.e. not worth it).

[Laine_16v]

Putting 34mm inlets in a head is going to be dreadful on anything less than 240bhp imo.

[Yanoo_]

In my opinion: a decent intake and exhaust porting (particularly at the valve throat) and a professional valve plate back modification are more important than a bigger valve.

[stan]

Putting 34mm inlets in a head is going to be dreadful on anything less than 240bhp imo.

dreadful in what way?!

[davidbuttigieg]

Valver inlet 30.7mm
Willy inlet 31.7mm
Megane inlet 33mm

Exhaust ones are all the same.

You can get bigger valve conversions like 34mm. I have heard of 35mm but apparently it needs a lot of work to get it right (i.e. not worth it).

valve stem and length for the inlet valves are all the same ?

[stan]

Yeah they are.