gt head vs g40

[G40_POWER_AD]

hello people my question is....the G40 head it is the same as gt one ? only the head nothing else

[Robin]

Yup they are the same.

Only difference is the exhaust valves.

[G40_POWER_AD]

Yup they are the same.

Only difference is the exhaust valves.

sodium valves im correct ?

[Robin]

Sodium filled - correct.

[PeteG40]

Inlet valves also have different part numbers too

[G40_POWER_AD]

tanks mates....i have one gt head in good conditions to rebuild a PY block because the original head have a serious crack betwen the valves

[Jimmy B]

So which head is best on the PY block? GT?

[G40_POWER_AD]

g40 head mate....but the gt head its the same but the exaust valves is a specif ones, read above

[paulg40]

Just so you understand with forced induced engines the running temperatures are greater, this was thought to create issues with overheating exhaust valve guides so they introduced sodium filled valves to help keep the heat down and stop excessive wear on the valve guides.

I think it might have been Saab who introduced it first?

I have been reading up alot about the actual gains from sodium filled valves on smaller engines with only small amounts of boost, I don't know what anyone else thinks?

I recently rebuilt my Golf TSI twin charged engine and they originally had sodium filled exhaust valves but the replacements I got from VW were not!

Anyway best stick with them just incase :-)

are the large valves used in big valve heads sodium filled?

[breadman]

are the large valves used in big valve heads sodium filled?

No Paul, I think they are just Golf items that are dimensionally ideal.

[paulg40]

So arguably the only difference from gt to g40 head is pretty insignificant.

I have been running a head on my tsi engine that was supposed to only work with the turbo only engines and it actually works fine on my twin charged setup.

[hayesey]

are the large valves used in big valve heads sodium filled?

No Paul, I think they are just Golf items that are dimensionally ideal.

most big valve heads use custom made 31mm ones.  They aren't from a golf or anything.  They aren't sodium filled either.

the golf ones are 33mm and they are too big really, they don't leave enough metal between the valve seat and the spark plug hole.  It can (and has) cause cracking.

[Nick_S]

My Jabba 31mm ones are bi-mettallic, run a magnet down one and you'll see. Whether thats sodium metal inside or just another alloy I'm not sure.

[paulg40]

The sodium filled valves that all snapped in my tsi made a right mess. When the sodium comes out it just covered everything.