06 vw tdi jetta head which valve is in take and

exhaust valve big or smaller. I think the smaller valve is intake, am I correct. please.Thanks

You should know by where they go on the head. But no. Intake is larger. Usually is.

I have 1 for small 1for large, anyone else have an opion

Intake is almost always larger. But for goodness sakes just line up the intake/exhaust manifold to verify.

Yeah, intakes are more bigger. Reason being that lower pressure is available to get the intake air into the cylinder.

Or look at the head. Outer two ports on the head are exhaust, inner two are intake.

INTAKE is LARGER
I really have to wonder how some people can't use a search like google to solve things like this, let alone start a thread properly. Why are so many threads now half in the title and half in the comment field?

I have yet to tear down or build or work on an engine with a larger exhaust valve. Im sure there are some out there but i have yet to see them. My favorite build THUS far with a 36HP gy6 engine i built for a offroad gocart Porting those heads untill your mm's away from going though the port walls. SO EASY, so fun.

Mongler98 said:

I have yet to tear down or build or work on an engine with a larger exhaust valve. Im sure there are some out there but i have yet to see them.

Click to expand...

In some 3-valve heads, there are two intakes, each of which are smaller than the single exhaust. That's pretty rare.

Matthew Lundberg said:

In some 3-valve heads, there are two intakes, each of which are smaller than the single exhaust. That's pretty rare.

Click to expand...

well, id say to that extent that the volume still is greater for the 2 intakes vs the exhaust. I know on the gy6, there is a 4 valve head, and even with porting, its actually less volume of air moved vs just the 2 valves.
Even 2 stroke engines, port or valved head, have larger intakes, but when port 2 stroke, i always see 2 or 3 smaller intakes as there is not much room for a single large intake, also fuel mixing and exhaust band tuning and so on.
Frank06 is our resident expert on heads, so im sure he is the guy to talk to around here on this subject.

heck even rotary engines and STEAM engines have larger intake ports, especially in steam

The 1.8T engines in the MKlV cars were 5 valve heads with variable valve timing. 3 intake valves and two exhaust. Pretty crowded design.

Yeahbut, we're talking about a PD motor. Only two valves per.

The total area of the two smaller intakes in a three valve cylinder are greater than area of the single exhaust.