oversized valves

[truckinwagen]

I am tinkering with the idea of putting oversized valves in my 1.6 head.

unfortunately I don't have the head/block in front of me to measure things, so I figure I would ask you guys what you think.

first off, what size are the stock valves in a 1.6 head?
and secondly, how big do you think one could go with the valves(with new oversized seats installed) could one go before the valves interfered with each other/the cylinder bore?

could I fit 42mm intake and 35mm exhaust vales in there?
(I ask because TT sells a kit for gassers to increase valve size to these numbers)

thanks,

-Owen

[truckinwagen]

by the way, does anyone know the valve length for the 1.6 diesel and 1.8 gasser?

I am starting to think that they are different, but am not sure.

-Owen

[rabbid79]

Yes, the diesel valves and gas valves are different.  The diesel ones are longer (104.8mm Intake and 104.6mm Exhaust) than the gas ones because of the flat head design.  The Audi 5000 2.0 TD intake valves are 2mm larger than the 1.6 (36mm vs. 34mm) and I image would fit into a 1.6 head without much trouble.  As far as I know the 1.6 and 2.0 diesel exhaust valves are the same at 31mm.  I don't know how the 1.9 valves compare but you might look there too.  You might also look into early (2V) VR6 valves since those engines use a flat head (no combustion chamber in the head) design.

[truckinwagen]

I will do that, thanks for the valve length specs for the diesel.

I am going to call Techtonics on Monday and see what they have that will fit in a diesel head.

the only issue with the tdi and aaz valves(or any stock valve for that matter) is getting the valve seats, but I am sure I can find a supplier somewhere.

[truckinwagen]

the other issue with AAZ and TDI valves is that they are all hydro lifter, which have shorter valves too.

I will see what TT has that is the same length or longer(cutting them down is no real issue) on monday when I talk to them.

[clarkrep]

I was recently discussing valve options with Colin at TT he said he's had good results with 36mm valves from an Audi 5000 in a 1.6. I assume seats would be a simple deal too. :-)

[truckinwagen]

it looks like the aircooled vw valves use the same diameter stem, and are available in many sizes(with matching seats) for cheaper than any of the water cooled ones(that dont work anyway)

they are about 12mm too long, but I think I could have them cut down for not too much money.

about $100 in valves and seats plus machining the valves to length and installing the seats should be pretty reasonable.

all I need to do now is see how big a valve I can stick in the head before the seats touch or the valve sticks into the cylinder wall.

-Owen

[macka]

it looks like the aircooled vw valves use the same diameter stem, and are available in many sizes(with matching seats) for cheaper than any of the water cooled ones(that dont work anyway)

they are about 12mm too long, but I think I could have them cut down for not too much money.

about $100 in valves and seats plus machining the valves to length and installing the seats should be pretty reasonable.

all I need to do now is see how big a valve I can stick in the head before the seats touch or the valve sticks into the cylinder wall.

-Owen

Well let us know what you finally go with.

[truckinwagen]

will do, I will also post my findings about the biggest cam we can cram in our motors.

[macka]

will do, I will also post my findings about the biggest cam we can cram in our motors.

awesome