Exhaust valve options

[Bryan Cotton]

I am digging through the internet looking for options for my head rebuild. The thought crossed my mind that I could even use non-VW based valves if the diameter was right. Might mean I would need a custom valve guide, plus springs & keepers might be a challenge. But then I found this:
https://scatvw.com/product/35-5mm-exhaust/

Scat was a really good name - are they still the same? Says valves are rated for 1600F which is pretty good.

[Bryan Cotton]

A couple more:
https://www.cbperformance.com/product-p ... pvalve.htm

https://www.cbperformance.com/product-p ... keskin.htm

https://www.cbperformance.com/product-p ... valves.htm

[Bryan Cotton]

So Empi is now using Manley valves.
https://empius.com/products/empi-manley ... and-locks/

[Murray Parr]

Are any valves available that are sodium filled? They would be a good choice if available

[karmarepair]

Are any valves available that are sodium filled? They would be a good choice if available

Sodium filled valves have bigger stems, and will not fit in Type 1 VW heads without major valve guide butchery.

[Murray Parr]

Rotax 912 valves are quite small, haven't been able to find the dimensions yet so maybe someone here knows what size they are?

[Kai]

Rotax 912 valves are quite small, haven't been able to find the dimensions yet so maybe someone here knows what size they are?

You probably won´t either. Such data Rotax will most likely only issue to their certified repair-overhaul centers. However, I would querie the wisdom of installing valves intended for liquid cooled heads in something aircooled. Perhaps better to find something for an aircooled motorbike? Someone previously wrote on these pages that some VW-1 racing exhaust valve would tolerate 1400F. That´s a lot!

While leafing through the R912 Heavy Maintenance Manual, I noted that they are quite specific about how much burnt oil residue they allow on their valve stems- especially in the region where the stem is welded to the head. Something to watch carefully during VW-1 head overhaul as well?

[Dave Wolfe]

The triple groove retainers promote valve rotation due to the retainers not actually clamping on the valve shank and thus the valve can rotate individually from the retainer / keeper / spring. The single groove style locks on the valve shank so the retainer keeper & valve are stuck together.

[Area 51%]

The triple groove retainers promote valve rotation due to the retainers not actually clamping on the valve shank and thus the valve can rotate individually from the retainer / keeper / spring. The single groove style locks on the valve shank so the retainer keeper & valve are stuck together.

Just so we keep our terms straight........there are no such things as triple groove retainers. Just keepers.

[Dave Wolfe]

My bad you're right on that one.

I just learned Lyc & Cont motors incorporate "rotators" in the exhaust valve thru two different methods. The cont uses a roto cap device that positevely rotates the valve thru a mechanism involving springs BBs and grooves located on top of the valve spring. The bigger lycs basically work the same way as the tripple groove VW valve stems but using different pieces including a cap over the valve stem.