RB Inlet/Exhaust Valves

[Roy]

Everywhere i look concerning the SR20DET i read how they use Sodium filled valves for better cooling.

Question is does the RB26DETT use Sodium filled valves? What about the RB20/25?

And whats a reasonable asking price for some good quality aftermarket valves...nothing truly exotic, at the minimum equiv to std Nissan RB26 valves or a bit better...

And if the aftermarket ones arent filled with sodium, is there any real world difference, especially since i would consider getting the HPC caoted anyway?

Cheers ppl

[ace_nz]

26 has sodium exhaust, 20 and 25 doesnt

[Roy]

So if they needed replacing would you grab std Nissan ones, aftermarker...respective prices for RB26 inelt and exhaust valves?

Thanks for the response

[DoughBoy]

Aftermarket ex valves are not sodium filled, they are made from stainless blanks. I don't think RB26 valves will fit in a hydraulic 20/25 head due to the valvetrain differences.

[Roy]

LOL...but i may be able to get my hands on an RB26 head with a few bent valves for an attractive price...considering id want to get the head rebuilt anyway...it may just start the ball rolling:)

[Cubes]

The RB20's exhaust valves are 27mm where as the rb26 exhaust valves are 29.5mm.

Unsure if the larger valves would fit as they are definately squeezed in there.

[Chris Wilson]

The RB26 uses 7mm stem diameter exhaust valves, probably so the stem strength isn't compromised by being partly hollow with the sodium within. RB25 engine has 6mm exhaust stem diameter and they are not sodium filled. The bigger stem diameter also gives a larger surface contact area with the guide, giving a better heat exit path into the head and waterways. Both engines use 6mm intake stem size, AFAIK.