Sodium filled exhaust valves
Turbo Mini Forums

Hi All,
I was told the other day that all turbo heads use "Sodium filled exhaust valves" due to exhaust temps running higher on forced induction engines.

Im also told that you can tell if you have them or not by looking at the head and seeing if the exhaust valve stem is a bigger diameter than the inlet, is this correct?

Im doing a supercharger conversion (No intercooler). So my Question is do I really need to use them? The reason I ask is that I have a flowed and ported head kicking around and was hoping to use that rather than shelling out loads of hard earned pennies on a new Turbo head? (Providing that the compression ratio is correct that is)

Your help would be appreicated

Many thanks

Rob

You don't need them. They are bad for flow and often break.

Do a search,

I'm still using them (i think)... I thought the breakage issue was more down to coil binding?

i havent used sodium valves for years with no problems

Sodium valves are common on turbo engines. However most of MX-5 converted to turbo still run with not sodium valves. The same is true for old Lancia/Fiat TC engines (Lampredi). I'm sure they are necessary in high flow and boost applications, but Mini engines are small, perhaps the exhaust gas volume is small to overheat valves ?

std 998 A+, g295, MD266, RHF4, 109hp @0.8bar/5400rpm

they are used as in the production tests of the engines they got hot, as they run them flat out for hours on end, you wont do this in a turbo mini ( well unless you are racing) so not needed.

always looking for them bigger bunches of bannanas

Thanks for all the info, think I'll stick to the head that Ive already got and see what happens?

All the best

Rob

I've not used them since 2004

Team Racing

acutally 2002 sorry

Team Racing

Im still using them not had any problems yet, still saving some money for something fancy!

It all depends on how you intend to use your car which dictates what spec you build the whole car to. I often ran mine flat out for over an hour in the wee hours on a road I care not to metion and have had no problems with my sodium valve set-up.

Own the day

You'll find all aftermarket modified Turbo heads use stainless race valves, rather than the sodium type. So there's no issue if you use them or not.

WWW.TURBO-MINI.COM

Worth bearing in mind that all sodium valves are going to be at least 19 years old.

I personally switched to larger modern stainless race valves with silicon bronze guides after hearing horror stories of heads dropping off valves.

One of my exhuast valves did pinch up in the guide after some "enthusiastic driving" and the piston gave it a helping hand back up :(

So I suppose it could be argued that the valve got a bit too hot or the tollerance was too tight in the guide... Maybe a sodium stem would have helped?

Ive never used them. Some good quality non sodium filled ones will be fine.

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

I intend to use the car for fast road and the odd track day, as I am in the process of putting together a turbo mini which will be specifically used for track and hill climbs, so wont be doing alot of speed events in the one I asked the question about.

I will be taking the head apart this week so will have a dam good look at the Valves and make sure they are all in good nick, and are of a decent quality!

If I do find some suspect ones, does anyone have any suggestions of where to get some decent new Valves from? Im thinking MED might be worth a try?

Minispares stainless race valves are popular.

Cheers Jay#2, may well be ringing them towards the end of the week, depending on what I uncover! Lol!

I personally prefer the MED ones, slightly more expensive but a better valve.

WWW.TURBO-MINI.COM