sodium exhaust valves
 

just wondering if any one know if the m102/3 engines have sodium filled exhaust valves??
i know some of the diesels do.

or has any one changed to these valves??

Thanks, Trent

Are you having a problem with burning exhaust valves???

It's done on diesel due to a need- I don't think your M102 needs them.

Even the vintage model Mercedes used Sodium filled Exhaust valves . Others will not work in these engines.
mak

im currently running avgas in these engines and that burns alot hotter, plus im soon looking to up the hp a bit and just wondering, just curiousity more than anything, no one else seems to having any problems as far as i've seen

Av gas doens't burn hotter unless you crank up the ignition timing b/c it has a higher octane. It does have a lot of extra chemical crap in it required for anti-icing, crash etc... If it's not free, you should re-think going back to pump gas.

it burns a hell of alot hotter! it has lead for higher octane
my car pings on 91, so i could either put 95 or 98 in OR a mix of 91 and avgas, which is what i do

and it doesnt have any chemicals for anti icing and what do you mean by crash? as in if the aircraft crashes???

it got Lead (TEL) a chemical for turning the lead into something else after its burnt, and a chemical that removes that chemical, or something like that, sorry for being so vague on those, lol

oh and yes its free :)

AV gas doesn't burn "hotter" than any widely available fuel. Octane numbers refer to anti-knock qualities, which in no way translates to "hot".
Sodium filled valves are generally found on engines that continually operate at higher throttle openings, such as aircraft and marine engines. Some car engines have used sodium filled valves, and Benz is one of them. Advances in materials and much better engine management systems have made sodium filled valves, for most car engines, unneeded.

yes i know what the ron number means

and ok your right, it probably doesnt actually burn hotter, but, it does burn longer, (well slower) which in turn can mean it still burning as it leaves the cyl. and i've burnt exhaust valve's on car b4 from running avgas which ran fine b4 it was on avgas, but that engine was piss weak compared to any thing merc ever built.

and as far as cars not using sodium valve's anymore

one of the best 6's ever built (along with the m103/4 :) ). the rb26, and nissan v8, the vh41/45 uses them aswell

If your that concerned about a possible valve burning, you should investigate what the racers use. Light weight ti or somesort of heavy duty Incconnel valve for high heat. Of course your looking at a full set of special seats.
Like I said before, it really doesn't buy you much until you turn up the timing. The USA cars came 6 degrees retarded timing. Maybe you should look through the performance archives here and set yours up for the higher timing. Of course, the Euro's had higher compression which helps you get more hp out of that fuel/timing.
I think the use of sodium valves is not just due to heat or heavy duty, but is an engineering repair for a weak design. By weak, I mean the geometry of the exhaust port, stem length etc, there just is more too much heat. Common on AV aircooled engine as I'm assuming like their street brothers run hotter.
Diesel stems are 9mm I believe where a gaser is 7mm. If you choose to purse it, check lengths/sizes... then ream the head out to take a diesel valve guide. Be aware of total valve weight with retainer as that will effect the valve float point (RPM) of the engine.

Michael