at what point are inconel exhaust valves necessary?
 

just tearing into my xmas present to myself. tired gen 6 L29. was shopping for heads for my mk IV and found a complete roller gen 6 instead. i am looking at under 450hp, over 112 lsa, under 5000 rpm engine use. and i don't even see inconels anywhere in 1.72 in. if an engine like this can live without, what is the second best choice?

competition 6000 stainless from Ferrea.,or something similar.

That engine should already have inconel exhaust valves. This is a replacement valve for that engine

http://www.race-mart.com/Sealed_Power-SLP-V2450X.html

http://www.napaonline.com/Catalog/Ca...50X_0204239889

It is a propane gas engine. 10 or 12 quart pan with multiple outlets on the side of pan like it was set up to change oil while running. I think some kind of industrial pump or something.

You sure its not a L21? Those had forged cranks in them.

don't have the pan off yet. good possibility. the ex valve; magnet has no attraction until the very top maybe 1/4 inch of stem. like they used a malleable steel for the wear point at the rocker tip. you can see the change in color above the valve lock where the material changed.

I believe the valves will be stellite and sodium filled.I remember using those valves from SBI.So thats why you see a cap like tip.

Yes I think stellite material. Stellite is also a material used on the faces of some flat tappet lifters

10114188 cast crank. oh well...got a 4-bolt roller engine for a nickel.

Must use inconel valves with a zz502 cam if you want to retain the oem cast iron exhaust lol jk its late .i mean early .but really the inconel and super duty valves seem to resist losing thier heads much better if something goes ugly with the exhaust water .

they do quite well for a bit of time.problem is,if you don't notice the skip/misfire/loss of power or rpm and that creamy oil,,the exhaust valve will pit so bad around the stem that it just breaks off.we know the drill after that.

I have had a drink or 10 so, forgive me! I saw air-j mention the zz502 cam is that what you planing to run with the l-29 vortech heads? That was the rout I was planning to take. Tore down my engine saw scared piston wall, long story short now in building a 540 for my 22zx. L29 heads in stock form can only support 510 lift. To run the zz cam the valve guids will need to be machined down for clearance with the access lift.along with new spings, and valve rotator eliminator's. There's hit and miss info available on forums about this setup just be careful what you believe. I would deal fine using stock gen 6 crank as well with this set up. Should be 400hp whit hour head work. Yet I stand to be corrected if need be. I read for months on this subject.

It was kind of a inside joke from another thread i dont think he has any intention of running the rumpita rumpita with the 7400 heads .

[Yea , but me, and ill bet you , dont have to worry about that happening .ive seen enough of other peoples motors grenade over fumbled riser gasket installs melted inner hose linings ect .beezwax or chapstick your riser gaskets and you can take a quick peek down the exhaust while your girlfriend grabs a fresh beer .thats how i caught a inner crack in a imco once before it did any damage to #8 .new spark plug and spare mani swap was out that afternoon

So much for the "reply with quote " still learnin the ropes of the new phone .

i will probly do a little guide work to get around 550 lift, but i ain't going under 112 lobe sep. that zz is 110lsa and 550 lift approx. i have a flat tappet 560 lift 230 duration cam i am gonna leave in my MK4 block. i hafta get a degree wheel and play a little to edjimicate myself a lil more on cams in general and this one in particular.

Do you already have exhaust ? I have a set of imco risers for standard merc cast manifolds. I planed to use them on a similar project. But plans changed. They're dry to the tip.

I did a lot of research on whether the black motors came equipped with inconel, and I was told by an engineer at Mercury Racing that the black motors came with whatever GM equipped them with, so he wasn't sure what kind of valves were in there. Only the blue motors were disassembled and blueprinted, and those had the upgraded Manley exhaust valves.

well my L29 is blue so i guess it has the good stuff...good cast crank, good 3/8ths rod bolts, good cast pistons, good low rise q-jet intake...but apparently the OE truck exhaust valve is the next best thing. and this motor is being built to be second best at best...probably put it in the
crownie after running it in the pantera for the season.

Considering what can happen, it's money well spent buying Inconel valves imo. Any money you can spend to increase Valvetrain reliability in a BBC is a win win.

Lol! Thats funny ! Ive been there one time with a islander 252 , knowing what kind of silly power the vortec 5.7 and ls motors can make , was curious what we could pull out of that base gen6 mpi big block motor. Back then the jury was out on the heads and were never coming back . With dilligent research you should be able to extract a reliable 400 or so out of it on the super cheap with some worthy mid range torque compared to a,71 chevelle ss454 style contemporary build , im sure your not going to miss a shift or wind out the 3.73 gears on a lonely highway. It will live .