GLENAMY 242SS

iTrader: (1)

When do you need Inconel exhaust valves and when are quality Stainless valves OK?
I am finishing my mild build 454 and trying to decide if I need Inconel exhaust valves. Boat is recreational in use but building to about 450ish HP.
What are determining factors for Stainless vs. Inconel. As everybody that has built an engine knows the budget is already blown so cost is a factor.
Thank you for your assistance.

F-2 Speedy

iTrader: (6)

300 to 400 bucks now could save you a few thousand down the road, IMO it's piece of mind

Bawana

You will get alot of opinions on this going both ways. They are in deed an insurance item. In my experience I have run with them and without, It all depends on your tune, and some will say how you run your boat.I run & always have run super charged motors in my boats and don't use them anymore, I run very hard and yet to have a problem. I have also built several NA motors for others and gave them the choice. It all depends on your budget. In a mild motor I would spend that money on other upgrades.

14 apache

iTrader: (1)

On your power I would not worry about Inconel valves. I ran some motors just like what your building and ran the nuts off of it never a problem.

GLENAMY 242SS

iTrader: (1)

My builder is of the same opinion. He say he uses them only on blower motors. I don't want to skimp on important stuff at the end of the build but I also can not see going overboard. I have very basic knowledge in subject so all opinions welcome. The builder suggest Ferrea valves, any comments/suggestions on valve selection greatly appreciated. Thank you.

BenPerfected

You will need Inconel valves if/after a regular SS exhaust valve fails. In a boat you have extended runs at high RPM (compared to short burst of high RPM in automotive application) so the marine exhaust valve gets significantly hotter for extended periods. You can save $ on the block, heads, intake/carb, rigging, etc. but the exhaust valve is not a good place to cut a corner.

mike tkach

iTrader: (3)

not knowing what kind of boat you have or how you run it makes it tough to say if you need them or not.i think merc put them in the 365 mag and up.if you can find the xtra cash put them in,you might sleep better at night.if you don,t put them in now you might find out that you needed them sooner or later,jmo.

Full Force

iTrader: (5)

my .02....for what the Inconel valve costs I would never build any engine over 400 hp without them, to me it's just stupid.... because it costs a ton more when the head snaps off and destroys pistons, and cracks a cylinder wall....

Any engine builder should recommend the Inconel for Marine use.... I would hope anyway..


first pic, regular stainless valves in my warmed up 420's with merlin heads, happened twice, the first time it didn't break piston and made some marks, flew out the exhaust... I replaced valve with another stainless valve, then the following season the hole in piston picture you see.... stainless valve failed, rebuilt engine completely pull all 4 heads put in Inconel never had issues again.....
[ATTACH=CONFIG]547206[/ATTACH][ATTACH=CONFIG]547207[/ATTACH]

The valve picture is my INCONEL after a fuel line got crap stick in a brass fitting and leaned out BAD, if that was a normal valve it would have broke.....[ATTACH=CONFIG]547205[/ATTACH]

MILD THUNDER

iTrader: (3)

Ferreas super alloy exhaust valves are commonly used in BIG power offshore engines by some high end builders. Also very popular in big high boost , nitrous stuff.
Supposedly they are good for 700 more degrees than manleys "inconel".

If your builder is a ferrea fan/dealer, i would ask him for the super alloy exhaust valves, and 6000 series intake valves.

"Inconel" is a trade name. GM used two piece inconel valves, that were prone to breaking. Not all valves are created equal.

No valve material is going to compensate for a bad tune. Guys break or tulip stainless valves because they were lean, or retarded timing, then blame the valve itself.

GLENAMY 242SS

iTrader: (1)

So Ferrea 6000/intake and super alloy exhaust? I believe he (engine builder) was looking at 5000/I and 6000/E. maybe 6000/I and 6000/E.