Offshoreonly.com - Inconel exhaust valves, when do you need them?

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could all come down to tuning, if you tune with wideband and have it right may be fine for a long time, but most do not so they are indeed insurance if they exhaust valves get overheated

Quote:

Originally Posted by Young Performance (Post 4372084)

Personally, I won't build a marine engine (that's all we build) without Inconel or Super Alloy valves. It's just not worth it to me. I'm not so much worried about the heat as I'm worried about some water hitting a smoking hot valve. That's my biggest worry. All it takes is a few drops of water from reversion, leaking header, whatever, to hit a hot valve and you could be in for a really bad day. It could happen very easily. While it's not guaranteed that it will fail, why take the chance. I've said it before and i'll say it again. I'm not building engines for myself. I'm building them for guys that, in most cases, beat the crap out of them like they were rentals. I have to make it as solid and dummy proof as I can. I can not rely of them to be on the lookout for potential problems, water leaking, etc. For some, it's a stretch to check the oil. That's just the fact of the matter.Some are great about paying very close attention to every little detail, but they are in the minority. If a few hundred can give us both a piece of mind, then it's worth it. I don't even give my customer a choice. I just put them in the quote and that's that.
Eddie

The water is a good point. Most of my marine experience has dry ex so that makes good sense.

Quote:

Originally Posted by MILD THUNDER (Post 4371846)

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.

Not to be a dickhead!! but the failure temp of Inconel is less than what aluminum piston failure would be, however strong enough to withstand a top fuel environment... the tuliping that occurs just prior to failure could be used as an early warning device therefore limiting catastrophic engine damage... having an exhaust valve that can withstand 700ish degrees more would make that manufacturer "Super" yes but would that extra be the very difference of costly additional damage??? I'm no rocket scientist, but I'd say that if you destroy an Inconel valve you have some other major issues that require attention!!! JMO

Quote:

Originally Posted by adk61 (Post 4372200)

if you destroy an Inconel valve you have some other major issues that require attention!!! JMO

Was thinking the same thing...

Just curious what valves are in merc black motors, as on another thread, people are saying they are getting 500 or more hours on engines untouched.

Quote:

Originally Posted by buck35 (Post 4372215)

Just curious what valves are in merc black motors, as on another thread, people are saying they are getting 500 or more hours on engines untouched.

Mine had basic GM stainless. I'd bet that is all they ever got, as these were essentially truck engines with a different camshaft, oil pan, etc.

I think only 385 and up got Inconel, but I could be wrong.... as far as 365's and such... the lower power levels and RPM seem to keep a lot together lol

Quote:

Originally Posted by buck35 (Post 4372215)

Just curious what valves are in merc black motors, as on another thread, people are saying they are getting 500 or more hours on engines untouched.

Quote:

Originally Posted by Full Force (Post 4372334)

I think only 385 and up got Inconel, but I could be wrong.... as far as 365's and such... the lower power levels and RPM seem to keep a lot together lol

Only asking because shortly after buying my boat I was looking at a power adder and was advised that a valve upgrade was prudent and necessary which I understood, but the op is only looking at a mild build , l agree insurance is good, but over insured is merely casting money to the wind.

[QUOTE=GLENAMY 242SS;4371534]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.[/QUOTE
]
As the OP I feel my question was answered. You may need to read between the lines on some of the responses but I think my take home answer is:
1) When you use power booster.
2) If you even dream any water may get to the valve. This was my rational for buying the "Insurance Policy".

Thanks again all who shared their knowledge and experiences.

Regarding the "black motor" and "truck motor" valves. I have a former Winnebago 454 in my boat with bone stock heads. Straight up truck motor. Keep in mind its probably only 300hp but I will run sustained 4500rpm across Long Island Sound without issue and have been doing this every summer weekend for 3 years.

So i guess the moral of the story is wimpy parts + proper tuning = reliability!