Life span of Iconel valves
 

My current engine combo combined some parts from my previous boat. Gen 6 509's with GM aluminum Bowtie heads(Performer RPM's), HP 525 cams with Crane lifters, and 8psi of Procharged/intercooled boost,

The heads were gone thru with new springs and valve job 80hrs ago. The s/s intakes(what ever GM Performance used) and the Manley servere duty inconel exhaust valves have 380hrs of N/A use, and 80hrs of boosted use on them. The Crane tiebar lifters have 130hrs on them.

I trying to get ready for my spring maint/tune up and I'm wondering if I should be worrying about my valves and lifters??

LE

I have seen Mercury Racing engines with over 1000 hrs. on the original valves. They used Manley inconel valves. If they clean up without thinning the edge too much, I'd use them again. I'd replace the lifters after 250-300 hrs depending on how intense the cam is.

Cams are pretty mild and spring pressures around 150# installed and 415# open so I will probabally just do a visual on the lifters this year.

Tom from Gellner Engineering sets up my heads and all was good the last go around(80hrs ago). He said that he has seen very few issues with the Manleys and only replaces them if beaten up by broken pistons and such.

The thought was put in my head this year after a few friends dropped some exhaust valves(not inconel though).

Why does Merc replace them during there 125hr rebuild on there 1075's? Just in case?

LE

The Mercury Racing engines I was thinking of were the lower powered ones like the HP500. I would have to guess that they live a harder life in the 1075. Higher spring pressure, more cam intensity, higher exhaust temp, higher rpm redline. And maybe it's also the cost is no object mentality with those engines.

Any engine builders on the site have any other input??

LE

???

With 460 hrs on them, I would change them. You could make arguments for either side......changing them or not changing them. Bottom line, it is cheap insurance to go ahead and change them. If it was still NA, then I would say leave them alone. Since it is running 8 psi of boost, I would swap them out for some new ones. They are less than $400 a set. The problem is that they will do thousands of dollars of damage if one of them lets go. Hope this helps.
Eddie

[QUOTE=. The problem is that they will do thousands of dollars of damage if one of them lets go. Hope this helps.
Eddie[/QUOTE]
I agree 100% :coolcowboy:

Thanks.


LE