Being somewhat unfamiliar with the longevity of the 502's, are there any signs as to when they should be replaced or rebuilt? We have a 2000 38' Fountain with twin 502/500efi's, we use amsoil 20w/50 racing oil, changed every 50 hours. What problems can I expect? Currently has 200 hours on it. We ride on the Chesapeake Bay.
Thanks, Rush

Youre ready for new valve springs to start, I would change the head gaskets also. Did my 2000 500EFI's last year at 155hrs...a few springs were sagging although I think they would have made it to 200hrs, but I had a head gasket that would not have made it through the season.

Use Comp 929 or equivelent Isky springs. Fel Pro or Cometic head gaskes. Good Luck

I need to have my heads gone over before i head to Florida this spring, valves,springs,gaskets and whatever else they find i need. What should this job cost? I am wondering if I shouldn't put that money into repowering. Also do they have to remove the engines to do the job?

Thanks, JD. Why do you think these problems occurred? Just poor quality valve springs and head gaskets? Anybody else have any problems with these motors? Thanks for your comments.
Rush

rush, do a search here in the tech section. There has been a lot written about the 500's valve springs. I believe Merc did fix the problem, I'm not sure what year.

Thanks Payton!

I have one new set of Comp 929-16 springs for sale $100 plus shipping. My engine builder used Isky after I had already bought the Comps.

Shawn

Thanks Shawn I will keep you in mind.

Doesn't matter if the motor has the updated springs or not. 200 hours is all you should expect out of those springs. It's not a design problem, it is simply a fact of metallurgy when you ask those 1.8" tall springs to mash to 1.2" over and over at 5000 rpm. They fatigue and go south.

And the exotic high dollar valvesprings that will last longer? Nobody really makes them in the relatively weak spring pressures you need. Unless you are running a smallblock...

Rush, the guys are right. I did my HP500s at under 200 hours and not only had the springs gone bad, but the head gasket was also on its way out and would not have lasted the season. My engine builder used Cometic gaskets. I also changed cam, had head work done etc. The only thing I did not do that I wish I had done was to change the rotating assemblies and made the engines 540s.

Good luck and change the springs and head gaskets, it will make next season last a lot longer.

Shawn