I'm sure that this has been asked in the past. What is the real poop on the 500hp's, as far as spring changes. Is it all, some serial numbers, just the carbed models? I have heard all the above. I have a pair of 95's with 200 hours. Thanks in advance........

Mostly 1998 and 1999 Carbs. Pull your valve covers and check inner springs and look for metal where oil returns to valley. I've repairs 5 boats so far. One had 2 pounds of valve spring material in oil pan.

Although I didn't weigh it, both of my '99's with 150 hours had a bunch of valve spring pieces in the oil pans. On one motor, a piece spring was actually wrapped around the camshaft. Also, I caught the spring problem too late and one of the roller lifters gave out, breaking the roller off and wiping out the cam lobe.

My 98's and a friends 99's both had the
disease.

Mine also had the broken roller problem
as 35/25 mentioned.

last year, I changed two sets on a 96',
with slightly over 300 hours, no broken
springs.

Mine are approaching 250 hours since the
"meltdown" and I'll be changing the springs
and lifters soon.

Pull the valve covers, and take a look.

jt

I've asked this question before and gotten a few different answers - what about 2002 models with EFI - are they still something that should be changed at the 200-300 hour mark? Thanks

Guys it doesn't matter if it is an HP500 or a 5.7Liter. Hyd. roller lifters are heavy and its all a spring can do to dampen that enertia load at the medium rpms a boat runs all day..its fine in a C5 running 80mph and turning 1800 rpm, its a little different in a 32fter turning 4600 rpm all day long. Its the nature of all the beast. I just think the HP gets the bad rap since those "blue" bullets are probly thrashed on the hardest.

Good insurance is an on the head spring checker where you can pop the VC off and periodically check the spring pressure. If you have new springs, take a baseline reading with this and when they are below 120# on the seat, change them.

Run a good valve spring with something around 150# on the seat and open pressure of around 440#. This will help control the lifter.

Use aftermarket lifters. I prefer the Morel lifter due to tighter tolerances and better material used to mfg the lifter. RM Builder sells these. They will take more spring pressure and more abuse.

Chris

cstraub69, How does a person get ahold of rmbuilder? Does he have a shop or phone we can call? Thanks

Your best bet is to just change the springs at 200 hours the manufacturer recommends it and for good reason as Cstraub stated those things take a hell of a beating and the chain of events that can follow a spring failure will cost alot more than changing them. Also, while checking spring pressure is not a bad idea it will not show you stress cracks that may be forming in the inner or outer spring.

What is an average cost to have this service done on two motors? Is it something that can be done by yourself fairly easily or not?

Very well stated Chris. Usually at 200 hours you will have a few exhaust valves leaking anyways because of the gas quality these days. Especially those guys who put that ARCO or ARCOhole in their motors. More power means more preventative maintenance, more preventative maintenance means less problems.