Tarheel,
Have you ever heard of the method of inserting small rope inside spark plug hole and turning motor over (by hand of course) therefore keeping valve in place while removing springs?

Sound like madness or genius???

Thanks,
Boatnick

Yes TomR its me....
know any knowledgable, enthusiastic volunteers that I can assist with my "maintenance items"?

Is this "spring maintenance" at 200 hours still necessary on the newer 2002 - HP 500 EFI's??

Splash,

I asked this question to the factory reps (2) at this years Lauderdale show. The reply was a confident 400-500 hours, with "normal" but well maintained usage. My dealer says the same. However, if you search this forum (of which I have quickly learned to respect) there is a general consensus that with the stress the high performance springs are under, both at rest and during usage, change them out. I would be interested in feedback from the forum, of those that have NOT had problems approaching 500 hours.

That's a GREAT question! How many out there have had NO problems and are well above the 200 hour mark??

A good question indeed, BUT the only problem is when you do have a problem you've likely already beat a lifter out of the motor, destroyed a cam, and not to mention all the "foreign material" thats floated throughout the motor and gone through the bearings.

An even better question might be, what year did Merc change over the valve springs, what "exact" spring did they change too, and why?

My 2000 500efi's w 155 hrs are getting changed out regardless this winter, and while I'm at it I plan to put on a set of Cometic head gaskets. Merc uses OE junk, and I personally know people who have had problems with them.

I would be glad to help you!:)

Actually, Thats sounds like a great idea! That way you eliminate the chance the motor will spin over from the air pressure if not exactly on TDC.

Valve spring life has so many variables it’s difficult to put a cycle value on them. Because they are affected by heat, RPM (even one “zing” can remove a substantial portion out of spring life), and profile, the degradation curve is not linear and varies greatly from application to application. I would suggest that you remove your springs (all or a good sampling), have them checked

http://www.precisionmeasure.com/valve6.htm

for current values at seat pressure and open pressure, compare that to new spec and see if you are within tolerance. Even if you do replace all your springs, these figures will give you baseline references for future fatigue evaluation and alert you to other potential valve train problems. Check springs for discoloration and/or cracks regularly.
Bob

RM Builder,

WOW, nothings easy huh! All the stories about the stock 496's and 502 mags, with 1000 hours, go to the "blue" motors, and buy problems. All for 3-4 m.p.h.

Biggest problem is finding competent shops to do the work. (Maryland/Del area)