What valve springs should I use ??
#1
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What valve springs should I use ??
I need to replace the stock valve springs in a pair of 2000 model year 500 EFI blue motors. They have 360 hrs on them. What do you guys recommend??
Thanks,
Smitty
Thanks,
Smitty
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That spring would give waaaaay too much pressure for that stock EFI. Unless your stepping up to a soild roller with +.700 lift! At 300 hours, and being your changing valve springs, your best bet is to have the heads checked for the right spring height after the valve job. We usually end up setting the springs at 1.900 inst. height on those engines. We use an Isky spring, 1.530 dia. dual with damper, p/n 8005. It gives a spring pressure of 130-135 at the seat.
#6
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I put Comp 929-16's on my old boat,
and did the same with a friends boat.
At 360 hours, you may want to check the
lifters too.
and did the same with a friends boat.
At 360 hours, you may want to check the
lifters too.
#8
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The carb motors used a Crane spring, the EFI's the Comp 929's. Both were marginal in quality, and prone to failure if run beyound 200-250 hrs. That's where Merc recomends they be "checked", which is Merc Speak for changed.
The Isky SP series are the ticket here, much higher quality, as with anything you get what you pay for. At your hours the roller lifters and rocker arms are up for replacing as well.
Last edited by RaggedEdge; 12-28-2007 at 07:15 AM.
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That spring would give waaaaay too much pressure for that stock EFI. Unless your stepping up to a soild roller with +.700 lift! At 300 hours, and being your changing valve springs, your best bet is to have the heads checked for the right spring height after the valve job. We usually end up setting the springs at 1.900 inst. height on those engines. We use an Isky spring, 1.530 dia. dual with damper, p/n 8005. It gives a spring pressure of 130-135 at the seat.
The Isky 9905 have a seat pressure of 165 lbs. @ 1.900 and 450lbs. open at 1.300. Max net lift of .600 coil bind @1.160
The Compcams 929 have a seat pressure of 148 @1.880 and 432 @ 1.230 coil bind at 1.160
I don't see why these wouldn't work. Merc is using the Comp929's as far as I know. These are are perfect mate, and a much better spring. No pizzing contest, just a fact.
Dave
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Last edited by axapowell; 12-28-2007 at 04:38 PM. Reason: Wrong part number corrected Isky 8005 (not 8805)