Broken valvespring. Fluke or installed wrong?
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Teching In
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Broken valvespring. Fluke or installed wrong? Is it possible to install them wrong and have one break? Motor only has 300 miles on the break-in oil and it just snapped off going down the road at 1800 rpm and the motor hasn't even seen WOT yet.
I'm losing faith in my machinist who assembled things so I'm wondering if this is something that may have been his fault. Thoughts?
I'm losing faith in my machinist who assembled things so I'm wondering if this is something that may have been his fault. Thoughts?
What kind of springs are they? If a spring is installed incorrectly it is definately possible to snap them. The wrong install height, incorrect retainer,seat, or seal combo could easily cause a problem like that depending on the spring.
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Thanks John. They're brand new Comp Beehives.
You need to check the installed height, then check pressure at installed height and make sure you had enough room to coil bind. If it all checks OK you should send the springs back to the manufacture for analysis.
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Thanks Guys. Comp stood behind the springs no questions asked but I'm quickly losing faith in my builder.
I also only had about 25 pounds of oil pressure at idle. Could the builder have forgotten the plugs in the front and/or back of the block?
I also only had about 25 pounds of oil pressure at idle. Could the builder have forgotten the plugs in the front and/or back of the block?
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It was probably a 918. Normally they'll handle .575 with no problems with just a "drop in" install @ 1.800. But if you're builder did anything funky with the seats or used the wrong seals as Matt said, it's possible that install height could be jacked up and causing premature spring fatigue.
A newer designed 918 should definitely not be breaking under .575 lift. I push them to .600 lift all the time with no problems.
25psi is a tad low @ idle, but it also depends on how the motor was put together. I personally like to see around 30-35psi @ idle.
A newer designed 918 should definitely not be breaking under .575 lift. I push them to .600 lift all the time with no problems.
25psi is a tad low @ idle, but it also depends on how the motor was put together. I personally like to see around 30-35psi @ idle.
Thread Starter
Teching In
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It was probably a 918. Normally they'll handle .575 with no problems with just a "drop in" install @ 1.800. But if you're builder did anything funky with the seats or used the wrong seals as Matt said, it's possible that install height could be jacked up and causing premature spring fatigue.
A newer designed 918 should definitely not be breaking under .575 lift. I push them to .600 lift all the time with no problems.
25psi is a tad low @ idle, but it also depends on how the motor was put together. I personally like to see around 30-35psi @ idle.
A newer designed 918 should definitely not be breaking under .575 lift. I push them to .600 lift all the time with no problems.
25psi is a tad low @ idle, but it also depends on how the motor was put together. I personally like to see around 30-35psi @ idle.
One more thing I'll add is don't bank on the gauge in the dash cluster being accurate, they hardly ever are. The only real way to confirm pressure is with a real gauge installed.
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TECH Apprentice
Joined: Jan 2008
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From: Gladstone, Queensland, Australia
918? bad spring mate, hard to kill a spring that easy even if the installed spring height is wrong it won't break that easy! wrong spring height equals possible float at upper rpm and then possible breakage, 918s are prone for it, put some pac 1218s in!
