Thread: G Spec VVL Crank Pully + High HP + High Revs = Fail...

I bought both parts brand new Oil Pump and Oil pump Drive spacer whatever you want to call it I put together the motor with stock VVL Pulley used..
ran the motor for a couple of moths without problems then I took the engine apart over boost on pump gas damage a piston.. I put the engine back together now this time with Aluminum pulley the engine didnt last a month running seized the oil pump and cracked the oil pump pinions or whatever you want to call it...
I took the motor apart today and at least pistons and rods are in good condition so this its good actually the crank never seized... The only thing was seized and destroyed was the oil pump....

I have a built VE. GTIR oil pump kit from GregV. No problems here in over 14K miles of torturous abuse.

The reason to run a Dampned crank pulley is to eliminate the harmonics. It doesn't matter how well your rotating assembly is balanced because the harmonics are introduced during the combustion process. Higher rpms and combustion pressure (higher HP) will cause more harmonics. They may not be so prevelent in an NA motor, but you will see more in a turbo motor. The first failure from excessive harmonics in any engine that has a rotor type oil pump on the front of the crank is a shatter oil pump. An inline 6, like the 2JZ or RB26, has a naturally balanced rotating assembly. But since the crank is so long, harmonics can be so strong, they will destroy clutchs. My professional advice for anyone going turbo is to either keep the factory crank pulley, or in high hp cases, go to the ATI pulley. The NA guys can probably get away with an undamped pulley.

Mark
[email]mark@mazworx.com[/email]

Mark,

Can you define higher RPM? I honestly don't think I'll ever push the envelope and have an 11K rev monster

^^^^^Thank you ^^^^ too late for me but good for the ones that are building projects with this kind of pulley... thats why I opened this thread not to bash X vendor parts...

For me High RPM = 9,000 + RPM

Has anyone tried to explain why this happens when the harmonics are in the direction of travel that the oil pump is designed to operate in? It just seems odd to me that rotating the oil pump in a jittery manner (versus a smoother, dampened manner) would cause so much damage. Why would it matter?

I am not a scientist and I dont like pretend to be one neither but the only advice I can give to anyone that its making 500+ whp and plan to rev the motor to 9,000 + rpm its to stay away from the undampened pulleys mine its not the only case i can guarantee that...

ATI - Super Dampers® for Nissan Engines

^Mazworx sent me a link to this.

What you guys think on using this over the Stock or GSpec crank for high HP and high REV turbo SR20 motors?

You are assuming that there is only torsional vibration. There's also natural frequencies of the individual components. When the natural frequency of the crankshaft matchs the oil pump then you achieve resonance. And of course damage to the oil pump will occur before damage to the crankshaft due to the mass of them.

Mark
[email]mark@mazworx.com[/email]