trying to confirm a problem - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

jackal264 · 04-15-2008, 04:30 PM

so i'm getting this intermittent knocking comming from under the valve cover. oh and this is on an s14 sr20. it is not there at idle but as soon as you rev there is a click then it starts.

things i have checked. since the knocking is clearly rotational i tryied taking every possible option out of the equation no matter how unlikely. first i removed all the ras just uncase they were making noise when hitting the cams. also i removed the valve guide and removed and reinstalled the chain tensioner.

the noise is still there.

so by process of elimination i came to the conclution that the vvt is dead and that the gears inside the unit are banging agaist eachother.

the motor was fine before but i just (like 500km ago) some serious engine mods and i'm wondering if maybe the big cams (only tomei 256's w/ 11.5 lift) and the added hp could have sent my vvt packing.

anyone know where to get a new vvt unit?

SoguRacing · 04-15-2008, 04:34 PM

I have no clue where to find one but i'd like to know more about this so free bump for you.

Z U L8R · 04-15-2008, 09:31 PM

your vvt solenoid is not your problem, what you're describing sounds like rod knock, but another possibility is the aggressiveness of the cam. if the block has been decked could the aggressiveness of that particular cam cause the piston to kiss the valve? did they recommend any headwork when using that cam? sr's are not my fortay, but anything over a 9mm lift on an rb25 = u need machine work. just throwing that out there, but the first thing that comes to mind was rod knock.

another possibility. maybe a lifter took a dump or ingested some air and won't pump back up all the way? maybe when you put in the rocker arm stoppers they ingested air? just throwing out some ideas since no one else has commented

gl bro
Dave =]

jackal264 · 04-16-2008, 12:24 AM

no it's definetly not rod knock. sounds totally different. and we checked all the rockers and springs and all the rest of the valve train when the cover was off and it was all a ok.

jackal264 · 04-16-2008, 04:06 PM

bump..

no one has ever had this problem?

04-15-2008, 04:30 PM	#1
jackal264 Zilvia Junkie Join Date: Feb 2007 Location: vancouver, canada Age: 39 Posts: 360 Trader Rating: (1) Feedback Score: 1 reviews	trying to confirm a problem so i'm getting this intermittent knocking comming from under the valve cover. oh and this is on an s14 sr20. it is not there at idle but as soon as you rev there is a click then it starts. things i have checked. since the knocking is clearly rotational i tryied taking every possible option out of the equation no matter how unlikely. first i removed all the ras just uncase they were making noise when hitting the cams. also i removed the valve guide and removed and reinstalled the chain tensioner. the noise is still there. so by process of elimination i came to the conclution that the vvt is dead and that the gears inside the unit are banging agaist eachother. the motor was fine before but i just (like 500km ago) some serious engine mods and i'm wondering if maybe the big cams (only tomei 256's w/ 11.5 lift) and the added hp could have sent my vvt packing. anyone know where to get a new vvt unit?

04-15-2008, 09:31 PM	#3
Z U L8R Zilvia FREAK! Join Date: Jan 2007 Location: Georgia Age: 43 Posts: 1,194 Trader Rating: (0) Feedback Score: 0 reviews	your vvt solenoid is not your problem, what you're describing sounds like rod knock, but another possibility is the aggressiveness of the cam. if the block has been decked could the aggressiveness of that particular cam cause the piston to kiss the valve? did they recommend any headwork when using that cam? sr's are not my fortay, but anything over a 9mm lift on an rb25 = u need machine work. just throwing that out there, but the first thing that comes to mind was rod knock. another possibility. maybe a lifter took a dump or ingested some air and won't pump back up all the way? maybe when you put in the rocker arm stoppers they ingested air? just throwing out some ideas since no one else has commented gl bro Dave =] __________________ RB25 280z GT30/76R 441hp/381tq 11.9@125

04-15-2008, 04:34 PM	#2
SoguRacing Post Whore! Join Date: Nov 2007 Location: (714) Age: 39 Posts: 2,967 Trader Rating: (23) Rides Gallery: SoguRacing Feedback Score: 23 reviews	I have no clue where to find one but i'd like to know more about this so free bump for you.

04-16-2008, 12:24 AM	#4
jackal264 Zilvia Junkie Join Date: Feb 2007 Location: vancouver, canada Age: 39 Posts: 360 Trader Rating: (1) Feedback Score: 1 reviews	no it's definetly not rod knock. sounds totally different. and we checked all the rockers and springs and all the rest of the valve train when the cover was off and it was all a ok.

04-16-2008, 04:06 PM	#5
jackal264 Zilvia Junkie Join Date: Feb 2007 Location: vancouver, canada Age: 39 Posts: 360 Trader Rating: (1) Feedback Score: 1 reviews	bump.. no one has ever had this problem?