thehelix112 Posted July 23, 2010 Share Posted July 23, 2010 (edited) Hey guys, Starting to do more research on the VK56DE that I got. Read this page: http://en.wikipedia.org/wiki/Variable_Cam_Timing which talks about nissan engines adopting the ford model where oil flow is used to control the phaser. But then read this page: http://en.wikipedia.org/wiki/N-VCT which is a little more vague and just talks about it being controlled via a solenoid. Does anyone have any authoritative information? I know I should just pull the engine apart to check, but my time with the engine is limited, while my time in front of a computer is not. Plus I couldn't find any prior articles about this so figured it may contribute to the knowledge base, as I will update the thread when I do pull it down. Aside: the reason I ask this question is that I'm talking to JWT about the cams to run on the intake side. I'm thinking it'd be good to know the limits by testing various cams with manual control over the solenoid and checking for interference. I also may be totally off the track as I have that feeling that I need to think about this a little more. Obviously if its just a direct solenoid actuator it'll be easier to control manually with the engine stopped than if it needs the oil supply. Also if anyone has any thoughts on cam specs for what I'm chasing (max power low 7000), specifically for a N-VCT system, I'm all ears. Based on my buggerall experience, for a normal cam that feels like it should be around the 245 deg @ 0.05 duration, but I have even less experience (zero) with VCT engines. Many thanks, Dave Edited July 23, 2010 by thehelix112 Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted July 24, 2010 Author Share Posted July 24, 2010 OK. Well, I'll keep this thread updated with whatever I find. Dave Quote Link to comment Share on other sites More sharing options...
260DET Posted July 24, 2010 Share Posted July 24, 2010 With the VG motors the valve timing was controlled by a solenoid switching oil pressure but that was for a on/off system. Surely the FSM for yours will explain. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted August 10, 2010 Author Share Posted August 10, 2010 Richard, Sorry I totally didn't see this update. Serves me right for not subscribing. The FSM is indeed on the to-buy list, but I don't have one yet. Let me outline what I'm thinking, from my current ignorant point. The danger with a VCT system is having it such that when the system comes on, it advances the inlet cam and opens them too much as the piston is coming to TDC between exhaust/intake strokes, causing interference. A little bit of googling suggests systems advance the cam as much as 25 degrees. So the first step will be measuring how much the VCT system advances things, hopefully this won't be too much of a hassle, though the FSM may prove far simpler The issue with piston/valve clearance towards the end of the exhaust stroke, could happily be mitigated by installing the cams such that when the system is ON (fully advanced) the maximum advance does not cause interference. It would seem that being able to install larger cams with more duration would necessitate either custom grinds offset backwards (retarded) by however many degrees the VCT advances the inlet cam, or vernier cam sprockets to customize where the cam is installed. So three questions: 1. Am I missing something/way off the mark? 2. Anyone know someone who makes such a cam? Or is it simply a billet job ($$$ that I don't have)? 3. Would it be cheaper to investigate a pair of vernier cam sprockets for this engine? Are they even possible/available for later engines, I know they are for the old L series. Thanks guys, Dave Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.