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Can any one give me a run down of how vct actually works? I'm picking up a vct motor ready to drop into my ef but I'm not sure wether to keep the vct on there or replace it with my reco Tickford head.
I have looked over the net and also Wikipedia but haven't found much help. Ef xr6 = 165kw Au vct = 174kw I was going to get a cms cam for my T head though the bottom end let go which is why I'm getting the vct but from the cms website it looks like you have to get a head and cam package for the au rather than just the cam like the ef, is there any where from Newcastle to Sydney that make a bigger cam for the vct without having to get a head aswell or am I better of putting the T head onto au block and camming it than??
_________________ ..wagonstyle.. Last edited by wagonstyle on Wed May 15, 2013 2:43 pm, edited 1 time in total. |
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| SWC |
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CMS sell the VCT cam seperate to the head packages. How are you intending to control the VCT with the EF ECU?
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Apparently the bloke had it running (supposedly) so ill be getting a j3 programmed in hopes it will run it properly.
_________________ ..wagonstyle.. |
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| SWC |
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I have been told
Quote "You can wire it up to constant 12v positive, and just get the negative feed from the BBM wire behind the washer bottle. That activates at 3000rpm, and lets the VCT work as it should." you simply need constant 12v (injectors) and then get the negative (switch) from the BBM switch. That's how it was wired up in mine. Quote If this was true wouldn't others be aware its possible?? I know the owner had the au vct conversion done at a shop including the cut sump and wiring but wether this method worked to run the vct I'm yet to find out. On a mother note I'm trying to get info on what the vct does and how it actually works??
_________________ ..wagonstyle.. |
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| TROYMAN |
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yes, you can set it up using the bbm feed but its not perfect...
the bbm switches at 3800rpm, where the vct normally switches at 3000rpm. I did it in my ed originally, I used a jaycar rpm switch so it switched the bbm solenoid off at 3000 rpm... now the vct solenoid has power under 3000rpm which allows oil pressure from the oil line to pressurise the vct unit, this advances the cam timing giving down low torque and at 3000 rpm it swithes off the solinoid cutting oil pressure allowing the cam timing to retard giving top end performance... |
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Cheers troyman that's the info I was after
 Now with the solenoid switching off at 3800rpm using the bbm method I'd think its a tad too high as you'd want it to turn off earlier to continue power up top (correct me if I'm wrong) I'm not the best with understanding electronics but it hasn't stopped me in the past with other projects though after reading the link swc put up I got a little lost. Will read over it again to get a better understanding but any tips or help about the rpm switch would be more than welcome. Ill be picking the motor up Sunday morning and although I have been lazy and still need to remove the old motor I'd like to set the vct up right the 1st time round.
_________________ ..wagonstyle.. |
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| TimmyA |
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I was going to say... "Check my build thread"...
SWC has done me the honours but... It's not too bad... The jaycar kit is pretty easy to put together and set up... Just wires into the negative side of the VCT solenoid as you said above... You tune it so it changes at 3000rpm... Robert's your mother's brother... The BBM drives as normal... Its not perfect in my ED with the EL manual XR computer... Sometimes it has a flat spot in the lower rev range and it still pings on hot days... My next stage because I can't get custom dyno work done here will be to convert to AUII front end wiring with full AU engine control... This will run the engine as intended in the AU and will give me reliability and a factory diagnosable system I can survive out here in the country... Simple system, but you're purchasing a completed motor so you don't have any of the timing issues I had to endure... I also was given the VCT gear in parts and expected to reassemble the phasor... I have the VCT pages from the workshop manual here and it says under NO CIRCUMSTANCE should the 4 VCT bolts be loosened... Doing so turns it into a throw away item... Mine came with no bolts in it and in a dozen pieces so I got some first hand learning and had to make some special tools to load the springs in it for reassembly... No idea how it goes together now... The timing it again was a task... The ford book gives lift but doesn't say if it is the adv or ret lift... Pretty sure I made it ret lift... I still don't know if it's right or what... Maybe that's why it feel as though it lacks down low... I also have a mild VCT cam here to go in it one day... Would be interest to here how much difference the VCT makes in yours... As I said without measuring a properly set up vct for lift and such I don't know if I ever dialled mine in right so may that is the origin of my weird and inconsistent flat spot... Cheers, Tim Cheers, Tim
_________________ 93 Red ED 5spd Manual Build Thread |
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So I picked up the vct this morning though its not as clean as described. Turned out it had a rocker cover bolt snapped into rocker train and 3-5 exhaust manifold stud holes are stripped.
Now the other issue is the intake manifold wiring, it looks like a chain saw has been at it and doesn't have the vct plug on it so I'm wondering what to do now. The vct plug looks like an injector plug so am I able to cut an injector plug off another loom to wire it in and if so is it just the negative wire to the bbm and the positive to an injector wire?
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| TROYMAN |
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yes its just a injector plug... you can get the 12v from the injector 12v if you wish, and the earth from bbm if your setting it up that way... my only concern would be how much load is the vct solenoid going to put on the bbm solenoid driver in the ecu??
unless you use the bbm earth to trigger a relay to take the load for the vct solenoid.. |
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As I'm better with tools than I am a computer I'm not sure on how to use the rpm switch so if all else fails ill wire it through the bbm. I have read through Timmy's thread but can't see to much info on the wiring so would you be able to throw me a link or a run down of how to use the rpm switch?
I have general soldering and wiring experience but its the technical stuff like ohms and currents that do my head in.
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| Greenmachine |
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As far as changing the switchover revs - that can be set with a J3 module - and I'm sure i read somewhere that someone ironed out flat spotting and pinging by bringing BBM switchover down to 2000 or 2500 rpm - so perhaps it's possible a sweet spot can be found?
_________________ Sold the Greenmachine - now driving 2015 Jeep Cherokee Trailhawk. |
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| efxr6wagon |
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I'm surprised that the AU VCT system has a discrete switch-over point at 3000 rpm. I had assumed that it would be progressive, gradually retarding the cam as the revs rise. That would more closely match the engines needs and give better overall performance. Is that even possible with the VCT? Or is it just a two-position solenoid, so it's either on or its off - no control of the amount of oil pressure in between?
_________________ 95 EF XR6 wagon, 17" FTRs, DBA rotors, KYB/Koni, AU bottom end, ported EF head, backcut valves, SS Inductions, Territory intake, 10.2 CR, Auckland 1258 cam, vernier gear, PH4480 headers, no cat, Tickford 2.5", 2800rpm stall, J3 chip |
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| TROYMAN |
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its just a 2 postion solenoid, on/off and the ecu determines the rpm its done at...
it has a 10 deg cam retard under 3000rpm |
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As greenmachine said is it possible to tune the switch down to say 2500 rpm?
To use an rpm switch what wire on the ecu does it adapt to so it runs the bbm at the right rpm? I have now stripped the motor of all bolt ons except head and phaser to clean it up and I have a couple issues to address like stripped threads in the outlet side of the head, snapped rocker cover bolt in the rocker assembly, and a thermostat housing bolt snapped into head as well as a couple corroded welsh plugs so ill be fixing all that than painting the motor and dropping it in (after removing dead ef motor) after all that's done I can concentrate on wiring up the vct so that it runs without issues.
_________________ ..wagonstyle.. |
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