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tapeworm |
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Hi there chaps, I'm asking this one out of curiosity. MY EF is running well, but is typically fairly sluggish down low thanks to the sky-high 1st gear in the Auto and 3.08 diff. Feel free to lol heartily, but can I advance the timing by moving the timing chain one tooth clockwise from the factory setting on the cam sprocket & in turn get more low down punch with a slight loss in top end? Or will valves collide? lol
Thanks
_________________ she dream't she was a bulldozer, she dream't she was alone in a field |
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bry40l |
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Diff ratio change, high stall torque convertor,or fit a proper vernier camgear to modify the cam timing. The problem is up towards the redline of the tacho they are pretty ordinary already, if you modify the timing you will lose more top end again
_________________ BF XR6 |
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tapeworm |
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A diff change would definitely be the way...I have a VCT head & it revs out really well, so I don't mind loosing some top end if the pay off is more take off down low. I can't fit a vernier if I keep the VCT, so I'm looking at just moving the chain forward one tooth, see if that helps..Is there any chance this may be effective do you guys think?
_________________ she dream't she was a bulldozer, she dream't she was alone in a field |
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efxr6wagon |
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I believe the cam gear has 42 teeth, so moving one tooth over is a change of 8.6 cam degrees or 17.1 crank degrees. That is probably way too big an adjustment to achieve what you want. A vernier gear is the only way to achieve the finer adjustments.
The Ford 6 isn't an interference engine, so there is probably no risk of parts clashing. +1 diff gears (3.45 from XR6 is a straight swap), high stall torque convertor (suggest 2500-2700 rpm with stock VCT cam). If you are happy running higher octane fuel, get a custom-tuned J3 chip from TI Performance to take advantage of the extra advance the engine will handle. That will give a torque boost across the rev range, but especially in the 2000-4000 rpm range where it may already be knock-limited.
_________________ 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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you can advance or retard the vct cam via the gear, as it has adjustments like a aftermarket vernea gear..
imo beast and easiest way to gain more down low is going to 3.45 or 3.77 diff gears.. |
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tapeworm |
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Thanks alot for the info guys. I'm a bit hesitant about adjusting the VCT as the Ford workshop manual creates a big circus that it must never be altered from the factory setting, but It's so easy and tempting just to rotate it a few degrees..I can't see the problem with this?. A 3.9 diff and a tune would really liven it up. I spose no one happens to have a 3.7/3.9 diff for sale even a single spinner?
_________________ she dream't she was a bulldozer, she dream't she was alone in a field |
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Greenmachine |
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For what it's worth, many years ago I advanced the std cam in my ED by one tooth (at the time I completely screwed up with calculating the effect and thought it was something like 8 degrees - but indeed it's actually twice that - very embarassing to see my old posts about it now) - the result was that it drove very much like a healthy VN Commondung - was VERY responsive and punchy for town driving but ran out of guts above 140kph (ie. engine had nothing above maybe 4200rpm).
Fuel consumption was also fantastic round town - if I was running a fleet of ED taxis I'd have immediately done that mod to all of them... Later I ended up trying various cams in that car along with adjustable cam gear and tried advancing and retarding all of them with the adjustable gear (ie. not as much as a whole gear tooth gives) - and found that the gain from advancing always causes a correspondingly larger proportionate loss of top end than the other way round - ie. retarding generally yielded better overall result - much more power in mid and top for the amount lost in the bottom vs the large loss of top end vs relatively small gain in the bottom by advancing. Point is that as long as you're starting with a healthy top end then there's no harm trying a bit of advance to trade a bit of that for stronger bottom - especially if you're only gonna lose from revs you never normally reach - but if you're already regularly reaching a peak in the top then be prepared for that to drop VERY noticeably. IMO it's worth giving the VCT adjustment a bit of a tweak and see what it does - just make sure to mark it so you can return it to the starting point if it doesn't like it. I strongly suspect Ford's hoo-ha about not messing with the VCT has everything to do with the result on CO emissions than any profound mechanical issue.
_________________ Sold the Greenmachine - now driving 2015 Jeep Cherokee Trailhawk. |
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