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Author: Subject: ST170 VVT Delete - What Cam Timing
bombero

posted on 9/7/16 at 08:19 PM Reply With Quote
ST170 VVT Delete - What Cam Timing

Hi ALL

I hope that I'm not opening up a can of worms here, lol! Okay, My mate has fitted an ST170 in my Westfield running vvt delete on an Emerald, 46mm bike TBs, gasflowed head, reprofiled cams to 284 duration with 10.5mm lift inlet/exhaust. Recent RR result was 199bhp@6500 and 184lb/ft@6000. We'd hoped for a bit more especially around the torque figure. We suspect maybe it's cam timing and need to know what anyone running a similar set-up might be using timing wise??

Cheers
Rab

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chris

posted on 9/7/16 at 10:25 PM Reply With Quote
why delete the vvt I use the mtec vvt controller
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bombero

posted on 9/7/16 at 10:48 PM Reply With Quote
The decision was made before mtec controller was available and none of the main ecu suppliers did any software/firmware for variable timing.

Reversible but I want to pursue this direction a little further.

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rusty nuts

posted on 10/7/16 at 05:37 AM Reply With Quote
Can't help with the setting but wouldn't it have been a good idea when building the engine to test the safe limits of the cam timing and "swung" the valve timing whilst on the rolling road to find the best results?
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chris

posted on 10/7/16 at 08:02 AM Reply With Quote
as well as the vvt I have a verneir pulley on my exhaust cam which I have advanced up to six degrees
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Rob Allison

posted on 10/7/16 at 08:22 PM Reply With Quote
Dont bother moving the exhaust cam timing. Thats only done when running the ford ECU with the VCT.

As for cam timing. The standard VCT cam will need advancing by 1 tooth on the cam wheel if the VCT system is removed. But with a new cam it should have cam timing details with it. If its reprofiled standard cam then it many need moving 1 tooth advanced as the standard cam but check with who made the cam.

A standard engine will max out at about 195bhp with the cam locked and advanced by 1 tooth so a reprofiled cam should give up to 230bhp with the longer duration.






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bombero

posted on 10/7/16 at 10:21 PM Reply With Quote
quote:
Originally posted by rusty nuts
Can't help with the setting but wouldn't it have been a good idea when building the engine to test the safe limits of the cam timing and "swung" the valve timing whilst on the rolling road to find the best results?

This is a good idea and something that we've now discussed (hindsight, and all that, lol!). We're going to double check our clearances which should give us an idea of tolerances, jot down a few sums and go back to the rolling road for the day. Would just be handy to know what results others may be getting..

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bombero

posted on 10/7/16 at 10:22 PM Reply With Quote
quote:
Originally posted by Rob Allison
Dont bother moving the exhaust cam timing. Thats only done when running the ford ECU with the VCT.

As for cam timing. The standard VCT cam will need advancing by 1 tooth on the cam wheel if the VCT system is removed. But with a new cam it should have cam timing details with it. If its reprofiled standard cam then it many need moving 1 tooth advanced as the standard cam but check with who made the cam.

A standard engine will max out at about 195bhp with the cam locked and advanced by 1 tooth so a reprofiled cam should give up to 230bhp with the longer duration.

Thanks Rob!

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Rob Allison

posted on 11/7/16 at 12:42 AM Reply With Quote
Just so you have some guidance on timing. The Zetecs are set 110 or 112 Deg TDC the ST170 is 85deg and 145deg fully advanced. The locking bar through the slots in the cams gives you the 85deg postition. You need to move it slightly more than the 1 tooth but its dificult to measure without a verner setup.






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bombero

posted on 11/7/16 at 09:34 AM Reply With Quote
quote:
Originally posted by Rob Allison
Just so you have some guidance on timing. The Zetecs are set 110 or 112 Deg TDC the ST170 is 85deg and 145deg fully advanced. The locking bar through the slots in the cams gives you the 85deg postition. You need to move it slightly more than the 1 tooth but its dificult to measure without a verner setup.

Rob, those figures are very useful, thank you! I think we may go back to the drawing board ie 85deg position and dial in the advance on the inlet as you suggest. I do have a vernier set-up so it should be straightforward to do..

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bombero

posted on 1/8/16 at 11:47 PM Reply With Quote
quote:
Originally posted by Rob Allison
Just so you have some guidance on timing. The Zetecs are set 110 or 112 Deg TDC the ST170 is 85deg and 145deg fully advanced. The locking bar through the slots in the cams gives you the 85deg postition. You need to move it slightly more than the 1 tooth but its dificult to measure without a verner setup.

#Rob, just so that I'm absolutely certain, the ST170 is 85deg BTDC is that correct? I'm sure I've read another thread where guppy mention it..

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Rob Allison

posted on 3/8/16 at 04:28 AM Reply With Quote
I'm not sure of the exact position the locking bar sets the zetec timing at for static timing. The figures qouted are for full lift on the inlet or exhaust cam lobes. But the ST cam will be about 26 degrees retarded compared to the blacktop so it needs to be moved about 1 to 2 teeth advanced on the pulley to timing belt. you would need to check the lobe lift to get it exact. just dont go past 145 degrees.






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