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Old 08-28-2010, 11:04 AM   #1
DJIMPREZA
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Default Removing AVCS on high HP ej series/avoiding gead valve drop

I have seen many valve dropping on cosworth heads running avcs on 500 plus engines, now they are rebuilding them using a more aggressive cam profile from GSC, stage III, we are advised not to run more than 10 deg advance on this setups, but we are afraid of a not good performing avcs setup with aem with this huge cams and resulting in a another valve drop on cosworth cams

So, what do you think about removing the avcs pulleys, tapping down the cams lubrication oil gallery at the pulley and putting wrx non avcs sprockets???
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Last edited by DJIMPREZA; 08-28-2010 at 11:04 AM. Reason: head vale drop, stupid typo.
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Old 08-28-2010, 12:25 PM   #2
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i cant see why pulling avcs cams and the avcs cam gears, and replacing them with non avcs cams and non avcs cam gears would be an issue. you just lose the benefit of avcs. for somebody like me with a non avcs ecu and harness thats the route i would take.

avcs is such a benefit though , if you can run it.

i have heard, but not sure how true it is, that running avcs cams plugged/capped or whatever in a non avcs application will cause the cam to operate in a retarded fashion.

confirmation, denial?
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Old 08-29-2010, 07:49 PM   #3
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Yes.. I heard that too if you leave the avcs cam sprocket in place, but when locked with non avcs sprockets it shouldnt be retarded...

any confirmation from anyone here??
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Old 08-29-2010, 07:56 PM   #4
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i heard that if you use a plugged avcs sti cam with a wrx cam gear it will be retarted from the start in proper timing. as much as 20* retarted. even with the timing advanced the avcs sti cam will not get far into the positive side of timing.

i have no proof of this and am wondering if it is true myself.

why not use non avcs cam and wrx cam gear and be good? aside from having to spend a grand on cams?

i have never heard of a plugged cam coming "unplugged" but that would make me nervous.

avcs is such an advantage i really wish i had the ecu and harness to run it...
dual avcs = NICE! someday i hope to be able to afford a 2011+ sti!
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Old 08-29-2010, 07:57 PM   #5
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Quote:
Originally Posted by DJIMPREZA View Post
Yes.. I heard that too if you leave the avcs cam sprocket in place, but when locked with non avcs sprockets it shouldnt be retarded...

any confirmation from anyone here??
Yep, just use a non AVCS gear.. Honestly tune the AVCS and you wont have an issue. Plus you will still have the low end advantages of AVCS

Jr
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Old 08-29-2010, 07:59 PM   #6
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i'm confused...
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Old 08-30-2010, 12:11 AM   #7
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clay degree it and youll know how much to run
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Old 08-30-2010, 12:34 AM   #8
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clay degree it and youll know how much to run
Ding Ding Ding, we have a winner!
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Old 08-30-2010, 09:00 PM   #9
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^^ this is very easy to do. If I remember right, you can simulate 7.5° of avcs advance by advancing the cam by 1 tooth. 30° would be simulated by advancing the cam 4 teeth.
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Old 08-30-2010, 09:07 PM   #10
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Ding Ding Ding, we have a winner!
shhhhHHH..... I know nothing...
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Old 08-30-2010, 10:07 PM   #11
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How do you degree the cams by claying them?
Adjust the gear in a clockwise direction ?
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Old 08-30-2010, 10:21 PM   #12
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Old 08-30-2010, 11:01 PM   #13
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^ Thank you
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Old 08-30-2010, 11:15 PM   #14
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^ Thank you
it's something close to that, except that your piston is at TDC. You rotate your camshaft until it touches the piston. You record how much degrees it took and that's how much AVCS you can run.
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Old 08-30-2010, 11:31 PM   #15
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Got it ,I was actually gonna degree AVCS cams w/ out using the AVCS.. I.E I have a 2.5 L.B in a 04 wrx set up Just to see if there would be a diff.in power
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Old 10-01-2010, 02:41 AM   #16
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so im looking at running 08sti cosworth heads with 02 wrx wiring, how can i run wrx non avcs cams and gears, will there be oiling issues?? i hear you can run the avcs cams and gears without hooking it up but non avcs gears are much lighter.

thanks
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Old 10-01-2010, 09:46 AM   #17
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Quote:
Originally Posted by Alaskan EJ20 View Post
so im looking at running 08sti cosworth heads with 02 wrx wiring, how can i run wrx non avcs cams and gears, will there be oiling issues?? i hear you can run the avcs cams and gears without hooking it up but non avcs gears are much lighter.

thanks
run non-avcs cam, run non-avcs cam gear, install non-avcs intake cam seal.. that's all you need. simple. Keep AVCS oil line plugged because that lubes the cam journal right behind the cam gear.
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Old 10-01-2010, 12:04 PM   #18
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winner^^^
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Old 10-01-2010, 01:51 PM   #19
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sweet, awesome thanks, so in the case of these heads i would plug intake and exhaust avcs oil feeds. one more question. are 08sti head valve covers year specific or with any 2.5 sti valve cover fit.

Last edited by Alaskan EJ20; 10-01-2010 at 01:59 PM.
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Old 10-02-2010, 09:43 PM   #20
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Originally Posted by Alaskan EJ20 View Post
sweet, awesome thanks, so in the case of these heads i would plug intake and exhaust avcs oil feeds. one more question. are 08sti head valve covers year specific or with any 2.5 sti valve cover fit.
You may want to put on the intake only AVCS valve covers. If you already have the '08 DUAL AVCS valve cover, just find a way to plug the sensor holes that are not used such as the upper/lower cam sensor.

What all do you have with the '08 head?
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Old 10-02-2010, 09:57 PM   #21
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Originally Posted by FuJi K View Post
You may want to put on the intake only AVCS valve covers. If you already have the '08 DUAL AVCS valve cover, just find a way to plug the sensor holes that are not used such as the upper/lower cam sensor.

What all do you have with the '08 head?
just the heads and cam caps. no cams, buckets, gears or covers. so valve covers for 04-07 sti then.
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Old 10-02-2010, 10:55 PM   #22
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Originally Posted by Alaskan EJ20 View Post
just the heads and cam caps. no cams, buckets, gears or covers. so valve covers for 04-07 sti then.
I just looked at the heads again. You can run '04+ AVCS head valve covers, intake only or dual AVCS.
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Old 10-06-2010, 07:03 AM   #23
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Fuji, can you explain what you mean by keeping the oil line plugged? On the exhaust side? You use non avcs cams and solid cam gears, but I get confused by how the oil is routed though the head, especially on the exhaust avcs side. So would it be better to keep all sensors and solenoids in place or make some kind of blockoff plate for the exhaust avcs solenoid. Just want to make sure the exhaust cam will get oil if not running the exhaust avcs
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Old 10-06-2010, 10:09 AM   #24
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What he means is some people "THINK" that no AVCS means that no oil line is needed to the AVCS solenoids anymore. This is a BIG mistake as it will stop lubrication to the area of the cam right behind the cam pulley where the large cap mounts. This will make the cam seize up. Keep all oil lines as they were. Just use Non AVCS cam pulleys and oil seals, etc. You can tap thread in the oil galleries inside the camshaft which normally guides the oil towards the AVCS cam pulleys. There are 4 holes that look like oil galleries. 2 should be tapped and sealed off to prevent oil getting out between the camshaft and the pulley. I hope this is clear enough.

Cheers,

Jasper Kopinga
CS Racing
Taiwan.
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Old 10-06-2010, 10:13 AM   #25
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Hmmm....sorry I believe ALL 4 holes need to be blocked off now thinking of it.

Cheers,

Jasper.
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