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Old 10-23-2005, 06:04 PM   #1
WRXINTX
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Default who makes adjustable cam sprocket sets for our engines???

I have found JUN makes for EJ205 and EJ207.....

but, does anyone in the U.S. make these cam timing gears or does anyone make them specifically for the EJ25- series engines.....????

HKS?

JUN?

ANyone?

how much and where do you get them???


Thanks!!!

RYNO
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Old 10-23-2005, 06:26 PM   #2
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.....in all my time here, I have only heard of them being used once or twice and If there was any real reason to use them, it would have been discussed a great deal more often.....

therefore, based on that.....forget cam gears
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Old 10-23-2005, 09:00 PM   #3
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If you really want them, JUN makes them and if I remember correctly they are $250 each(you need 4). If you want cheap, there are OBX ones on Ebay for a little less than $400 for all four.

http://cgi.ebay.com/OBX-Cam-Gears-fo...QQcmdZViewItem
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Old 10-23-2005, 09:04 PM   #4
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or get an AVCS head and program the ECU to adjust the cam timing?
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Old 10-24-2005, 11:30 AM   #5
WRXINTX
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Quote:
Originally Posted by Silver '02 REX
If you really want them, JUN makes them and if I remember correctly they are $250 each(you need 4). If you want cheap, there are OBX ones on Ebay for a little less than $400 for all four.

http://cgi.ebay.com/OBX-Cam-Gears-fo...QQcmdZViewItem

awesome info!!!

Thanks!!!

RYNO
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Old 10-24-2005, 12:33 PM   #6
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Sweet! Finally there's an afordable option. Tuning them might take a while though.
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Old 10-24-2005, 02:21 PM   #7
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no dawg, adjusting the cams gives mad power yo

Well actually when i had my Integra, we only had a 2 HP spread over the entire range of cam adjustment which didnt make any bang for the buck of my toda cam gears since the range of dyno error is more then that.

as far as I see things, I'd only use them with decked heads and/or non-standard head gasket sizes, otherwise it isnt worth it
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Old 10-24-2005, 03:01 PM   #8
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FastSS ,

There's a lot of reasons cam sprockets do and do not work for people. You mentioned a good one though. Most of the time, folks just through them on and don't even bother to adjust them. They can help move the power around to the left or right, depending on which way you want to go and your mods. Simply saying that it only added 2HP across your entire rpm range doesn't mean that much. How about torque, were you able to tune timing advance/retard and fuel? Did you have a turbo? Camshaft(s) upgrade? Did you pick up any torque by advancing them?

I think they than can be a good mod when used to their full extent.
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Old 10-24-2005, 04:29 PM   #9
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No, I got a peak gain of 2hp, and the curve didnít seem to shift much at all.

Stock N/A B18C with V-AFC

Basically the only change in power was from spark and V-AFC which also helped straighten the curve on the VTEC crossover, other then that, it didnít really matter.

I'm simply suggesting that cam gears are all but worthless when the stock geometry is kept, especially for their cost. If you move your relative cam positions with decking the head or fatty head gaskets, adjust away, your valves depend on it.

On my built motor, the only time I adjusted my cam gears was while claying my head to ensure good valve piston clearance. 12:1 Civic Type R pistons with Toda Spec Cs on a slightly decked head means that clearance is a minimum. After I polished the markings off the top of the head, I had a 0 piston Ė deck height. With the stock head gasket I would have been stamping the arrows, words and whatnot that are on top of the piston into the head.

I learned from an entire day of dyno time, plus watching other people do it, that adjusting the cam gears didnít gain or change enough to bother with. Such a small change really isnít worth the cost of cams, or the pain of putting them in.

Like I said though, change the dimensions of the cam locations, gear away. With stock gears on my motor, my valves were making a b-line for my pistons. What ever the cost is, its cheaper then messing up your valves/head/pistons/whatever else.

As for variable valve timing, you wont find a better system then VTEC. Iím not saying that as a ricer fan boy, Iím just saying that itís a very simple system that works all the time and has been proven effective. I laugh at systems that use only variable cam timing, because while it puts area under the curve its not nearly as much as a variable timing and lift system.

I honestly think that if I were building a motor, especially a turbo motor, I wouldnít use any variable valve timing system. There is just too much extra stuff to go wrong that I donít need.

PS, I might mess with things sooner then I thought, my buddy with a 240 that I helped build says its going to be all out war when I buy my STi. But since he runs low 12s on street tires, and I donít even have an STi yet, I will continue to lurk the forums learning as much as I possibly can while trying to be as helpful as I can be with my limited real-world Subaru knowledge. I try to relate what I can under the assumption that what is historically true, remains true and applies itself to these cars as well as any other.

I may be dead wrong, but I kinda doubt it.

OOPS, forgot another key point. Valvetrain mass. If you want to rev anything to insane RPMs, cam gears are often lighter then their OEM versions...
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Old 10-24-2005, 04:49 PM   #10
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Comparing cam sprockets on a Honda and a Subaru is pointless. The truth is that they make a hell of a difference on the EJ motor. Advancing cam timing can bring your under 5k rpm power up alot. I have run AVCS maps from 0 to 15 degrees across the board on the Dyno to see how intake cam advance effects every point in the power band. Retarding the Exhaust cams can really help the Redline power as well. I have seen as much as 20whp at redline by doing this. The problem. Almost nobody has the budget to tune them on the dyno. Adjusting the sprockets is not a simple job on the EJ motor.

Clark
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Old 12-07-2005, 07:48 PM   #11
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Can these be used in conjunction with AVCS?
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Old 12-07-2005, 08:11 PM   #12
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cam gears are great for seting overlap.
I do agree they are not a cheap bolt on. Not for the Bling Bling at heart.
But alot can be gained.
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Old 12-07-2005, 08:51 PM   #13
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im guessing that avcs cam gears are very different from the ej20?
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Old 12-07-2005, 10:23 PM   #14
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The cams are different, but I'm not so sure about the gears.
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Old 12-07-2005, 10:33 PM   #15
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Quote:
Originally Posted by AZScoobie
Adjusting the sprockets is not a simple job on the EJ motor.

Word!
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Old 12-08-2005, 12:42 AM   #16
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Jun cam sprockets cannot be used on AVCS cams.
They can only be used on non-avcs cams only.
By the way,I am using those on my exhaust sides only.
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Old 12-08-2005, 12:59 AM   #17
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Thanks, I looked more at the AVCS mechanism and I can see you can't. I suppose you might be able to use them on the exhaust side only with AVCS intake cams.
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Old 12-08-2005, 02:24 AM   #18
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yea it doesnt sound bad just having them on the exhaust side, saves money and cant the AVCS for the intake cam be tuned with EMS?
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Old 12-08-2005, 10:37 PM   #19
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Yes you can tune the AVCS to adjust overlap. I'm looking for a greater lobe angle separation between the intake and exhaust cams. I figure if the exhaust cams are advanced slightly, I can do this. I looked at a pulled motor today and the exhaust sprockets look like they could be swapped for adjustable ones. Now the question for me is can I try this out without having to take the engine out of the car. I think they change timing belts without pulling the motor, but I could be wrong.

I'm going to do some more research on this. There may be some ignition timing issues to think about and I think the cams turn in opposite directions making getting the sprockets set a little bit of a head scratcher.
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Old 12-08-2005, 10:44 PM   #20
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Quote:
Originally Posted by bboy
I'm going to do some more research on this. I think the cams turn in opposite directions making getting the sprockets set a little bit of a head scratcher.

Please Please Please, Learn on a test motor. Playing with cams, Cam timing, overlap or anything with engine timing could leave you walking with a 5K motor rebuild bill.

Cam gears are not for everyone as far as install and playing with.
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Old 12-09-2005, 12:10 AM   #21
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It's a very complex topic. It will take awhile before I understand it.

As far as I can tell you can add adjustable sprockets to the exhaust cams and retain the AVCS sprockets on the intake. Swaping the sprockets with the engine looks tricky, but doable. Now I need to see if this will truly benefit performance or just start up and idle. I've got a few emails out to some gurus.
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Old 12-09-2005, 12:27 AM   #22
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Quote:
Originally Posted by bboy
It's a very complex topic. It will take awhile before I understand it.

As far as I can tell you can add adjustable sprockets to the exhaust cams and retain the AVCS sprockets on the intake. Swaping the sprockets with the engine looks tricky, but doable. Now I need to see if this will truly benefit performance or just start up and idle. I've got a few emails out to some gurus.

There is alot you can do. You can even increase compression by changing valve overlap. Less overlap more comp. But remeber you need some overlap to help the motor pump air out(exaust). A motor is only a giant air pump. You can retard or advance cams to move the power curve around the RPM band.

Always remeber to spin the motor over by hand before starting it up after playing with: Cam timing, Cams, Timing Belt.
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Old 12-09-2005, 01:10 AM   #23
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Quote:
Originally Posted by 06STi
There is alot you can do. You can even increase compression by changing valve overlap. Less overlap more comp.
This was/is the initial motivation:
increase compression at low speed (like idle and start up)
increase overlap in the mid range
whatever it "wants" up top

I'm not sold yet.
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Old 12-09-2005, 06:25 AM   #24
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I asked a motor builder about this 'cause I wanted dead on balls accurate cam timing since I'm using Cometic gaskets.. turns out the gaskets throw timing out by about 1-2 degrees (not a big deal considering the following).

The long Subaru timing belt stretches, especially in the higher RPM range. Timing can be thrown as much as 5 degrees (from what I've been told). Adjustable gears would definately help in this situation, but you may lose some bottom end to gain proper cam timing and maximum higher RPM power. Or the reverse if you're looking for better low end power.
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Old 12-09-2005, 09:32 AM   #25
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The cam sprockets can EASILY be changed with the engine in the car to answer that question. The radiator/fan assembly, valve covers/coil packs, timing belt covers, timing belt/belt tentioner, and finally the sprockets themselves all need to come out. In order to get the sprockets on and off reliably you will need a 30mm open end wrench to hold the cams in place.
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