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Group Buy 2.5T AVCS inlet cam gears and OCV solenoids

PostPosted: Tue Mar 05, 2013 12:51 pm
by bigBADbenny
AVCS inlet cam gears: available from Celtic Motorsports & Flatirons Tuning C$300 (2x gears)
OVC solenoids: available from Celtic Motorsports C$190 (2x OCV's)

E.g. http://www.flatironstuning.com/p-2126-2 ... gears.aspx

Local price is not economical. Let me know if otherwise...
USA price with express post is almost do-able (shipping is +2/3 the cost of the gears).
Shipping direct from the vendor is around $56 per 2x gears.
With duty etc we can send either 2 or 3 orders per shipment.
Or we can ship to my company's USA HQ and have them shipped at the cheapest possible rate...
I'm still nutting out the details with the vendor...
If you are not in a rush, personal delivery is possible around Easter.

Symptoms of AVCS out of sync issues:
Rough idle, random flat spots, hesitation, stalling on takeoff, whole car rocks just off idle at around 1300rpm if held at those revs, poor economy.
The issue may be experienced independently of OVC CELs.
Factory diagnosis of my issue reveals the system is working in terms of its feedback loop, it's just unable to operate correctly due to clogging, jamming or wear and tear of one or more of the components.
Logging my Lib reveals laggy VVT operation on the RHS bank (turbo side) during city driving, and oscillation on the RHS bank from 0-51 degrees when cruising in 6th.

Background:
The AVCS system on the 2.5T is implemented to enhance power and economy.
The system is somewhat prone to failure, mainly limited to one side/bank of the engine.
These failures can be caused by a variety of issues including but not limited to oil and long term wear and tear.
Failure of the system is not usually catastrophic, but power and economy may be limited from the optimum possible.

From research:
- an oil/filter change has been reported to have fixed mild issues.
- the various electrical plugs and looms relevant to the system should be checked as should battery condition/connection.
- intake cam gear sensors may become dirty and require cleaning but rarely require replacement.
- OCV valves may become clogged with oil sludge or debris, or become worn, requiring at least cleaning but more commonly replacement.
- OCV banjo bolts and or filters (still unconfirmed) may require unclogging
- AVCS inlet cam gears may become blocked with oil sludge or debris or the actual mechanical parts and seals etc. may be damaged preventing correct operation.
- the issue has been linked to phantom knock, presumably noise from struggling cam gears.

Suggested fixes:
UEC, oil flush, oil and filter change.
Inspect, clean and or replace OCV solenoids.
Inspect and clean intake cam sensors.
Replace intake cam gears and do a timing belt service.

Why replace intake cam gears:
Your car has AVCS out of sync issues etc that weren't fixed by cleaning or replacing the OCV solenoids, removing, replacing or cleaning the OCV oil feed line filters, or by cleaning the inlet cam gear sensors. Or if low oil pressure, by checking the oil pickup. Or if hesitation, checking your MAF for cleanliness.
If you have slight AVCS out of sync issues and your oil light stays on for 5-10 seconds on start up, check the condition of your oil pickup: it may be fatiguing.
Check your battery connection and condition as poor battery performance can affect the OCV solenoids.

When to replace intake cam gears:
You have an upcoming timing belt service, engine rebuild, new heads etc. and want to change out all related items for long term reliability.
Or you just want your car running 100%.
A timing belt change is required when replacing the inlet cam gears.

To be sure log your car:
Buy or borrow a Tactrix and just log RPM, Speed, and the L & R VVT, OCV duty and OCV voltage parameters.
Log warmup, 60 sec of stationary in-gear 2K rpm, 60 sec of stationary in-gear 3K rpm, then driving below 70Kph, then some freeway K's.
Open logs in ECUedit or Megalogviewer Lite and look for lag or oscillation in the VVT angles.

If they are way out of sync its the inlet gears, solenoids or sensors.
If just a little out of sync: check your oil pickup, oil level and or battery condition/connection.

What does this issue affect and do I need to fix it immediately:
AVCS is implemented for power and economy, thus the issue will affect those aspects negatively: ballpark figure 20%.
Unlike the 2.0t (where the issue of blocked filters in the OCV oil lines would affect flow to the turbo, leading to blown turbo bearings) the issue may not be quite as severe on 2.5's, with the aforementioned reduction in power and economy being the primary effect.

Thus if your timing belt service is too far away or is presently too expensive, consider changing out your OCV's and cleaning/inspecting your intake cam sensors as this operation is independent of the timing belt and is even DIY-able.

Long term prevention:
Research suggests that a shorter oil change interval than recommended e.g. at 5K may be beneficial.
Some recommend doing shorter OCI's along with using an oil with a more aggressive detergent pack, e.g. Delvac MX 15W40.
The ultimate solution could be the addition (and extra complication) of 1 micron bypass filtration.


1: Bruce
2: BBB (quite likely)
3: Bosco
4: alexiwoody

Let me know if I've missed anything! Cheers, BBB

Re: Group Buy 2.5T AVCS inlet cam gears

PostPosted: Tue Mar 05, 2013 1:08 pm
by bass_straitener
I'm in. :D

These are the ones we need for facelift cars.

http://www.flatironstuning.com/p-2126-2008-subaru-sti-cam-gears.aspx

Re: Group Buy 2.5T AVCS inlet cam gears

PostPosted: Tue Mar 05, 2013 1:16 pm
by bosc0
I haven't read your long ass thread Benny, but i'm assuming the gist of the symptoms are shakey idle, random hesitation, flat spot? To be sure, logging is required?
Timing belt upcoming, if bees knees are the gears of cam... it may be worth it.

Re: Group Buy 2.5T AVCS inlet cam gears

PostPosted: Tue Mar 05, 2013 1:47 pm
by bigBADbenny
There's a lot of tail chasing in that thread.
I'll wrap it up in the first post very soon.
Let me know when you want to borrow the Tactrix or just log RPM, Speed, and the L & R VVT, OCV duty and OCV voltage parameters.

Log warmup, 60 sec of stationary in-gear 2K rpm, 60 sec of stationary in-gear 3K rpm, then driving below 70Kph, then some freeway K's.

Open logs in ECUedit (ask Bruce) or the app I mentioned in the thread.

If they are way outta sync its the inlet gears, solenoids or sensors.
If just a lttle out of sync check your oil pickup, oil level and or battery condition/connection.

Re: Group Buy 2.5T AVCS inlet cam gears

PostPosted: Wed Mar 06, 2013 12:18 am
by alexeiwoody
Hey benny my cams are in sync but just wondering - is the total cost of the gears $300 or $600...I've heard they cost 500 so just clarifying your first post, 300 for both seems cheap :)

Oh wow just clicked the link....that is cheap!

Re: Group Buy 2.5T AVCS inlet cam gears

PostPosted: Wed Mar 06, 2013 7:18 am
by bigBADbenny
Reasonable prices for these items in the USA.
We're expecting to save a little on shipping by scraping orders in under the $1k duty limit.
If not flatirons then celtic who can also supply by request sensors at $190/pair & solenoids at $180/pair.
The latter items can be done irrespective of the timing belt service.

Re: Group Buy 2.5T AVCS inlet cam gears

PostPosted: Wed Mar 06, 2013 8:49 am
by <GB>
i need to log mine with bruce then ill know if i need some.... being my cars low km im hoping it doesnt as the cam belt is 3k old

Re: Group Buy 2.5T AVCS inlet cam gears

PostPosted: Wed Mar 06, 2013 9:12 am
by bigBADbenny
Here's hoping it's OK.
The issue is certainly a power and economy killer (17L+ in traffic atm :shock:).
Needless to say I'm doing this ASAP.

Re: Group Buy 2.5T AVCS inlet cam gears

PostPosted: Wed Mar 06, 2013 9:17 am
by bosc0
bigBADbenny wrote:The issue is certainly a power and economy killer (17L+ in traffic atm :shock:).


In that case i think i'm in the clear 8)

Re: Group Buy 2.5T AVCS inlet cam gears

PostPosted: Wed Mar 06, 2013 9:44 am
by bass_straitener
bigBADbenny wrote:Here's hoping it's OK.
The issue is certainly a power and economy killer (17L+ in traffic atm :shock:).
Needless to say I'm doing this ASAP.


That's just your tune. :)

Even with my cam gears on the way out I'm still getting under 10 combined.

Mick logged my car on the dyno and advised mine need replacing. Enough said. I don't feel I need to continue with various logging scenarios, examining other investigation paths via STI etc.

I think he's also advised you from his experience that your cam gears are stuffed.

Re: Group Buy 2.5T AVCS inlet cam gears

PostPosted: Wed Mar 06, 2013 11:55 am
by alexeiwoody
Hey benny can you put me down for the GB? Just in case :)

Re: Group Buy 2.5T AVCS inlet cam gears

PostPosted: Wed Mar 06, 2013 12:08 pm
by bigBADbenny
For sure :-)

Re: Group Buy 2.5T AVCS inlet cam gears

PostPosted: Wed Mar 06, 2013 3:57 pm
by <GB>
bass_straitener wrote:
bigBADbenny wrote:Here's hoping it's OK.
The issue is certainly a power and economy killer (17L+ in traffic atm :shock:).
Needless to say I'm doing this ASAP.


That's just your tune. :)


this

Re: Group Buy 2.5T AVCS inlet cam gears

PostPosted: Sun Mar 10, 2013 12:11 pm
by Kekotic
Thanks to Ben for telling me what to do.

Here is a graph of mine, do I have the issue?

http://i.imgur.com/6lEhmBO.png

Re: Group Buy 2.5T AVCS inlet cam gears

PostPosted: Sun Mar 10, 2013 12:52 pm
by bass_straitener
chaotic2050 wrote:Thanks to Ben for telling me what to do.

Here is a graph of mine, do I have the issue?

http://i.imgur.com/6lEhmBO.png


Ouch!!