When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
As part of replacing the cam chain tensioner pads, I am resealing the cam covers. No big deal, they weren't leaking horribly. Both cam covers were powder coated almost 20 years ago. The powdercoating is holding up acceptably. So, the new seals should be no problem.
My question is the breather elbows. S3 engines are oil pumpers, at least in that oil collects in the outer plenums and in the bottom of the throttle body shoe.
I am replacing the O-rings that seal the two elbows on the passenger's side cover and the plugs on the driver's side cover.
Are there any upgrades I should look at?
I ventured into the dark realm of 'search' on Rennlist for breathing on 32V engines. Most of it is centered on S4 and later engines.
Take away's I got:
-not much for S3's
-not much effective for S4's without a ProVent or such.
I am replacing ALL the intake hoses and such as part of the intake refresh. I have an old Devek baffle and a new Greg Brown baffle going under the oil filler neck. I have verified that the little check valve is present for the rear port on the base of the oil filler neck.
The Red Witch is a street car. I don't see any track time or extended high RPM's in her future. Do I just reassemble everything as stock?
Or, should I be looking at adding elbows and hoses...?
Should I add an oil separator to the other elbow in the passenger's side cam cover?
Passenger's side cam cover with elbows.
Driver' side cam cover with plugs.
I have noticed that the underside of my cam covers are black. I had thought they should be a more metallic color? IE raw magnesium.
Passenger's side cam cover, lock nuts, tabbed washers, and single oil separator intact.
Driver's side cam cover, retaining rings in place for plugs.
Made a custom, high-tech bolt holder/organizer for the driver's side cam cover bolts, as well.
I know that Greg has a provent system that you can add with all of the pieces needed. It replaces a lot of the stock hoses and keeps the crank case closed. It is $$$ though.
A less expensive option is to install a provent and connect the vent to the smog pump to get a poor man's crank case vacuum system ( I did this on my 89 S4, works great). Otherwise just root a hose to the air box.
I personally say to keep the crank case closed because it reeks if you vent it to atmosphere.
There are a number of theories as to how to breath these motors and some use all four connections. If you do not have a specific system in mind it might be prudent at this stage to install such vents and cap off the ones you do not use at this stage knowing that future conversion would be a walk in the park rather than having to remove the covers again to fit them in the future.
There are a number of theories as to how to breath these motors and some use all four connections. If you do not have a specific system in mind it might be prudent at this stage to install such vents and cap off the ones you do not use at this stage knowing that future conversion would be a walk in the park rather than having to remove the covers again to fit them in the future.
+1
That is where I was going next on mine.
With the same intent.
The problems and solutions to S3 and S4 crankcase breath problems should be pretty similar.
This is one of those situations in which every operating mode should be thought thru separately and made sure it works. Accelerating, breaking, cornering, etc.
I agree that installing breather tubes and drilled out elbows in every port is a reasonable starting point, _provided_ that you'll then think thru which hoses need calibrated restrictor orifices and install those.
The way we set up my car works on street tires. You want to breath out of the rear ports when the throttle is closed and out of the oil filler neck when the throttle is open. The in-block chimney baffle should in my opinion be designed to first block oil spray and then decelerate the air-oil mixture temporarily. The valve cover port separators stop working around the gas velocity of 1 m/s so you need to calibrate restrictors for those if you breathe a lot of volume out of them. You want cross-overs to connect the valve covers to help with piston pumping pulses and to deal with some potential pressurization scenarios when cornering. In any case, those have worked for my car.
There are a number of theories as to how to breath these motors and some use all four connections. If you do not have a specific system in mind it might be prudent at this stage to install such vents and cap off the ones you do not use at this stage knowing that future conversion would be a walk in the park rather than having to remove the covers again to fit them in the future.
Fred -- If I recall, your system is set up pretty similarly to mine. How is it holding up? I don't have much more data because of the exhaust fabrication and the shop accident.
I will contact Tom at 928 Intl and ask for the following:
928 107 731 01 oil separator (qty 3)
928 107 733 00 adapter
928 107 733 02 adapter
I will install adapters in the driver's side cam cover, and install oil separators on all four adapters. I understand two of the oil separators will need to be notched to clear a casting rib in the cylinder head.
I will drill out all four adapters, and fabricate calibrated orfices as required. I will block off the driver's side adapters until I come up with a plan for hoses and venting.
I will initially consider crossover hoses for the driver's side to passenger's side adapters.
ptuomov, I think I understand what you are saying. When the throttle is closed, suction should be on the rear ports, meaning the hoses for the rear ports should run to a port above the throttle body. When the throttle is open, suction should be on the front ports, meaning the hoses for the front ports should run to a point below the throttle body.
However, there still will be some suction on the rear ports, correct?
Fred -- If I recall, your system is set up pretty similarly to mine. How is it holding up? I don't have much more data because of the exhaust fabrication and the shop accident.
As I can tell it is working reasonably well. Oil consumption dropped noticeably but it still goes through some- just that now I consider it reasonable.
Whether or not your system design can be applied to the earlier models I have no idea but presumably it is just a case of what needs to be done rather than whether it is possible or not.
I will drill out all four adapters, and fabricate calibrated orfices as required. I will block off the driver's side adapters until I come up with a plan for hoses and venting.
I will initially consider crossover hoses for the driver's side to passenger's side adapters.
ptuomov, I think I understand what you are saying. When the throttle is closed, suction should be on the rear ports, meaning the hoses for the rear ports should run to a port above the throttle body. When the throttle is open, suction should be on the front ports, meaning the hoses for the front ports should run to a point below the throttle body.
However, there still will be some suction on the rear ports, correct?Thanks!
Some, but very little. The throttle body shouldn't see much vacuum under WOT, and the oil will have to fight against the acceleration g-force to get there.
The simplest thing for your purposes would in my opinion to block the driver side rear valve cover port, run the passenger side rear port to the throttle body with a 2mm orifice restrictor in there, interconnect the front valve cover ports with large ID hose, and breathe from the oil filler neck into an external separator (such as the BMW cyclone separator) which feeds the MAF rubber elbow Y-pipe rear port (this is for S4, does S3 have that Y-piece?), preferably from an added large port at the top but base is probably ok too. The BMW separator should drain to the sump with a fluid check valve in line. Block the existing 2mm port in the oil filler neck. As in the factory setup, I'd leave in the safety hose with a pressure relief valve that runs from the oil-filler neck base to the second MAF rubber elbow Y-pipe port (or the S3 equivalent).
I agree while you have the cam covers off plumb all 4 - use the wide open ones and drill out any that are restricted (you can always add back an external restrictor - but you can't drill out the elbow in situ. Fit the separators (but one on the pass side probably needs a modification to fit).
Make sure to seal them well they tend to leak.
You can decide how to plumb them later. In the end I only breath in through those cam ports on my system - fresh air in the back 2 whenever the vacuum is >10" Hg and recycled oil from the AOS in the front 2. All my evacuation is from what used to be the filler neck via the vacuum pump. Not suggesting you should go this far BUT breathing out of the cam covers when the heads are packing with oil - means 2 things: the oil will be restricted from draining back down - and you risk gulping oil - neither is good. With the vacuum pump there is nothing going to the throttle body - cleaned/separated air just goes back to the CAI.
You will need to come up with your own strategy - at least you will have options - these ports are easy to cap off.
I know that Greg has a provent system that you can add with all of the pieces needed. It replaces a lot of the stock hoses and keeps the crank case closed. It is $$$ though.
Unfortunately, that is for the S4/GT/GTS only. He might be working on an S3 system, but it isn't to market yet
Originally Posted by Alan
Make sure to seal them well they tend to leak.
Alan
I am replacing the O-rings on the fittings. Do you recommend I use a sealant of some kind?
10-08-2017, 12:56 AM
S3 cam covers and breathing...
