jeff spahn

I just got done with my Intake Refresh. I have buttoned everything up and there is a vac leak around the cam cover breathers and plugs. I put new O Rings on that Roger sent me so I know they are new.

When I pressurize the system, it holds air for 20 seconds maybe, it runs out around these two elbows and caps (two on each side).

My question is: Is this something to take the covers off, replace the O Rings (again) or do I need to worry about this?

Pretty sure I am going to need to take the cam covers off, clean everything up, put new o rings on and put it back together again.

I was excited to get it running and drive before leaving on vacation for 10 days of skiing but I can wait and do it again if that is the right answer.

Please chime in.

Jeff

FredR

Jeff,

After regards- your post is somewhat confusing [to me at least]. Perhaps you can clarify exactly what circuit you are testing, what pressure you are applying, where you are seeing a leak and whether it is vacuum or pressure leakage.

You talk about vacuum problems initially and a pressure test which further confuses things for me at least. Are you leaking under pressure or vacuum and exactly where? If yu have fitted new seals at the four locations in the cover then it is difficult to understand why they should leak unless you have done something totally naff.

To be clear here, the breather system should see little to no pressure especially when in the garage and presumably the engine is under no load. If the breather connections are weeping you will see oily residue settling with use. It is not a major problem- more cosmetic.

Your avatar suggests you have the stock S4 breather system which is somewhat pathetic if you look at the hole it has to pass through on the way back to the induction system at the base of the oil filler unit- the GTS system is better in that regard [but still too small apparently].

I suspect you are carrying out a test that may not be appropriate and therefore perhaps misleading you.
Did you set up the test based on something in the WS manual or something you feel is appropriate?
If you are pressurising the breather system to a nominal pressure [say 5 psig] it will quickly lose pressure unless you isolate the circuit as it will very quickly breathe any pressure applied back into the inlet manifold or crankcase.

Apologies if I have misinterpreted what you have written but I suspect you are needlessly chasing your tail here

jeff spahn

Fred. I am testing it under pressure in the same method that Dwayne (and others that I can't remember he mentioned as inspiration) did in his intake refresh write up. https://rennlist.com/forums/6188035-post4.html is post 4. This describes a unit you can build to pressure test your intake system through the MAF. Then in post 146 https://rennlist.com/forums/6262926-post146.html Dwayne begins the actual pressure test to determine if there are any leaks.

So my leaks are coming from the two cam cover ports that have O rings in the caps on the drivers side and in the elbows on the passenger side. The system leaks down in 10-20 seconds from 2.5 psi to 0

Sorry about not giving all the information on what type of test I was performing.

It rained, froze and then snowed a bunch last night. I won't be driving this week or next anyway so I'll take my time here on the fix
Thoughts now?

Lizard928

All that will really happen is an oil weep.

Depending on the finish you used will depend on their ability to seal.

the flyin' scotsman

Not sure I get it either.

If you're pressurising the system the air will flow through the MAF boot and hoses to the valve covers where you'd expect to hear the air pressure escape ..........no?

Speedtoys

The Orings for these ports live in un-finished areas.


Jeff, I found it VERY easy to pinch these Orings..if yer not careful.

the flyin' scotsman

were the circlips replaced on the cam cover vents?

jeff spahn

Circlips were replaced

The O rings were very loose fitting and flush with the sides of the cap and the elbows. Didn't "stick out" to seal.

Sean told me to just run it for a couple weeks and see how it goes. Then if it weeps oil or runs like crap, pull the covers and replace.

SeanR

It won't run like crap. Worst thing that will happen is you will get oil seepage there and it gets dirty. I doubt you will have a flow of oil leaving the covers there. Unless you are running the car at high RPM all day.

I'm surprised that the o-rings didn't give you a good seal though. When you had them powder coat it, did they cover up that area so there is no longer any material in the hole?

FredR

Jeff,

I know the test and it leaks down quickly- more the kind of test you continuously feed air to replace that leaking. Assuming you are correct and it is definitely leaking from where you think it is [did you use a soapy water test to prove leakage?], I would be inclined to run it and see whether it settles down or leaks oil mist.

If it leaks oil and you are pained by the quantum, remove the covers and re-seal using some silcon rtv gasket sealant.

Regards

Fred

the flyin' scotsman

Its interesting that they are leaking air which will mean they will weep oil.

I also replaced the same orings on the cam covers only to have the same weeping issue return. I even made a special tool for the passenger side; Sean has it now and were going into manufacturing to make our millions

Given the cam covers haven't changed dimensionaly are the new Orings correct?

SeanR

That tool is a godsend.

Find it really weird that they don't fit as well. I've got an extra set of covers and if I can find the elbows again I'll see if the 0-rings I have are doing the same as you guys.

ROG100

Jeff told me the O rings are green which raised a ? with me as they have always been black. We buy them in batches of 50 from Mr.P. Sure enough my stock is green - something has changed maybe.

Measured the O ring and the ID is correct at 17mm and the CS is about 2.4mm which is slightly down from the spec 2.5mm. Probably still within tolerance as far as O rings are concerned.

I know green is more in line with AC O rings. HBNR but probably fine for this application and probably better than some of the black rubbers.

Maybe if this is a common weep spot we need to source a slightly larger CS O ring - say 3.0mm.
Any thoughts from the guru's.

SeanR

I must have some from the old batch, black ones that are 2.5mm in dia.

They fit perfect in these cam covers. Take note though, the powder coating is inside the hole also, as the enamel would be in stock ones.

Herman K

What size did Dwayne use he is holding pressure for 4 minutes according to his write-up.

I'm planning to go and do this same job changing flappy and throttle bearings and seals as I understand it with the installation of a Provent I'll cap off the breather inlet let to the MAF and re=route the cam cover outlets.

However still would like to stop any oil seeping.