Pressurized pcv problems continued...

davins130

New Member
May 21, 2004
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Ive been burining oil under boost since i bumped my car up to 13psi, i replaced the pcv valve with the supercoupe valve, changed the rubber grommet and the filter under the valve and added a breather to the oil cap barb. I also have an oil leak in the back of the engine comming from right above the tranny/engine mating spot. It looks like the intake gasket area, but i dont know if there are oil passages over there that would be leaking (can someone confirm if there is?)...Im going to do a compression test tomorow to check the rings, but i was also thinking that maybe it was the pressure that blew out that gasket? I guess i could cap the pcv system off and check and see if the burning oil stop, and if it does then what else can i do to prevent a pressurized pcv system?
 
You might end up converting to large breathers. You don't want to cap the PCV off unless you have sufficient crankcase ventillation elsewhere (otherwise, you'll start blowing oil out the RMS and any other seal that will allow pressure to vent).
You might find that the leak is a result of a bottleneck of pressure. Once sufficient crankcase ventillation is established, the pressure doesn't try and find other ways out (or atleast doesnt succeed) and the leak stops.

Anyhoo, I'd consider a couple of nice fat breathers and possibly a breather on the oil filler (in lieu of a 710 cap) if necessary.

MHO.
Good luck.

Oh, if you do a compression test, do a dry and then wet test on each cylinder. A leakdown test would be more effective, but short of that, the comparison in wet and dry compression is much more useful than just dry compression.
 
the push in kind that you need to drill holes into the valve cover for? or where are you talking about puting these breathers?

If you dont have any plugged bosses already, an oil filler breather might work ok (check hood clearance). If that's enough, cool. If not, then one could consider another breather (which could require a little fab work or swapping VC's).

Good luck.
 
Sounds like you are pushing boost past your pcv valve. Pushed the gasket right out of the pocket.

I used to run turbocharged 2.3l Fords. We had the same problem with the VC gasket. To resolve the issue, we used a PCV/backcheck valve that was found in the vacuum system on the RX7. The NAPA part number is 29411. It is about $3.00. The valve works in conjunction with your (FORD ONLY!!! All others are CRAP!) T bird valve. (Just cause it's metal, doesn't make it the right one.) This is a link with a pic of the end of the Ford PCV box, it has the complete/correct Ford part#: http://www.merkurtech.com/merkurtec...php?merkurtech/picturepages/images/pcv002.jpg

The RX7 valve needs to be vertical to work properly Also, it needs to be oriented so that the valve is kept closed using gravity. (I know, I didn't need to explain that. You'd be surprised how many guys didn't just "know" that on the Merkur boards.) It is easy to put it in upside-down.

We used these in excess of 25psi. ;)

I hope this helps.
 
Sounds like you are pushing boost past your pcv valve. Pushed the gasket right out of the pocket.

I used to run turbocharged 2.3l Fords. We had the same problem with the VC gasket. To resolve the issue, we used a PCV/backcheck valve that was found in the vacuum system on the RX7. The NAPA part number is 29411. It is about $3.00. The valve works in conjunction with your (FORD ONLY!!! All others are CRAP!) T bird valve. (Just cause it's metal, doesn't make it the right one.) This is a link with a pic of the end of the Ford PCV box, it has the complete/correct Ford part#: http://www.merkurtech.com/merkurtec...php?merkurtech/picturepages/images/pcv002.jpg

The RX7 valve needs to be vertical to work properly Also, it needs to be oriented so that the valve is kept closed using gravity. (I know, I didn't need to explain that. You'd be surprised how many guys didn't just "know" that on the Merkur boards.) It is easy to put it in upside-down.

We used these in excess of 25psi. ;)

I hope this helps.


I may have to try this. I deleted my PCV system which worked nicely, but now I have to close off all my vents because it reaks of oil smell. And, oil is eating away at all my polished aluminum! Not good!
 
i'll try that...btw i did end up buying the tbird valve from advance auto, i'll swing by ford today and pick the right one up. thanks i'll let you know how that goes. Also you think that i should reconnect the hose from my oil fill tube to the intake tract? my afm powerpipe didnt have a barb on it for that hose, but i guess i could make one so that way im venting it with metered air, or does it really not matter?
 
i'll try that...btw i did end up buying the tbird valve from advance auto, i'll swing by ford today and pick the right one up. thanks i'll let you know how that goes. Also you think that i should reconnect the hose from my oil fill tube to the intake tract? my afm powerpipe didnt have a barb on it for that hose, but i guess i could make one so that way im venting it with metered air, or does it really not matter?

Remember, PCV flow is bi-directional. That small oil-filler to CAI hose allows air back into the crankcase (the flow of the hose with the PCV valve is obviously only one-way). Additionally, that small hose will help vent crankcase vapors at WOT, which only helps keep seals from having oil blown through them.

Simply stated, I'd want a way to have air ingress and egress the crankcase. Obviously a breather allows this as well.

Good luck.
 
Isn't it true that if you have a breather cap on your oil filler and a normal pcv setup, it's like having a vacuum leak? I read somewhere that it was pulling unmetered air into the intake.

That's how I feel about it. I'd not run a pure PCV system if I had breathers myself (or an opening in the crankcase ventillation. A large point of the OEM set-up is to close the system, which is moot with a breather).

Now if someone has a fat tune, the unmetered air should not be a biggie anyhow.

MHO.
 
well about that lower intake manifold gasket, there isnt anything special about the one that came with my intake was there? also i dont remember if there was a gasket on the upper manifold on the end cap thing (where there is a bolt on the inside of the edelbrock manifold) or if i just use rtv. and the lower to upper manifold gasket also, is that same as stock, or do these things all have to be edelbrock?
 
You really should only use the intake gaskets that go between the heads and the intake. Those little valley gaskets (that are indexed to the "port" gaskets) are a real problem, cork or rubber. You should use a 1/4" bead of RTV, there. Put the bead on, let it sit for 15-20 minutes and then put the manifold in the valley.

As far as whether to try to run a PCV system or not, we all used this set-up and it worked really well. Remember, even if the factory design is "ingress/egress", you (by adding boost) are changing the factory set-up to something else. "Egress only", because you don't want boost in the crankcase. A little vacuum in the crankcase is needed to keep rings from letting blowby occur, as well as pulling oil INTO the crankcase. In some areas, you won't pass a visual emissions inspection with breathers that vent to atmosphere, even if you have E.O. numbers for all of the rest of the components.

:OT: >>>>>>>go-stang5.0-That little engine is as bada$$ as our 5.0's! I have a friend that has a 1985 Mustng GT Turbo CONVERTIBLE that run's 10.30's, all day long. He drives it to the track. The cars (Merkurs) are VERY good, too. Very stiff chassis, IRS(think BMW trailing arm), decent power, etc. I have one now, that has a 5.0 and T5 in it. (Never came that way.) 2800# + about 275 rwhp= a LOT of fun!
 
well columbus ohio is like a 3rd world country when it comes to emissions, as in there are 0 emissions tests here...I never use the end gaskets either, just rtv, but i do need to know about the lower manifold, mid-manifold and cap gasket on the edelbrock performer 5.0 intake, and where to get them (or if stock ones fit) thanks!
 
Reddy, thank you for the catch. :nice:
When I posted earlier, I had not re-read the thread (email notification) and did NOT have forced induction on the brain when talking about the secondary crankcase breathing (oil filler to inlet hose).
 
I forgot to mention my crank case issues...with all the merkur talk:nonono: . I had a pinched hose (the one that goes from vc to intake) when I switched to an rpm 2 and sure enough when I went auto crossing a few days later I blew out the rear intake seal. I fixed the hose issue but it still leaks back there and I bet even if I take the manifold off and redo everything I am still gonna have the problem (even with the rear leaking my front is starting to leak now). I have been considering welding a nipple to my pass side VC and running a hose from there to the bottom of the upper intake (I have some extra holes there that are just plugged) to help with things. Anyone think this is a bad/good idea?
 
Can you run some hoses around like in this picture and plug off all the vac lines?
Would this work? :shrug:
pcv.JPG