PCV Noise/woes, Vortech 95 Cobra

[RossA81]

I have a 60k mile 95 Cobra with a Vortech V-1, stock short block, edelbrock heads. I have owned it for about 2 years. None of the work was done by me.

It has always made a weird screeching noise that continues for a few seconds after you shut the car off. The noise would start once the car was fully warmed up.

I never thought much of it, while it was a little annoying, the car is loud enough that I did not really notice it.

Yesterday I finally figured out that it is the sound of air trumpeting past a gasket somewhere(rear main? oil pan? intake? all of them?) While the car was idling I pulled the dipstick and air was coming out somewhat forcibly. Next I took out the PCV valve and fired it up. Noise, and dipstick air both stopped.

Current setup has been (stock) PCV valve in lower intake where it belongs, breather(with one way check ball) on oil fill, the "nipple" on the fill tube has been removed and the hole welded shut. FWIW I had a breather on the fill tube without a check ball when I got the car and it made the same noise(And idled high)

Car does not smoke out the tailpipes, and does not coat plugs with oil. But tt has been consuming oil. It mists out the valve cover breather pretty good under boost.

I am at a bit of a loss. I fear the engine is hurt.

I am tempted to just delete the PCV system for now and put a baffled/vented catch can in the passenger side fenderwell. I do not drive the car often, I have put around 1500 miles on it since I bought it.

Thoughts?

 

[RossA81]

After a ton of research today I am going to start by putting a line from the oil fill to the supercharger inlet... since my oil fill outlet is gone I will be using this:



Ross

 

[cobrajeff96]

You have blow-by. I think that's pretty clear from what you've stated.
Maybe if you actually give the car some PCV function again it will go away or at least quiet down a bit.

 

[95opal]

I have a 60k mile 95 Cobra with a Vortech V-1, stock short block, edelbrock heads. I have owned it for about 2 years. None of the work was done by me.

It has always made a weird screeching noise that continues for a few seconds after you shut the car off. The noise would start once the car was fully warmed up.

I never thought much of it, while it was a little annoying, the car is loud enough that I did not really notice it.

Yesterday I finally figured out that it is the sound of air trumpeting past a gasket somewhere(rear main? oil pan? intake? all of them?) While the car was idling I pulled the dipstick and air was coming out somewhat forcibly. Next I took out the PCV valve and fired it up. Noise, and dipstick air both stopped.

Current setup has been (stock) PCV valve in lower intake where it belongs, breather(with one way check ball) on oil fill, the "nipple" on the fill tube has been removed and the hole welded shut. FWIW I had a breather on the fill tube without a check ball when I got the car and it made the same noise(And idled high)

Car does not smoke out the tailpipes, and does not coat plugs with oil. But tt has been consuming oil. It mists out the valve cover breather pretty good under boost.

I am at a bit of a loss. I fear the engine is hurt.

I am tempted to just delete the PCV system for now and put a baffled/vented catch can in the passenger side fenderwell. I do not drive the car often, I have put around 1500 miles on it since I bought it.

Thoughts?

View attachment 46933

You cant leave the pcv intact if you welded the nipple on the oil fill. Your creating pressure. Plug the pcv and run a vent line to catch can off both valve covers.

 

[RossA81]

Yeah that nipple was welded shut by the PO/shop that worked on it(Alternative Auto in Detroit)... Today I ran a 3/4 hose from the PCV outlet to a breather in the fenderwell, and put a breather on the oil fill(no check ball) Took it out and made a few WOT pulls, minor oil vapor smell under boost but nothing crazy. Will be fine temporarily. I intend to restore a closed PCV system this winter.

Ross

 

[95opal]

Yeah that nipple was welded shut by the PO/shop that worked on it(Alternative Auto in Detroit)... Today I ran a 3/4 hose from the PCV outlet to a breather in the fenderwell, and put a breather on the oil fill(no check ball) Took it out and made a few WOT pulls, minor oil vapor smell under boost but nothing crazy. Will be fine temporarily. I intend to restore a closed PCV system this winter.

Ross

Never had any luck keeping the pvc on any of my blown mustangs. Hope it works out for ya

 

[cobrajeff96]

I think if I ever boost my motor I'm just gonna put in a dry sump system.

 

[Musturd]

Delete pcv and vent both valve covers . Preferably -8 to -10 hose with a catch can

 

[cobrajeff96]

In a boosted application, you are going to be draining those cans a lot. And the smell of oil vapor is going to be heavy.

 

[RossA81]

Did some experimenting today-

1) Completely closed/stock style system- drilled an oil cap and put a fitting in it, then ran 3/8 hose to a fitting in the blower inlet tube (mimic stock setup) It seemed ok initially but later it refused to idle down and it had some crankcase pressure(air coming out dipstick tube)

2) PCV hooked up, and open breather on fill tube. Seemed ok- but surging and did not want to idle likely due to the large vacuum leak.

3) Returned the car to the way it was when I bought it... PCV hooked up, and oil fill tube packed tight with rolled red scotch brite pads and an open K&N breather. Seemed to run best this way- I assume it ran best this way because the shop that built it and did this tuned the car around this... Basically tuned to idle with a slight vacuum leak?? No crankcase pressure issues here.

Note- the setup that was making the PCV noise/ crankcase pressure was the PCV hooked up, and an open breather with a check ball on the oil fill.

I would be fine with running deleted PCV and catch cans but I think it will need tuned to idle that way...

Ross

 

[ttocs]

I have been quiet because they know 10x more than me but I thought I read or heard that they recommend a thunderbird SC pcv for supercharged/boosted applications but I am probably wrong.

 

[RossA81]