PCV Explained?

[blueboss]

Interesting read considering my latest conundrum:

http://forum.diyefi.org/viewtopic.php?f=24&t=357

Thoughts?

[MikeFleming]

Interesting.

Most OEM systems lack vapor separators (to return the liquid factions back to the crankcase) probably cause it's too complicated. Additionally, most OEM systems have too small a capacity when the power output is doubled.

I have some pics of Hubers race cars with a full-scale vac pump sucking out crankcase gases all the time. Unfortnately they vent to atmosphere (cause racecar).

[blueboss]

It is interesting to note, some people in the SVO world (myself included up till I read this article) will add the Villager booster check valve inline with the pcv valve. Thinking that the reason oil is blowing out the dipstick is because the turbo is pressurizing the crankcase through the pcv valve. When in all likelihood, (provided the pcv valve is good) the valve cover vent/intake simply isn't large enough any more to pass the volume of pressurized air/blowby that's trying to get out of the engine. The system was more than adequate when the engine was new and blowby was minimal. After a hundred thousand miles and increased boost, not so much anymore. Doesn't necessarily mean the engine is shot, just well worn with plenty of service life left. In some cases.....

[Chalky]

It's an interesting read for sure, but I have to politely disagree with you on the adequacy of the original SVO breather system.

Mike or Pat can correct me if I'm wrong but i do believe there was a TSB released early on about the blow-by issue and oil condensing in the intake tract. This was in the 83 thru 85 engine. I believe there may have also been some issues with the later Gen. II engine used in the 85.5-86.

On my car I built a catch can set-up. I have a hose from the dip stick tube to a t fitting at the valve cover that then goes to the inlet of the catch can. CC outlet goes to the turbo inlet. Still get a little oil in the VAM but no where near stock levels.

[Patrick]

There was more than one fix over the years. Early on, the fix was to add the round baffle from the 85.5-86 to the back of the 84-85 valve cover. After that, the T-Bird style valve cover with the larger passage, grommet, and screened baffle were offered as a replacement by Ford.

If you want to see a well thought out alternative for the hot rodder or racer, you should see what Mike Fitzwater came up with. Mitch and I have pics somewhere. That took some ingenuity.

[Raven855]

The hot setup around here has been from here: http://www.et-performance.com/automotive.html. The local Harley guys use them, Especially with the boosted crowd. Pricey though

[MikeFleming]

There was more than one fix over the years. Early on, the fix was to add the round baffle from the 85.5-86 to the back of the 84-85 valve cover.

The first "fix" was increasing the hole size in the fitting that goes into the turbo inlet - so it would flow more air. Next was adding the breather can (more surface volume to collect/condense vapors) to the cam cover. Last was the super large inlet to the turbo inlet, larger tube and huge hole in the cam cover for the larger grommeted breather in the 87+ engines.

[blueboss]

It's an interesting read for sure, but I have to politely disagree with you on the adequacy of the original SVO breather system.

Mike or Pat can correct me if I'm wrong but i do believe there was a TSB released early on about the blow-by issue and oil condensing in the intake tract. This was in the 83 thru 85 engine. I believe there may have also been some issues with the later Gen. II engine used in the 85.5-86.

On my car I built a catch can set-up. I have a hose from the dip stick tube to a t fitting at the valve cover that then goes to the inlet of the catch can. CC outlet goes to the turbo inlet. Still get a little oil in the VAM but no where near stock levels.

I didn't know about the TSB's. Interesting.....

The first "fix" was increasing the hole size in the fitting that goes into the turbo inlet - so it would flow more air. Next was adding the breather can (more surface volume to collect/condense vapors) to the cam cover. Last was the super large inlet to the turbo inlet, larger tube and huge hole in the cam cover for the larger grommeted breather in the 87+ engines.

I'll post up pics later but this is pretty much (all combined) what I installed yesterday. I hogged out the cam cover vent and the turbo inlet to accept a 1/2" npt to -10 adapter. Installed a Moroso air/oil separator (pn 85471) which is air tight when the cap is on. The whole system now breathes through -10 (5/8") line so it should move a much greater volume of air both in and out of the crankcase compared to stock. And being that this is a much smaller restriction than my dipstick tube, the drivers side of the engine *should* stay nice and clean from here on out.

[Under Pressure]

Mike is not using the VAM. Nice setup. The others are not running A/C. Looks like you have to work around if you have a/c or Vam. I have work to do.

[svslow]

Is deleting the pcv and adding a can not relevant to this situation? That's what I did yesterday. I have the factory set up on the cam cover.

[Under Pressure]

I did the catch can but did not open up the hole in the valve cover. The cover does need the hole bigger. I have a spare so I'll see how it goes.

[brsvo]

I went with the pcv delete and -10an valve cover to catch can vent to atmo. My car see's very few miles per year and the catch can does a very good job. My filter on top is not oily at all. This takes any possibility of oil in the intake tract out of the equation. A very good thing in my opinion. I am not running AC or a VAM though so space is available.

[Under Pressure]

I removed the short steel tube & drilled out the breather hole & tapped it to 1/2"npt on my spare cover. I still have to blow out all the shavings. It's tricky drilling out the cover. Best to put it on a good rubber mat and hold it down with your foot as you step up the drill size using lots of WD40. Work in progress.

[MikeFleming]

I removed the short steel tube & drilled out the breather hole & tapped it to 1/2"npt on my spare cover. I still have to blow out all the shavings. It's tricky drilling out the cover. Best to put it on a good rubber mat and hold it down with your foot as you step up the drill size using lots of WD40. Work in progress.

Be sure to remove both baffles and scrupulously clean the inside. Then re-install the baffles.

HINT: there is no way to adequately clean the cover without removing the baffles.

The early covers (pre-1987 non-humped flavors) Are held in with twisted rivets - lever them straight out. Then drill/tap the holes (four total) for a 5mm or 10-24 course thread and install with short bolts/screws.

The later humped flavors are already mounted with screws.

[Under Pressure]

I picked up some AN fitting from Summit. I had to go with blue as the black Earls 90* are back ordered. Did you put any kind of baffling in the hoses? It will be awhile before I can get it on as I'm doing House painting which I hate. I'll get er done later.

[svslow]

I would imagine that deleting the pcv and running the cam cover (unmolested) to the can too would be adequate. I think that's what stinger did. Can you post picks when you're done ?

[Under Pressure]

I already have the hose off the PVC going to a catch can and a hose off the breather to the can on a non-enlarged breather hose. The hose off the cover to the breather is as tall as I can get it. I think I'm getting more pressure in the cover as to the bottom end. I want to leave the PVC in place because I don't want condensation running back into the sump. I'll post some pics later.

[Under Pressure]

I'm going to redo my catch can. I'm using 5/8 heater hose. It will be awhile before I can get it on. Here's some pics
enlarged breather hole.jpgbreather fitting.jpg

[svslow]

That's what I'm going to do.

[MikeFleming]

Get some 5/8" PCV vent hose. Heater hose material, usually, doesn't do well with oil and petrol vapors. Unless it's neoprene, viton, etc.