S/C Question......

[Marauderjack]

I have wondered how much crank case pressure you "S/C Boys & Girls" build while in "da boost"??

I would think that 8-10 intake PSI would back-feed through the PCV system and pressurize the crank case and possibly cause oil leaks at front and rear main seals?? Is this possible or has it been taken care of.....like eliminating PCV or putting in a check-valve??

Marauderjack

[RF Overlord]

jack, intake manifold pressure has nothing to do with crankcase pressure. All of the "boost" is contained within the intake manifold and combustion chambers. The only way you would pressurise the crankcase under boost is if there was a gasket/seal leak, or through blowby from bad rings.

BTW, the PCV valve IS a check-valve...

[Marauderjack]

My PCV is not a check-valve?? I tried to replace it but couldn't take the old stuff apart.....so I cleaned it and you can blow through it both ways??

If it don't check you would get a pressure in the CC too...wouldn't you??

Just wondering 'cause.........I HATES OIL LEAKS!!!!

Marauderjack

[Warpath]

Its an interesting question nonetheless. An easy way to find out is to hook up a boost gauge to the pcv system on the crankcase side of the PCV valvel. My guess is that it will be too low to easily pick it up on the gauge.

[Marauderjack]

Thanks Guys!!

I don't think it will be a problem but I'm trying to cover the bases!!

I do know that some racers use vacuum pumps on the CC to eliminate pressure against the rotating and reciprocal systems!!

BTW....I HATE OIL LEAKS!!! Had one from HELL on my Cobra.....Embarrasing!!

Marauderjack

[FordNut]

The OEM PCV valve does not seal from backflow. Change it to a t-bird s/c type which is more like a check valve.

[thePunisher]

usually when superchargers are installed... the pcv system is somehow connected to the inlet pipe of the supercharger by a hose...this prevents the crankcase from being pressurized....even engines with good integrity and ring seal can pressurize the crankcase while in boost...

[HwyCruiser]

I have wondered how much crank case pressure you "S/C Boys & Girls" build while in "da boost"??

I would think that 8-10 intake PSI would back-feed through the PCV system and pressurize the crank case and possibly cause oil leaks at front and rear main seals?? Is this possible or has it been taken care of.....like eliminating PCV or putting in a check-valve??

Marauderjack

On the FIT Procharger kit the PVC system is modified to route the cam covers to intake tube prior to the blower and the manifold PVC tube is capped. There isn't any way to blow boost into the covers. Like Warpath said, the vacuum would be pretty small since this is the "open" end of the system. I believe this is pretty standard on the Procharger kits.

[thePunisher]

exactly.......

[HwyCruiser]

exactly.......

You beat me to it, lol. Anyway, that's specifically for the FIT system, I don't know how the others handle the PVC issue under boost as in check valves, breathers, or whatnot.

[RF Overlord]

The OEM PCV valve does not seal from backflow. Change it to a t-bird s/c type which is more like a check valve.I stand corrected. :) Every other PCV valve I've ever seen is a ball-and-spring type of check valve...I didn't realise the MM one wasn't...

You can tell I haven't replaced MINE yet... :rolleyes:

[FordNut]

You beat me to it, lol. Anyway, that's specifically for the FIT system, I don't know how the others handle the PVC issue under boost as in check valves, breathers, or whatnot.
The FIT kit is one way, but most other centrifugal systems replace the PCV valve with a check valve type PCV valve from a s/c application and move the crankcase inlet (opposite valve cover) from the intake tube to the s/c inlet tube. That keeps the crankcase under vacuum (or being evacuated) most of the time but prevents backflow when under boost. Keeping the crankcase evacuated is a good thing because any blowby has potentially corrosive chemical components which don't necessarily get evacuated under a pressure relief system like it does with a vacuum system. Also, some cars that use the vents/filters on the valve covers do not allow adequate pressure relief to prevent eventual seal leakage.

Actually, there was an article awhile back about connecting a vacuum pump to the crankcase to increase power output slightly (maybe 5 hp or so). I believe there is a thread about it somewhere here on MM.net.

[thePunisher]

ive installed quite a few s/c's (mostly fords, windsors and modulars) and never touched the pcv valve at all....just routed a hose from one of the valve covers to the blower inlet...keeping the crankcase in somewhat of a vacuum at all times...the fit kit sounds like most every other ive seen...

a vacuum in the crankcase improves ring seal which as stated above may add a bit of power....lots of race cars use crankcase evacuation systems...

[FordNut]

ive installed quite a few s/c's (mostly fords, windsors and modulars) and never touched the pcv valve at all....just routed a hose from one of the valve covers to the blower inlet...keeping the crankcase in somewhat of a vacuum at all times...the fit kit sounds like most every other ive seen...

a vacuum in the crankcase improves ring seal which as stated above may add a bit of power....lots of race cars use crankcase evacuation systems...
Actually the FIT kit connects both valve covers to a tee which is connected to the inlet pipe to the s/c. The PCV connection to the manifold is blocked off.

[HwyCruiser]

Actually the FIT kit connects both valve covers to a tee which is connected to the inlet pipe to the s/c. The PCV connection to the manifold is blocked off.

True. The completed path is through the low pressure / vacuum state of the inlet tube. I admit I have only a rudimentary understanding of the PVC system so that's why I rely on the expertise of the man who lived and breathed this stuff for a good part of his career. I'm always up for to learn more though. :)

[Marauderjack]

This has been interestimg as well as enlightening!!

I am picturing crank case fumes entering the ProCharger inlet....Is that true?? If so won't that gunk it up?? Just curious.

PCV is a good thing and accounts for 2x to 3x engine life when compared to no PCV....It sweeps "lights and corrosive contaminants" out of the oil and into the combution process. The military developed the PCV system in the 1950's...I think!!

Thanks for all the replies!!

Marauderjack

[RR|Suki]

This has been interestimg as well as enlightening!!

I am picturing crank case fumes entering the ProCharger inlet....Is that true?? If so won't that gunk it up?? Just curious.

PCV is a good thing and accounts for 2x to 3x engine life when compared to no PCV....It sweeps "lights and corrosive contaminants" out of the oil and into the combution process. The military developed the PCV system in the 1950's...I think!!

Thanks for all the replies!!

Marauderjack

Yes it will come through, cuz it does on my car... as you can see in pic one (look at the opening of the blow off valve... In pic 2 you can see the tree where drivers side meets passengerand go on to the SC inlet... so what I figure I'll do is put an oil separator in line after the tree... any thoughts on that?
http://www.msu.edu/~taylorab/madrive.jpg

http://www.msu.edu/~taylorab/mapas.jpg

[Marauderjack]

I'm going with the EV-111 mounted on the driver's side valve cover and the existing OEM PCV valve plumbed to the suction side of the blower!! I found that the OEM PCV valve can be pulled apart and the plunger removed to give you basically a 90* fitting.....functioning like the elbow currently on the driver's valve cover!!:beer:

The EV-111 will be connected to the intake where the current PCV valve is.....This should work exactly like the OEM setup only pulling air through the engine in reverse!!:cool:

I will keep an eye on blowby build up on the PCV and may even run a pressure gauge for awhile to be sure there is no pressure in the crank case!!:bows:

Marauderjack:rasta:

[Todd]

On the FIT Procharger kit the PVC system is modified to route the cam covers to intake tube prior to the blower and the manifold PVC tube is capped. There isn't any way to blow boost into the covers. Like Warpath said, the vacuum would be pretty small since this is the "open" end of the system. I believe this is pretty standard on the Procharger kits.



Same here. My turbo kit (which was just installed 1 week ago) routes the hose to the inlet side of the turbo. Same scenario as above.

I like the idea of the s/c pcv valve as mentioned in Fordnuts post.... I might look into that.

I will also be getting an oil seperator just in case to make sure no oil goes through my intercooler. Steeda sells them as well as others. Or you could use an water seperator from an air compressor (craftsman etc..) which is backyard mechanic'ish but it works great.