Crank case evac on street/strip car. Help me out please

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I ran a Moroso evac on my Cuda with the blower. I had 2" Super Comps and 3" exhaust that exited right in front of the rear wheels and used the Bullets. The evac didn't work for me. Among other internal problems, I had valve cover and oil pan gasket leaks..I haven't figured out what I want to do with the Dak. It has 2" fenderwell headers,3" exhaust pipe and Bullets. Exits in front of the rear tires.. Kinda coincidental here.. The gaskets are seeping a little. I may pull the engine and install new gaskets before the tracks open..

Put a vac/pressure combo gauge on the engine. If you
are making pressure you either give it more venting
(breathers) or put a vac pump on it.... of course
this is if the engine isnt messes up inside like
broken rings

Wedge
If you pull the breather off the valve cover and
rev it up a few revs you should feel it on your hand
(sucking), if its not working you will feel it blowing
on your hand(this is the part with the hose on it)
also if its broken/failed the air will be hot(exhaust)

funny you say that as i bought a vac/pressure guage today...... are you saying when the engine is runnin it can show pressure not vacuum if the evac syatem isnt working also...

the evac kit has a check valve on it, if it is broken then yes you can see pressure in the motor, or if you have bad rings.

Posted By: KatFysh

Re: Crank case evac on street/strip car. Help me out please - 02/03/09 12:26 AM

I ran a Moroso evac on my Cuda with the blower. I had 2" Super Comps and 3" exhaust that exited right in front of the rear wheels and used the Bullets. The evac didn't work for me. Among other internal problems, I had valve cover and oil pan gasket leaks..I haven't figured out what I want to do with the Dak. It has 2" fenderwell headers,3" exhaust pipe and Bullets. Exits in front of the rear tires..

Kinda coincidental here..

The gaskets are seeping a little. I may pull the engine and install new gaskets before the tracks open..

Posted By: MR_P_BODY

Re: Crank case evac on street/strip car. Help me out please - 02/03/09 12:42 AM

Quote:

I ran a Moroso evac on my Cuda with the blower. I had 2" Super Comps and 3" exhaust that exited right in front of the rear wheels and used the Bullets. The evac didn't work for me. Among other internal problems, I had valve cover and oil pan gasket leaks..I haven't figured out what I want to do with the Dak. It has 2" fenderwell headers,3" exhaust pipe and Bullets. Exits in front of the rear tires.. Kinda coincidental here.. The gaskets are seeping a little. I may pull the engine and install new gaskets before the tracks open..

Put a vac/pressure combo gauge on the engine. If you
are making pressure you either give it more venting
(breathers) or put a vac pump on it.... of course
this is if the engine isnt messes up inside like
broken rings

Wedge
If you pull the breather off the valve cover and
rev it up a few revs you should feel it on your hand
(sucking), if its not working you will feel it blowing
on your hand(this is the part with the hose on it)
also if its broken/failed the air will be hot(exhaust)

Posted By: firefighter3931

Re: Crank case evac on street/strip car. Help me out please - 02/03/09 01:27 AM

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So I have been wondering, what is the best way to vent the crank case on a street strip car?
Thanks alot

My setup ; raised breathers with baffled valvecovers and baffled tubes.

Ron

Attached picture 4995999-enginebaybp11.jpg

Posted By: moparniac

Re: Crank case evac on street/strip car. Help me out please - 02/03/09 01:35 AM

whats the point of a PCV then if the header evac dont work....

Posted By: moparniac

Re: Crank case evac on street/strip car. Help me out please - 02/03/09 01:37 AM

Quote:

Quote:

I ran a Moroso evac on my Cuda with the blower. I had 2" Super Comps and 3" exhaust that exited right in front of the rear wheels and used the Bullets. The evac didn't work for me. Among other internal problems, I had valve cover and oil pan gasket leaks..I haven't figured out what I want to do with the Dak. It has 2" fenderwell headers,3" exhaust pipe and Bullets. Exits in front of the rear tires.. Kinda coincidental here.. The gaskets are seeping a little. I may pull the engine and install new gaskets before the tracks open..

Put a vac/pressure combo gauge on the engine. If you
are making pressure you either give it more venting
(breathers) or put a vac pump on it.... of course
this is if the engine isnt messes up inside like
broken rings

Wedge
If you pull the breather off the valve cover and
rev it up a few revs you should feel it on your hand
(sucking), if its not working you will feel it blowing
on your hand(this is the part with the hose on it)
also if its broken/failed the air will be hot(exhaust)

funny you say that as i bought a vac/pressure guage today...... are you saying when the engine is runnin it can show pressure not vacuum if the evac syatem isnt working also...

Posted By: MR_P_BODY

Re: Crank case evac on street/strip car. Help me out please - 02/03/09 02:05 AM

funny you say that as i bought a vac/pressure guage today...... are you saying when the engine is runnin it can show pressure not vacuum if the evac syatem isnt working also...

Since you bought the gauge hook it up to the crank case
(I run my gauge on the back of the drivers side valve
cover), hook up the exhaust and run the engine at
assorted RPMs and take some reading on your vac gauge.
This is only reading the engine pressure. Then hook
up the evac and re-do the RPMs again and see if they
are higher or lower.If the valve in the evac were
to fail and you have more back pressure in the exhaust
it WILL back up into the engine pressurizing the
engine with hot exhaust gasses

Posted By: moparniac

Re: Crank case evac on street/strip car. Help me out please - 02/03/09 02:07 AM

I dont have any type of hookup on the back of the valve covers... what about the back of the intake manifold?

edit. hooking it up to the VC gives out a pressure reading instead of vac reading...

Posted By: MR_P_BODY

Re: Crank case evac on street/strip car. Help me out please - 02/03/09 02:16 AM

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I dont have any type of hookup on the back of the valve covers... what about the back of the intake manifold?

edit. hooking it up to the VC gives out a pressure reading instead of vac reading...

The intake is NOT part of the crank case, the valve
cover is(via the intake valley and down thru the
cam tunnel) you want the crank case
EDIT
If you have cast covers you can drill and tap it,
if sheet metal you can do a extruded hole(punch it
with a pointed punch and push the metal inward, then
tap it lightly with a 1/8" pipe tap just to get a
start thread then start a 1/8" pipe fitting that will
hook up to your gauge(put some sealant on the fitting

Posted By: moparniac

Re: Crank case evac on street/strip car. Help me out please - 02/03/09 02:19 AM

gotch ya p..... but how did you hook up to the VC.... weld a fitting onto it or something....

Posted By: bigtimeauto

Re: Crank case evac on street/strip car. Help me out please - 02/03/09 04:38 AM

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whats the point of a PCV then if the header evac dont work....

It takes the crankcase fumes and recycles them into the intake to get burned again. It will never create vacumm in the engine because it has a breather on the other valve cover to supply fresh air into the engine.

Posted By: Bill MeLater

Re: Crank case evac on street/strip car. Help me out please - 02/03/09 07:17 PM

I've always wondered what the differnce is between a pcv valve and a huge vacuum leak...

Posted By: moparniac

Re: Crank case evac on street/strip car. Help me out please - 02/03/09 08:57 PM

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Quote:

whats the point of a PCV then if the header evac dont work....

It takes the crankcase fumes and recycles them into the intake to get burned again. It will never create vacumm in the engine because it has a breather on the other valve cover to supply fresh air into the engine.

I had a pcv on my old setup. some on here dont even run them..... are they really needed and i read somewhere that on a big hp setup the pcv going back into the intake can be bad going back down the ports???

thoughts

Posted By: MR_P_BODY

Re: Crank case evac on street/strip car. Help me out please - 02/03/09 09:12 PM

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I've always wondered what the differnce is between a pcv valve and a huge vacuum leak...

It has a controlled orfice which you over come when
setting the carb

Posted By: moparniac

Re: Crank case evac on street/strip car. Help me out please - 02/03/09 09:15 PM

the one guya above just runs 2 breathers...

Posted By: MR_P_BODY

Re: Crank case evac on street/strip car. Help me out please - 02/03/09 09:15 PM

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gotch ya p..... but how did you hook up to the VC.... weld a fitting onto it or something....

I use a cast cover and I drilled and taped it for
1/8" pipe

Posted By: MR_P_BODY

Re: Crank case evac on street/strip car. Help me out please - 02/03/09 09:24 PM

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the one guya above just runs 2 breathers...

Understand something..... he will NEVER create a vac
in the crank case, the most that he can do is get to
0 pressure. The purpose of a vac source is create a
vac to help seal the rings

Posted By: moparniac

Re: Crank case evac on street/strip car. Help me out please - 02/03/09 10:54 PM

Quote:

Quote:

So I have been wondering, what is the best way to vent the crank case on a street strip car?
Thanks alot

My setup ; raised breathers with baffled valvecovers and baffled tubes.

Ron

so this wont hurt anything really just doesnt creat a vacuum... but I like i said before i read a pcv can be bad running back into the intake and cause plug misfire or something...

and a improperly working header evac setup will cause to much pressure and cause motor leaks..

Posted By: emarine01

Re: Crank case evac on street/strip car. Help me out please - 02/03/09 11:52 PM

I was following post so I hooked up a vacuum gauge to my sb running a header evac & found 1/2" HG total vac , went strait to header with gauge and had 2" total at 4500 rpm ,how much vacuum is needed to have any gain?

Posted By: MR_P_BODY

Re: Crank case evac on street/strip car. Help me out please - 02/03/09 11:59 PM

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I was following post so I hooked up a vacuum gauge to my sb running a header evac & found 1/2" HG total vac , went strait to header with gauge and had 2" total at 4500 rpm ,how much vacuum is needed to have any gain?

If you are reading any vac on the engine you are getting
a gain...anything - of 0 is a gain

Posted By: emarine01

Re: Crank case evac on street/strip car. Help me out please - 02/04/09 12:09 AM

How much vacuume is needed to help with high piston speed ring flutter ? and can can it be done with header evac?

Posted By: firefighter3931

Re: Crank case evac on street/strip car. Help me out please - 02/04/09 12:47 AM

Quote:

Quote:

the one guya above just runs 2 breathers...

Understand something..... he will NEVER create a vac
in the crank case, the most that he can do is get to
0 pressure. The purpose of a vac source is create a
vac to help seal the rings

Agreed Mr.P, there is zero vacuum with a dual breather setup. How much vacuum does the typical engine have at WOT ?

PCV is nothing more than a controlled vacuum leak. I'm not a fan of introducing oil mist into the induction system.

Ron

Posted By: firefighter3931

Re: Crank case evac on street/strip car. Help me out please - 02/04/09 12:56 AM

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so this wont hurt anything really just doesnt creat a vacuum... but I like i said before i read a pcv can be bad running back into the intake and cause plug misfire or something...

The dual breather system will allow the crankcase to ventilate itself. What do you think works better ; forcing all the crank case pressure through a 3/8in hose or letting it escape through a pair of 1.5in tubes w/breathers.

The bottom vent breathers can create a mess so that's why mine are raised on the VC....to allow for drainback.

Different strokes for different folks.

Ron

Posted By: torkrules

Re: Crank case evac on street/strip car. Help me out please - 02/04/09 01:29 AM

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Hey,

So I have been wondering, what is the best way to vent the crank case on a street strip car? I have a solid cammed 493 street/strip engine. Right now I am running a breather on one side and a pcv on the other. Are there better ways to do it?
Dual breathers?
Crank case evac using the headers?
Vacume pump?

Thanks alot

I did it with my 496 Charger using Ultraflow mufflers and kept the exhaust pipe as straight as possible (exhaust dumped at the axle). worked great. If you put your finger over the hoses you could feel the suction.

Posted By: ahy

Re: Crank case evac on street/strip car. Help me out please - 02/04/09 01:50 AM

Quote:

Hey,

So I have been wondering, what is the best way to vent the crank case on a street strip car? I have a solid cammed 493 street/strip engine. Right now I am running a breather on one side and a pcv on the other. Are there better ways to do it?
Dual breathers?
Crank case evac using the headers?
Vacume pump?

Thanks alot

Another perspective. If you are using a standard ring pack - not low tension - and parts are machined correctly there shouldn't be a lot of blow by on a street strip engine. An evac system or vacuum pump isn't really needed and wouldn't help much with a typical engine. On a race engine with low tension rings it could help a lot.

The benefit of the PCV valve + breather is constant changing of the air. The PCV sucks some out and the breather lets some in under light load. This helps remove moisture and other bad stuff. Under heavy load, blowby can still exit the breather. Unless you are having a particular problem with your setup I'd just run it. That's what I'm using on a 496 without problem.

Two breathers would work OK also but you don't get the benefit of circulating fresh air through the crankcase.

Posted By: MR_P_BODY

Re: Crank case evac on street/strip car. Help me out please - 02/04/09 02:03 AM

Agreed Mr.P, there is zero vacuum with a dual breather setup. How much vacuum does the typical engine have at WOT ?

PCV is nothing more than a controlled vacuum leak. I'm not a fan of introducing oil mist into the induction system.

Ron

Ron, when you say vac at wot, I assume you mean
what can a evac make. A proper set up evac can create
5"hg without a exhaust system

Posted By: BEEQUIK

Re: Crank case evac on street/strip car. Help me out pl - 02/04/09 02:20 AM

this may not help anyone but let me tell you what happened to me and maybe someone will be able to tell me what happened.
I had a moroso crank case / header evacuation setup on my 68 GTX.Car ran mid- high 11's and we went to a track for a muffler race. I had an exhaust system put on the car 2-1/2 " with flowmasters.Man it sounded good and when I made a pass it was a SECOND slower,and it blew the intake valley pan up like some stovetop popcorn,all bulged up and blew out the valve cover gaskets!! Unhooked the exhaust and back to 11.70--

Posted By: MR_P_BODY

Re: Crank case evac on street/strip car. Help me out pl - 02/04/09 02:26 AM

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this may not help anyone but let me tell you what happened to me and maybe someone will be able to tell me what happened.
I had a moroso crank case / header evacuation setup on my 68 GTX.Car ran mid- high 11's and we went to a track for a muffler race. I had an exhaust system put on the car 2-1/2 " with flowmasters.Man it sounded good and when I made a pass it was a SECOND slower,and it blew the intake valley pan up like some stovetop popcorn,all bulged up and blew out the valve cover gaskets!! Unhooked the exhaust and back to 11.70--

Very simple, your 2 1/2" with Flowmasters had more
back pressure than 5"hg, once you got on it it went
above 5"hg and the back pressure burnt out the check
valves and pressurized the crank case

Posted By: BobR

Re: Crank case evac on street/strip car. Help me out pl - 02/04/09 02:33 AM

Quote:

this may not help anyone but let me tell you what happened to me and maybe someone will be able to tell me what happened.
I had a moroso crank case / header evacuation setup on my 68 GTX.Car ran mid- high 11's and we went to a track for a muffler race. I had an exhaust system put on the car 2-1/2 " with flowmasters.Man it sounded good and when I made a pass it was a SECOND slower,and it blew the intake valley pan up like some stovetop popcorn,all bulged up and blew out the valve cover gaskets!! Unhooked the exhaust and back to 11.70--

Baffled mufflers like Flowmasters DO NOT WORK on evac systems. To get any real power gain you need to use a low tension oil ring and a mechanical vacuum pump that pulls 15" or more vacuum. This much vacuum also helps seal the whole ring pack.

Posted By: moparniac

Re: Crank case evac on street/strip car. Help me out pl - 02/04/09 05:08 PM

my valve covers started leaking actually spilt one and I was running a breather and pcv setup

Crank case evac on street/strip car. Help me out please