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11-30-2012, 02:30 AM
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CC Member
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Join Date: May 2002
Location: Ashburton, New Zealand,
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Cobra Make, Engine: UK Ram SC. KC-Yates 373, Jerico 5 speed.
Posts: 1,240
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Not Ranked
Dry sump venting open or closed.
Running a 3 stage Peterson dry sump pump, I am seeking information to see if its worth running a closed vacuum system with no engine venting or some valve cover venting, due to the pump only having 2 scavenge sections. I have valve covers that have a pop off pressure valve in one cover, the only venting is from the scavenge line through the oil tank which has two fittings for breathers to a puke can.
I was considering removing the pop off valve and fitting a vent so air can flow through engine for more road use than race, as one issue with a closed system is condensation build up causing rust?
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A J. Newton
The 1960's rocked!
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11-30-2012, 07:29 AM
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Senior Club Cobra Member
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Join Date: Jan 2005
Location: saratoga,
ca
Cobra Make, Engine: Kirkham #185, Shelby Alloy 482; sold
Posts: 1,190
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I run a system with an Aviaid Dry Sump system on a stroked alloy 427. Used to have several small leaks, one probably was the rear main side seals and one at the distributor. These engines can develop quite a lot of crankcase pressure.
I sealed the engine and used a calibrated vacuum leak on the manifold, so that at idle I get around 2-3 inches of vacuum. I still vent the dry sump tank.
I used a regulator from Peterson:
http://www.petersonfluidsys.com/engine_breath.html
No more leaks! Love it.
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Dave
Last edited by 4pipes; 11-30-2012 at 07:40 AM..
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11-30-2012, 09:44 AM
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CC Member
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Join Date: Dec 2004
Location: Kansas City,
KS
Cobra Make, Engine: jbl
Posts: 2,291
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you can vent with no problems, if you run a closed crankcase you should put some type of regulator in, or provide for it, or the possibility of pulling too much vacuum which the consensus is anything above about 12" can be detrimental to the engine. the size of the pump sections also has an effect on how much vacuum you will pull. with my 3 scavenge sections i can pull around 5" running at 2000 rpm, so i do run a vacuum regulator. i have also owned a race car from a knowledgeable individual that used an open system, with a breather, so either way imo, whatever works.
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11-30-2012, 05:47 PM
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CC Member
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Join Date: May 2002
Location: Ashburton, New Zealand,
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Cobra Make, Engine: UK Ram SC. KC-Yates 373, Jerico 5 speed.
Posts: 1,240
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Vacuum or vent?
Thanks for the info. I am running an alloy engine, Peterson pump has a large pressure section and std 2 stage scavenge, in hindsight maybe I should have gone with a 3 scavenge section pump if I wanted to increase HP. This engine isnt running over 7200rpm.
I assume the regulator allows air in (as it has a filter) to reduce vacuum.
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A J. Newton
The 1960's rocked!
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11-30-2012, 06:21 PM
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CC Member
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Join Date: Dec 2004
Location: Kansas City,
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Cobra Make, Engine: jbl
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from what i understand with vacuum you could estimating increase hp 10-20, it also helps the oil drop out of the crankcase because the vacuum doesn't hold liquid as well.
the regulator does have a filter. you can also experiment with putting a hole in the blowoff valve piece below the spring. if that doesn't work then put a piece of aluminum between the spring and valve to block it and put a regulator in. if you are pulling 2-3" at idle which is what mine does, you will need something. the 2 scavenge stages are probably enough, they just have to be in the right places. sounds like you have a good handle on it.
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11-30-2012, 06:22 PM
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CC Member
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Join Date: May 2008
Location: Brisbane,
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Cobra Make, Engine:
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The regulator is adjustable for the maximum vacuum that be generated in the crankcase.
Why it adjustable up to 29 inches (near perfect vacuum) is anybody's guess.
Here's another type:
http://www.gzmotorsports.com/VCV102B...rol-Valve.html
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Gary
Gold Certified Holden Technician
Last edited by Gaz64; 11-30-2012 at 06:30 PM..
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11-30-2012, 06:29 PM
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CC Member
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Join Date: Dec 2004
Location: Kansas City,
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Cobra Make, Engine: jbl
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btw i have read you don't want to run any vacuum til the engine is broken in as the rings won't seal properly.
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12-01-2012, 02:10 AM
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CC Member
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Join Date: May 2002
Location: Ashburton, New Zealand,
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Cobra Make, Engine: UK Ram SC. KC-Yates 373, Jerico 5 speed.
Posts: 1,240
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Dry sump venting
Quote:
Originally Posted by vector1
btw i have read you don't want to run any vacuum til the engine is broken in as the rings won't seal properly.
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Thats a good tip thanks.
I have read that running a non vented engine on the street can promote condensation/rust in the engine, this car will see some road miles for testing etc.
As you mention there maybe some benefit to run the regulator, I thought closed at the track and vent for the street. I will try and rig up a system where I can alternate the plumbing between the regulator or the puke tank.
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A J. Newton
The 1960's rocked!
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12-01-2012, 06:40 PM
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CC Member
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Join Date: Dec 2003
Location: Gurnee,
IL
Cobra Make, Engine: Kirkham #259
Posts: 1,393
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Ant
We use 3 scavenge sections......2 each in the oil pan.....and 1 in the back of the intake manifold.......with a tube mounted in the valley....
Vent with blue thunder valve covers and -12 vent hoses to a catch can......also -12 line off of dry sump tank.....to another catch can....
That was the only way we could stop oil puking out of the motor.....BTW....we run the motor hard 2800-7000
PS....unless a engine and it seals are built to run a vacuum ....might not be a good idea....seals need to be reversed....
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Morris
Last edited by Morris; 12-01-2012 at 06:47 PM..
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12-01-2012, 11:46 PM
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CC Member
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Join Date: May 2002
Location: Ashburton, New Zealand,
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Dry Sump venting
Quote:
Originally Posted by Morris
Ant
We use 3 scavenge sections......2 each in the oil pan.....and 1 in the back of the intake manifold.......with a tube mounted in the valley....
Vent with blue thunder valve covers and -12 vent hoses to a catch can......also -12 line off of dry sump tank.....to another catch can....
That was the only way we could stop oil puking out of the motor.....BTW....we run the motor hard 2800-7000
PS....unless a engine and it seals are built to run a vacuum ....might not be a good idea....seals need to be reversed....
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Morris, I tend to agree with you, as some racer friends have had similar problems with oil puking, and reversing the seals makes sense as well, dont want to go down that path really. I gather you solved the puking when vented the covers?
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A J. Newton
The 1960's rocked!
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12-02-2012, 04:38 AM
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Cobra Make, Engine: jbl
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reversing the seals is one way, the other is to use double lipped seals.
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12-02-2012, 08:51 AM
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CC Member
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Join Date: Dec 2003
Location: Gurnee,
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Cobra Make, Engine: Kirkham #259
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Quote:
Originally Posted by Ant
Morris, I tend to agree with you, as some racer friends have had similar problems with oil puking, and reversing the seals makes sense as well, dont want to go down that path really. I gather you solved the puking when vented the covers?
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Ant.....yes we did solve the puking issue.....and I believe the Blue Thunder valve covers helped a bunch......I'll get you some photo's tomorrow...
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Morris
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12-06-2012, 12:14 PM
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Location: Gurnee,
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Cobra Make, Engine: Kirkham #259
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Ant
Here's a couple of Photo's of the valve covers and catch can and tank and catch can vent..... Hope it helps out...
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Morris
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12-06-2012, 02:01 PM
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Join Date: May 2002
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Quote:
Originally Posted by Morris
Ant
Here's a couple of Photo's of the valve covers and catch can and tank and catch can vent..... Hope it helps out...
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Thank you for the photos, that is a good adequate system I gather the FE can breath a bit more compared to SBF when you have the hp and rpms like you have.
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A J. Newton
The 1960's rocked!
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12-06-2012, 03:06 PM
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CC Member
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Join Date: Dec 2003
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Quote:
Originally Posted by Ant
Thank you for the photos, that is a good adequate system I gather the FE can breath a bit more compared to SBF when you have the hp and rpms like you have.
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We believe that the more you can allow a motor to breath..... the better it is.... When you get half way thru a race ..... and it's hot and everything has a strain on it .... you are glad it can breath....
Vacuum is for short drag racing type of motors....... not extended time on a track.... like a Cobra is made for...
Look at the 3 Scavenge section hose on the back of the intake....
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Morris
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12-06-2012, 06:52 PM
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CC Member
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Join Date: Jan 2008
Location: Nashville,
TN
Cobra Make, Engine: Backdraft, SBF 351w (463 CI)
Posts: 272
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Quote:
Originally Posted by Morris
We believe that the more you can allow a motor to breath..... the better it is.... When you get half way thru a race ..... and it's hot and everything has a strain on it .... you are glad it can breath....
Vacuum is for short drag racing type of motors....... not extended time on a track.... like a Cobra is made for...
Look at the 3 Scavenge section hose on the back of the intake....
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You might want to tell NASCAR that. They pull 18+Hg for 500 miles every Sunday.
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12-06-2012, 07:24 PM
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CC Member
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Cobra Make, Engine: Kirkham #259
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Quote:
Originally Posted by PLDRIVE
You might want to tell NASCAR that. They pull 18+Hg for 500 miles every Sunday.
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That's right.....and the thickness of their scavenge sections are the reason for that.......a Cobra just doesn't have enough room for the size of their pump .... 4 scavenge sections and a pump section.....also the newer pumps are much more efficient then the older pumps..... On our Cobras ....their is barely enough room in the motor area....at least not in our FE configuration.
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Morris
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12-06-2012, 09:37 PM
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Dry Sump
Quote:
Originally Posted by Morris
That's right.....and the thickness of their scavenge sections are the reason for that.......a Cobra just doesn't have enough room for the size of their pump .... 4 scavenge sections and a pump section.....also the newer pumps are much more efficient then the older pumps..... On our Cobras ....their is barely enough room in the motor area....at least not in our FE configuration.
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For what it's worth I am pulling 13" of vacuum on my 498" FE, I have a Dailey
Dry Sump with #16 lines to and from the tank. My valve covers are sealed
and the only vent is on the Stef's dry sump tank in the trunk. I have not really had any problems with this system and don't seem to have an oil vapor problem in the trunk. We tried it on the dyno with vented vs unvented valve covers and there was a difference of about 20 HP. What I really like is the engine compartment stays really clean compared to the times I had remote valve cover breathers with baffles etc. The only time oil gets out of this thing is when it is not running, then it leaks like an old Harley.
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12-07-2012, 08:59 AM
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CC Member
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Quote:
Originally Posted by Cobra #3170
For what it's worth I am pulling 13" of vacuum on my 498" FE, I have a Dailey
Dry Sump with #16 lines to and from the tank. My valve covers are sealed
and the only vent is on the Stef's dry sump tank in the trunk. I have not really had any problems with this system and don't seem to have an oil vapor problem in the trunk. We tried it on the dyno with vented vs unvented valve covers and there was a difference of about 20 HP. What I really like is the engine compartment stays really clean compared to the times I had remote valve cover breathers with baffles etc. The only time oil gets out of this thing is when it is not running, then it leaks like an old Harley.
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Well that just shows that being out of commission for a few years will do for you....Thanks for the info on the Daily pump....and it appears to be smaller...
We tried sealing up the motor before and it never worked....and I did it like you did, by closing up everything but the dry sump tank....should of looked at a different pump......Thanks again and will get on it....
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Morris
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12-07-2012, 09:10 PM
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CC Member
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Join Date: Jan 2008
Location: Nashville,
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Cobra Make, Engine: Backdraft, SBF 351w (463 CI)
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Morris i have the same Dry Sump setup on a small block as Cobra 3170. Tank in trunk (Patterson), -16 lines to and from a 5 stage Aviaid S2 pump, one remote breather off of tank. I have not run the engine yet, but planning on about 10 to 12Hg. and hopping for a cleaner engine bay as well.
They will fit, but you my have to make up your own brackets.
Last edited by PLDRIVE; 12-07-2012 at 09:20 PM..
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