Resticting evac breather lines
#655407
03/29/10 09:28 PM
03/29/10 09:28 PM
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UK
602heavy
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Pulling a hell of a lot of oil/vapour out of breathers & into exhausts (full exhaust) , got the covers baffled as good as i'm gonna get , was thinking of restricting the breather tubes? , can put a valve in line from breather to evacs which will enable me to play with the restriction , anyone had to do this?
TIA
Last edited by 602heavy; 03/29/10 09:30 PM.
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Re: Resticting evac breather lines
[Re: 602heavy]
#655410
03/30/10 02:33 AM
03/30/10 02:33 AM
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Joined: Dec 2008
Posts: 176
Rome, GA
GTXX
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I know it's not the problem, but when you blocked off the check valves they overheated because no air was flowing through them. remove the valves and install a 1/2 NPT pipe cap if you need to run without check valves again.
'71 GTX w/Air Grabber, Super Trak Pak, Spoiler Pkg. been apart for 22 years, thinking it's time to do something about that....
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Re: Resticting evac breather lines
[Re: GTXX]
#655411
03/30/10 04:33 AM
03/30/10 04:33 AM
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Romeo MI
MR_P_BODY
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Quote:
I know it's not the problem, but when you blocked off the check valves they overheated because no air was flowing through them. remove the valves and install a 1/2 NPT pipe cap if you need to run without check valves again.
Either this or the exhaust has too much back pressure
and it burnt the valves... for every inch HG of back
pressure on the exhaust it will reduce the engine vac
by the same amount.... the evac has about 5"HG max.
You could put a catch bottle in line on the evac to
collect the oil or put a better baffle in the valve
covers
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Re: Resticting evac breather lines
[Re: MR_P_BODY]
#655414
03/30/10 09:35 AM
03/30/10 09:35 AM
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Posts: 8,165
Left Coast
BobR
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Quote:
Quote:
I think it was last month some one posted a pic of home made breather caps that were around 3.5" tall, kinda like a catch bottle on the valve covers,
I sorta think he has the nipple in the collector
mounted wrong... it very well could be pressurizing
the crank case and pushing oil up past the rings and
blowing it out the exhaust..... just a guess because
he doesnt have blowby with the hoses off OR he just
needs a better baffle.... like I said ... just a guess
OR his exhaust has more back pressure than he thinks
I agree. I think that there is VERY LITTLE chance his problem is what he thinks it is.
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Re: Resticting evac breather lines
[Re: MR_P_BODY]
#655415
03/30/10 01:58 PM
03/30/10 01:58 PM
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UK
602heavy
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Quote:
Quote:
I think it was last month some one posted a pic of home made breather caps that were around 3.5" tall, kinda like a catch bottle on the valve covers,
I sorta think he has the nipple in the collector
mounted wrong... it very well could be pressurizing
the crank case and pushing oil up past the rings and
blowing it out the exhaust..... just a guess because
he doesnt have blowby with the hoses off OR he just
needs a better baffle.... like I said ... just a guess
OR his exhaust has more back pressure than he thinks
The baffles are sealed on all four sides with a slot cut @ the side tight to side of valve cover , the oil would have a hell of a job finding it's way into the baffle with splash , the evacs pull vac from idle to full throttle , @ idle i can pick a box of ciggarettes up with the breather , when ran with no evac just breathers the filter/baffles are clean as a whistle , no fouling plugs either , just gotta find a way to make this work , this is a 605" with 2 1/8th primaries , i remember reading someone on here had to restrict the breather into valve cover , another guy also had issues running ex evacs with full exhaust , just need to play around till the problem gets sorted out. 
Last edited by 602heavy; 03/30/10 02:00 PM.
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Re: Resticting evac breather lines
[Re: 602heavy]
#655416
03/30/10 03:22 PM
03/30/10 03:22 PM
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Joined: Oct 2004
Posts: 8,165
Left Coast
BobR
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Quote:
Quote:
Quote:
I think it was last month some one posted a pic of home made breather caps that were around 3.5" tall, kinda like a catch bottle on the valve covers,
I sorta think he has the nipple in the collector
mounted wrong... it very well could be pressurizing
the crank case and pushing oil up past the rings and
blowing it out the exhaust..... just a guess because
he doesnt have blowby with the hoses off OR he just
needs a better baffle.... like I said ... just a guess
OR his exhaust has more back pressure than he thinks
The baffles are sealed on all four sides with a slot cut @ the side tight to side of valve cover , the oil would have a hell of a job finding it's way into the baffle with splash , the evacs pull vac from idle to full throttle , @ idle i can pick a box of ciggarettes up with the breather , when ran with no evac just breathers the filter/baffles are clean as a whistle , no fouling plugs either , just gotta find a way to make this work , this is a 605" with 2 1/8th primaries , i remember reading someone on here had to restrict the breather into valve cover , another guy also had issues running ex evacs with full exhaust , just need to play around till the problem gets sorted out.
We pull 17 pounds with a vacuum pump and end up with very little oil in the puke tank. Restricting the vacuum sounds counterproductive to me especially since the header evacs do very little anyway. Unless you have racepak data or a vac gauge somewhere in your crankcase you really don't know what's going on. I think that it's far more likely the scenario that Raff suggested than the evac system is pulling oil out of the baffled breathers.
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Post deleted by Defbob
[Re: BobR]
#655417
03/30/10 03:41 PM
03/30/10 03:41 PM
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Re: Resticting evac breather lines
#655418
03/30/10 04:01 PM
03/30/10 04:01 PM
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Posts: 8,165
Left Coast
BobR
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Quote:
he's blowing exhaust into the motor and somehow it's pushing oil out 
That's exactly what Raff said and exactly what I think is going on.
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Post deleted by Defbob
[Re: MR_P_BODY]
#655420
03/30/10 04:18 PM
03/30/10 04:18 PM
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Re: Resticting evac breather lines
#655421
04/02/10 04:07 PM
04/02/10 04:07 PM
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602heavy
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Had a leak on the valley plate , seems the air leak had a path to breathers that carried oil mist , smoke seems to of disapeared from tail pipes , just took a bit of time for this to work. Seems all is ok regards ring seal although the rings are gapped for the spray. Thanks. 
Last edited by 602heavy; 04/02/10 04:11 PM.
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Post deleted by Defbob
[Re: 602heavy]
#655422
04/02/10 06:24 PM
04/02/10 06:24 PM
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Re: Resticting evac breather lines
[Re: 602heavy]
#655423
04/02/10 08:59 PM
04/02/10 08:59 PM
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Joined: Oct 2004
Posts: 8,165
Left Coast
BobR
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Quote:
Had a leak on the valley plate , seems the air leak had a path to breathers that carried oil mist , smoke seems to of disapeared from tail pipes , just took a bit of time for this to work.
Seems all is ok regards ring seal although the rings are gapped for the spray.
Thanks.
Are you sure that oil wasn't leaking from the lifter valley into an intake port? This is fairly common.
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Re: Resticting evac breather lines
#655424
04/02/10 09:26 PM
04/02/10 09:26 PM
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Joined: Dec 2008
Posts: 1,200
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602heavy
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Quote:
Quote:
Had a leak on the valley plate , seems the air leak had a path to breathers that carried oil mist , smoke seems to of disapeared from tail pipes , just took a bit of time for this to work.
Seems all is ok regards ring seal although the rings are gapped for the spray.
Thanks.
no sorry but that wssn't it.. if you had a leak there then there would be no vacuum or suction at the evac line thus no oil getting pulled out
Guys , seems you're making something out of nothing , it's a well known fact evacs with full ex will pull oil out of engine , the original question was feedback on guys that run evacs with full exhaust & how they overcome pulling too much oil mist , seems the leak was smaller than what the evacs pull , still had vacumme but was pulling oil mist due to the air leak/stream being sucked into valve breathers , all is good & have no issues with blowby/ring seal , sometimes we tend to delve too deep for a simple solution.
Thanks again.
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Re: Resticting evac breather lines
[Re: BobR]
#655425
04/02/10 09:30 PM
04/02/10 09:30 PM
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Joined: Dec 2008
Posts: 1,200
UK
602heavy
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OP
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Quote:
Quote:
Had a leak on the valley plate , seems the air leak had a path to breathers that carried oil mist , smoke seems to of disapeared from tail pipes , just took a bit of time for this to work.
Seems all is ok regards ring seal although the rings are gapped for the spray.
Thanks.
Are you sure that oil wasn't leaking from the lifter valley into an intake port? This is fairly common.
This engine uses a valley tray as oposed to a pan , the only way it can suck oil is if the hold down bolts on Jessel stands are not sealed.
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