460 to pcv or not to pcv that is the question

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88CARRERA

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« on: April 23, 2013, 11:10:27 AM »
I currently run  a pcv on the passenger side valve cover and breather on the driver.

Any reason i couldnt run a breather on both? other than possibility of oil coming out?
 
Thanks

Chris
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« Reply #1 on: April 23, 2013, 11:51:01 AM »
I would keep the pcv to keep the engine from building up crank case pressure. If u have too much crank case pressure u can develop oil leaks or if u have some they can get worse but it's not always the case. just my .02 cents
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berkbryan

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« Reply #2 on: April 23, 2013, 12:42:36 PM »
I say no pcv just get good quality breathers and you will have no pressure problems pcv is for smog reasons

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RockyCapone

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« Reply #3 on: April 23, 2013, 01:24:51 PM »
Besides for emissions racers will remove them because if you introduce oil fumes into a combustion chamber it causes preignition/loss of power and will make it impossible to read plugs if ever decide to do so. Run a breather and you should be fine.....Run a GOOD breather and you will be fine.
Edit: 2 breathers.
« Last Edit: April 23, 2013, 07:42:12 PM by RockyCapone »
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RockyCapone

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« Reply #4 on: April 23, 2013, 01:29:07 PM »
Besides for emissions racers will remove them because if you introduce oil fumes into a combustion chamber it causes preignition/loss of power and will make it impossible to read plugs if ever decide to do so. Run a breather and you should be fine.....Run a GOOD breather and you will be fine.
I was going to run my breather tubes to the exhaust to pull vacuum inside the engine but after reading the laws you cant purposely dump oil and fuel into the river. And besides I have short Bassetts that shoot crap all over my floater anyways. Maybe if I get bored I'll convert a smog pump into a vacuum pump.  ::)
« Last Edit: April 23, 2013, 01:31:16 PM by RockyCapone »
1978 Southwind Formula 1 T body
454 Berkley
IF I GET BORED AND HAVE NOTHING TO DO I'M CALLING GTJETS AND ASKING HIM IF I SHOULD RUN A T-STAT IN MY JETBOAT--THAT SHOULD BURN OFF 8 HOURS EASY
....it would have been cheaper to spend our money on cocaine and hookers

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« Reply #5 on: April 23, 2013, 03:50:47 PM »
If you have a pcv valve in one side and a breather in the other you have created a vacuum leak. Just plug the carb and put another breather in the valvecover.

kwood

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« Reply #6 on: April 23, 2013, 05:00:21 PM »
I just put new valve covers on my boat and I put one k&n breather on the driver side should I put one on the other side or is it good with one?


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« Reply #7 on: April 23, 2013, 07:37:27 PM »
Run the PCV, helps keep the gaskets from pushing out.
Thats what I do on mine.
Full race deal, run the header evacs.

Dan'l
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« Reply #8 on: April 23, 2013, 09:54:09 PM »
I have a pcv on the rear pass side on my ford...works just fine.

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« Reply #9 on: April 23, 2013, 10:19:12 PM »
Run the PCV, helps keep the gaskets from pushing out.
Thats what I do on mine.
Full race deal, run the header evacs.

Dan'l

I run a pvc also right rear valve cover.  Seen a lot of gaskets push out because of this inexpensive item.    :D
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« Reply #10 on: April 23, 2013, 10:38:23 PM »
Why wouldb2 breathers cause an issue?
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« Reply #11 on: April 23, 2013, 11:14:09 PM »
I have Pcv one side and breather the other. Vacuum leak? Huh? Lol. You absolutely have to get the crankcase pressure out unless you like to blow out end seals, etc. Two breathers will work but not optimum. Why you think vacuum pump adds power? Piston doesn't fight pressure in the pan. Obviously pan evac system would be great, pulls a little vacuum except the oil in river, lake etc thing may not be cool.

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« Reply #12 on: April 24, 2013, 07:33:45 AM »
Why wouldb2 breathers cause an issue?

You could try it, but bring some engine degreaser along to get the oil film off everything.
PCV works well at idle below ~2000 rpm (higher vacuum) and works less @ wot, but crankcase pressure has a route to the motor to 'burn' the fumes.
Merc, Indmar, Hardin, KEM all use PCV valves, and I'm not an engineer.

Dan'l
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« Reply #13 on: April 24, 2013, 09:15:35 AM »
I currently run  a pcv on the passenger side valve cover and breather on the driver.

Any reason i couldnt run a breather on both? other than possibility of oil coming out?
 
Thanks

Chris
The most noteworthy thing about PCV/evacuating your crankcase is that it keeps the oil cleaner/less dilute. This is important for a recreational engine and unless you are changing your oil more regularly (such as in a  competition engine) PCV is very wise to have.

LO

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« Reply #14 on: April 24, 2013, 09:20:19 AM »
thanks.
i will just keep my current pcv set up then.

Thanks
 all
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« Reply #15 on: April 24, 2013, 12:55:13 PM »
Kodiac Marine, 1 PVC / 1 Breather.....

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« Reply #16 on: April 24, 2013, 01:22:29 PM »
Without all the people who approve of the pcv valve jumping down my throttle I have a few questions. What gaskets have you always seen blown out? Oil pan? Are we sure its not just poor dirty assembly? Has anyone had a pressure/vacuum/compound gauge on the block to verify with 2 breathers that huge pressures are even present? And even at WOT we wont have any vacuum worth mentioning, but a car where the rpms fluctuate and de-accelerates every shift we have excellent vacuum. Personally I cant even see gaskets being pushed out, if anything maybe oil past seals. How does a pcv pull moisture from oil from a machine? I've had 302's with Vortech T-trims pushing around 20 psi of boost and had the PCV remove with just breathers and no problems.
And what I really cant understand is with a pcv valve the whole idea is to have a sealed engine compartment and in theory keep the crankcase in a vacuum if its possible or at least try to. So if the system works why would you have a breather on the other valve cover? If the pcv valve works now we are sucking in dirty air from the other valve cover directly into the engines oil.
I will say this if your engine is covered by a top and its just the family cruiser then I agree with a pcv valve to keep oil fumes/mist away from everything. If you are building a max effort engine then no pcv. If I had a max effort engine I wouldnt want to use my engine's intake and combustion chamber as a garbage dump for excess oil and fumes.
« Last Edit: April 24, 2013, 01:27:23 PM by RockyCapone »
1978 Southwind Formula 1 T body
454 Berkley
IF I GET BORED AND HAVE NOTHING TO DO I'M CALLING GTJETS AND ASKING HIM IF I SHOULD RUN A T-STAT IN MY JETBOAT--THAT SHOULD BURN OFF 8 HOURS EASY
....it would have been cheaper to spend our money on cocaine and hookers

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« Reply #17 on: April 24, 2013, 06:46:52 PM »
Without all the people who approve of the pcv valve jumping down my throttle I have a few questions. What gaskets have you always seen blown out? Oil pan? Are we sure its not just poor dirty assembly? Has anyone had a pressure/vacuum/compound gauge on the block to verify with 2 breathers that huge pressures are even present? And even at WOT we wont have any vacuum worth mentioning, but a car where the rpms fluctuate and de-accelerates every shift we have excellent vacuum. Personally I cant even see gaskets being pushed out, if anything maybe oil past seals. How does a pcv pull moisture from oil from a machine? I've had 302's with Vortech T-trims pushing around 20 psi of boost and had the PCV remove with just breathers and no problems.
And what I really cant understand is with a pcv valve the whole idea is to have a sealed engine compartment and in theory keep the crankcase in a vacuum if its possible or at least try to. So if the system works why would you have a breather on the other valve cover? If the pcv valve works now we are sucking in dirty air from the other valve cover directly into the engines oil.
I will say this if your engine is covered by a top and its just the family cruiser then I agree with a pcv valve to keep oil fumes/mist away from everything. If you are building a max effort engine then no pcv. If I had a max effort engine I wouldnt want to use my engine's intake and combustion chamber as a garbage dump for excess oil and fumes.


 :thumbup:
Does anyone here really think that a PCV valve can move enough volume to keep the pressure in the crankcase lower than it would normally be with two breathers?  :screwy:

The PCV valve will literally ONLY do anything at idle... Period... End of story.

The vacuum levels will be so low at WOT that it will not do a damn thing.

Much rather see MOPAR style breathers (with the hose fitting built into them) with hoses routed to the flame arrestor/scoop, or to evac tubes in the headers.

Mercruiser probably builds more marine engines than anyone on the planet and they do not utilize PCV valves.

The PCV valve is an engineered vacuum leak designed to pull excess crankcase pressure from a tight engine under the condition of freeway driving in an automobile that has an approximate manifold vacuum greater than 12" of vacuum. I can assure you, your jet boat does not do that.

PCV's do not work on a jet for the same exact reason a vacuum advanced distributor does no work.

LO, sorry if you disagree... I respect your opinion but have to bow out this time.  ;)

GT
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Ray

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« Reply #18 on: April 24, 2013, 08:39:43 PM »

 :thumbup:
Does anyone here really think that a PCV valve can move enough volume to keep the pressure in the crankcase lower than it would normally be with two breathers?  :screwy:

The PCV valve will literally ONLY do anything at idle... Period... End of story.

The vacuum levels will be so low at WOT that it will not do a damn thing.

Much rather see MOPAR style breathers (with the hose fitting built into them) with hoses routed to the flame arrestor/scoop, or to evac tubes in the headers.

Mercruiser probably builds more marine engines than anyone on the planet and they do not utilize PCV valves.

The PCV valve is an engineered vacuum leak designed to pull excess crankcase pressure from a tight engine under the condition of freeway driving in an automobile that has an approximate manifold vacuum greater than 12" of vacuum. I can assure you, your jet boat does not do that.

PCV's do not work on a jet for the same exact reason a vacuum advanced distributor does no work.

LO, sorry if you disagree... I respect your opinion but have to bow out this time.  ;)

GT
Disagree about what?  Perhaps you might have mis-read my post.   ???

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« Reply #19 on: April 24, 2013, 08:44:48 PM »
Disagree about what?  Perhaps you might have mis-read my post.   ???

Maybe...

It looks like you are advocating the use of a PCV valve as a device... Ventilation and evacuation is a must I agree.

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« Reply #20 on: April 24, 2013, 08:59:43 PM »
Maybe...

It looks like you are advocating the use of a PCV valve as a device... Ventilation and evacuation is a must I agree.
I don't care which method is utilzed in a recreational engine as any of them can and will extend engine oil life.

Aside from engine oil life, I offered no opinion on any of the other matters and concerns discussed in this thread.

LO

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