BBC valve cover baffles

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RJC5778
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BBC valve cover baffles

Post by RJC5778 »

I am having a bad issue with oil coming out of the valve cover breathers on my engine, I have a tall aluminum valve cover with around 80-100 psi oil pressure at cruise and higher rpm. just want to see what you guys have done for tried and true baffles for airboat engines, I am thing about bending a piece of flat plate in the shape of a c channel of sort and tig welding to underneath of breather hole, right now it just a grommet and open breather, no baffle, I know I need one, just trying to get ideas.....

loudmouse
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Re: BBC valve cover baffles

Post by loudmouse »

U need a crank case evac system to pull the blowby out of the engine but I have seen where some valve covers positioned the cap right over the rocker arms and would sling the oil out. Two different problems and you would need to figure out which is causing the oil to come out. Either way all engines need a cces.
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RJC5778
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Re: BBC valve cover baffles

Post by RJC5778 »

dual breathers wont work with a good baffle/ shield from the oil getting pushed up the open hole? I can run a standard pcv setup if needed

Joe
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Re: BBC valve cover baffles

Post by Joe »

Dual sheilded breathers is all I have on my BBC and I have no oil coming out of them.i suggest a leak down on your cylinders and see if your rings are good. If the rings are shot causing blow by breathers or a crank case evacuation system will not help you. Is this a new motor or and old motor with a new problem?
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Joe
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Re: BBC valve cover baffles

Post by Joe »

[imghttp://www.southernairboat.com/photopost/showp ... re/cat/500[/img]



Pic won't come up but it shows the 2 pipes I have on my valve covers,I have 2 k&n sheilded breathers on top of them with the shields to the front
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Deano
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Re: BBC valve cover baffles

Post by Deano »

Image

I think this is one you were after. That engine is beautiful!
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but it is not the path to knowledge; it has no place in the endeavor of science."
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RJC5778
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Re: BBC valve cover baffles

Post by RJC5778 »

brand new bbc 498 professionally built motor that was dyno tested, leaked down tested and the whole 9, I think that's its just an issue with my breather style and valve cover style, motor maybe has 4 hours on it since dyno test

Joe
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Re: BBC valve cover baffles

Post by Joe »

Yep that's it,have a hard time posting pics from my phone,thanks deano. It's 6 years old now and still runs great!! Doesn't use or loose any oil. Had a few small problems over the years but nothing I consider major.

I would agree on the breathers being the issue. Motor should be good being that new. Can you post a picture of your set up? Also if your cage is open pull the breathers off and see if oil is squirting out of the hole. That would be a breather hole placement problem if it is.
Compromise is for those that cant get it done!!

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RJC5778
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Re: BBC valve cover baffles

Post by RJC5778 »

her are a few pic of the 2 breathers I have, ill be sure to take them out and see if just squirts oil right under the breather, makes sense, if so im a just weld a small deflection plate under the hole and that should solve my problem, I ran an evac sys on the old motor and asked my engine builder about it, he said its not necessary, so that's the reason behind the breathers, plus I didn't want to cut into a brand new set of headers.
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IMG_3638.JPG
IMG_3520.JPG

Joe
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Re: BBC valve cover baffles

Post by Joe »

They sell breathers with a deflector in them so you don't have to weld unless you want to. The stand pipe and different style breathers I run make a difference too.
I run them both on the back of the motor not 1 In front and 1 back like you have. With them back there and the shields facing forward the prop pulls a bit from the breathers so it's almost like an evac system but not as strong. It works great on mine. The lil dome ones you have can catch air and force it in you motor especially when you have the stagered like that.
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RJC5778
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Re: BBC valve cover baffles

Post by RJC5778 »

I originally bought some k&n shielded breathers and thought they didn't fit, come to find out they do, well I got these and installed some grommets and thought it was good to go, well after running it this weekend I saw it dumping oil out the breathers, so im a remove the dome ones and see if oil is shooting out the hole, if so I will put a baffle, I saw they ones that have the holes on the side not underneath but they screw on, not a huge fan with a expensive motor and if that nut comes loose. man oh man id be heart broken, idc if I have to weld it, id rather have the piece of mind of a good tig weld than an small baffle falling in my motor.....trial and error

Afflicted
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Re: BBC valve cover baffles

Post by Afflicted »

My mas BBC has them staggered like yours but they have good baffes/shields in the valve covers. An seems to do pretty good

barhopper
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Re: BBC valve cover baffles

Post by barhopper »

I have the same as Joe on my SBC. No problems. I had what you're talking about doing with the welded shields on my last motor. They didn't help much.

ranger1424
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Re: BBC valve cover baffles

Post by ranger1424 »

Had same issue with my496 stroker, tried baffles, tried breather shield facing forward, put in regular breather with 1/2 inch crankcase tube on side of cap, put 1/2 hose to cage an angle cut hose up close an let prop wash evacuate, works fine. Nice rig.

RJC5778
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Re: BBC valve cover baffles

Post by RJC5778 »

thanks for all the quick reply's, im not really wanting to cut and weld on my new stainless headers, so im thinking of wither adding the baffles first and see and if that don't help run to hoses up the cage and angle cut close to the prop, im a shoot shane (engine builder) a text and see what he says.

Joe
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Re: BBC valve cover baffles

Post by Joe »

You can try plugging the front breather off and put the sheilded breather in the rear with the sheilded at the front and see if that helps it. Bigest problem I've seen with the stagered breathers,especially the little pop in dome ones like that, is on the front one as the air comes around the rigging and motor it pushes in that breather and creates pressure in the motor and with the prop so close the the rear one there's less pressure there so it naturally comes out and when you get a flow started while cruising it pulls oil out with it.
If your motor needs an evac system it's either set up wrong has big ring gaps or has other issues.
Compromise is for those that cant get it done!!

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RJC5778
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Re: BBC valve cover baffles

Post by RJC5778 »

I spoke with the engine builder and he tells me to not put baffles and run an evac system, I like the idea of the hose running to just in front of the prop, as stated before its brand new engine and the ring end gap is normal to a race motor, I am not sure what it is off hand but its a fresh engine by a very good builder, I know everyone has their own opinion, but I am looking for a tried and true solution to this problem, and I understand not one engine and setup is the same, im also wondering about a stand pcv setup as on a street engine.....what are your guys thoughts on that?

RJC5778
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Re: BBC valve cover baffles

Post by RJC5778 »

he builds a lot of race and airboat motors and does all the warranty work for mas motors from Wisconsin who has a motor down here in south la, he knows airboat motors and understands the rpm range and use of them and what the motor needs to be, I also am confused about the non baffled valve covers, but I want this thing to work and be reliable, I guess I am going to try a few different things and see what works best, process of elimination I guess

mcm4
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Re: BBC valve cover baffles

Post by mcm4 »

On my valve covers I welded a short 1.5" nipple and put a clear flex 1.5 " line on each side, routed up to the top of the cage and back to about 1" from my prop.... in the nipple I put steel wool. When running the prop creates a vacuum, oil does go up in the line but drains back down when the engine is shut down.... marshal miller ran this on his airboat and no more oil on prop..

RJC5778
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Re: BBC valve cover baffles

Post by RJC5778 »

im leaning towards the hose idea to just in front of the prop as I already have the parts to do so minus the clear hose, im a try that and see how it does

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crowhater
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Re: BBC valve cover baffles

Post by crowhater »

Look this has been done, I have posted pictures of how to do this. Go to home depo or lowes, purchase some of the clear hose with the string in it, put the hose on your valve cover pipes and run it strait up to the cage. Run the hose along the inside of the cage to the front of the top of the prop. Cut the end of the hose at a 45*, long part / point part up! zip tie the end of the hose about 5" from the end of the hose so the end will hang down a little. it will angle down after it gets warm a few times. As your run your engine the prop will pull air past the hose and suck your crank case pressure out. You will see oil mist climb up the hose but it will only climb about a foot or so, when you shut your engine down the oil mist will go back into your valve covers. If you pull oil all the way out the end of the hose you need to cut about 1/2"-1" off the end of the hose and try again. The end of my hose was a couple inches from the prop.

My valve covers had no baffle in them at all and neither did the boat before that. I did not blow any oil out of any place after I did this and I have done it on 3 different boats.

If your search through my threads you will find pictures.
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Joe
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Re: BBC valve cover baffles

Post by Joe »

Just to be clear,I wasn't trying to imply that your ring gap was to big, I believe it's all in your breather system. I was implying that if you have to have one on an airboat you have bigger issue's.
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CactusJack
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Re: BBC valve cover baffles

Post by CactusJack »

You can always run a braided hose to a stainless catch can breather like this above the tappet cover in the rigging.... then any oil that blows up there will drain back once the engine is cool, like what mam4 said.... these are polished aluminum and less than $50, but you can prolly get stainless as well. This one is on Ebay.
Attachments
polished alloy breather catch can.jpg
I was told I was wrong, once (not sure I believe it though)
If you can't blind 'em with brilliance, baffle 'em with BS
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LoxStroker383
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Re: BBC valve cover baffles

Post by LoxStroker383 »

http://www.summitracing.com/parts/mor-6 ... Aplt8P8HAQ

I used one of these on my 383. I had the same problem as you. I ran the hose from this breather to my air filter. and a pcv valve on the other valve cover. I have no more oil leaking on the valve covers or anything. These breathers have a high quality steel wool in there that trap the oil and let it drip back into the valve cover. They are awesome quality too.


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RJC5778
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Re: BBC valve cover baffles

Post by RJC5778 »

joe,

your fine, its hard explain sometimes on these forums, it is in my breather system, I need a better one

its a shane Lejeune race engine, its nothing with the engine itself as I have all the good parts in it, motor is good to 8k rpm and 1200 hp if I wanted to, my issue is the breather system obviously, so any big block guy who wants post some pics of their setup I would greatly appreciate it guys. im trying to find at least 2 solutions to this problem to try that will work and be very simple

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