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-   -   How to prevent oil from pushing through breathers? (https://www.offshoreonly.com/forums/general-q/178921-how-prevent-oil-pushing-through-breathers.html)

mrhorsepower1 02-03-2008 10:58 AM

Install a vac. pump. You will be bolting on 35-40 Horsepower and keep the engine sealed! I run them all the time on pleasure boat applications.

cdscarab 02-03-2008 12:23 PM

mrhp1, what make pump and do you have a pic or 2 to show how you did it. thanks chuck

nwimbush 02-03-2008 01:43 PM

1 Attachment(s)
:cool-smiley-027:
Yeah, MrHP1, perhaps you cna show us which part goes where? I've attached a spec for reference...:party-smiley-048:

Vinny P 02-03-2008 04:34 PM


Originally Posted by mrhorsepower1 (Post 2431356)
Install a vac. pump. You will be bolting on 35-40 Horsepower and keep the engine sealed! I run them all the time on pleasure boat applications.


Yes, that is an interesting idea. A few pictures would be great. Although I dont know how or where I can mount the pump, especially with the serp belt that I run.

Vinny P 02-03-2008 04:39 PM


Originally Posted by nocigarette (Post 2431321)
Are the breather holes threaded in your valve covers if so you can use aeroquipp fittings to get to what ya need i will find a pick for ya.........If they are not ya have to weld a threaded fitting from the back side......

Yes, they are threaded. From information on Hardin Marines site, it seems that they are threaded to -20 an. I am thinking about getting 2 oil fill plugs from Hardin, then just drilling and tapping whatever size pipe thread I need into the plug. Summit has Moroso puke tanks that may work well.


Dick,
Yeah, I will keep you posted. Did you get the barn plowed out and the engine out today?

BenPerfected 02-03-2008 05:57 PM

I run a vacuum pump and it is great for oil blow-by control. I don't agreed with the 30+ hp in a wet sump marine application. My dyno experience with standard tension oil rings @ 15" of vacuum is less than 10 HP. Any more vacuum than 15" caused my oil pressure to fluctuate on the dyno...VP fighting the oil pump.
For absolute blow by control on a wet sump system, all you need is any negative pressure. To rig this VP system right, figure on a $1500+ project.
You can use one VP on twin BB....works great.

BY U BOY 02-03-2008 07:44 PM

Why not just run some hoses to the flame arrester??

team Tickfaw 02-03-2008 08:42 PM

Having the same problem with my 454's wet sump system.I have the old school alum valve covers with the ribs on top and push in breathers. 1 on each side. After a day running I will have oil in the ribs of covers. I thought that if I plumbed this to the air cleaner it would foul my carb. Am I right ? Plus really liked the clean look of nothing going flame arrester. I can't see spending 1500 to keep me from wiping alittle oil but interested in any other ideas.

ROB FREEMAN 02-03-2008 09:24 PM

a complete vcumm pump kit can be had for 750 bucks v belt im going to run this comming season on my 598 it looks pretty clear on the set up .

Vinny P 02-03-2008 09:52 PM


Originally Posted by BY U BOY (Post 2431807)
Why not just run some hoses to the flame arrester??

Yeah, that seems to work, but I dont like the fact that it pumps more hot air and possibly a bit of oil to the intake. Theres enough horsepower robbing hot air in there, dont want to pump any more into it.


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