Oil spitting out from my breathers

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Duster360LA

Duster360LA

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I wanted to get some input on this new issue. I am running a 5.9 with 9.75 compression, a roller street cam and EFI. The engine is new, with about 1600 miles on it and runs strong.
Based on a suggestion from my engine builder, I moved to a heavier oil (Valvoline 20/50 racing oil). After the oil change, I took it out and noticed my oil pressure was up 10+ lbs on a short run. When I got home and did a quick inspection, I noticed the K&N breather on the passenger side valve cover (I run a breather on both sides) was oily and there were small spots of oil around the breather. Not a ton of oil, but certainly a new development spitting oil out.
Wondering now if it was a mistake to move to heavier oil for a car that is a street-driven cruiser?
 
Are you just running breathers on both valve covers? If so you will get oil out of them. To avoid this use a PCV valve to a vacuum source on one cover and a filtered outlet like stock and a 5/8"-3/4" hose from the other valve cover to the air cleaner base.
 
Positive-Crankcase-Ventilation-System.jpg
 
As noted above the breather just allowed air in and out, so with blowby the only air movement is out, and with it some oil. It seems a bit odd that a new build would need 50 wt oil unless the gaps are set for it. Most new cars recommend 20W maybe 30W.

The question I have is does your new build have excessive blowby? Maybe rings have not set in yet?
 
Valve cover baffles and a pcv valve for a street car. If your engine builder told you to run 20w50 then do it. But I would definitely ask him what the bearing clearance is and how he correlates clearance to oil weight.
 
Eventually the seals and gaskets will start leaking without a proper PCV or evac system.
 
Thanks, I will get a PCV and install it. With 10-30 synthetic there was no oil blowby after 600+ miles of driving, it just started with the 20-50 oil. I'm probably also going to back down to a straight 30 weight synthetic.
 
Changing engine oil weight isn't the solution. Some good suggestions have been made here I would start with using a proper PCV and baffle set-up.
 
Duster360LA said:
I wanted to get some input on this new issue. I am running a 5.9 with 9.75 compression, a roller street cam and EFI. The engine is new, with about 1600 miles on it and runs strong.
Based on a suggestion from my engine builder, I moved to a heavier oil (Valvoline 20/50 racing oil). After the oil change, I took it out and noticed my oil pressure was up 10+ lbs on a short run. When I got home and did a quick inspection, I noticed the K&N breather on the passenger side valve cover (I run a breather on both sides) was oily and there were small spots of oil around the breather. Not a ton of oil, but certainly a new development spitting oil out.
Wondering now if it was a mistake to move to heavier oil for a car that is a street-driven cruiser?
Click to expand...
What valve covers are you running? Do they have baffles under the breathers and PCV?
 
Duster360LA said:
Thanks, I will get a PCV and install it. With 10-30 synthetic there was no oil blowby after 600+ miles of driving, it just started with the 20-50 oil. I'm probably also going to back down to a straight 30 weight synthetic.
Click to expand...
I’ll hold my opinion of your oil choices to myself but again I recommend you communicate with your engine builder.
 
Are you running a Holley EFI? they recommend a orifice pcv valve for a proper vacuum signal to the map sensor, smothes the idle. I used a 1/2" felt under the stock breather that catches small oil fog.
Marco
 
Modern precision machining work and proper clearance make 20w50 pretty obsolete. If the clearance and machine work are good, no need to run syrup in your engine. What was the oil pressure with the 10w30?
 
Answering questions:
Yes, I have a Holley Sniper 2. I missed that recommendation, so I will set up the PCV.

And my oil pressure was good (55 pounds at 2200 RPM) with the 10-30.
 
Duster360LA said:
I wanted to get some input on this new issue. I am running a 5.9 with 9.75 compression, a roller street cam and EFI. The engine is new, with about 1600 miles on it and runs strong.
Based on a suggestion from my engine builder, I moved to a heavier oil (Valvoline 20/50 racing oil). After the oil change, I took it out and noticed my oil pressure was up 10+ lbs on a short run. When I got home and did a quick inspection, I noticed the K&N breather on the passenger side valve cover (I run a breather on both sides) was oily and there were small spots of oil around the breather. Not a ton of oil, but certainly a new development spitting oil out.
Wondering now if it was a mistake to move to heavier oil for a car that is a street-driven cruiser?
Click to expand...
toolmanmike said:
What valve covers are you running? Do they have baffles under the breathers and PCV?
Click to expand...
I'll ask again.
 
Duster360LA said:
I wanted to get some input on this new issue. I am running a 5.9 with 9.75 compression, a roller street cam and EFI. The engine is new, with about 1600 miles on it and runs strong.
Based on a suggestion from my engine builder, I moved to a heavier oil (Valvoline 20/50 racing oil). After the oil change, I took it out and noticed my oil pressure was up 10+ lbs on a short run. When I got home and did a quick inspection, I noticed the K&N breather on the passenger side valve cover (I run a breather on both sides) was oily and there were small spots of oil around the breather. Not a ton of oil, but certainly a new development spitting oil out.
Wondering now if it was a mistake to move to heavier oil for a car that is a street-driven cruiser?
Click to expand...
I am not a big fan of those K&N breathers. Look at the size of the hole in the grommet that pushes into the valve cover. Even with a good PCV valve, the engine will likely need more breathing than that little hole will allow. It's like a scuba diver using a straw to breathe instead of a full size snorkel.
 
Ricks70Duster340 said:
I am not a big fan of those K&N breathers. Look at the size of the hole in the grommet that pushes into the valve cover. Even with a good PCV valve, the engine will likely need more breathing than that little hole will allow. It's like a scuba diver using a straw to breathe instead of a full size snorkel.
Click to expand...
Scuba divers don’t use snorkels. Snorklers do.
:poke:
 
Ricks70Duster340 said:
Yes they do! I used to dive and we still used them on the surface until we went down!
Click to expand...
Lol. Well then at that point you were a snorkler. Because by definition the “U” in the acronym S.C.U.B.A stands for underwater and the “B” stands for breathing.
 

It's not drawing through that little hole, the baffles are open ended. He may need an oil mist separator too, I have one on mine, they work.
 
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