Breather Filter Baffle

[John Ibele]

I figure someone somewhere might be helped by this tip, so I'll post it.

I've been on the road two years now in gel coat, having a blast putting miles on the car and trying out dozens of tuning tweaks on the Sniper using the Holley software. Not everyone's thing, but a ton of learning and rewards for me.

One thing's been nagging at me, though. Quite often when turning right while doing some fairly spirited driving, I could catch a definite whiff - although very brief - of burning oil. Not any other time. But I couldn't find any problem spots on the engine inspecting under the hood and under the car. I even started to doubt my nose, and checked for any sign of scrubbed tires or interference points from the left front wheel well or suspension. All clear.

In doing a thorough winter cleaning this year under the car, it seemed like there might just be a bit more dirt / smudge on the driver's side of the frame under the engine, and it got me thinking. I set my engine up to take the old style push-on oil cap, using a Scott Drake fill tube adapter on the DS valve cover. It doubles as a breather filter, with a filter element built into the cap.

This style of breather filter doesn't have a baffle built into it, and in doing some reading, turns out the inside of the cap can get hit by splashing oil coming up through the tube adapter (open 1" diameter tube), and some of that can make its way into the breather filter incorporated into the outer portion of the cap. There were signs that the filter element had gotten oil soaked (but no oil dripped on the valve cover). I'm almost certain that oil accumulates in the filter element in the oil cap, and then drips off the filter and is periodically flung directly onto the header in a right turn. There'll be doubters (including me) until I verify the problem is gone, but that's what I'm going with.

I didn't want to take the valve cover off to put a baffle under the tube, and after some searching around I found Moroso 68775, a breather baffle made to fit the 1-1/4" value cover hole. Turns out it also fits the Scott Drake part perfectly. After some gentle persuasion the baffle actually goes over the spring steel in the oil cap, and is now a permanent oil baffle on my oil cap. The cap goes on a bit more firmly than it did before, but works perfectly fine now and should keep the oil out of the breather element.


Untitled by John Ibele, on Flickr


Untitled by John Ibele, on Flickr


Untitled by John Ibele, on Flickr


Untitled by John Ibele, on Flickr

[MB750]

Now that I'm putting miles on my car I'm surprised how many different smells I'm noticing. Either just the normal outdoor smells, or something from the car. Specifically clutch, brake, exhaust, and fuel (I'm still tuning the carb).

I went with breathers that route a high temp hose into the exhaust. I like a clean engine bay.

[John Ibele]

I like a clean engine bay.

We all do. Main point was to document what for a newbie is not a straightforward problem to diagnose. Easiest way to solve it is to get a sealed cap with an intake hose up to the air cleaner. But I liked the look of this one along with one less hose, so I'll try this first.

[phileas_fogg]

To confirm your suspicion, could you zip tie a paper towel around the neck of the breather? Any oil would discolor the paper towel.


John

[Ted G]

Think about a catch can. For me, that has virtually eliminated any and all breather leaks, however small. Mine is connected to the driver side breather (PCV) and the back of the carb.

CatchCan2.jpg

[John Ibele]

To confirm your suspicion, could you zip tie a paper towel around the neck of the breather? Any oil would discolor the paper towel.


John

Good idea John. I'll leave the baffle in place, but zip tie a paper towel around it for a drive or two just to make sure it comes out dry.

Think about a catch can. For me, that has virtually eliminated any and all breather leaks, however small. Mine is connected to the driver side breather (PCV) and the back of the carb.

CatchCan2.jpg

I'm good on the PCV valve side, Ted. I go from there to a catch can, and then to the vacuum port on the Sniper. It's the fresh air breather side I'm focused on. If this isn't a fix, I'll move to a sealed design with a hose connection, and run the hose up to get filtered air from the air cleaner.

Nice looking engine bay! Way different from mine ... just so many different ways to make these cars look cool.

Thanks for the suggestions, guys.

[StangRacer]

What dipstick are you using? Does it go into the block or into the oil pan?

A few years ago, when I was road racing a fella that was pitted next to us in the paddock was complaining he could smell oil burning on right hand turns. He told me he just put the engine in the car after getting it back from being rebuilt and ask if I would take a look... I confirmed it was a stock roller block, noticed the dipstick went into the oil pan, and knew right away the problem... the fella that rebuilt the engine failed to put a plug in the dipstick hole that is machined in the block. I cleaned up the area around the block with some brake cleaner, slathered a 5/16 bolt with some Permatex RTV, and stuck it down into the hole in the block. He went on and ran the remainder of the weekend with no issues.

[John Ibele]

What dipstick are you using? Does it go into the block or into the oil pan?

A few years ago, when I was road racing a fella that was pitted next to us in the paddock was complaining he could smell oil burning on right hand turns. He told me he just put the engine in the car after getting it back from being rebuilt and ask if I would take a look... I confirmed it was a stock roller block, noticed the dipstick went into the oil pan, and knew right away the problem... the fella that rebuilt the engine failed to put a plug in the dipstick hole that is machined in the block. I cleaned up the area around the block with some brake cleaner, slathered a 5/16 bolt with some Permatex RTV, and stuck it down into the hole in the block. He went on and ran the remainder of the weekend with no issues.

Another good thought. It is a Lokar dipstick flex line down to the oil pan. But this is a new Dart block, so no hole to worry about plugging.

[mrglaeser]

What dipstick are you using? Does it go into the block or into the oil pan?

A few years ago, when I was road racing a fella that was pitted next to us in the paddock was complaining he could smell oil burning on right hand turns. He told me he just put the engine in the car after getting it back from being rebuilt and ask if I would take a look... I confirmed it was a stock roller block, noticed the dipstick went into the oil pan, and knew right away the problem... the fella that rebuilt the engine failed to put a plug in the dipstick hole that is machined in the block. I cleaned up the area around the block with some brake cleaner, slathered a 5/16 bolt with some Permatex RTV, and stuck it down into the hole in the block. He went on and ran the remainder of the weekend with no issues.

When I got my short block from Ford Racing it came with a little freeze plug in a bag I couldn't figure out what it was for. It drove me crazy. I finally called them, sent them pics, etc. It was to block off the dipstick tube in the block. So good call on that being something to check for everyone. Especially if you use a pan with a dipstick. I had only worked with non-roller blocks and had no idea that was a thing.

30 Years ago I missed the frost plug in the back of the valley on a 302 and ruined an engine due to Oil starvation on the drivers side head. So now I do my best to make sure I don't have anything like that left over.

[Avalanche325]

Can you run an open breather with the Sniper?

Anyways. With an open breather there is always the chance that you will smell oil, and even see some vapor. More HP usually means more crankcase pressure. I had to put in a locking dipstick after I popped mine up at high RPM.
I did a catch can that is mounted to the drivers F-panel. I can sometimes see some vapor coming up at the front corner of the hood.

[John Ibele]

Can you run an open breather with the Sniper?

I do not have an open breather setup, I have positive crankcase ventilation set up with a PCV valve on the passenger side valve cover connected through a catch can to manifold vacuum. For makeup air, I have a breather style oil cap on the DS valve cover. Oil can splash up and contaminate the filter element of this kind of cap unless properly baffled. That is my issue.

I can stay with my present oil cap if my fix works, or switch to a conventional sealed cap with a hose up to the air cleaner to get clean makeup air from there. I prefer to stick with the present cap and avoid one more hose if I can. Plus I like $10 solutions to problems wherever I can find them. But no big deal either way.

[Avalanche325]

II have a breather style oil cap on the DS valve cover.

That is the part that I was wondering about. I was wondering about unmetered air.

Back to your question.
I see that you have the baffled grommet.
Are there no baffles in the valve covers themselves? That is the only other thing I can think of besides a catch can.

s-l1200.jpg

As far a contaminating the filter, that is not a problem. They are made to have oil in them.