Fixing oil coming out air filter box 4.9
05-31-2014, 04:34 PM
#1
Martin
Thread Starter
Fixing oil coming out air filter box 4.9
Fixed my problem of oil spitting out breather tube and coming out the air filter box making a mess. Just routed the breather tubing in the same fashion as a 96 4.9 into the intake tubing. Also modified the pcv so it draws more vacuum.
06-01-2014, 03:09 PM
#4
Martin
Thread Starter
This particular truck has about 300k on the clock. It has blow by that is common to the inline engines as they age, the Ford 4.9 and the Jeep 4.0 develope this problem. Now before anyone chimes in about how their rig doesn't do it, great for you but this truck is an old utility co. Vehicle so overall maintenance is not known.
Normally the kids drive this truck locally and blow by is not a problem. In the summer it gets used a lot more, taken on the highway and whatnot. That's when the oil will start coming out the air filter box. Obviously being pushed out the breather tube. So the solution is easy route the breather tube, into the intake tubing. All that oil that would normally be on my driveway, is burn in the combustion chamber. The fitting I used on top of the valve cover is for Chrysler product. At highway speeds this truck had enough pressure to spit oil on top of the valve cover from that fitting.
Opening up the flow of the PCV allows the breather to inflow more air. For a mild case of blow by this would work perfect. The 4.9 for 1995 has 3 different PCV numbers depending on what type of vehicle the motor is in. This tells me the PCV breather system on these trucks is pretty delicate and doesn't take much engine wear to throw off the balance of air flow. Having an adjustable PCV is common in hot Rod engines so I think it's appropriate to use in this case also.
Does this stop the blow by, no. Does it stop oil from getting all over my driveway, yes. The only way to truly stop the blow by is with the new or rebuilt engine. But this is a 20-year-old XL, it's not in the cards for this truck.
What I did is pretty close to a 4.9 with mass airflow. Look up a picture of that engine and you'll see what I'm saying. They're pretty hard to locate in the junkyard, so I went this route instead.
Bottom line it works and would also work for the v8's. Most owners of these old trucks aren't willing to throw a new engine in, so I think it's a perfect solution.
Normally the kids drive this truck locally and blow by is not a problem. In the summer it gets used a lot more, taken on the highway and whatnot. That's when the oil will start coming out the air filter box. Obviously being pushed out the breather tube. So the solution is easy route the breather tube, into the intake tubing. All that oil that would normally be on my driveway, is burn in the combustion chamber. The fitting I used on top of the valve cover is for Chrysler product. At highway speeds this truck had enough pressure to spit oil on top of the valve cover from that fitting.
Opening up the flow of the PCV allows the breather to inflow more air. For a mild case of blow by this would work perfect. The 4.9 for 1995 has 3 different PCV numbers depending on what type of vehicle the motor is in. This tells me the PCV breather system on these trucks is pretty delicate and doesn't take much engine wear to throw off the balance of air flow. Having an adjustable PCV is common in hot Rod engines so I think it's appropriate to use in this case also.
Does this stop the blow by, no. Does it stop oil from getting all over my driveway, yes. The only way to truly stop the blow by is with the new or rebuilt engine. But this is a 20-year-old XL, it's not in the cards for this truck.
What I did is pretty close to a 4.9 with mass airflow. Look up a picture of that engine and you'll see what I'm saying. They're pretty hard to locate in the junkyard, so I went this route instead.
Bottom line it works and would also work for the v8's. Most owners of these old trucks aren't willing to throw a new engine in, so I think it's a perfect solution.
06-01-2014, 04:10 PM
#5
http://www.aa1car.com/library/pcv.htm
You don't want OIL going back in, you want the gases to recirculate. At least that's what its designed for. If oil is a problem you can set up a catch can system that will trap/collect the oil from blow by. There's also supposed to be a smaller filter attached to the hose on the inside of the air box that is supposed to trap the oil vapor and prevent it from getting through the TB, manifold, and into the combustion chamber. Oil vapor in the chamber messes up the fuel/air ratio.
You don't want OIL going back in, you want the gases to recirculate. At least that's what its designed for. If oil is a problem you can set up a catch can system that will trap/collect the oil from blow by. There's also supposed to be a smaller filter attached to the hose on the inside of the air box that is supposed to trap the oil vapor and prevent it from getting through the TB, manifold, and into the combustion chamber. Oil vapor in the chamber messes up the fuel/air ratio.
06-01-2014, 04:47 PM
#7
Martin
Thread Starter
Look up how the breather tubing is set up on the 96. The breather tube goes directly to the intake tubing. The small filter is no longer used in this instance. The reason there was a filter in the first place, was the breather tube was prior to the air filter. It filtered incoming air.
In theory you could have a worn-out 96 and never know it. The only hint would be some oil residue in the intake tubing. I would guess that's why Ford redesigned the system for MAF. If it worked so well it could've been left just as it was.
I don't really have any desire to mess around with the catch can set up. Ones that work pretty well are also pretty pricey.
In theory you could have a worn-out 96 and never know it. The only hint would be some oil residue in the intake tubing. I would guess that's why Ford redesigned the system for MAF. If it worked so well it could've been left just as it was.
I don't really have any desire to mess around with the catch can set up. Ones that work pretty well are also pretty pricey.
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06-01-2014, 04:55 PM
#8
Senior Member
Look up how the breather tubing is set up on the 96. The breather tube goes directly to the intake tubing. The small filter is no longer used in this instance. The reason there was a filter in the first place, was the breather tube was prior to the air filter. It filtered incoming air. In theory you could have a worn-out 96 and never know it. The only hint would be some oil residue in the intake tubing. I would guess that's why Ford redesigned the system for MAF. If it worked so well it could've been left just as it was. I don't really have any desire to mess around with the catch can set up. Ones that work pretty well are also pretty pricey.
As far as my experience goes, I had bad blow by and this fixed it. There has to be a certain vacuum going to the crankcase breather because they designed the motors that way. From the factory the breather is ran from the crankcase and into the air filter box with a little filter. I did mine the same way but I still reap the benefits of a large open cone filter used as a warm air intake for MPGs.
06-01-2014, 06:05 PM
#9
Martin
Thread Starter
http://images.gtcarlot.com/customgal...e/50987349.jpg
http://www.sunsetclassics.com/1996-f...150-engine.jpg
Couple pictures of a 96 4.9 engine compartment. For our trucks this is as updated as the system got.
http://www.sunsetclassics.com/1996-f...150-engine.jpg
Couple pictures of a 96 4.9 engine compartment. For our trucks this is as updated as the system got.
06-01-2014, 07:23 PM
#10
Happen to have any pics of inside the intake tube or the valve cover? I bet there's still an oil screen or filter of some kind like there's supposed to be on the ones that go to the airbox. Like olnavy when he did his DIY set up. That filter is also supposed to trap oil vapor that can, and does, blow back toward the intake tubing/airbox.
Last edited by Forge-World-FORD; 06-01-2014 at 07:27 PM.