When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Need some help here. I have a 1978 F150 4x4 with a freshly rebuilt 351M in it. When driving the truck, it has quite a bit of oil coming out of the PCV hole located on the passenger side valve cover. The valve covers are aftermarket; however, they do have baffles in them (I know that some do not). Currently I do not have an actual PCV installed since we are not running a factory style air breather on it. Therefore, I have an aftermarket breather installed on the valve cover instead. The oil is only coming out when driving. If idling, there isn't any that comes out. Some back story on the engine; it was rebuilt roughly 2 years ago and the cam and everything was broken in on a dyno by the builder. But it then sat on the stand until recently when my son and I installed into the truck. It starts fine and runs fine, except for the oil issue listed above. Any help is much appreciated.
That is the problem
Inadequate baffle and no PCV valve
Add valve and retest
I ran MT covers on my Boss 302 for years before finally getting pissed enough at the blow by leaks made me get factory covers again
Good luck
Most aftermarket lifters oil more, a LOT more than stock ones which also aggravates the problem and it doesn't take any significant blow by to cause them to toss out oil. Some aftermarket covers have very small baffles that are not adequate. The covers that are on my truck were that way so now they've been modified with some much larger baffles that are welded in and that's the nice thing about aluminum covers. The PVC valve side is similar with a large baffle welded inside of the cover to keep oil from splashing onto the bottom of the valve. It seems to be working.
I wouldn't recommend using a high volume oil pump necessarily but see how much oil comes out of each rocker when you crank up oil pressure by hand the first time. I think that a drip every second or two from each rocker arm is plenty but it will probably flow more than that but you never know Crane probably sold a pretty high quality lifter that's better than what's available today.
Oil flow for lubrication and valve spring cooling is important but in a wet sump application once the oil leaves the rocker arm it becomes a nuisance inside of the engine where it gets beat on by everything on its way back to the sump. It can become too much of a good thing.
When I originally built the 460 that's in my truck about 20 years ago I felt that it oiled too much so I put in some restrictor pushrods from Trend which got it under control. When I rebuilt it last fall with a new cam and lifters these oil quite a bit more even with the restrictor pushrods. I can't imagine what it would be like with them wide open. Maybe I would need a larger oil pump.
Need some help here. I have a 1978 F150 4x4 with a freshly rebuilt 351M in it. When driving the truck, it has quite a bit of oil coming out of the PCV hole located on the passenger side valve cover. The valve covers are aftermarket; however, they do have baffles in them (I know that some do not). Currently I do not have an actual PCV installed since we are not running a factory style air breather on it. Therefore, I have an aftermarket breather installed on the valve cover instead. The oil is only coming out when driving. If idling, there isn't any that comes out. Some back story on the engine; it was rebuilt roughly 2 years ago and the cam and everything was broken in on a dyno by the builder. But it then sat on the stand until recently when my son and I installed into the truck. It starts fine and runs fine, except for the oil issue listed above. Any help is much appreciated.
PCV valve doesn't connect to the air cleaner, it connects to the large vacuum port at the base of the carb or one in the carb spacer, a standard vent hose connects to the opposite side oil cap and the air cleaner, this allows vapors to return to the carb when the PCV valve is closed.
That is the problem
Inadequate baffle and no PCV valve
Add valve and retest
I ran MT covers on my Boss 302 for years before finally getting pissed enough at the blow by leaks made me get factory covers again
Good luck
So, I have taken your advice and will be adding an actual PCV valve and if the problem still persists I will put the factory valve covers back on also for the added baffling.
