We just built a 390 FE. Specs are: Forged aluminum TRWs, cast crank, Holley 670, C4AE 6090G heads, Comp 292H, and headers. When we started it for the first time, it ran fine. Then, we shut it off after break in to check things and started it again. This time, if you revved it up it would take a long time to come back down to idle (about 30 seconds). I hand choked the carb and the RPM went up significantly. If you turned the idle screw less than 1/4 of a turn, it would jump to 1100 RPM, and if you turned it back, it would go down to 500 RPM. No middle ground. So we took the intake off and resealed it, and the leak is still there. But now its burning oil on the drivers side pretty bad. The heads were redone about two months ago. We also ran it with the valve covers off for a few seconds and noticed that there is A LOT more oil coming out of the drivers side rockers instead of the p***enger side. The oil pressure is pretty high too. About 60 - 70 at idle. Yes the oiling bolts are in the correct holes. What is causing this mess of problems?
Make sure head gaskets are correct. Make sure the oil p***age in the heads under the middle rocker pedestal is clear on both sides. I usually restrict mine with a Holley 80 jet. Make sure you intake has no pinholes. If you have a factory intake, make sure it's not rotted out in the valley under the heat shield from the exhaust gas crossover. Thats my $.02.
If you are running a PCV valve, make certain the valve cover has a shield inside between PCV valve and valve train. If not the valve ****s oil into the carb and engine. Check under carb to see if oil is present in intake. In addition, the oil in the heads drains to the rear of the heads back to crankcase, and quite often, folks use to much RTV in corner of intake when installing. The excess RTV squishes into the p***age restricting oil drainback, now the excess oil surrounds the valve guide on a rear cylinder and that side smokes. This is also caused when no restriction is used in oil p***age as "barstowpo" indicated. The oil stud on p***enger side is #3 cylinder and #6 cylinder on drivers side. You have a lot of oil pressure, and to much oil in the heads causes all sorts of smoking problems. Pull the plugs on drivers side to see if oily, also look in cylinder with flashlight to see if oil puddled on piston. Thats a clear indication oil entering cylinder from intake via PCV issue or head oil drainback problem. Its also an indication of wrong size piston rings installed on bored engine, i.e. Std rings in .030 overbore. The reason the drivers side is smoking is beacuse of oil drainback I feel certain, and is not the end of the world. As bad as it is to pull the rockers, pull them off and drop a Holley jet in the feed hole to restrict oil to the head if you havent already done so. FE's are awesome, but damn tickey and require attention to detail. Good Luck BOutlaw
I forgot to mention, FE intakes are difficult to install properly. Dont know if you are running an aftermarket aluminum intake or stock cast unit. You should dry fit the intake with gaskets, especially with aftermarket intake, and carefully check the perimeter of the intake for gaps. Aluminum FE intakes, especially old ones, were not cast very well, and may require machining to fit properly. Proper intake fitment is necessary or you have a vacuum leak, which sounds like what you have. Make sure you have the correct intake gasket for your head and intake combination. I also use Right Stuff around water p***age holes on both side of gasket. Torque and tighening sequence also important. BOutlaw
It would not cause more oil on the drivers side but FE are bad about pulling oil at the intake gaskets because it is under the valve cover and oil just sits there. Check the plugs for oil pull the valve cover and spray some carb cleaner at the gasket and see if the engine responds
We fixed the oiling issue, there was some material in the rocker shaft on the p*** side and we cleaned it out. We are going to put jets in the oil p***ages. We think that oil might be pooling and leaking into the valve stems.
Sounds like intake leak , inside on valley . Vacuum leak pulling oil in from under the intake . FEs are one MFer to get intake to seat properly . Especially cast iron . Look for leak at carb base also stock had a pacer the may be omitted
OT MAG,but rellavent to the Q- In the last couple of issues of Car Craft,someone had the same issue's as described VVVVVVV It covered proper,and a different torque sequence on the intake.Seemed that the author responding had encountered the same issue,and once it was changed up,the problem went away. Now this is just for the torqueing sequence- cannot cover machining throughout the years,or older/worn(cycled) parts. Also- proper gaskets,and possibly a lil sealer.... Just a lil food for thought is all. Waiting to see a resolution found.
e-z way to test for internal vacuum leak, such as intake gasket,hole ported through intake port, push rod hole leak, etc. put masking tape over oil fill ,and pcv holes in valve covers, (basically seal it off ) and start it, if tape "****s in" then there's your proof, that there is indeed an internal vacuum leak.(you will have vacuum in the crankcase, without a pcv valve) hope that helps !
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