Reply to "Oil Flooded Valve Cover"

BD & All

If there's a point I need to get across in regards to the Cleveland lubrication system its the lifter plays a very important part in that system, Ford used the lifters to limit the amount of oil flowing to the valve gear. The motor is very picky about what lifters are installed because of the fact the oil galleys intersect the lifter bores and because of the need to meter oil with the lifter. Ford originally used a special lifter in the Boss 351 with an internal oil metering system. That lifter was manufactured by Johnson Lifters and is still available, its sold by Crower under part number 66915X980-16P. If you are using a solid flat tappet camshaft that is the lifter to use. Period. Eaton sold a very good solid flat tappet lifter, but Eaton is out of business.

Read the description of the Johnson/Boss 351 lifter in the OHO Newsletter at the bottom of the page, it specifically mentions the lifter is designed to insure there is no pressure loss in the lubrication system.

Another variety of lifter uses an inertia valve (aka piddle valve) for metering oil, that type of lifter allows too much oil to flow to the valve gear, do not use a lifter with an inertia valve type metering system. Another type of metering system is the "edge orifice" design. Flat tappet lifters with an edge orifice should never be used in a Cleveland, because as the lifter rotates in its bore, the orifice will line up with the oil galley frequently and then there is no metering of oil, it flows too much oil to the valve gear. However, a roller lifter with an edge orifice metering system is OK because the lifter doesn't rotate. As long as the roller lifter is oriented properly it will meter oil as it is designed.

Which brings me to BD's problem. I believe the Comp Cams roller lifter is an edge orifice design. The orifice should not line up with the oil galleys. The lifters are oriented properly when the link bars are oriented towards the middle of the motor, if the link bars are oriented towards the outside of the motor the edge orifice will be aligned with the oil galley and too much oil will flow through the lifter. I'll bet the lifters on the right hand side of BD's motor are oriented improperly.

In general, roller cams and their lifters are much harder on the motor, many old time Cleveland guys will advise you to run a flat tappet camshaft if you corner them & ask them privately. At this point I want to point out to you that installing bushings with 0.040" orifices in the lifter bores is the big fix for the 351C, I've been pushing this modification with you guys since day one. The 351C original design parameters were 7200 rpm with a Boss 351 lubrication system and with the oem iron crankshaft. Engine speeds above 7200 rpm, aftermarket crankshafts and the use of the wrong lifters is when lubrication issues arise. Bushings in the lifter bores is essential if the 351C is to be operated at engine speeds above 7200 rpm, they are the fix for aftermarket crankshafts and they make the motor less picky about what lifter is being used because the orifice in the bushing is metering the oil, edge orifices work properly, etc. Even Ford Motorsport (aka SVO) sold a kit for installing bushings in the lifter bores back in the hey day of the 351C. Today a do-it-yourself bushing kit is available from Denny Wydendorf.

There are more details involved in doing the 351C lubrication system right, but that's enough for you to chew on for now.

Tom, as far as blue printing the drain back holes, open up the holes in the head gasket to align completely with the holes in the head, then lay the head gaskets on the decks (block's head mating surface) and chamfer the holes in the block to align them with the holes in the head gasket .

-G