Technical What is too much oil to the top end?

For sure not. The manufacturers would definitely have tested the engines for this in any normal situation, such as running the engine fast in very cold weather when the oil is thick and slow to drain back.

 

My "A" Hiboy has an SBC engine w/ solid flat tappets with the ".012 hole in the face towards cam lobe to help out with cam/lifter wear. Also has full roller rockers, fulcrum and tip.
Comp Cam said that with the 16 ".012 holes bleeding off oil down at cam level a high volume oil pump might be a good idea, and I installed one during build. SW mech oil gauge shows no flutter with # 4 AN line to it. But I'm considering some push rods with a reduced size oil hole. Comments?

 

Do you remember Chet Herbert cams recommending installing a pipe cleaner inside each hollow sbc push rod to restrict oil flow? This was printed in their brochures. Sounded pretty crude, never did try it. Most area circle racers put aprox ,060" restrictors behind rear cam bearing. Greg White

 

look into lifter bore grooving tool ( comp cams 5002) this seems to be a good way to supply oil to the cam right before the lifter acceleration ramp but it needs to be done while the engine is just a bkock

 

My new Comp Cams and used Johnson solid flat tappets have a very subtle machined flat surface on the side of the lifter. I guess that may be the same as grooving the lifter bore?

 

A trick that I used on a 455 Pontiac I built years ago was to drill an oil galley plug with a .030" hole to lubricate the distributor gear. I also took the time to deburr the lifter galley to aid in oil return.

 

Lots of factors to consider in engine design: cost, performance, durability and fuel economy are a few.

Oil system design cuts across a lot of these, but to simplify things, you want to minimize oil flow through the engine for best fuel economy and performance output. It takes fuel and power to pump oil. Typically you size the pump to be off the regulating spring at peak torque speed. Having a lot of unnecessary oil flow in the valve train means you need wider oil pump gears, which saps power, and may require a larger pan at high engine speeds.

The original post discounts drainback area, but more oil flow to the overhead requires more drainback, especially when operating in cold conditions. That leans towards larger, heavier castings, all else equal.

 

My experience with top-end oiling has been with the last two first-generation Chrysler Hemis that came through my shop.

Both had spun rod bearings. You might ask what that has to do with top-end oiling.

Both engines had all four of the oil return holes in the lower corners of each head, and down through the block, either partially or completely restricted. The combined volume of the top of the heads and the generous valve covers is more than capable of holding everything that should have been in the oil pan.

Oil went up, it did not come down. Bearings went into retirement.

Both cranks did weld up fine. I discarded the ***ociated rods.

Y'all can think on that scenario when considering whether or not to run a detergent oil.

 

Also to consider: for rocker-shaft mounted rockers, when they wear, either from shaft or rocker body wear or both, the increased clearances dump more oil, & will then flood the heads w/oil due to way too much oil, partially plugged returns - esp when those aren't large to begin with -, (maybe) too much blowby pressure trying to vent thru the valve covers. Heaven help the mill if owner decides to do an "Itailian Tune-up". Pan gets emptied, resulting in smoking engines, if they're lucky, no bearings if not. Not the rings' fault, but for some reason, very few will send the rocker shafts & rockers out for correcting via hard-chroming/machining the shafts, & machined/honed bushingsw/proper clearances for the rockers. IDK why? Stude v8s suffered from this, esp when they weren't taken care of properly(clean oil n filters) by Cheap***edOwners. Rebuilt bottom ends, & still had topend "issues" - & then bad-mouthed as being "junk".
Guessing that Studes weren't the only ones...
Marcus...