Restricted Pushrods?
 

What’s your guys opinions on running restricted pushrods on a street app? I have a set of Crower SR lifters I want to run on a HR cam and have never run the restricted rods but a lot of people do. What are the pluses and minuses of using them on the street.
The Edelbrock heads have poorer oil drain back than stock heads so in my thinking having less go up top isn’t necessarily a bad thing, or is it?

I use 0.040" restricted pushrods on my race motor with a SR cam and in my brother's motor with a HR cam and both motors get plenty of oil to the top end and don't have any issues.

Basically 2 schools of thought,

One, that flooding the valve train, and springs removes heat and less likely to burn a pivot point on rocker arms, and keeping the springs covered removes heat that lessens spring life.

Two, that too much oil in the upper end with marginal drain back from the restricted aftermarket heads can cause oil pump starvation leading to bottom end failure due to oil starvation, and aeration of the oil.

My own preference, is to keep oil in the pan as much of the time as possible. If I were to use aftermarket heads, I would look into exterior oil drains plumbed from the heads to the pan. It also might lessen windage/aeration, keeping some of the oil out of the valley that would return outside of the valley. Keeping oil off the spinning crank is always a good thing.

You have to deduce which line of reasoning you think will have a better outcome.....:confused2

With your drain back, I know when I got my heads from Butler they cleaned up the drain holes and ground little "pathways" to help with oil flow. I run a solid roller on the street, just normal 3/8" pushrods that aren't restricted. I think the smallest orifice is the hole in the rocker arm (Crower SS) so figured that it's an unneeded deal for me. No issues with sucking the pan dry, oil pressure or drain back here. I went with the theory that oil up in the top is better to cool the springs in a street deal and run a Canton trap door sump, around 6-7qt from memory with a home prepped 60psi pump.

This is sore spot for me since i purchased e-heads in 09. The drains holes are basically horizontal, big engineering mistake in my opinion. So I’ve been trying to keep oil out of the top end . Ive run restricted rods for yrs without issue . This engine is beat on regularly , no part failures.
I have ground channels to expedite flow and have 2 drain lines per head to help with oil drain.

Another consideration is how much clearance you have with your lifter bores. Bill M reminded me of this recently... if they are sloppy and using restricted push rods, you will be pushing more oil up around the lifters vs increasing available pressure/volume for bearings.

Although you would still accomplish the goal of less oil going up to the heads, but maybe not adding much additional volume to the bearings. The better fix is oil restictors in the lifter bores, but of course not quite as convenient as push rods!

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I've ran restricted pushrods for quite a few years. When the heads were reworked a few years ago Dave Bisschop, he said there was zero issues with my valvetrain.