[Singleton]

Originally Posted by Mike S

My restrictors for a solid roller are .030 but tapped into the oil feed to the lifters in the block. But this is a mainly strip car with occasional street driving. Myself, I would rather have restricted push rods.

Here’s a recent video from Powell’s Machine Shop, where he says the same thing about not restricting flow to the lifter, and shows the damage done to a customers roller lifters by restricting the lifter bore. http://https://youtu.be/KRt55CphSqU?is=zWZhVwuzjss33_W_

[Region Warrior]

Oil lubricants and cools entire engine.
Especially any rollers, springs, and rockers.
Think about it.
E-hds so easy to make drain better.
Sheet only takes an hour massage 3 beers. Pint of bourbon helps.
If nothing else oil pools up and runs back over.

Back in 79 sump would go empty in 100' burnouts.
1 extra qt oil shoved prob.
No power braking. Thats for tards on tv shows.

[Region Warrior]

Ok let's go...
Why would anyone use any kind hydraulic lifter since 60s?

[Jay S]

The .040” orifice pushrod with a 50 psi pressure gradient will flow 3.5 gpm thru 16 pushrods, at crusing speeds total flow of around 6 to 8 gpm there really won’t be much difference in oil volume to the top end. At best you’re hoping to gain a couple lbs of oil pressure. The very most oil that could get pushed through that .040” restrict pushrod is 4.5 gpm with a full 80 psi gradient. The total flow at full throttle for the oil pump is around 12ish gpm, 3.5 gpm is plenty of oil to the top end. Using .020” orifice in a 50 psi drop the flows drops to .8 gpm from 3.5 gpm, that is a very big restriction of oil to the top end that must be requiring some kind of special needs. I have not had any reason to use something like that.


I usually run.040” to .045” restrictors on street engines and have added them with no other changes and could not tell any difference anywhere. Results vary from engine to engine.


We sold a set of mechanical Morel lifter last summer to someone running a Ford Windsor with an HR cam, he couldn’t get the HR lifters to quiet down. The mechanical lifters solved that, but then he seemed to think he had issues with it pumping too much oil into the top end. We told him to get .040” restricted pushrods. He didn’t listen, instead he made grooves on the lifters to send the oil back to the crankcase. I don’t know if he was just cheap or crazy, or both. lol

[Jay S]

Originally Posted by Singleton

Here’s a recent video from Powell’s Machine Shop, where he says the same thing about not restricting flow to the lifter, and shows the damage done to a customers roller lifters by restricting the lifter bore. http://https://youtu.be/KRt55CphSqU?is=zWZhVwuzjss33_W_

That guy in the video had his oil restricted down to about 1 gpm with his .1” orifice before the oil even made it to the lifters. Maybe he had 2 plugs on each bank, maybe 2 gpm at most. Either way, is a lot of restriction before the oil is even close to getting to the top end.

[Jay S]

Originally Posted by chiphead

So if I understand this right, if you build a motor with a HR and the lifters make some noise, first try a .030-.040" restricted pushrod? I guess the restriction in the pushrod helps the lifter metering keep oil below the plunger?

Keeping oil in the lifter to crutch bleed rates makes some sense. The spring pressures with HR are higher than HFT, so I can see issues with keeping the lifter plunger pumped up at lower engine speeds. This could reduce the clacking at and above idle.

You have the right idea. Rather than huge changes, it is a mod that is a small improvement, but is something that I think it adds up to make a difference. Maybe it will gain 2 to 5 psi of oil pressure. It is hard to quantify or document how that improves the life or performance.

To have any kind of success to correct a poor bleed rate on a lifter would take a .020” restricted pushrod. It would be a crutch, not a good solution.

[sdbob]

Just add a little info. About 1970 when Jim Miller built the RAV approximately 467" dirt track engine with small journal crank. He had information from Pontiac how to tap those restrictions into the lifter bores and the sizes. I got from this info about 30 pages of how to build a 303. The first page is missing that might be the oil restriction diagrams. Just saying.

[ponjohn]

From Butler...
We don’t recommend oil restrictors in the block with hyd roller lifters, we recommend and use restricted pushrods.
We feel the Johnson and COMP lifters don’t meter the oil down as much as a flat tappet lifter so we restrict it with the pushrods.
Morel Lifters do restrict the oil more and we usually don’t use restricted pushrods with those.
But like everything in the engine, it’s always the engine builders final call.

me: Is the idea that the restricted push rod keeps more oil feeding the mains?

Yes, we feel it pumps much more oil than needed into the valve covers.

[Region Warrior]

Jay S.

[Region Warrior]

Gona start a oil viscosity vs different weight oils shear strengths.
Join in!

[Dragncar]

Not the dreaded oil viscosity thread !
We all have opinions.
Truth is, I don't think it matters "that" much beyond picking a quality oil with a reasonable viscosity and running it.
Most important thing about oil is keeping it clean and changing it.

[steve25]

The most important thing about oil is having enough of it where it’s needed.

[KEN CROCIE]

Classic overthinking the "problem". People forget that the hydraulic lifter has a metering orifice or disc to control the oil flow to the heads.
I tried to find out if the evolution cartridge has metered oil flow to the heads, but no luck. was on the phone (on hold) for 15 min at comp tech, plus 10 min at sales but no luck. You would think sales would answer. A holding co. ruining another classic industry.