Non cross drilled crank
 

Is a non cross drilled aftermarket forged crank a good idea to use?

pros/cons?

If your main bearings you use are at least half grooved then it’s not a issue , and for a non flat out race motor the loss of bearing support area due to these grooves should not be a issue either!

Some good info in this post #75 on this topic.
https://forums.maxperformanceinc.com...=508084&page=4

That’s a great informative article and really opened these old eye’s!

It also makes it quite clear why the Rod bearings do not live in factory 4.00” and 4.210” cranks which are cross drilled at birth!
I here by retract what I posted in number 2 of this string!

So my factory 421 nitrated crank that has been in the engine for like 22 years with 6000 RPM launches and going through the lights at 6000 and thousands of street miles is on borrowed time?Tom

Don’t know!
I am assuming that all the 3.250” main cranks are cross drilled.
Is such only found in the 455 cranks which I know are .

I believe with those huge mains, cross drilling is not a bad thing. Especially with 1/2 groove bearings. That poor oil hole has a lot of ground to cover before it gets another drink with a non cross drilled main. Would that starve the rod bearing?

Also, on the centrifugal force thing, with the main bearing clearance, how much oil is rushing out the other side? It`s a lot tighter than the rod side clearance. And, it`s not like the main clearance is under no pressure while the oil is trying to rush out the other side, no?

Am I crazy? :noidea:

It would seem that the needed oil pressure feeding the mains carry’s the added load of the ever increasing oil back pressure of the crank spinning , and this oil back pressure increases when a cross Drilled crank comes into play, no less by the normal force of the rpm rising.

The only good thing in terms of oil flow and a spinning crank is that the centrifugal force is always trying to feed the rods any oil that does get in to that feed passage leading to them!

Its the one you want to use. Unless you like working against centrifugal force/physics.
Its hard to believe someone would actually make a crossdrilled forged crank.

Use the correct 10w30 viscosity engine oil instead of the "racing" "high performance" "heavy duty" 20w50 syrup and your bearings, lifters and rockers will live just fine crossdrilled crank or not.

The racers might do things differently, but they are used to break parts all the time.

JMHO

Are all the aftermarket stroker cranks cross drilled?

My buddy has a 4 inch stroke, 3 inch main, that is.

I am running full synthetic 10w30 now. But, I have run 20w50 in my old motor for decades with no problems. I have 3 cases of 20w50 waiting to go into the new motor.

good info on this. my 455 was built in 2012, non cross drilled aftermarket forged crank/grooved bearings. have always used 20 w 50 full synthetic.

It has always had, higher oil pressure then what i am used to. always wondered if its due to the crank/grooved bearings. same psi now as it had at start up. been a great engine.

Because folks have done wrong or been ignorant for 50 years does not make it right today.

Viscosity

Viscosity is defined as the resistance of a fluid to flow.
The more resistance the liquid creates, the higher the viscosity.
The higher the viscosity, the higher the fuel consumption, engine
temperature, and load on the engine.
The most important aspect of an oil is its viscosity.
To create the correct hydrodynamic cushion for maximum protection for any given velocity, surface area and diameter/tolerance, you need a specific viscosity.
In the design of an engine this ideal viscosity is calculated and then recommended.
As mentioned above, an oil too thin will not provide enough hydrodynamic lubrication, and an oil too thick will not flow properly.
Eventually, as an engine wears, it may be necessary to compensate by slightly increasing this viscosity. “High mileage oils” do this by being in the upper portion of the range for a specific viscosity.
The following table shows the different SAE viscosities that meet engine design characteristics.

I didn't know oil viscosity was still an issue. A properly built automotive engine with proper bearing clearances does not require 20w50 oil or a high volume/pressure oil pump.

The good ones are not. I believe Ohio has some cross drilled cranks. Eagle maybe ?
The Chi Coms started the aftermarket forged crank deal. Since they are just a bunch of copycats they must have started out with a 455 crank and copied it, they are cross drilled.
Scat, Molnar both have straight shot oiling where centrifugal force helps out the situation.