Oil through pushrod, oil preassure

[Jimmy Jakobsson]

We restricked the pushrods,NOT to the rockers.

How did you restricked the pushrods? Heres the pushrods i use https://www.summitracing.com/parts/cca-7922-1
The lifters is Comp cams 822-16

 

[HEMI-ITIS]

I use a solid roller 848 comp lifter. Different worlds

 

[Slap Stick]

Never thought about oil through push rods on a Mopar engine....

The 92 up Magnums do.

 

[Jimmy Jakobsson]

Well you can suppose to loose some preassure with both pushrod and rocker shaft oiling but if the preassure is enough, you have oil enough with a bigger pan and a HV pump its maybe not a bad thing, you reduce the risk getting a burnt cup. I think my preassure is enough, 15-20 psi hot idle, around 40psi 1500-2000 rpm and at 3000 rpm i have 60 psi with 10w-30 oil

 

[andyf]

I always oil thru the pushrods on serious race engines. It costs a little bit of oil pressure but not much. Maybe 3 to 5 psi on the gauge. On some engines I'll oil thru the shaft as well as thru the pushrods. When you build engines like that you have to sit down and think about what you're doing for a bit. Figure out where you are controlling the oil flow. Do the math before you build the engine.

 

[cryplydog]

what diameter oil hole would you want in a ball/ball push rod just to oil the adjuster cup?

 

[Jimmy Jakobsson]

I always oil thru the pushrods on serious race engines. It costs a little bit of oil pressure but not much. Maybe 3 to 5 psi on the gauge. On some engines I'll oil thru the shaft as well as thru the pushrods. When you build engines like that you have to sit down and think about what you're doing for a bit. Figure out where you are controlling the oil flow. Do the math before you build the engine.

I build the engine for street use and i have both oiling through pushrod and through the shaft and belive its the cause of lower idle preassure. It was not my plan to oiling through pushrod from the beginning but the comp cam pushrods i ordered have the oil through and have the lenght i needed so it be that way, the lifters i had also supported it, it not do any harm, i have a 7qt pan and not rev the engine so much on the street, my choise of camshaft is more for the low end power witch i like the most on the street, xe275hl 231/237@050, 10,04:1 static compression ratio, pretty mild cam for my cui, bearing clearances is on the tight side 0,002" both main and rod. I not think the preassure is any problem here, 15-20psi 900 rpm idle hot with 10w-30 oil, 40-45 psi 1500-2000 rpm and around 60 psi at 3000 rpm

 

[66Satellite47]

15-20 at idle & below 50 @ 2000 is too low for me. Seems like a little too loose clearances in the oil pump. Good luck.

 

[Jimmy Jakobsson]

15-20 at idle & below 50 @ 2000 is too low for me. Seems like a little too loose clearances in the oil pump. Good luck.

Thank you! The lower preassure is because i have double oiling to the rockers, through the pushrods and through the rocker shaft. The preassure is lower but enough, it follows the rpm good, but i know everybody have their own comfort zone

 

[coloradodave]

Thank you! The lower preassure is because i have double oiling to the rockers, through the pushrods and through the rocker shaft. The preassure is lower but enough, it follows the rpm good, but i know everybody have their own comfort zone

Jimmy, As I wrote above, I have run my 440 both ways. Initially, with shaft and pushrod oiling, but found it too hard to seal the valve cover gaskets with the increased oil to the top end and my old 4 bolt covers on max wedge heads. Reverting back to stock Mopar oiling through the shafts and using Smith pushrods without the oiling hole helped immensely in getting the covers to seal. I would say that I gained 3-5 lbs. pressure by closing off the pushrods. In my experience, I don't think you're going to gain much by changing. My hot oil pressure is 35 lbs. at 1,000 rpm (idle) and 70 lbs. at 6,000 using 10W30. Of course, every engine is different due to bearing clearances and a variety of other variables. And, your right, everybody does have their own 'comfort' zone.

 

[Jimmy Jakobsson]

Jimmy, As I wrote above, I have run my 440 both ways. Initially, with shaft and pushrod oiling, but found it too hard to seal the valve cover gaskets with the increased oil to the top end and my old 4 bolt covers on max wedge heads. Reverting back to stock Mopar oiling through the shafts and using Smith pushrods without the oiling hole helped immensely in getting the covers to seal. I would say that I gained 3-5 lbs. pressure by closing off the pushrods. In my experience, I don't think you're going to gain much by changing. My hot oil pressure is 35 lbs. at 1,000 rpm (idle) and 70 lbs. at 6,000 using 10W30. Of course, every engine is different due to bearing clearances and a variety of other variables. And, your right, everybody does have their own 'comfort' zone.

Thank you for your answer! I know whats important in an engine is the flow of oil, with bigger clearance more flow needed beacuse more leak out of the bearing edges. The oil pump not create any preassure, its create flow, all pump does. The preassure be created of recistance to flow, tighter clearence make it harder for the oil to flow, it be resistance, preassure. Higher viscosy oil also have harder to flow in tight areas and it be higher resistance, cold oil have higher viscosy than hot and so on. Preassure is a surrogate measurement for flow beacuse we can not measure the flow in a good way in an engine and a well proven roul for that is 10lbs/1000rpm, thats enough flow for any engine. You have greater bearing clearances in a race engine to create more flow around the bearings, resistance/preassure create heat and you not want the oil to hot to loose film strenght and viscosy, its more variables than that but seen in the big way. Resistance/preassure also cost power, its harder to pump around the oil. So much preassure isn't always a good thing, enough preassure is good. Tighter bearing clearances have more load capacity than looser clearance but creates more recistance and therefore need lower viscosy of oil to flow easier but not to low to loose viscosy and film strenght when it reach a certain temperature. Its alot more to say about it, i have study it alot and this how i have understood it so far, its the flow not the preassure thats important, preassure is a surrogate reading for the flow and the well proven roule for enough flow is 10 lbs/1000rpm. Here you can read about it little more.
https://kennedysdynotune.com/oil-pressure-tech/

https://blog.k1technologies.com/bearing-clearance-and-oil-viscosity-explained

 

[Jimmy Jakobsson]

Hi! I drive the car yesterday with Lucas hot rod classic 10w-40 and my hot preassure now at idle is 40 psi 900 rpm and when i put the rpm up to 2000 i have 60 psi, so i guess the 10w-30 was a little thin

 

[steve340]

Good news those new pressures would make you happy.