Oil through pushrod, oil preassure

[Jimmy Jakobsson]

Hi! I have a pretty new built 493 cui stroker engine with about 400 miles on it. The set up is a eagle 4,150" crank, eagle H rods 6,760" , Mahle forged flat top pistons 4,350", Mahle plasma moly metric ring pack file fit, Kings main and rod bearings 0,002" clearance both, Edelbrock e-street 84cc cylinder heads, Comp cam xe275hl 231/237@050 camshaft, Edelbrock avs2 800cfm carb, prw 1:5 stainless steel roller rockers. I use comp cam 822-16 hydraulic lifters with comp cam 3/8 pushrod with 5/16 tip ends and oil through, the lifters also support the oil through pushrod so it just be that way, i use a HV pump and a 7qt pan so suck the pan dry not going to be an issue on this street driven engine. I just wonder and it probably is that way, do this oiling through pushrod and the rocker shaft make a drop in oil preassure? I have between 15-20psi warm engine at idle 900 rpm, the preassure follow the rpm good and at cruise 35-40 psi at 2000 rpm, this is with 10w-30 oil. I have read a few posts about it and someone loose up to 15psi with oil through pushrod set up. I just want to hear what you guys has to say about it?

 

[steve340]

I would have thought maybe 5 pounds at most. The push rod oiling is not like oil coming out all the time it should be little spurts. It is not like open holes and it is metered in the hydraulic lifter itself.
However the oil you are running is pretty thin for an old engine designed for much thicker oil.
I use a thicker oil because I think it has more of a "cushion" effect for want of a better word.
My 340 has about 40 psi at idle and 75 psi when a few revs are up - hot pressure.
I use Castrol Edge 20 - 50

 

[66Satellite47]

I don't have experience with the oil through pushrod setup, but hard to believe that results in much pressure drop. Key elements to the oil pressure are the bearing clearances, side clearance and the internal oil pump clearances & pressure relief spring. My builder recommended the 20-50W for my 512 based on my clearances. Maybe try a little thicker oil, see what happens.

 

[justcruisin]

Can't tell you what you would loose with oil through pushrods, you would need to do a back to back test to be sure. What I can tell you is I have a very similar build to yours but on a stock stroke 440. 10.2:1, eddy RPM's, 1.5 PRW stainless rockers, xe275hl, K1 H beams and SRP's at zero deck. I use Hylift Johnson lifters which oil through the pushrods, HV pump. I have 0.002" on rods and mains, 5W30 oil. 77psi cold @ 1200, 43psi hot @ 900 and 72 psi @ 2000. Have you checked your gauge reads right.

 

[Cranky]

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

 

[Ranger16]

I have between 15-20psi warm engine at idle 900 rpm, the preassure follow the rpm good and at cruise 35-40 psi at 2000 rpm, this is with 10w-30 oil.

I don't see anything wrong with those pressures.

 

[coloradodave]

I've run my 440 both ways. Didn't see any appreciable difference in pressure.

 

[Jimmy Jakobsson]

Thank you guys for your answers, i have read different stories about this and if you thinking about it this way, it is 16 more internal oil leaks than without pushrod oiling so lower preassure just make sence. My preassure is still good so its not a problem, i have never understand why everybody want have so high oil preassure? You can readin forums " i have 70 psi, i have 60 psi, i have 40 and so on". Higher preassure is not always good, higher preassure stress bearing surfaces, intermedian shaft gear and so on, 10 psi per 1000rpm is all it takes. I belive my little lower preassure is because the pushrod oiling, i have atleast 10 psi higher without them but its not a problem, i just wanted to hear other peoples experience

 

[steve340]

I my opinion if that was my engine I would be a worried man if my oil pressure on a 500 cubic inch motor was only 40 psi at 2000 rpm.
Your oil pressure is low for that size motor assuming as mentioned by another poster the gauge is reading correctly.
The factory manual states the oil pressure at 1000 rpm should be 45-65 psi.
Also states minimum oil pressure at 500 rpm is 20 psi.
Your pressure is nowhere near what it needs be be but I do hope it stays together for you.

 

[Jimmy Jakobsson]

I my opinion if that was my engine I would be a worried man if my oil pressure on a 500 cubic inch motor was only 40 psi at 2000 rpm.
Your oil pressure is low for that size motor assuming as mentioned by another poster the gauge is reading correctly.
The factory manual states the oil pressure at 1000 rpm should be 45-65 psi.
Also states minimum oil pressure at 500 rpm is 20 psi.
Your pressure is nowhere near what it needs be be but I do hope it stays together for you.

I do not belive oil preassure has anything to do with CUI on an engine, i do belive it has alot to do with bearing clearances, internal leaks and so on, a factory built or a original rebuilt engine has pretty tight main and rod bearing clearances and with that also higher preassure. If you build an engine for more power and higher revs you want more clearance for more oil to hold up the components and with bigger clearance you have more internal leaks also if you had excessive wear or loose lifter to bore clearance and with that lower preassure, you can compensate for that with thicker oil, oil viscosy choise depends on what bearing clearance you have in the engine and so on. For me its just logic with 16 more internal leaks in the system you get lower preassure, you can compensate for that with restrictions in the pushrods if your preassure gets to low. But my engine runs great and has do that for 400 miles now, i have change the oil 4 times under this 400 miles and cut the filter open, no metal or dirt what so ever and like i said 10 psi for every 1000 rpm is enough, more is just a comfort zone and to much is just more stress to the components. I had 10 more psi without the push rod oiling but still its not a problem. I just wanted to hear other people that have both pushrod and rocker arm oiling if they have noticed the same thing

 

[BSB67]

The pressures are fine assuming nothing else is going on in the motor.

I do not belive oil preassure has anything to do with CUI on an engine, i do belive it has alot to do with bearing clearances, internal leaks and so on, a factory built or a original rebuilt engine has pretty tight main and rod bearing clearances and with that also higher preassure. If you build an engine for more power and higher revs you want more clearance for more oil to hold up the components and with bigger clearance you have more internal leaks also if you had excessive wear or loose lifter to bore clearance and with that lower preassure, you can compensate for that with thicker oil, oil viscosy choise depends on what bearing clearance you have in the engine and so on. For me its just logic with 16 more internal leaks in the system you get lower preassure, you can compensate for that with restrictions in the pushrods if your preassure gets to low. But my engine runs great and has do that for 400 miles now, i have change the oil 4 times under this 400 miles and cut the filter open, no metal or dirt what so ever and like i said 10 psi for every 1000 rpm is enough, more is just a comfort zone and to much is just more stress to the components. I had 10 more psi without the push rod oiling but still its not a problem. I just wanted to hear other people that have both pushrod and rocker arm oiling if they have noticed the same thing

Does your lifter also oil the lifter face/cam lobe?

It just seems like today's lifter are already challenged to do the simple job they were designed to do. Then we add fast rate cams, higher spring pressures, then add two more oiling responsibilities to the marginally adequate lifter not to mention 32 more oil leaks. But as long as oil pressures are fine, which yours are, no harm.

I'd mostly be concerned that the valve is actually doing what the cam is trying to tell it.

 

[Jimmy Jakobsson]

The pressures are fine assuming nothing else is going on in the motor.



Does your lifter also oil the lifter face/cam lobe?

It just seem like today's lifter are already challenged to do the simple job they were designed to do. Then we add fast rate cams, higher spring pressures, then add two more oiling responsibilities to the marginally adequate lifter not to mention 32 more oil leaks. But as long as oil pressures are fine, which yours are, no harm.

I'd mostly be concerned that the valve is actually doing what the cam is trying to tell it.

Hi and thanks for your answer! No the lifter does not oiling the cam lobes it is just up through the pushrods but anyway it is 16 more leaks. I have noticed that these lifters do bleed down pretty quikly when the engine is off and this cam is also a bit noisy with this fast rate lobe profile. The engine runs really great and the preassure follow the rpm just fine so im not worry, i just thinking if there was someone else running this combo and notice this drop in preassure because of the extra 16 leaks.

 

[BSB67]

I know of a case where a guy has push rod oiling with a hydraulic cam and a standard length oil pump rotor that had pretty low oil pressure at idle. His/builder solution was to restrict the oil going to the rocker shafts, which gave him enough of a bump in idle pressure to make everyone happy.

Those lifters have instant lifter bleed down. You needed to know what you are doing to set preload.

 

[Jimmy Jakobsson]

I know of a case where a guy has push rod oiling with a hydraulic cam and a standard length oil pump rotor that had pretty low oil pressure at idle. His/builder solution was to restrict the oil going to the rocker shafts, which gave him enough of a bump in idle pressure to make everyone happy.

Those lifters have instant lifter bleed down. You needed to know what you are doing to set preload.

Thanks for your answer! Ok, yes thats one way to go with restriction to the rocker shaft, i think i have enough preassure like it is now because of the hv pump but your story confirm that you get a lower preassure with both pushrod and rocker shaft oiling. Ok so it is normal for this type of lifters to bleed down than, yes you need to have really good feeling in your fingers to set proper pre load on this, i have it set at 0,025".

 

[dvw]

My race 572 is pushrod oiled. The inner diameter of the push rod makes a huge difference. Think about it. Stock heads feed with a single timed hole to each head. Guys running Indy -1 heads feed each head with a .040" orifice. This is the equivalent of one .056" hole. My experience; At first the oil pressure in my engine wouldn't go over 40-45psi @7000. This was with the adjustable screw at the pump turned all the way in. After chasing my tail with bearing clearance the feed holes in the lifters were restricted with epoxy. A .040" hole drilled thru the epoxy. The pressure was now 65@7000. After a year on tear down the epoxy had come loose. The pushrods have .107" feed. A total area of .1438". The pushrods themselves were sleeved with 3/32" outer diameter brass tube held in with locktite. Some of the tubes came loose. I didn't want to buy another expensive set of push rods (7/16" tapered Trends). Made one last attempt. Roll pins were pressed into the push rods. I had my doubt since they were aprox .053" each, .0353" total area. This has worked great. They haven't moved. The adjustable regulator at the pump has been turned all the way out. Pressure was still up around 90. The oil pump relief spring has now been trimmed 1 1/2 coils. Pressure is 70@7000.
Doug

 

[HEMI-ITIS]

I sent oil up the exhaust on my hemi and all on a wedge and lost 15 lbs of OP. Put restrickers in the PRs and the pressure came back. Just my experience changing over to the AMC lifter with pressurized oil to the needle bearings and up to the adjusters.Never burnt a cup again in the 500 wedge!!

 

[Jimmy Jakobsson]

I sent oil up the exhaust on my hemi and all on a wedge and lost 15 lbs of OP. Put restrickers in the PRs and the pressure came back. Just my experience changing over to the AMC lifter with pressurized oil to the needle bearings and up to the adjusters.Never burnt a cup again in the 500 wedge!!

Thanks for your answer! Ok so its not strange to loose some preassure with this set up than, logic thinking it is 16 more internal leaks so the preassure will drop a bit. Thanks for the advice with restrictors, im going to take a look at how i can restrict the pushrod holes.

 

[Jimmy Jakobsson]

My race 572 is pushrod oiled. The inner diameter of the push rod makes a huge difference. Think about it. Stock heads feed with a single timed hole to each head. Guys running Indy -1 heads feed each head with a .040" orifice. This is the equivalent of one .056" hole. My experience; At first the oil pressure in my engine wouldn't go over 40-45psi @7000. This was with the adjustable screw at the pump turned all the way in. After chasing my tail with bearing clearance the feed holes in the lifters were restricted with epoxy. A .040" hole drilled thru the epoxy. The pressure was now 65@7000. After a year on tear down the epoxy had come loose. The pushrods have .107" feed. A total area of .1438". This is the equivalent area of one .428 hole. Think about that. That's nearly a 7/16" hole, huge. The pushrods themselves were sleeved with 3/32" outer diameter brass tube held in with locktite. Some of the tubes came loose. I didn't want to buy another expensive set of push rods (7/16" tapered Trends). Made one last attempt. Roll pins were pressed into the push rods. I had my doubt since they were aprox .053" each, .0353" total area. Equivalent of one .212" hole. This has worked great. They haven't moved. The adjustable regulator at the pump has been turned all the way out. Pressure was still up around 90. The oil pump relief spring has now been trimmed 1 1/2 coils. Pressure is 70@7000.
Doug

Thanks for the answer and the information!

 

[BSB67]

Thanks for your answer! Ok, yes thats one way to go with restriction to the rocker shaft, i think i have enough preassure like it is now because of the hv pump but your story confirm that you get a lower preassure with both pushrod and rocker shaft oiling. Ok so it is normal for this type of lifters to bleed down than, yes you need to have really good feeling in your fingers to set proper pre load on this, i have it set at 0,025".

Be careful. Those are reasonable conclusions, but the reality is there was not back to back testing conducted, so we do not know for sure. Nor do we know exactly what parts/lifters you have verses my friend's.

Also, they decided to restrict the shaft oiling. Seems like a marginal bandaide, but it worked, and he is happy.

 

[HEMI-ITIS]

We restricked the pushrods,NOT to the rockers.