Opinions Needed: Oil Pressure Changed

[68X426]

I've been fighting with an oiling problem (lack of oil to the rocker roller tips) in my Hemi all summer. It's been quite the learning experience for me (my first Hemi).

Background: INDY heads, hydraulic roller motor, mostly INDY components, with Comp cam and springs. A proven build from a top flight builder.    Except that INDY rocker arms were used. He doesn't do that anymore.

After 1000 miles on the new motor, a check under the valve covers revealed that one intake roller tip was seized, several were showing very bad wear. We determined it was a design flaw and INDY agreed.

Except they WOULD NOT back up their product (their disgraceful lack of service and pissy attitude is not the issue in this thread). The fix that INDY has, and we paid for, was the drilling of oil passages in the "valley" of each intake arm. Along with new rollers and pins (they actually did those at no charge  ). So, done and reassembled.

Here's the issue: having reinstalled the arms, the oil pressure has changed dramatically. Previously was 75# at idle (cold and hot) and 90# under load. Now it is 25# at cold and hot idle and 50# under load. Oil pump is an INDY custom built MAXX unit with high volume and high pressure. Wix filter, 9 quarts of Valvoline VR1, custom Charlies pan with external oiling. Same before and after.



I attached a picture to show where the oil passages were drilled. The pic is a sample Mopar arm, not INDY, but the arrow shows the location of the new oil hole. The Mopar arm has a large square passage. INDY had no passages in mine, said there should have been, and couldn't understand why they weren't there. Turns out that INDY forgot to drill holes in them in the past (2005, 2006).

My "fixed" INDY arm now has tiny round passages, maybe an eighth inch (haven't measured). The intake arms and tips are now getting oil (the covers are off at the moment). We primed the cam and valve train on assembly and it is clear now that oil is there on everything.

Question: would these tiny passages, only on the 8 intake arms, result in the change in pressure? Seems far fetched to me, but nothing else was done. The new numbers certainly seem normal and adequate. Or did we miss something?

Opinions on the cause? Also opinions on if I should have any concerns on the oil pressure? Thanks guys. 

[BSB67]

The devil is in the details.  But yes, I think it could.  If you have full time oiling to the the rockers, and depending on the shaft grooving/oiling hole locations, and the location of the hole in the rocker itself, I think it could.  Is it possible that the shafts were mistakenly put on upside down?

I also think that your oil pressure is okay, presuming that the pressure continues to go up past 50 psi when the rpms go up higher.

[68X426]

Thanks for the response. We marked the shafts so they went back on correctly.

I don't know if it'll go more than 50# because I haven't pushed it past 3000 rpm since reassembling. Going slow until I know it's all 100% solid then I can start making the motor do its job.

I'll add another thought to this: could we be having a lifter problem with the oil draining out (collapsed lifter)? How does one test for a bad lifter in order to rule out any other issue? 

[charge69]

I  wish I could tell you the straight answer but, I am not sure. I do know that my HEMI was making good horsepower and torque using an all- comp cams kit (hydraulic roller cam w/custom grind) and was making a constant 70psi in the dyno test. I had to replace ALL rocker arms due to wear and I replaced them with new OEM rocker arms.

Those were a little expensive but made good power and were about as inexpensive as you could get! Still over 2100.00 for the set! Guessing yours were considerably more expensive! However, it is a numbers-matching block and it does make consistent and reliable horsepower up to 6600rpm. (as far as we took it) and the oil pressure was a near-constant 70psi. Not really sure about the roller-rockers from Indy. Mine are from Comp Cams and work great.  Any ticking noise would be suspect, though.

[Challenger340]

Need to know a few things before deciding if the Rockers could be bleeding off THAT much Oil ?

How are you delivering the Oil to the Rocker Shafts ?

Is it from #4 Cam Journal or External Lines ?

[68X426]

Yes, oil delivered through number 4 (standard INDY shaft retains the stock Hemi oil route).

Also measured the oil passage and it is 1/8 th inch. It works great, the tips have oil.

[jeryst]

8 holes that are 1/8 in diameter are equivalent to one hole that is 1/8 inch wide by 1 inch long.
You can push a lot of oil through a hole that size.
That can result in a lot of pressure difference.

[Challenger340]

HEMI Rocker Oiling problems are very common, and the solutions could fill an Encyclopedia.

Typically, the use of a groove cut in the #4 Camshaft Journal to Facilitate "Full Time" feed has proven useful to some, but remember, the extra supply has it's costs, namely robbing peter to pay paul,
and,
can cause excessive Oil retention in the top end if not monitored or restricted elsewhere to a balance.

But back to your problem,
all things being the same, you would have to be bleeding off quite a bit of Oil to notice such a dramatic decline in system pressure?

Do you have a Groove in the #4 Cam Journal for "full time" top end supply ?
If so,
then,
The Rocker Arm Bushings themselves would have to be pretty darn loose to be leaking THAT MUCH Oil so as to crater the pressure?
because,
Banana Groove in the Shaft or NOT, the hole drilled out to feed the Rocker would only "line up" twice per cycle for a momentary 'squirt' through the hole, then be sealed up again by the Rocker Bushing.

IF NOT, and you are still running just the Cross Drilled Cam Blank for Top End Oiling, I highly doubt even sloppy Rocker Arm Bushings could bleed off that much oil pressure ?
Have you checked your Rocker Arm Bushing sizing ?

[68X426]

Do you have a Groove in the #4 Cam Journal for "full time" top end supply ?

No way of knowing about the groove. I bought the car with the motor already built. 

Have you checked your Rocker Arm Bushing sizing ?

The arms are tight on the shafts, and the bushings appear correct and tight.

So we are still left with a bunch of unknowns. Nothing seems to obviously explain the change in pressure.

Update: we just finished another lash (preload) adjustment and finally know we nailed it. It has never sounded better and the adjustment is perfect. A new friend, Rich, who is a great Mopar guy, has provided invaluable insight into the matter.

He also found that the push rods are too long and we will be replacing them ASAP, but that's another issue entirely. At least we now have good oil lubrication on the entire upper end. Man am I lucky to be part of the Mopar family.

The pressure issue may be affected by an oil breakdown, as it is due now for a change. The motor saw some hot useage lately, and fresh oil as well as a change to 20-50 will be appropriate. We'll also cut into the filter and examine.

I'll report back in a few days.

[68X426]

Update: the pressure is back to normal.    Have 75# and 90# under all conditions, hurray.

It was not the rocker arms and the new oil passages, it was a combination of clogged PCV, 10-30 oil, and oil breakdown.

Mostly the oil breakdown. Shame on me. 

Shame on me because I should have killed the PCV a long time ago, and changed to a second breather. Shame on me because the oil had lost its viscosity (even VR1 isn't immune to hard wear). Should have changed it sooner. And 10-30 just won't cut it for my driving conditions (no matter the builder's recommendation). Using 20-50 now.

Learning the simple things the hard way.   Thanks everyone for the input.