There used to be a great site with an article for "blueprinting" the stock oil pump to eliminate some of these problems. It was pretty much what the guys who built my engine did to a new stock pump. But I can't find the article any more. It was in a GoFastNews.com post, but the guy went back and deleted the content. Thread is still there, but the original post is empty.

 

I think it's the spring. I had the same issue once I changed my spring. I have since rebuilt the motor and still have the issue. I am willing to bet the white spring is the culprit.

 

I agree with you.

Same thing was suggested to me, but plenty of guys on this board are using the stock pan with no issues. If I was autocrossing and having this issue, I would change the pan. However, I'm having this issue on the street and never had it until I made the changes I mentioned earlier.

 

i have been trying to find that also, i had it saved on my old computer but that is long gone - if anyone has it saved or knows where to find it please let me know

i really do not understand how the spring could be the problem, however... i do believe that changing the spring will mask or cover up the problem - because the pressure will not get high enough to cause the issue, or at least the drop will be minimal at that point - not a 15 to 20 psi drop like now

 

I know I'm stretching and could be flat wrong.....

The only thing I can figure is that there are waves of pulses generated by the oil pump. I'm going to speculate that those waves are reflecting back towards the pump creating our pressure drop at a certain RPM. It's like two currents of the opposite direction canceling each other.

I have got my engine down to the block and have found no cause for it. Of course, I'm no engine expert, enthusiast yes...expert no, so I have to go back to my troubleshooting skills and do a process of elimination.

I see no way for the rockers, pushrods, lifters, and cam to cause a pressure drop of this type(drop then come back 60psi). The spring directly effects the pressure, so I'm going after that as the issue. I got side tracked after finding my number one main with those grooves and am now hung up on the cam bearings. I've got to get a tool from my Dad's machine shop to knock down those sharp edges on the cam bores, so I don't get a bunch of metal in the oiling system from the cam bearing installation. He is also going to machine me a tool to draw those bearings into place rather than hammering them.

But that's for my issue....I agree with you that Wrd's drop is really concerning. I'm not sure if reflected waves could create that quick of a drop, but it's something to try if all his bearing clearances look good and there are no cracks in the oiling system opening up under load.

I also go back to that High Performance Chevy article mentioning that too high a pressure creates air pockets in the system. I wish they had mentioned why and how.

 

the other night when i was ridin around with my wife i noticed this same thing happenin . i never noticed it before hand with the car so i quickly got the car back to my shop and looked at things i took it back out and it did it again . well i though for a min about what have i done new to it and i was using cen-pe-co 20w50 in the car i recently switched to b-g pm racing 20-50 oil to see if i liked it so i dropped the oil and put in cen-pe-co again ,well the problem did it still so i was pissed and was gonna do a manual gauge test instead of my cars gauge . well on the drive sure enough i dropped down to 20 lbs at 6k so i was heated .crawled back under it and saw the champ oil filter, we have at the shop "I USUALLY USE NApa gold but used the champ seein as i had it " well i spun that off and cut it open well the paper had come apart and what not .so i went to napa and grabbed a napa gold filter went out with both gauges on my car hot/cold no diff the oil was the same pressure it always was before . so after mt severe happiness i said f-it and put another champ on it and sure enough the pressure drops off at higher rpm,s . so long story short ,im stickin wit the napa gold filter





p.s im sorry for the **** poor grammer and what not i have bad grammer lololol

 

I have the same problem. At WOT, pressure will climb to 60, then back off to about 30 PSI. I just put an additional quart of oil in my car and it made no difference.

I have the stock oil pan, the windage tray was left in there, Jegs 23501 Standard Volume pump with 65-70 quick relief spring installed, a melling 55S1 5/8” pickup that has been installed correctly and tack welded in, 6 quarts of Valvoline 10w-30 and a standard Wix oil filter. Motor has 260 miles on it. Stock oil pressure gauge and now a mechanical is installed.

 

I installed a K&N oil filter and changed my oil to 10w-40 this morning. Same problem. I'm about to order a Canton pan and pickup.

 

What oil pump are you currently running?
What is your pressure at idle?
Do you have the bypass in the adapter plugged?
Does it drop in 1st-3rd gears just like mine as seen in the video?

 

-I'm running this pump. http://www.jegs.com/i/JEGS/555/23501/10002/-1
Standard volume

- My idle pressure is about 15 psi hot, 65 psi cold. My idle is around 750 rpms warmed up.

- Nope

- Mine drops in all gears. Sometimes is seems to drop lower than other times, it depends on how hard I launch.


I just watched your video and mine does not seem to go back up after it drops. It stays there.

 

GreenZ,
If you rev the motor up in neutral meaning no load on the motor, does the pressure still drop?

When I rev mine in neutral, I dont see the drop at all. I am not sure what the difference is between loaded and unloaded oil pressure although its still possible it could be a oil sloshing problem near the pickup. My engine builder wants me to ditch the Melling 10554 oil pump and try something else.

 

If I rev mine up in neutral, I don't have any problems. I'm going to order the Canton oil pan and pickup tonight and should have it installed by this weekend. My buddy has the same oil pump as me with the Canton pan and pickup and has zero problems with pressure.


Rob

 

Obviosly I am very eager to hear your results so please post ASAP once you know something.

I talked to Chad Golan today and he was extremely helpful and gave me some things to try. He is leaning toward that particular oil pump (10554) possibly doing something wierd. He reccomended me to use the M55HV pump but after first going to 10W40 oil and assuming that fails. From everything I provided him, he does not seem to think I have a bearing clearance issue.

 

Wrd,

Any update on solving your pressure drop?

I'm putting my engine back together now. I have to roll through checking all the new rod bearing clearances. After that, I should roll pretty quick on getting it back together. Barring no issues with getting a new oil gallery ball bearing and the front oil gallery plugs from Chevy, I'm hoping to have some news for you in 2-3 weeks on my issue.

 

I have not done much more to address it as of yet. When I recently replaced my oil pressure sender (now on the 3rd), the problem is much less obvious than with the recent more sensitive (the 2nd). I think the 1st was the same as the current 3rd and they came from the same store. The 2nd came from somewhere else and was a different color and was definitely more sensitive to pressure change.

Greenzlt1 says he fixed his problem by going with the Moroso pan and pickup. I am going to ride the problem out a bit longer and replace the pan in the winter. I am confident I have had this problem for years now and I have blasted on it hundreds of time. I doubt its really an issue or I would have already killed the motor.