Oil pressure/Oil restrictors
 

I have a 540 big block with solid roller cam and The oil pressure is not as good as I would expect it to be. cold it's like 55when it's hot running it's like 40 and drops down to 15 idling hot have a new millodon high volume oil pump ,bearing clearances are all good somebody was talking about putting oil restrictors in the back of the block and that it might be bleeding off in the roller lifters. Oil temperature is between 190-230 . I'm at wits end with this I pulled the motor apart because the pick up tube cracked but before that I had about the same pressure. Oil pump clearance was a little loose but the mains and rods were perfect I put a new oil pump in it and a bigger capacity oil pan read did all the oil lines to the filter and it still doesn't have the pressure I think it should have ! I would expect to have 80 cold and at least 60 cruising hot and 30-40 at idle hot . I would appreciate any input on this thanks
Ritchie

What was done to the block at the filter?
Are you using a remote filter and if so which one?
What size are your lines?

Have you read through this thread?

http://www.offshoreonly.com/forums/g...-hardware.html

Smitty did a good job with that thread. What gen is the engine? I remember years ago I had one engine noticeable down from the other but never showed any signs. I ran excessive bearing clearance then due to cold water temps and no oil stats so I just put it off on that. It didn't fit the rule of thumb of 10 pds per 1k rpm. Hot I was at 40 psi wot extended run periods.

Do you have the screw in plugs in the oil galleys behind the timing chain in gear or are they the drive in type that look like freeze plugs? I haven't had the pleasure of dealing with all the newer generations so I'm not sure if they are still screw in or not. Just trying to think outside the norm a bit.

Or regulator stuck open on the pump...wouldn't be a first time.

True.
Also OP is this a new build for you or a rebuild. Any changes in oil plumbing, bypass. Just trying to think of any changes you may or may have not done.

You may have a cross-drilled crankshaft, they use quite a bit more oil.

Verified with a mech gauge? Mine was reading about 20-30psi low until I checked it and bought a new sender.

what is the lifter to bore clearance?

what oil pump did u use, and did you install the higher pressure spring.. A stock melling pump comes with a 40# spring

BB chevys do not need a bunch of oil pressure to live, some try to run 75-90psi and only thing you are doing is using up HP to drive the pump that hard. As long as your clearances are good and you are maintaining that and oil temps good, you are fine, in drag racing we restricted the oil to the top of engine, but that was for short term runs, on boats you need the oil up top as that is the only cooling for the valve springs and they are high on failure list, running them with little cooling only kills them quicker. The oil lines/cooler/adapters are another story, make sure that is done with good parts and at least #10 lines, 1/2 fittings..

Yes to much isn't good either. Gauge was mentioned earlier. Did you try an mechanical gauge to confirm pressure is consist with electronic?

I changed the stock remote filter adapter on the block to a canton adapter and ran 5/8 id hose , the connectors are 7/16 id to the external filter housing witch is stock merc unit

Re did the motor about five years ago it was a ZZ502 block and we stroked it and made it a 540 even with a ZZ502 block the oil pressure was kind of the same situation I have now.the pick tube cracked last year and we put a new oil pump in it milodon 18760 and pick up tube and canton oil pan and block adapter. It had a meling hv pump in it before. Changed the oil lines to 5/8 id and the connectors are 7/16 id . The housing where the filter mounts is a stock merc unit. The clearances on the mains and rods are .002 . When we made it a 540 I also put a 30lb bypass valve in it

Have tried mechanical gage and reads the same

The 7/16 ID would be for standard oil flow and IMO this is a restriction point. If yours was like mine I removed those fittings and replaced with 1/2 NPT to AN-10 fittings.

Stock
[ATTACH=CONFIG]565477[/ATTACH]

AN-10
[ATTACH=CONFIG]565478[/ATTACH]

Since you are using a Canton adapter and 5/8 ID (AN-10) lines I'm assuming the center filter fitting was removed

[ATTACH=CONFIG]565479[/ATTACH]

Center fitting removed
[ATTACH=CONFIG]565480[/ATTACH]

Dumb question, but are you sure that you have the right bypass valve in it? I'm not going to pretend that I have the slightest idea of what the issue is, but even too many 90* fittings can be a problem. If there's a restriction it overwhelms the bypass valve. This is all assuming there are no mech issues.

Yes I removed the filter fitting , the canton screws in there, the fittings on the 5/8 lines I used are 7/16 id, could that be causing the low pressure?

When I had the motor done 5 years ago I made a special trip to the engine builder to give him a 30lb bypass valve to put in it! It's a possibility he didn't change it witch would be ****ed up!! Would that cause it to have lower oil pressure? I'm going to buy another one and Change it to make sure

I've never liked those bypass valves and eliminated when ever given the chance. If oil has to go through bypass you already have issues. Block and change filter more frequent.

Thanks for your input I appreciate it

what brand&weight oil are you using?also,.002 rod&main clearance is to tight for a bbc,espically a 540 marine engine imo.

I'm just figuring out the oil sizing stuff my self. Have changed out all my stuff last month in prep for this season. PM Smitty for comment

change the oil filter adapter to a moroso or canton and try a wix(napa gold) filter, I lost 15psi by switching filters once, scared the hell out of me...but the stock merc adapters I've seen are very restrictive..

Lucas racing 20/50, I run it in all my old muscle cars also because it has a high zinc content, when I pulled it apart when the pickup tube cracked the mains looked great and the rods had a little wear on them so I replaced them but they really weren't bad at all

I changed the adapter on the block to a canton , but not the one the filter screws onto , only filter I use is wix racing, been using them for years on the boat and my old muscle cars

I to am using wix racing on the boat, but wouldn't use them on a car unless its just used for track racing. They don't filter as fine and there is a lot more crud passing by a car, just an opinion

Two of my cars I raced at the dragstrip and drive on the street I've always used those filters and never had an issue I got 500 passes on my GTX and I still haven't pulled it apart maybe this summer just to replace the bearings and hone and re ring it. Oil pressure is as good as when I first put it together 17 years ago

The stock filter head has a tiny passage inside of it. But it's super easy to just dremel it out to double its size.

Just info not trying to change the way you maintain your motor.

Wix 51060 flow rate 0f 9 to 11 GPM and filters at 21 microns
Wix 51060R flow rate of 28 GPM and filters at 61 microns

So the standard flow filter will filter a particle smaller then a human hair, the racing filter will let something that size pass.

I don't have high flow oil pumps in my car/trucks, but sounds like you do and may need the flow rate

[ATTACH=CONFIG]565511[/ATTACH]

Great thanks !! ill do that

Yes I do have high volume pumps in them , thanks for your input very interesting

If your fitting ID is 7/16 , your restricting the oil flow basically down to a - 7 . AN is sized by 16ths , 5/8 is 10/16 or AN -10. So your down between -6 & -8 through your
7/16 Fittings.

I seen a bypass in pump stick open before, under 900 rpms pressure dropped to zero.

Good info

Definately less than ideal at 7/16 id but if he really has .002 rods and mains the flow requirements to maintain static pressure wont be as high, i could also see it possibly being a restriction cold but hot I'd be looking harder.
Stock filter head with restrictive passages, they suck. Dont be afraid to take any steel adapters in your oil system that look restrictive and carefully port them if hard to find larger replacements. Ive seen hyd hose fittings on oil systems, terribly restrictive, not running 5000 psi so doesn't need as much beef! I also think if your engine builder didn't put in 30lb bypass and it was opening oil temp would be sky high

bottom line is the merc filter mount belongs in the round file for anything other than a stock setup..

their is no getting around the fact that the smaller micron filter restricts flow,do i need a filter that restricts to 21 micron in my boat engine that get,s a new filter& oil change at 10 to 12 hours?NO.not with 20w50 motor oil.do i want 21 micron filtration in my daily driver that uses 5w30 and get,s changed every 5000 miles,YES.jmo.

Hi I really appreciate your input you seam to be the guy with a lot of knowledge with oil pressure issues, I've read your articles and they are very informative. Is it possible for me to call you and bother you for a 5-10 minutes of your time I would really appreciate it thanks
Ritchie