Oil pressure is low
Thread Starter
TECH Resident
Joined: Sep 2019
Posts: 819
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From: Melbourne, Australia
Oil pressure is low I have a built lsx 454, solid roller,Callie’s crank and rods, je pistons, Mamo heads n intake, .937 jesel keyway lifters ,new bearings throughout
I had mamo put titanium valves in the heads and had block machined to accept the jesel lifters,
I was running a melling 10294 low volume, standard pressure ol pump. At hot idle was seeing 16psi and wot 33psi
Changed out pump to melling 10296 high volume high pressure At hot idle its 20psi and wot 39psi , max It
will go is 39psi
.
Changed engine oil , looks good. No debris in oil filter. No funny noises, no oil leaks , it doesn’t smoke
the car absolutely rips
Whats your thoughts????
I’m was thinking go to mamo ported melling 10355 but I don’t know if it’ll help
I had mamo put titanium valves in the heads and had block machined to accept the jesel lifters,
I was running a melling 10294 low volume, standard pressure ol pump. At hot idle was seeing 16psi and wot 33psi
Changed out pump to melling 10296 high volume high pressure At hot idle its 20psi and wot 39psi , max It
will go is 39psi
.
Changed engine oil , looks good. No debris in oil filter. No funny noises, no oil leaks , it doesn’t smoke
the car absolutely rips
Whats your thoughts????
I’m was thinking go to mamo ported melling 10355 but I don’t know if it’ll help
Last edited by Mickyinks; Jan 30, 2025 at 11:02 PM.
What is your bearing clearances and what weight oil are you using? Have you cut the oil filter open yet and inspected the filter element? Correct o-ring on pickup tube? Pan to pickup clearance adequate? LSX cam retainer plate seal? Pressure verified by a mechanical gauge?
Just brainstorming some of the likely culprits.
Just brainstorming some of the likely culprits.
Thread Starter
TECH Resident
Joined: Sep 2019
Posts: 819
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From: Melbourne, Australia
.0025 mains , filters has been opened, pan to pic up hasn’t changed , I am getting fluctuating gauge
Driven 15w50 oil
I think I’ll get mechanical gauge and see what tht does
Driven 15w50 oil
I think I’ll get mechanical gauge and see what tht does
I was running a 10295, added an oil cooler, big remote filter and about 12 feet of -10 AN line. At the road course I'd see very similar pressure after 30 min stints. Bearings are .0025 give or take .0001 on rods and mains. This was with 0w40 mobil1
Bought Tony's 10355 pump. Seeing no less than 30 at idle, 60-70 wide open to 7200. On a mechanical gauge though. If you haven't ran a mechanical gauge, do that first.
I am also running a vacuum pump, so my numbers are artificially lower than expected.
Mine is a 99 fbody though. The dash gauge never goes over 40, which was freaking me out initially before the mechanical gauge got added. They are known liars.
Bought Tony's 10355 pump. Seeing no less than 30 at idle, 60-70 wide open to 7200. On a mechanical gauge though. If you haven't ran a mechanical gauge, do that first.
I am also running a vacuum pump, so my numbers are artificially lower than expected.
Mine is a 99 fbody though. The dash gauge never goes over 40, which was freaking me out initially before the mechanical gauge got added. They are known liars.
What kind of clearance are you running on the lifter bores?
those 16 holes have a lot to do with oil pressure.
I would think with 10296 oil pump with a block with priority oiling (lsx )with main bearing clearance @ .0025”and rod bearing @ .002 you would have great oil pressure.
may you have good luck finding your problem
those 16 holes have a lot to do with oil pressure.
I would think with 10296 oil pump with a block with priority oiling (lsx )with main bearing clearance @ .0025”and rod bearing @ .002 you would have great oil pressure.
may you have good luck finding your problem
Last edited by Last 1; Jan 31, 2025 at 11:35 PM.
This is the only way to tell what the pressure rally is.
I believe there's been more money pissed away chasing non existent oil pressure problems because of a "dash" gauge than anything...
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Joined: Sep 2019
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From: Melbourne, Australia
What kind of clearance are you running on the lifter bores?
those 16 holes have a lot to do with oil pressure.
I would think with 10296 oil pump with a block with priority oiling (lsx )with main bearing clearance @ .0025”and rod bearing @ .002 you would have great oil pressure.
may you have good luck finding your problem
those 16 holes have a lot to do with oil pressure.
I would think with 10296 oil pump with a block with priority oiling (lsx )with main bearing clearance @ .0025”and rod bearing @ .002 you would have great oil pressure.
may you have good luck finding your problem
I can’t remember what jesel wanted for lifter bore clearance, I’m confident the machinist board correctly.
I slowed a scan replay and I see 49psi show , it’s all over the place so will mechanical test it
That pressure is way too low for those clearances and the oil weight you're using. Both of my cars are f-bodies and the electronic gauge readings on those cars are coming in10-15 psi higher than what my mechanical says. When I built the LSX I measured .0027 mains and .0025 rods and with 5w30 on hot idle the mechanical gauge reads 50-60 psi. I have those same clearances on the LS370 with 5w30 and have similar oil pressure at hot idle. I'd also mention that I have high volume oil pumps on both cars. Could be you just have a faulty electronic so put a mechaincal on it and report back.
On The Tree
Joined: Jun 2022
Posts: 111
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From: Las Vegas, NV
My low hot oil pressure on a newly rebuilt LS3 was corrected with different cam bearings... prior attempted fixes were oil pump/COPO relief spring, pickup O ring and lifters (replaced 2110r's with ls7's). Luckily I had a repair shop recommended by the machine shop work together to chase down the issue and the majority of the costs were taken care of by the machine shop. Machine shop found that the cam bearings (clevite) were on the loose side with the cam motion LS3 stage 3 cam and replaced them with durabond. Hot oil pressure (220*) is now ~35 at idle with the johnson 2110r lifters (goes to 70+ above 2.5k) with 10-40w oil. Before warm (less than 10 minutes running) oil pressure was ~15 psi and would only reach about 30 psi when revved... startup oil pressure was ~ 40 but would start dropping within a few minutes. Oil pressure was measured using a electronic gauge with the sender in the oil cooler blockoff plate and compared with the valley cover sender. Both readings were within 5 psi... the repair and machine shops used a mechanical gauge in place of the oil cooler blockoff plate sender which was verified and within a few PSI of each other.
Thread Starter
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From: Melbourne, Australia
I am referring to the lifter to bushing clearance numbers. Did you guys hone the iron block lifter bores to accommodate the bigger lifters, or did you bore the block and install bronze bushings? I would think you went bushings with the lifters being keyway style…
Thread Starter
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From: Melbourne, Australia
Yes had to install the keyway bushings
Teching In
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hey, just a thought i have just learned that the 6.0 block loses the middle cam bearing. it turns just enough to get no oil. the bear crumbles and the cam left with no bearing in the middle. motor will run untill cam breaks i had to use a larger or wider cam bearing the ch23 is what goes in it but found out the ch25 bigger oil hole hole fits tight and about twice as wide i dont know if this will help you but a
Do you think the blow off valve in the pump is just opening up too early. The idle PSI is a little low but the high rpm one is pretty low. But I guess you changed out the pump so both of them can't be bad. Keep us posted on the mechanical pump. Are you running an oil cooler?
Thread Starter
TECH Resident
Joined: Sep 2019
Posts: 819
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From: Melbourne, Australia
Yes I am running an oil cooler
i hvnt put a mechanical gauge on it yet but I hv done about 2500 miles , no weird noises, hv done 2 oil changes with nothin in oil filter. I have time this week t check with mechanical gauge, I’ll report back on what I find
i will say that the cam mamo specced for me is freaking nuts, pulls way harder than my last cam, without a doubt it’ll be 700+rwhp…..
i hvnt put a mechanical gauge on it yet but I hv done about 2500 miles , no weird noises, hv done 2 oil changes with nothin in oil filter. I have time this week t check with mechanical gauge, I’ll report back on what I find
i will say that the cam mamo specced for me is freaking nuts, pulls way harder than my last cam, without a doubt it’ll be 700+rwhp…..
