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Discussion Starter · #1 ·
After f'n around with intake gasket crap, now I have oil pressure crap.

Stock-ish bottom end build 5.0.
Stock block, rods, crank, .020" over.
HCI + exhaust.
Nothing crazy.

Cold engine (70-90F), stock oil pressure gauge is a hash or 2 above middle and steady regardless of rpm.
After driving about 5 miles, oil pressure is down to about 1/4 up from low on stock gauge when running at about 1700rpm on highway (2.73 gears) when hot, which seemed low to me.
Above about 2500 rpm, gauge is right around the middle, maybe a touch under.
Idle it was dropping down to bottom hash mark.
No unusual noises that I can tell.
I know it wasn't that low at the beginning.

Running 10W30 conventional oil, fl1a filter.
First oil change was after about 30 miles so current oil/filter is around 500 miles.
Primed engine before first start and had about 60psi on mechanical gauge.

Hoping it was just the crappy factory gauge/switch, I connected a HF mechanical gauge and it was sitting at about 15psi at 800rpm idle hot.
Rev it up to 3k rpm in neutral, gauge goes up to about 30-35psi (I cant remember exact number).
I plan to connect the mechanical gauge cold and take it for a drive to see what it shows as oil heats up.

I assembled this engine this spring.
I had the block bored, decked and the crank polished and balanced (with my balancer and flywheel) since it was the only new(er) part.
Bearing clearances checked. Mains were a little tight at .002-.0023, but not crazy.
Rods were right around .002-.0025"
Melling M68 pump.
Front oil plugs were threaded/plugged.
Really just your regular stock build.

I haven't beat on it really.
Small stack of pulls up to 5k rpm and 1 or 2 up to 5500, but mostly mix of city/highway driving.
Doesn't burn any oil.

Oil is still light in color, but I haven't been able to really look for an shiny flakes.
I plan to drain oil and cut open filter this weekend, but I'm worried that engine will be coming back out.
I'll run my borescope up into the oil pan see if I can spot something obvious.

What are chances it's not serious?


I should have left the other "full home garage" stock rebuild in the car.
While it had no power above 4k rpm, at least it idled and drove like a stock engined foxbody.
 

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Discussion Starter · #3 ·
Roger that.
My main concern is that it seems to be noticeably lower (hot) than it originally started 500 miles ago.

I know this is beaten to death (with comments from all sides), but conventional, blend, synthetic? Whatever I can find in stock?
 

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The factory gauges are notoriously inaccurate. 15psi when hot and at idle is fine.
 

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What does it make at 6000rpm?
That’s what I’d care about.
 

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10 per 1000 rpm
in all my years of hot rodding etc.. thats usually always been great.. plenty of oil pressure..

even in my pro mod, i havent been real concerned about oil pressure.... and i know i need to modify it.... i'm topping out at around 65psi spinning 7700rpm.. but hey.. no sign of that being a problem yet..

what has gotten me to raise an eyebrow lately, is a few races i've been to, i've tried to easedrop on some of the other guys when it comes time to talk tech... and they are running 100+ oil pressure.... even at idle they are concerned if it drops below 50.. they wanna see 120 or more on the data logger at peak rpm.. i know i'm about to have to make some modifications because of aeration.. my pan and windage tray arent the best and i need to get that fixed... but should i be looking at trying to do something different with my oiling system over the winter? fwiw most of these cars are 2k to 3k horsepower.. most hemi/proline/bae/etc..
 

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After f'n around with intake gasket crap, now I have oil pressure crap.

Stock-ish bottom end build 5.0.
Stock block, rods, crank, .020" over.
HCI + exhaust.
Nothing crazy.

Cold engine (70-90F), stock oil pressure gauge is a hash or 2 above middle and steady regardless of rpm.
After driving about 5 miles, oil pressure is down to about 1/4 up from low on stock gauge when running at about 1700rpm on highway (2.73 gears) when hot, which seemed low to me.
Above about 2500 rpm, gauge is right around the middle, maybe a touch under.
Idle it was dropping down to bottom hash mark.
No unusual noises that I can tell.
I know it wasn't that low at the beginning.

Running 10W30 conventional oil, fl1a filter.
First oil change was after about 30 miles so current oil/filter is around 500 miles.
Primed engine before first start and had about 60psi on mechanical gauge.

Hoping it was just the crappy factory gauge/switch, I connected a HF mechanical gauge and it was sitting at about 15psi at 800rpm idle hot.
Rev it up to 3k rpm in neutral, gauge goes up to about 30-35psi (I cant remember exact number).
I plan to connect the mechanical gauge cold and take it for a drive to see what it shows as oil heats up.

I assembled this engine this spring.
I had the block bored, decked and the crank polished and balanced (with my balancer and flywheel) since it was the only new(er) part.
Bearing clearances checked. Mains were a little tight at .002-.0023, but not crazy.
Rods were right around .002-.0025"
Melling M68 pump.
Front oil plugs were threaded/plugged.
Really just your regular stock build.

I haven't beat on it really.
Small stack of pulls up to 5k rpm and 1 or 2 up to 5500, but mostly mix of city/highway driving.
Doesn't burn any oil.

Oil is still light in color, but I haven't been able to really look for an shiny flakes.
I plan to drain oil and cut open filter this weekend, but I'm worried that engine will be coming back out.
I'll run my borescope up into the oil pan see if I can spot something obvious.

What are chances it's not serious?


I should have left the other "full home garage" stock rebuild in the car.
While it had no power above 4k rpm, at least it idled and drove like a stock engined foxbody.
Im not worried about mine like you, but I can give you my experience, and before I do that you may want to actually get a good gauge that tells you a reading instead of just a dial with no numbers.

Anyway my car when I put 20-50 vr1 in will have about 70psi cold and goes to about 50psi at idle hot. When I put 10-30vr1 in the car is will be around 55-60psi cold and goes down to about 40-45psi hot.
 

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Mine is 25psi hot 50psi cruise 55-60psi at 7000rpm with 0w-40. At first I was concerned that was too low but Woody told me to not worry, so I’m not. Car has ran like a beast for 10k miles so far plus open track. I believe the pump in mine is a melling 68 high volume. But, I’ve learned there are so many inconsistency’s with gauges, even mechanical ones. Just look at the range and make sure that’s good.
 

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Discussion Starter · #13 ·
We'll see what the oil and filter look like tomorrow. Pulled drain plugs and letting it drain overnight.

Figured $40 for oil/filter change to inspect the current oil/filter would (hopefully) give me the peace of mind something isn't messed up. Should be able to get borescope in there to check the pickup as well.

@massacre - no idea what oil temp is. Coolant runs about 200+/- and I havent been beating on the car, so I would guess oil temps are similar.
 
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If there is any chance that crap is in the pan then it will never drain out by flushing it. I've been through this miserable process using a camera through the drain plug hole and no matter how much I flushed thru the pan the debris wouldn't even flow to the drain hole. Debris was caught in the screen and simply sitting in the corners of the pan. I ended up taping a wire finger to the end of the camera then hooked/pulled the junk thru the drain hole. Very time consuming but worked fantastic.

ks
 

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Discussion Starter · #15 ·
Yeah, I didn't think letting it drain overnight would remove any more crap, more of it's too hot and I'm too lazy to pick up oil/filter tonight. Plus, I want to drain as much oil out so when I use the camera, less oil to coat it.
 

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I raced a little rwd Corolla in SCCA for 7-8 years a thousand years ago. 1588cc pushrod hemi. We machined a small groove in the front cam journal to get a bit more oil to the topend. It worked - BUT we lost oil pressure. 55-60 races, 30 minutes to 3 hours long, the little engine lived between 4500 and 7000 rpm. Once warm (1 racing lap) I never saw more than 25 psig. Motor never missed a beat - won 2 Division Championships. Hot Houston summers - I was a lot more concerned with the temp gauge than the oil pressure gauge. Fwiw

Edit - I should elaborate - after a few races of watching the oil pressure gauge more than any other gauge, I realized that engine under those circumstances was happy with about half the oil pressure I'd believed I needed. Then - I let go of the oil pressure "problem" that turned out not to be a problem. On that engine.

Edit #2 - Just put 30 miles on my current "hot rod" Corolla this morning on the way/back to a Cars/Coffee here in Charlotte. Just got through swapping in a JDM Toyota twin cam engine -- same short block as described above. 65psig cold start, oil pressure gauge mimics the tach. At full hot (200F operating temp) at a 900 rpm idle I see about 12 psig on the gauge on 5w-30. Not uncommon with these engines. And not a problem. Although, after the first 100 miles or so - dump oil, cut open filter, etc. - I'll probably try 10w-40 or 20w-50 to see if I get a little bump.
 

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Discussion Starter · #17 · (Edited)
Ooohhhh, shiny/$hitty.

Bottom of drain pan. I wiped it out really well before draining engine into it.

Automotive lighting Fluid Gas Circle Tints and shades


Oil filter. A few specs.
Brown Product Textile Wood Pattern




There is a small possibility that the specs in the filter are from when I cut off the top of the oil filter with a tin snips, but I don't think so.
 

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Discussion Starter · #20 ·
Ran out there quick, pulled belt off and tried to move crank around from the top.

I don't think I felt or saw any movement, at least it wasn't obvious.

Maybe I can get under there later and try again.
 
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