Bad oil pressure?

L

ling102

Member
I have a 8BA in a 1946 Ford Coupe.
It has Edelbrock aluminum heads, 3 deuces and Reds Headers and straight pipes "true duals".
It has been converted to 12V. It has new 30w non detergent oil and new oil filter.
It has all new aftermaket guages to include two water temp gauges.
When the car is up to temp. 175° at 2000 rpm the oil pressure is 25-30 psi.
At a stop sign, the psi drops to ZERO. What should the psi be at, at operating temperature, at idle?
What should the psi be at, at higway speed?
What can I do to increase the oil pressure?
Thanks guys.
 
Non-detergent oil is for engines without an oil filter. Lawn mowers specifications call for a non-detergent. Old cars without an oil filter used non-detergent oil. The dirt drops out of the oil and lays on the bottom of the oil pan. You don' t want it circulating in the oil with no filter to remove it. Engines with oil filters use detergent oil which keeps the dirt suspended in the oil where it can be carried to the oil filter and removed.

As for the oil pressure. You can try a different weight oil or bump the idle rpm up a little What is the oil pressure at idle when the engine is cold and the oil is thicker..
 
Just a idea . Some aftermarket gauges read to 100 psi , and aren’t that accurate at showing low pressure. I would try finding low pressure gauge , say one that reads to 50 psi as max .
It may show some oil pressure at warm idle .
Do you know when the last time your oil pan was removed? It may have a large amount of sludge giving a false oil reading on the dipstick. Probably not related to your situation.
Does your mtr make any noises ? I hope this is making sense , no coffee yet.
 
There is currently a thread on the H.A.M.B. titled "Old Wives Tale about non detergent oil". It is rife with posts testifying to the large amounts of sludge found in engines run with non-detergent oil. Sometimes it gets so bad that it covers the oil pickup in the pan. Surprisingly, there are no statements of real life situations where running detergent oil after non-detergent oil caused any fatal problems. I have two suggestions for the O/P. First, remove the pan and intake and clean the sludge out. Second, DO NOT USE NON-DETERGENT OIL. It is completely outdated and will quickly sludge up an engine.

And the referenced thread is properly titled when it says that the information floating around is "old wife tales". I would suggest reading that thread all the way through.
 
Do you have the restrictor fitting on the inlet to the oil filter? Disconnect the supply line to the filter and screw a plug in the block and see if the pressure comes up.
 
Ggmac said:
Just a idea . Some aftermarket gauges read to 100 psi , and aren’t that accurate at showing low pressure. I would try finding low pressure gauge , say one that reads to 50 psi as max .
It may show some oil pressure at warm idle .
Do you know when the last time your oil pan was removed? It may have a large amount of sludge giving a false oil reading on the dipstick. Probably not related to your situation.
Does your mtr make any noises ? I hope this is making sense , no coffee yet.
Click to expand...

If you are using electric oil pressure gauge ensure the needle is on '0' with power on. I had this problem with some expensive gauges (it showed -10psi) so I installed a mechanical gauge on the engine which showed the electric gauge was in fact reading low. I verified this with 2 other mechanical gauges. I have heard of more inaccurate reading with electric gauges than mechanical, even the cheap ones seem accurate.
 
In reality 5/10 lbs is all you need at idle 20/30 in cruise and 30/40 at WOT. Running 60/70 lbs of pressure in our first stock car engine We broke the crank do to cavitation erosion. It also had a bad effect on the bearings. This is called a learning experience.
 
As I've post'd 'some time back': Am I right? to wit, the typical '30s, '40s owner would waste no time thinking about oil in her/his flathead; i.e., there was a family to raise, daily job in order to stay alive.

1963, '64, '65 high school days, I worked weekends at the local
(independent oil co)'gas station', full service which included advising the owner driver at the pump: "You're a quart low" reply: "Put it in."

I'd oblige with '30' non-detergent by pulling a metal-spout quart bottle off the office quart-oil table, and return . . . "That'll be 30 cents." and dump in.

Although, we stocked doz+- detergent on that table as well for those "You're a quart low" replies; i.e,
"My husband remarked as I left, TELL 'EM 30 WEIGHT DETERGENT! 30 WEIGHT DETERGENT . . . . ! Whatever that means."

"A can quart of (Pennzoil) detergent; none 'a that bulk-quart detergent-stuff that you sell."
*****

Also, have you ever . . . ever heard of anyone pulling the pan to scoop out the (oil) sludge during those early decades? Not I. It's not goin' anywhere; it's stayin' right here on the bottom. It's made outta oil; leave it there!

Joe Blow: "I'm gonna have a mechanic, ah, how do you say - drop the pan and scoop out the sludge? Scoop out the sludge."

Typical would-be in-group reply: "I think he's a little teched in the haid. . ."
 
Many times the sludge would build up to the point that it would cover the inlet screen. Seen that in many old engines I've pulled apart. What do you think that does for oil flow?
 
Regardless of the oil you're running - 0 PSI (if true) is not good. First figure out if your gauge is actually accurate (I always use mechanical gauges). Then make sure your filter in correctly setup --> if it is a Fram-Style drip-feed, then it should have an orifice in the inlet side - with about a .060 hole.

If the above checks out, then you have an issue that needs to be figured out and addressed. There can be multiple reasons for low oil-pressure . . . everything from worn out bearings, incorrect bearing clearances, blown out oil-plugs in the crank, etc.. Do you know which crank is in it? Ford or Merc 4"?

History: You gave us no history on the engine? Is it new, old, recently acquired, etc.. Did it use to have good oil pressure and now it doesn't? When was it built - what do you know about its history (especially related to oil pressure), etc.

Give us some more info to work from.
 
Thanks for all the replies.
To clarify: I have a mechanical oil gauge.
I have no information on the motor, as the car is a recent purchase.
I found information on the H.A.M.B regarding a "better" oil pump, that being
a Melling M19 which I have ordered.
I will be cleaning and dropping the pan and installing the Melling oil pump along with adding Valvoline VR1 oil.
I will post my results when I have time to perform these tasks.
Thanks again for all the replies.
 
Well, don't pin a lot of hope on tha tnew pump. I had a new Melling in an 8BA new build and best pressure was 45 at cruise and 5-8 at idle @ 180 temp. Reputable builder & every part was new but the crank. I'm not impressed.....
 
The M-19 is a copy of the stock 49-53 Ford/Merc pump. Your engine should already have that style of pump in it. There are a few posts about some bad Melling's pumps out there - though I haven't had one.

I have had a bad 'Speedway' brand pump - where the casting didn't quite cover the hole in the block - would have had a major pressure leak. It went back to Speedway and I rebuilt a stock pump.
 
Mart did a video on this very thing. I'd recommend mart's garage on you tube.

Sent from my SM-G960U using Tapatalk
 
flatjack9 said:
The stock pumps very seldom go bad. I have tested many.
Click to expand...

This. Jack did a couple for me. I had made the mistake of putting a new Speedway Motors pump in a fresh rebuild, and it idled at 15 psi and ran at 40 psi. I've done a few flatheads (8BA's), and knew this wasn't right. I had two original Ford pumps in my stash, and Jack kindly tested them for me and returned them with a note that they were both "in spec". I installed one and the engine idled at 25 psi (hot) and run at the relief spring pressure (57 psi) at speed. I would never use anything but a tested original Ford pump again. I'm kinda surprised "Ol' Ron" hasn't chimed in here, as he has had some bad experiences with Mellings pumps.

I also learned to get a new gasket set with seals when you replace an oil pump. Since it was a fresh rebuild that didn't leak, I thought that if I was super careful, I could get by with reusing the gaskets. I ened up with a persistant (but very small) oil leak out of the rear main.
 
A can of STP on top of the 10w30 pennzoil syn made about a 10 psi difference on my recently acquired (750 miles and 8 months ago) stock 8ba. It otherwise runs fine, burns no oil, and good compression. It was reading about like yours.
 
You guys covered the subjeck pretty well. I never used ab aftermarket pump since I had the problem back in the 90's. Most guys now use a checked out stock pump now days. Unfortunately, not many people can check them any more??
Gramps
 
Thanks for all of the replies.
I purchased and installed a new M19 oil pump.
I purchased and installed an oil temp gauge in the oil pan.
I put in 2 quarts of Valvoline 50wt VR1 Racing oil.
I put in 2 quarts of Valvoline 20-50 VR1 Racing oil.
1 can STP.
1 can Lucas Break in oil.
All is good.
I let the car run stationary for about 30 minutes with the engine temp at 180 degrees, and the oil temp at 200 degrees.
I did stop and go driving for approx: 35 miles with the temp. at 180 degrees, and the oil temp at 200 degrees.
At 800 rpm at traffic lights and stop signs the oil pressure was 15psi.
At approx 50-55mph the oil pressure was 40psi, and the oil temp. at 200 degrees.
i am very happy with the results.
Thanks again for the replies.
 
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