oil pressure

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famous bob

famous bob

mopar misfit
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any body got any idea how to drop upper and cold start oil pressure , "with out" , dropping the hot idle pressure ????????????????????????????????????????????????????
Not loose bearing clearances, single line system, 7 qt alum. pan , full time restricted oil to the top end , hi volume pump.
AROUND 20 POUNDS AT HOT IDLE @1150 RPM : 95 ON COLD START UP.
Finally got under it and looked for my oil leak that I thot was my girdle to block seal, turned out to be the oil pressure looks like it over comes the filter gasket at hi rpm >???????
 
Race motor? Just wondering so I can move this thread to the right forum.
 
change the oil to something that fits your needs
if your running 15-30 now, got to straight 30
(just an example)
 
diymirage said:
change the oil to something that fits your needs
if your running 15-30 now, got to straight 30
(just an example)
Click to expand...
So ur saying a straight weight oil would change the upper and not the lower, if the weight was right ?
I have ran 20w50, and now have 10w40 in it .????????????????
 
I missed this post the other day
I'm not saying run straight oil...per say
I'm saying take whatever grade oil you have now (10w40) and raise the cold (first) number
So, try 20w40 and see how you like if
 
diymirage said:
I missed this post the other day
I'm not saying run straight oil...per say
I'm saying take whatever grade oil you have now (10w40) and raise the cold (first) number
So, try 20w40 and see how you like if
Click to expand...
Don't you mean the other way around? Say like a 5w40? That would lower the oil pressure when cold and keep the same when hot?
 
Lelo Dart said:
Don't you mean the other way around? Say like a 5w40? That would lower the oil pressure when cold and keep the same when hot?
Click to expand...
You might be right...but shouldn't the higher number flow better then the low number ?
Warm oil flows better then cold oil, doesn't it?
 
I am going to go the other way. 95 PSI is a lot, but it ain't a WHOLE lot. I say look closely (magnifying glass close) at the filter boss for any imperfections. Make sure it's perfectly flat and even all the way around. Try another filter. I have seen other cars have more oil pressure and not leak. I have owned some.
 
I would think a lighter relief spring should do the trick as it stays closed until it reaches a predetermined pressure then opens up. That shouldn't affect idle pressure
 
New engine ? Recently replaced any oil system parts ? Just trying to figure why you have a problem. High volume pump won't change pressure. so...
 
diymirage said:
You might be right...but shouldn't the higher number flow better then the low number ?
Warm oil flows better then cold oil, doesn't it?
Click to expand...
Yes, my understanding is that the first # is what the oil acts like when cold and the second # is when the oil is hot.
 
Lelo Dart said:
Yes, my understanding is that the first # is what the oil acts like when cold and the second # is when the oil is hot.
Click to expand...
this ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
I have the hi volume pump spring shimmed to get the hot / idle pressure to what it is, thus the hi cold start up pressure.
ONLY run mopar filters, and have had to tighten them a hair more than normal on install. , just forgot to this time.
I used to run Phillups troparctic 20w40 in my new 68 barracuda back in the day, but haven`t seen any for yrs., would not be vmuch diff. than 20w50 I just took out , because of colder weather!
 
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Bob, Mopar filters are made by whoever gave them the cheapest bid this week. I'd run Wix (or NAPA since Wix makes them). No inconsistency with them. Since it's easy to do with a BB I'd try a stock pressure spring shimmed to give you the hot pressure your after. It is a weaker spring so it might relieve better cold. Worth a shot IMHO
 
I had a similar problem with my 367 but with a twist; at high rpm I would get a lotta smoke from under the hood which I traced to oil dripping onto the header. Thinking the filter was crap, I replaced it with another brand. And another;with no change. Since I love to hear that little 6.0 singing to 7000, this had to stop. So, I drilled four more holes in the filterplate,reamed out the attaching fitting,and chamfered it all.That solved the leakage. But I also switched to 10W30 soon afterwards.
I can't tell you the operating pressures cuz I don't have a gauge. No joke. Just the factory rally gauge. That was about 80,000 miles ago, perhaps 2002
I don't know if this helps cuz I'm not near your power level.
 
AJ/FormS said:
I had a similar problem with my 367 but with a twist; at high rpm I would get a lotta smoke from under the hood which I traced to oil dripping onto the header. Thinking the filter was crap, I replaced it with another brand. And another;with no change. Since I love to hear that little 6.0 singing to 7000, this had to stop. So, I drilled four more holes in the filterplate,reamed out the attaching fitting,and chamfered it all.That solved the leakage. But I also switched to 10W30 soon afterwards.
I can't tell you the operating pressures cuz I don't have a gauge. No joke. Just the factory rally gauge. That was about 80,000 miles ago, perhaps 2002
I don't know if this helps cuz I'm not near your power level.
Click to expand...

After making a couple of runs back in November, I may not be at my power level either ! LOL mostly severe traction problem I think-------
 
Traction? What's that?
It was a typical hot muggy July day here in Southern Manitoba, and the temp gauge hovered right at it's "normal" indication on the factory Rally gauge,lol.Yeah and I still run a 7-blade,all-steel,hi-attack, oem A/C mechanical fan,on a T-clutch,lol.
This is a seldom-used airport runway, that the local car-club (I'm not a clubber), rents almost every year, along with a rented tree.This is my first time here with this combo and she's 60footing in the 2.4x range, if I baby it out.
Hyup, crap street suspension on a crap track.But it sure was a lotta fun.
One of the starter guys came over to tell me I should let some air out of my DRs, as it was still hazing the tires thru the traps; his words not mine. I had thought my clutch was slipping, on account of the tach was hovering around 7000 the whole way. But when I returned to the pits, no stinky clutch did I smell. The Drs were already down at 12psi. That was the first successful, and last, run that day, and I called it good enough.
I tossed the keys to my 18year old son, and said "your turn".
He tossed 'em back and said "maybe next time Dad: such a good son he is,lol.
So we went for some track food, bought some T-shirts to commemorate, and hit the bleachers for a bit; then toured the town, and finally, hit the hiway for the drive home. That was 2004,the second time,and last time the car was at a track.
Nothing broke!
Out of the 4 runs that day; She went 93 in the 1/8, @3467#; and the math on that, IIRC, is 437hp, so a long way from yours.
 
FB, change to a full synthetic oil. The viscosity is much more stable across temperature range, especially at lower temps like when the engine is cold.

It's misleading to look at the cold end weight ratings of oils to decide what the cold start oil viscosity will be. The low end temp for the viscosity tests is 40C which is 104F. Your engine is not at 104F but at a much lower temp when you start it cold, and many multi-viscosity petroleum oils will thicken up considerably when the actual temp drops to 70F or lower.

Synthetics do not thicken up nearly as much when you lower the temps to normal cold start temps. Trust me....A 10W40 synthetic WILL be a lot thinner at 50F than a 10W40 petroleum oil... you can clearly see the difference when you pour it out of the bottle. Yet at 200F, they will be the same viscosity. (This better cold viscosity of synthetics is also reflected in their much lower cold pouring minimum temps, which are typically 20-25F lower than for petroleum oils.)

And yeah, I've had a cheapo oil filter gasket let go under those levels of cold oil pressure... I had loaned my car to someone else and the end result was not good LOL. So IMHO, you are wise to address this. The real wonder is how come the big swing in the first place. Is this a small block?
 
famous bob said:
any body got any idea how to drop upper and cold start oil pressure , "with out" , dropping the hot idle pressure ????????????????????????????????????????????????????
Not loose bearing clearances, single line system, 7 qt alum. pan , full time restricted oil to the top end , hi volume pump.
AROUND 20 POUNDS AT HOT IDLE @1150 RPM : 95 ON COLD START UP.
Finally got under it and looked for my oil leak that I thot was my girdle to block seal, turned out to be the oil pressure looks like it over comes the filter gasket at hi rpm >???????
Click to expand...
If you're running a high volume pump, you should be getting plenty of flow to your bearings, especially since you've restricted oil flow to the top end.

FWIW, the Hemi oil spring (PN 2406677) is rated at 75 psi. My DC Racing Manual recommends 50 psi up to 5000 RPM plus 10 psi for each additional 1000 RPM increment of crankshaft speed so your oil system now good to 9500 RPM.
famous bob said:
I have ran 20w50, and now have 10w40 in it .
Click to expand...
With a 40 grade oil (ie, 10W-40) and a high volume oil pump, I would expect that your hot idle pressure would be well above 20 psi. I get 40-50 psi at hot idle with the original 200k+ mile oil pump in my slant six with 10W-30. Running high pressure with a high volume pump unnecessarily stresses your oil pump's drive gear.

famous bob said:
I have the hi volume pump spring shimmed to get the hot / idle pressure to what it is, thus the hi cold start up pressure. ONLY run mopar filters, and have had to tighten them a hair more than normal on install. , just forgot to this time. I used to run Phillups troparctic 20w40 in my new 68 barracuda back in the day, but haven`t seen any for yrs., would not be vmuch diff. than 20w50 I just took out , because of colder weather!
Click to expand...
Shimming your oil pump's relief valve spring will not help your hot idle pressure. The oil pump is obviously what generates the flow and the developed pressure is the result of downstream flow restrictions. The relief valve prevents the pump from building excessive pressure resulting from high flow and/or high viscosity fluid friction. See Engine Wear.

Are you sure that you don't have loose bearing clearances?
 
fjr said:
If you're running a high volume pump, you should be getting plenty of flow to your bearings, especially since you've restricted oil flow to the top end.

FWIW, the Hemi oil spring (PN 2406677) is rated at 75 psi. My DC Racing Manual recommends 50 psi up to 5000 RPM plus 10 psi for each additional 1000 RPM increment of crankshaft speed so your oil system now good to 9500 RPM.

With a 40 grade oil (ie, 10W-40) and a high volume oil pump, I would expect that your hot idle pressure would be well above 20 psi. I get 40-50 psi at hot idle with the original 200k+ mile oil pump in my slant six with 10W-30. Running high pressure with a high volume pump unnecessarily stresses your oil pump's drive gear.


Shimming your oil pump's relief valve spring will not help your hot idle pressure. The oil pump is obviously what generates the flow and the developed pressure is the result of downstream flow restrictions. The relief valve prevents the pump from building excessive pressure resulting from high flow and/or high viscosity fluid friction. See Engine Wear.

Are you sure that you don't have loose bearing clearances?
Click to expand...

All interesting comments. I had synthetic 20w50 in it this summer, I think I might have switched to it too soon, may have some rings that aren`t seated yet. Only about 500 miles and 2 trips down the 1/4 in it , plus some hotrodding. ????
It actually has tighter clearance than I like, about .0022 .0024 when built. I would have preferred .0027 to .003 .
And YES, shimming the oil pump spring DID help my hot , low oil pressure !
I had an adjustable Milodon relief valve in it for a while, and really got it high playing w/ it , and took it out for the currant set up. If I had it on the engine stand to play w/ while running the pump, where I could really examin things , I would still be running it. But kinda scared to mess w/ it , my set up seems to be ok, I`ve checked diff. main and rod bearings a few times and all seems well for now. The low pressure at hot idle still bugs me tho. One thing is, the pressure is read at the back of the block, after it feeds everything in the engine on a big block .
(440/505" wedge) I haven`t tried a straight weight oil tho---------
I owned two hemi`s back in the day, raced one for 14 yrs. , they are set up oiling wise better than the 440 engines, they have dedicated oil return holes, front and back, in the block straight from the corners of the heads, and a 1/2" pick up to start with. We ran hi volume pumps, and really large alum. tie rod tube pan with 9 qts of oil back then, it had .003 clearance straight across the board , from the factory.
The hemis were both spot on in machining from the factory too.
This 1966 block required only .002/.003 decking to blueprint, so it was pretty close too-------------
My biggest problem right now is traction, but at my age , I`m not sure I can get up inside the trunk rear cage struts to tub it , too stiff and beat up now. May just try 10x29" slicks first. ( not that I`m going to race it that much at 72 anyway ! )----------And the beat goes on ----------
 
famous bob said:
One thing is, the pressure is read at the back of the block, after it feeds everything in the engine on a big block.
Click to expand...
That is small but very crucial detail that you should have mentioned in your first post. Where you measure pressure in a hydraulic system matters a lot and it did not occur to me that your pressure gauge was not connected to the normal pressure tap between the pump and the relief valve. It's as if you're concerned about the water pressure in your house but you've put your pressure gauge at the end of a garden hose.

A positive displacement pump (ie, your oil pump) generates a flow rate that is directly proportional to oil pump speed. The pressure measured at the outlet of the pump is actually measuring the oil's flow resistance downstream of the pump. If you were to hook up your pressure gauge to its normal location (where the oil pressure switch is located), you will see a much higher pressure at idle. See Engine Wear.






famous bob said:
All interesting comments. I had synthetic 20w50 in it this summer, I think I might have switched to it too soon, may have some rings that aren`t seated yet. Only about 500 miles and 2 trips down the 1/4 in it , plus some hotrodding. ????
Click to expand...
If you're still using your oil pressure switch, add a tee to pressure port and move your oil pressure gauge to it. With a high volume oil pump, my guess is that your oil pressure will be constant at all times because it will most likely be always at the relief valve pressure setting and oil will be constantly relieving back to the sump. I would try a lower viscosity oil like a 10W-30 API CK-4 HDEO (with a Ford WSS-M2C171-F1 approval), which will get more oil to the bearings and less to the sump. I like PetroCanada Duron SHP 10W-30.
 
fjr said:
That is small but very crucial detail that you should have mentioned in your first post. Where you measure pressure in a hydraulic system matters a lot and it did not occur to me that your pressure gauge was not connected to the normal pressure tap between the pump and the relief valve. It's as if you're concerned about the water pressure in your house but you've put your pressure gauge at the end of a garden hose.

A positive displacement pump (ie, your oil pump) generates a flow rate that is directly proportional to oil pump speed. The pressure measured at the outlet of the pump is actually measuring the oil's flow resistance downstream of the pump. If you were to hook up your pressure gauge to its normal location (where the oil pressure switch is located), you will see a much higher pressure at idle. See Engine Wear.







If you're still using your oil pressure switch, add a tee to pressure port and move your oil pressure gauge to it. With a high volume oil pump, my guess is that your oil pressure will be constant at all times because it will most likely be always at the relief valve pressure setting and oil will be constantly relieving back to the sump. I would try a lower viscosity oil like a 10W-30 API CK-4 HDEO (with a Ford WSS-M2C171-F1 approval), which will get more oil to the bearings and less to the sump. I like PetroCanada Duron SHP 10W-30.
Click to expand...


You sound like u never messed with a big block Chrysler. I have 2 mech oil pressure gauges on mine , one in the cockpit, one on the firewall, both come off at the stock location in the rear top of the block, both read the same thing, even tho they are on opposing ports, one is 1/8" pipe and the other is 1/4" pipe bushed to 1/8" for the oil fittings, which are at the end of the line in the oil system------------
NO FORD STUFF ON MINE !!`
 
It's been a while since I've looked at one but your description suggested that you weren't using the stock oil pressure pressure tap location. Since the pressure tap is downstream of the relief valve at the end of an oil gallery, what I wrote earlier is still true.

The "Ford Stuff" is a oil specification that requires the phosphorus content (the antiwear component of ZDDP) of the oil to be a minimum of 1000 ppm. API CK-4 specifies a maximum phosphorus content of 1200 ppm for 40-grades and higher and 800 ppm for 30-grades if they're also approved for API SN.
 
fjr said:
It's been a while since I've looked at one but your description suggested that you weren't using the stock oil pressure pressure tap location. Since the pressure tap is downstream of the relief valve at the end of an oil gallery, what I wrote earlier is still true.

The "Ford Stuff" is a oil specification that requires the phosphorus content (the antiwear component of ZDDP) of the oil to be a minimum of 1000 ppm. API CK-4 specifies a maximum phosphorus content of 1200 ppm for 40-grades and higher and 800 ppm for 30-grades if they're also approved for API SN.
Click to expand...
full roller engine ----------not concerned w/ zzdp--
 
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