oil pressure

[75valiant]

I wa wondering waht should I do to increase the oil pressure while the engine is out. It seems to me at a hot idle it looks like 10-15psi.It has one of those wal mart oil pressure gauges so its hard to tell exactly what its reading but its a little bit under the 25psi mark. Is this to low? what can I do to increase it? While the motor is apart.

Has a stock volume meiling oil pump.

[dwc43]

It's too low. First problem is a high volume pump. Unless you have a deep sump race pan swap it for a stock Mopar unit. Add the Mopar Performance oil pressure spring. IT will cost you about $4.00 bucks. That will get you what you need.

[TK]

Stock pump dwc......................ERRRRR!

Damnit, where is my midol!


Most engines I have built, uh, built RIGHT.......(LOL, I am quite the farmer Bob sometimes) idle about 20, and peak at 75-80.
10 PSI per 1000 RPM's is fine for a street motor, remember, pressure is restriction.

[dwc43]

Yeap, stock pump with pressure spring just like we use in our race engines.

And you don't need any midol. Just go get your normal fix of sheep ( farmer Bob Brown ) and you will feel much better ...

[75valiant]

So I should just add a high pressure spring to the pump I already have? It has a stock pan.

[72Challenger]

The high pressure spring won't do a thing for you at idle. It is a bypass spring and it controls the pressure at which oil from the pump goes directly back into the pan instead of flowing through the oil passages in the engine. The only time it is in use is at high RPM. If you really do have a problem with pressure at idle, and I bet you really don't, you need to look elsewhere (like maybe a good gauge? )

Check this out for a good discussion on the topic:

http://www.moparchat.com/forums/showthread.php?t=97792

[dwc43]

Originally Posted by 75valiant

So I should just add a high pressure spring to the pump I already have? It has a stock pan.

Put it in a stock pump. You don't need a high volume on your car with a stock pan. Your just wasting hp and heating the oil up like that.

[turbododge]

If you have a stock volume pump now, and do nothing else to the engine, a high volume pump will kick up your idle pressure. As DWC says, you need to make sure it will clear the pan, but most I have seen fit OK.

As was said, putting in a high pressure spring does nothing for idle oil pressure, only max pressure at speed.

Bottom line-if your old pump is worn out, a new stock pump might fix it, but I have rarely seen a shot pump without the rest of the engine in the same condition, so you would need to fix the rest of the engine to get it right. If the engine is in good shape and just has need of a little more oil volume to hold pressure, a high volume pump should do it. Forget the high pressure spring unless you are going to run high rpm.

One thing that many folks forget is that the recommended clearances that most shops use for older "muscle" car engines are on the loose side and need more oil. The fits of the bearings were much tighter when the engines were new, in most cases. I have seen very many rebuilt engines come out of shops that need to use a high volume pump, most of them with bearing clearances in the .0015 range, and slightly worn lifter bores that were still in spec.

DW-you're not back on the "pump the pan dry" baloney again, are you?

[75valiant]

the motor does not looke good disassembled all today rod bearings and main bearings are all scored up copper is showing on one rod bearing. So I'am glad I took it apart cam looks fine and cam bearings look pretty good lifters look good. just the bottem end bearings. Sand or something must of gotten in the oil galleys some how.

[dave571]

I don't think the pressure you lited in the openiong posted is bad at akk, for a high mile motor

As indicated, a high pressure spring will make zero difference at idle. The spring is the high pressure cut out. It' won't be cutting out at idle

In a worn engine, a High Volume pump will increase your pressure. It is a patch

Originally Posted by 75valiant

the motor does not looke good disassembled all today rod bearings and main bearings are all scored up copper is showing on one rod bearing. So I'am glad I took it apart cam looks fine and cam bearings look pretty good lifters look good. just the bottem end bearings. Sand or something must of gotten in the oil galleys some how.

That's why your pressure is down. Bigger clearances, the oil flows right through without restriction, result, low pressure.

Low Oil pressure is a result of excessive brg clearance 99% of the time.

Proper repair is turn the crank, and put in new bearings.

Sound like time for a rebuild, or swap in something else.

[75valiant]

Thats just the thing it has less then 500 miles on it but its getting rebuilt where putting in a new crank kit with bearings taking the block to the machine shop to get it cleaned tommorrow. Making sure there is no sand from there bead blaster in anything have him check the cam bearings and heads to make sure thre a ok and be one are way. They have the rods and pistons now I will be bringing them the balancer, flexplate and torque converter to be balacnced at wheeler tomorrow.

[dwc43]

Originally Posted by 75valiant

Thats just the thing it has less then 500 miles on it but its getting rebuilt where putting in a new crank kit with bearings taking the block to the machine shop to get it cleaned tommorrow. Making sure there is no sand from there bead blaster in anything have him check the cam bearings and heads to make sure thre a ok and be one are way. They have the rods and pistons now I will be bringing them the balancer, flexplate and torque converter to be balacnced at wheeler tomorrow.

Is this the engine from another post that vibrated so bad cause it was not balanced before it was built?? If so, now you know why it's so important to balance an engine when adding non stock pistons and rods. The out of balance is what ate the bearings.

[TK]

Could be the oil he is running too....................

Royal Purple 20w50 idles at a lower pressure, than 10w40 dinosaur oil. Of course, I know nothing.

[dwc43]

Originally Posted by dodgetruckboy

Of course, I know nothing.

Of course not. After all your the sheepmaster.

[75valiant]

Yep its the same motor. It had 15W-40 rotella in it.

[dwc43]

Good thing you tore it down. The out of balance condition is what caused that mess.