oil pressure

[keithcar72]

What oil pressue should I use on a 318/360. both have hyd cam stock rods. also how do you achive this? did you change spring if so where did you get it from? or did you shim it if so how much? both engins will turn around 6000 in a 3400 lb car also any opinons about automatic vs strait drive ?

[9dodge]

10 PSI for every 1000 rpm

6000 rpm have 60 PSI don't go overboard on oil presure, as more presure is HP loss and more heat in the oil.

[crackerg]

I have had good sucess with running high oil psi. The mopar performance spring in the oil pump is a must and I reccomend installing the new spring in a good HV pump.

I have never had a oil related problem and I run a lot of oil pressure. when the engine is cold the oil psi peggs out the 100psi gauge and during the heat of battle the psi does not get lower than 30 even under hot temps.

I would highly reccomend installing the oil system modifications suggested by mopar performance if you have not already, this is key to a long life of the 318/360.

Some may disagree but the nascar guys run high prsseures as well and as I mentioned I have yet to have an oil related problem in 10 plus years.
Good luck

[sanborn]

The old rule of thumb of 10 lbs. of oil pressure per 1000 RPM under full race load is a good one. A couple of twists however. Check your oil pressure at the end of the line. If you use a standard wet sump pump, the best place to get oil pressure from is the front of the oil gallery at the #1 main passage. Why? Because if you have 60 lbs. of pressure at the rear of the block, you may have only 50 lbs. at the front main bearing. It depends upon how much restriction/losses you have getting from the front to the back.

Why don't you want more oil pressure? Because if your pump produces more oil volume than the engine can use, the excess oil is bypassed through the pump until it can be used. This continued bypassing of oil builds up serious oil temperature.

A lot of stock class oval track racers really don't need a high volume pump, they may need a high pressure pump only. Unfortunately, the only way to knpw is to try each type.

[Buddy]

Sanborn, I've heard to stay away from HV pumps if you're using a stock capacity pan, as you run the risk of pumping it dry at high RPM. Does this sound right to you?

[sanborn]

That's a loaded comment regarding HV pumps and stock pans. And it not easy to give a straight answer. Let's see if I can answer it this way.

A race engine need a certain amount of oil at high RPM to satisfy the lubrication needs of the engine. The amount of oil is different for each engine depending upon how the oil is managed. Main/rod bearing clearances only partially determine how much oil to needed. How tight is the lifter bore fit, are the lifter bores sleeved, how are the rocker arms lubricated, do you force feed the timing chain/gears, etc. These factors all determine how much oil volume is needed.

Then you have pressure requirements. The rule of thumb of 10 lbs. per 1000 RPM is a good safe rule.

The you have one of the most commonly overlooked and least understood areas- than of drainback/evacuation. Most stock pans hold 5 qt. of oil, an additional quart for the filter, total of 6 quarts. Thats fine for the street but at sustained high RPM(high banked ovals) the topside of the engine can get pumped full of oil and is prevented from returning to the pump pickup.

Let me explain how this happens on a Mopar small block. The main and rod bearings can pretty much take care of themselves, they only allow in as much oil as they can take(unless you have excessive bearing clearance or crazy rod side clearance). Where most of the topside oil comes from is the lifter bores, excessive windage from the crank slinging oil up past the cam to the lifter valley and the worst culprit, excessive rocker arm oiling. All this oil goes to the topside where it just sits. Its held up there by positive crankcase pressure(caused by windage). This starves the oil pump pickup(and the bearings). This leads to the old "rule of thumb" of adding 2-3 quarts of extra oil. This solves the problem(maybe) because the pickup has oil but it also leads to excessive oil temperature and windage drag on the crank.

What should we do it? The simple answer is learn how an engine oils. The hard part is doing it. Sure, sleeving lifter bores helps to control excess oil all you must find is a shop that does it(about $200) but there are other areas that are as effective and less expensive. We talked about baffling oil pans in a post earlier this week(very important). Camshaft/rocker oiling is the next major loss. First, I recommend oiling the rockers externally. I mean block of the oil passages in the head, drill and tap an external passage on the outside of the head and feed the head from the oil filter boss on the block or from an external oil filter mount. The rocker shafts on a Mopar only need a .065" ID line to each head and this gives enough oil to keep the springs cool as well(a Holley jet is easy to use for sizing). By feeding the rockers externally, you also can reduce the size of the cam bearing hole down to .075". This also makes sure that practically all the oil gets to the main/rod bearing. Next, block off those large slots directly above the camshaft to prevent oil being slung up past the cam to the valley. Moroso makes a slick, snap in plate for this or you can make one that bolts in. Next, you want to evauate the oil from the right side valve cover. Either run a 3/8" ID line(or #8 hose) from the lower edge of the rear of the valve cover to the upper left side of the oil pan or as I prefer drill and tap the head (to get the oil return line even lower). While you are at it, drill the two upper cam retaining bolts with a .080" drill bit to allow oil to pass through to the timing chain.

Grind away all flashing on the inside of the heads and block to allow easy flow of oil back to the pan. Paint it if you want to with Rustoleum dirty metal primer to help flow even more.

If you do all that, you won't have to worry about pumping the pan dry. And you will be surprised how it effects oil temperature as well.