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This is the reason my engine builder didn't want to use a hi-vol. pump, he said excessive pressure could cause leaks. I can't keep oil in this motor, but it's not because of leaks. I'm still fighting the problem of oil blowing out through the valve cover breather. I have a new PCV valve in one valve cover and a breather in the other and whenever the engine sees higher rpms it blows oil out through the breather. I put a new grommet in the valve cover under the breather with just a narrow slit in it but the oil still blows through. It's been frustrating.
My dad's S10 w/350 SB did the same thing see T.Jerman's post that's how I fixed his as well,with splash plate.It would suck out all the oil he couldn't figure it out for the longest time he just thought it burned oil.The new valve covers had no baffle to stop the oil from being sucked up through the PCV.
 

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I have a 434 just got back from dyno and it Makes good power and from 3800 - 7300. . . i have 74psi at 3800 and 71 at 7300 . 100 psi at start up thats with 10/40 i use Mobil synthetic motor ran 190 195
 

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My 383 runs 40psi at 1100rpm idle
50-60psi on the highway 1500-2500rpm (5th gear)
80psi at 7000rpm
These numbers are when the oil temp. is heat saturated.
I have 70-80psi before heat saturation. (never over 80psi). But I do not run it hard before complete temp. saturation.
I run NAPA straight 40 wt. oil
P.S.
When I let the clutch out on a "granny"/normal start, the rpm drops back to appx. 600 and the oil pressure drops to around 20-25psi momentarily.
I guess if I set the idle to 600rpm I would have somewhere in the 20-25psi range.
Don
 

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Bearing clearance as well as cross drilled cranks will reduce idle pressure.The biggest thing that will get hurt at low idle is the cam.GM's lubes from bottom up.
JMO Paul
I'm no expert on this, but Sorry, but I have to interject a few things here. Not to be argumentative, but... we are talking about a SBC Chevy here.
I agree with the bearing clearance issue being a HUGE factor is oil pressure, BUT, the comment about the GM oiling from the bottom up????
The small block 383 that JWT is talking about,,,, oil is pumped up to the main oil galley where it is fed to the lifters, then DOWN around an annulus around the cam bearings, then down to the mains, where the crank distributes it to the rod bearings. The front main and the #1-2 rod journals are the LAST to see oil. The Chevy small block oils from the top DOWN. Again, not trying to be argumentative, just felt that needed to be clarified. Not taking in account aftermarket blocks here with priority main oiling. We are talking about GM production small blocks. Right?

With that said, We have all heard the internet chatter of the ills of high volume/high pressure oil pumps, exploding oil filters, high pressure causing leaks,,, I'm sorry but I just don't buy into it. There is no pressurized oil in the heads, no pressurized oil under the rocker covers (with the exception of the oil pumped by lifter action up through the pushrods which is then splashed around, but certainally not oil pump pressure), no pressurized oil in the intake manifold, and none under the timing cover. HOW does oil pressure cause leaks!. The only possibility is a loose / cheap garbage oil filter seal, and the rear main seal where the rear main bearing is so close to the rear seal. IF oil pressure were to squirt out of the rear main bearing with such force to push the rear seal out, you have more of a bearing problem than an oil pressure problem. Again, just trying to clarify things, not point fingers at any post. IF you were to have oil leaking out of the rear cam plug, or the oil passage plugs in the block, it's going to leak at 20psi just as well as at 65 or 80psi. Properly installed and sealed block plugs should seal at ANY pressure a oil pump is going to make.

High oil pressure does have it's evils. I'm not saying it doesn't. The energy it takes to spin a pump that is making 80-100psi is wasted horsepower. The stress and wear put on the distributor / cam gear WILL be a significant maintenance issue when your running a bronze distributor gear. And I have witnessed ONE incident where the small rubber gasket around the top of the oil filter was pushed out because of excessive oil pressure. In days of low tech poured babbet bearings high oil pressure would errode the bearing. (not so much an issue with todays bearings, but the theory is the same. If you offer a channel in the bearing for oil to flow, it won't provide a 'film' over the entire bearing surface. THAT'S what our oiling system is supposed to do. Provide an oil film to protect and cool the bearings. Any more than 'enough' is a wast of energy, any LESS and your burning bearings.

Trying not to sound like I'm on a rant here. Where are 99.9% of the cars out there taking the oil pressure reading! At the top back of the block, BEFORE any oil is delivered to ANY bearing or lifter. If you want to scare your self to death.... Most of the small block castings are drilled from the top side of the timing chain housing, down to the annulus around the front cam bearing. Put your oil pressure fitting there (after the oiling system has delivered pressure to the rear 4 main saddles) and see how much you like your low volume/ low pressure pump.

Oil presure and oil temp. Todays oils are formulated for cold flow, and high temp viscosity. In a perfect world those formulas work and we have 30-40 weight oil that cold flows like water! Yeah RIGHT! Not with Dino juice that has a the best additive package. The closest science can get is with synthetics like the 0-40 synthetic racing oils like Amsoil and Royal Purple. Go visit that Bobistheoilguy.com for a bunch of opinions on oils and filters. There is a lot more to oil than just the oil. The additives make the oil and in todays world, the best we can hope for is to start with a good synthetic base stock, and build the additive package to suit the need. Go look around the race track and see what the Comp Eliminator guys are using. No one beats on the oil like these 9500+rpm little monsters. It's amazing that these things stay together with what little oil pressure they run. I know of many that say they keep oil pressure to a max of 50-55psi at 9000+, and if it shows ANY psi at idle it's OK. That OK for a motor that is torn down and inspected / freshened many times a year I guess.

All this rambeling started over oil pressure, what is enough and what is too much. I'm sure if you ask 100 guys you'll get 100 different answers. Just my opinion, but the old 10psi per 1000RPM is fine until you start spinning the snot out of your motor. I have never hurt a crank or bearing spinning my long stroke small block to 8000rpm, and it never sees anything over 70-72psi (oh the wonders of data logging ;) ) I run 0-40 Mobile One synthetic and at 155-170° oil temps it has 40psi at a 1300rpm idle.

But that's just my 2cents, and take it for all that it may be worth. In the end it's your motor and YOU have to make the choices and live with the results. But ,, if it were my motor, I'd dump the straight weight oils and the straight 40 weight and see how oil pressure is with a 10-30 synthetic. I know it would protect your investiment better, and I bet it would stabilize psi on both ends of the temp and rpm spectrum.
 

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My little 283 runs 15-20# at a warm idle with 10/30 and no more than 45-50# @4500. Fairly tame engine. Now as long as you have decent oil pressure in the parameters needed, don't you think 40w oil is a little over the top? No? That seems a little too high a pressure. What are your concerns for the way you run your set up 63chevytoo?
 

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In my wife's 305 and my 327 we actually use cut down oil pump relief springs to reduce pressure. At 7500 RPM we have 40 pounds and at idle its about 20 pounds. Thats using 5-30 oil.
 

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Oil pressure is a hot topic and I'm sure will always be controversial.

It comes down to two arguements:
1. "high pressure is needed for protection".
2. "high pressure wastes power, increases oil temp and reduces protection by aerating oil"

I used to be in camp 1.
I ran high pressure and thick oil thinking it was "better"....until I spun a main bearing in my V-8 Vega on a cold morning. 50 weight is like sticky molassas when cold, but even with regular weight oil I've personally seen a high volume and pressure pump shaft break from the load.

Later when I worked at a place called Synthetex, I worked on project that put a clear oil pan on an engine on a tilt fixture to study the oiling effects of 4x4 vehicle tilt in off road situations.
This gave me an opportunity to see what actually goes on in an oil pan. Windage is real and eye opening to watch.

Then at Roush I learned the importance of oil pans, oil viscosity and pumping pressure on performance. We would expend great deal of effort on the oil system getting impressive power gains with no loss of durabilty. In fact durability often improved by reducing oil aeration and oil temps.

Even hardcore skeptics are being convinced. I just read a side bar by Dave McClelland in the December issue of Chevy High Performance magazine. On a 441 hp 350 with a high pressure 82 psi spring, gained 7 hp simply by reducing the oil pressure by 10 psi to 73 psi.
"This change really got my attention", he writes. He even goes on to speculate that 55-60 psi is probably better.

Funny, I've been reporting that tip for years here!


Bottom line is to get away from the faulty linear logic where "more is always better".
I wouldn't go to extremes the opposite direction and over reducing the pressure for more power either.
For some things, there's too little, there's too much and there's just right.
 

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Marv, When I read the post I figured the motor guys referring to oil leaks and High volumn pumps referred to excessive oil up in the top of the motor not from oil leaks due to the pressure. My personal experiences lead me to beleive oil pressure is an over rated concern on a drag motor. I've had motors with 5 to 10 lb idling and less than 40 at 7500 and they all looked fine on freshen up. I know alot of guys running motors stockers with a couple qts of oil in the pan and the low pressure oil lights burning bright going through the traps setting world records or trying to win a race. Like you said 100 people, 100 replies. Do what makes you feel good. Pressure over 60 or under 10 hot would make me personally unhappy. Anything in between lets me sleep well. JMO. RM
 

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JTW here is the cure for your problem. My 408 was doing the samething. Grant I do not have baffle in my v/c, do you. Is your PVC plugging from oil being sucked up in there thats what mine was doing and then it would start blowing oil. I fab. some baffle plates that bolt to my poly-locks on my roller rockers. I used the 2 one in on both ends. Removed my allen set screw for the poly-lock and used a 2" long set screw. Do you normal adjusting on rockers and tighten set screw. I used a 3/8 fine thread nut for a spacer because of the rocking motion of the rocker just finger tight on top of poly.
Put my splash plate on and nutted it down. Here is a couple of pictures simple to do and you will not have a problems.

Hope these help any question just ask or PM me.
Thanks for the pics and the tip about the PCV possibly being plugged, I'll pull the PCV out today and take a look. I like your deflector setup and I'm certain that would solve my problem. The only reason I had not done that yet is because I know that setup won't fit under my valve covers, but I'm tired of the oil mess so I bought a used set of tall Moroso valve covers on ebay this morning. It looks like it would pretty simple to fab those deflectors, but for $23 I'll probably take the easy route and buy the Moroso kit. Yours looks identical to the Moroso, nice job!

Okay, another question --- what is the purpose of that braided hose with 90* fittings running from the front to the rear of your intake?:confused:
 

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My little 283 runs 15-20# at a warm idle with 10/30 and no more than 45-50# @4500. Fairly tame engine. Now as long as you have decent oil pressure in the parameters needed, don't you think 40w oil is a little over the top? No? That seems a little too high a pressure. What are your concerns for the way you run your set up 63chevytoo?
littleduce2;
My engine builder has been in the engine building business for over 40 years and has done literally thousands of SBC's many for himself. He races in circles and drags. He would prefer if my engine had a little less pressure. He said as long as I do not run it in the winter the 40 wt. oil is fine. I never planned to run my car in the winter months. I get a discount on insurance by not driving it Nov, Dec, Jan. As far as your question about my concerns for the way I run my set up is... My main concern is the wear on the bronze distributor gear. As mentioned by Marv D.
I could go with 30 wt. oil and I may try that.
I am not concerned about the loss of HP. The thing runs great and pulls hard.

Don
 

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He said as long as I do not run it in the winter the 40 wt. oil is fine
I didn't think anyone still ran a single weight oil. The last time I did was just to slow down consumption on a wheezer!
I've heard some Top Fuel guys run multi-weight now, instead of the old 50 or 60 stuff.
 

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Bill Jenkins ran 50-55 psi hot in 10,000 rpm small blocks seting records 30 some years ago BEFORE we had the wonderful oils of today.
 

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I thought today's oils are not as good as they used to be since there is less zinc and stuff. I guess depends on whether you have flat tapper or roller cams. :confused:

~Aaron
 
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