I'm talking about a 88 camaro w/ ~180k on a 305 TBI engine.

My father pulled the engine out and rebuilt it. It was rebuilt because it had no oil pressure after it warmed up on hot days. Days where the air temperature was over 90 degrees.

Any ways, he rebuilt it. He looked thru the engine and couldn't find any reason for the low oil pressure. He replaced the pistons, rod bearings, oil pump and a few other sensors and sending units that were much easier to reach w/ the engine out.

After the car is all warmed up,
The car now runs down the road w/ an oil pressure of 40. Its oil pressure at an idle is 8 to 10.

That pressure is being reported by the stock guage. I don't recall what normal was before the car started having problems.

 

That's sufficient, you should replace the guage sender if it's the stock one, though. 180k is a long time for one to last. Never hurts to hook up a mechanic guage and check.

 

thats pleanty of oil psi,,,V8 touring cars here run at 7200rpm all day at 7psi,,,like the other guy said hook up a mechanical gauge and check it,,,high volume oil pumps are a waist of money,,,if the engine is ok

 

just hook up a good gauge and see,,then put the old setup back if you are satisfied

 

Cool! It seems a wee bit on the low side.

Thanks for the input.

I'll try a good aftermarket guage to make sure the old stock unit isn't lying to me.

 

I doubt that. You mean 70 psi right?

A good rule of thumb is 10 psi for every 1k rpms.

 

no 7 psi,,,just look at www.v8supercars.com.au larry perkins motor sport,, holden racing team ,,FTR ford tickford racing,tickford is aston martin,,,dick johnson motor sport , stone bros racing,,and 700HP on pump gas,with under 10.1 comp,,run 500 mile sprint races at over 7000 rpm at bathurst,,the greatest race in the world,,,says the critics,,and yes carroll shelby said so in 1982,,,,mark martin in 1993,,aj foyt,, john andretti recons he aint seen racing like this,and wants to race here,,,,,,high compresion,,big oil preasure,,,that was 70,s stuff,,,the oil of today is supperior,,,to the junk of yesterday,,,,i run a 400 vortec roller motor with a stock sbc pump,,,and mobil 1 ,,no worries,,,idle 10psi 5000rpm 30psi,,,no addatives,,,it wouldnt worry me if the thing ran at 10psi at 5000rpm,,,sorry,,

 

Sure that's not fuel pressure.

Our cars need more than 7psi doin 7200 rpms period.

 

Don't confuse pressure with flow. 7psi is enough if the volume is there.

 

what harm can be done to an engine if theres TOO MUCH oil in there? its just question out of curiosity since having too little oil is obviously a bad thing, how about the oppossite of that?

 

Too much oil or too much oil pressure ? Too much oil will cause the crank spin through the oil whipping air into the oil. Air in the oil decreases lubrication, leading to component failure. Too much oil pressure indicates a blockage in the oiling system, plugged oil filter or passage.

 

Also crank hitting the oil puts a stress on the crank, causing a loss in horsepower.
Later, Garrett

 

thank you ricktpi,,,
volume isnt preasure,,,i can empty a bucket of mobil 1 onto a table ,,,that is flowing at around 3 1/2,psi,till the bucket runs out,,,now if i have a scavange to keep replacing the oil in the bucket,,,3 1/2 psi is fine,,and imagine the lubrication,,,of 5 gallons every 6 secons,,,,yes please look at the V8 supercar site,,its 5 liter chev racing at its best ,,GM versus FORD,,,who are getting there doors blown off,,year in year out,,,this is circuit racing at 180mph,,on pump gas,,with low oil preasure,,,, thats about it,,,steve in australia

 

Steve, maybe I just missed it, but exactly where in the Supercars site (or the links) do they talk about 7psi oil pressure being sufficient?

Now, I DID read how quickly they wear out their engines and how some drivers had to retire because their engines failed due to low oil pressure.

 

I really am interested in the question of 7psi but I also have a little experience from when I made industrial sales calls.

Many people just starting in a given type of business would naturally ask me all sorts of technical questions that a newbie should. Then I'd hear the advice given to them by their competitors and -- surprise!! -- the advice given was just the opposite of what it should be.

Yep. Knock them out of the growing season with bad advice (in this case) for one, maybe two years, and that's one less competitor they have to deal with.

How many $65,000-a-pop failed racing engines would it take to discourage a newbie in Supercar racing... ?

Just a thought.

 

,,,the good teams dont loose engines,,,,,,there is an article in there,,,in regards to an engine builder called neal burns,,in the domination of peter brock from 1976,,to 1986,,,they go through a typical engine build up,,that took normally 40 hours to complete,,,he goes on to say,,HE USED standard GM oil pumps ,,,for the 308 engine ,,,and 7 psi was no concern,,,the cars ,,like i said ran at over 170 mph,,for 6 hours in the endurance races,,in heat of up to 90 degrese on the day,,,that was out side temp,,,,the cars used rochester carbs,,,,,,this is stock block racing,,,,in a few weeks the 500 mile race will be on,,,63 cars will start and there will be engine failure like normal,,,but around 40 will finish,,,at 4pm,,they race all day,,,anyway,,,i can get the magazine article,,if anyone feels like e mailing me i will dig out the same article,,and send it,,,,yes at first i was surprised,,,after buying big mellings oil pumps for years,,,and trying to get the big psi,,,,look it cant hurt,,,to run 40,50 psi ,,,but it isnt needed,,,really,,,the car will run fine,,long as it aint getting hot,,,when the oil psi is low,,,and the engine is starting to smell like its cooking,,starting to smell like a burning pot handle,,

 

Steve, my guess is that you are mis-remembering the info on 7psi. Maybe the quote was that the oil pressure at idle dropped down to 7psi and they thought *that* was still ok. Or maybe they were in a race (and the oil pressure gauge was faulty) and showed 7psi and they decided to go for it anyway. If you would like to dig out the article, that's great too.

Anyway...

Back to the original topic.

Copperhead 110, I think as others have said that the oil pressure indicated should be fine in your street driven engine.

 

Whatever they race in europe, 7 Psi is NOT enough oil pressure for a small block. 40 at cruise is OK but 10 at idle is just below the limit in my opinion. Since you have a very high mileage engine you could go with a HV pump as a crutch. I would guess that one of the mains is worn, probably #5. You could also run a heavier viscosity oil or a synthetic if you live in a really cold climate and are worrying about cold startups.

On another note, Honda in past years found that they could decouple there oil pump on the RC-45 race bike at high speed and the rotating assembly would act as apump supplying enough oil through a suction caused by the centrifugal action of the spinning crank and rods to keep the motor alive ( said to be worth 5-7 hp).

A small block engine needs oil pressure to feed the valve gear, and keep the bearings alive. Street motors run tight clearances to keep them alive for many miles. This requires high pressure to keep an acceptable flow. High pressure insures that under heavy load bearings get fed and that valve gear ( hydraulic lifters !!!) stay well lubricated. Pressure is more important than flow, also you get high pressure by restricting flow, IE tight clearances