Oil Pump Dyno

[blykins]

Back in 03 the thing to do was replace the dummy gauge in the 03 Marauder with a real one, then marvel, (or be terrified) by how much the pressure moved with 5w20 oil. I know the low viscosity oil was driven by mileage but still I don’t recall any pressure higher than what I remember to be a 20f start after a 12hour cold soak,it pegged the 100psi gauge at 2000 rpm but was well off 100psi in minutes.

The 5W20 oil is dictated by bearing clearances.  All-aluminum engines need tighter main bearing clearances so that when the engine gets hot, it doesn't lose significant oil pressure. 

Your all-aluminum 4.6L DOHC in that 2003 Marauder probably had main bearing clearances at around .001-.0015".  If an oil with higher viscosity was used in colder climates, the bearings could be starved. 

[Blueoval77]

Thats kind of the second thing I was getting at . If the relief wasnt opening or was pushed higher , would the cavitation then be stopped all together ? I dont think it would but who knows. If it indeed did stop then we know that the relief dumping back into the inlet needs to go... We may know that already honestly.
In either case it seems that killing the pump relief all together and creating another fuse in the system that dumps back in another location is a better idea...I am putting together a step child 427 right now that doesnt have the side oiler valve in it but however has been made into a side oiler and will spend some time on a  dyno so I want to play with this a bit.

[Blueoval77]

Back in 03 the thing to do was replace the dummy gauge in the 03 Marauder with a real one, then marvel, (or be terrified) by how much the pressure moved with 5w20 oil. I know the low viscosity oil was driven by mileage but still I don’t recall any pressure higher than what I remember to be a 20f start after a 12hour cold soak,it pegged the 100psi gauge at 2000 rpm but was well off 100psi in minutes.

The 5W20 oil is dictated by bearing clearances.  All-aluminum engines need tighter main bearing clearances so that when the engine gets hot, it doesn't lose significant oil pressure. 

Your all-aluminum 4.6L DOHC in that 2003 Marauder probably had main bearing clearances at around .001-.0015".  If an oil with higher viscosity was used in colder climates, the bearings could be starved.

Brent I understand the logic behind this and believe me ive been told by engine builders time and time again this is the case . But im here to tell you that ive run a teksid based 4 valves with stock clearances with Royal Purple 20/50 for thousand upon thousands of laps without a single failure . Im talking hours on end at 4000 to 7500....
Of course I never had to start it in February in canada either....   
I only say this because there is no blanket rule for those....

[blykins]

Back in 03 the thing to do was replace the dummy gauge in the 03 Marauder with a real one, then marvel, (or be terrified) by how much the pressure moved with 5w20 oil. I know the low viscosity oil was driven by mileage but still I don’t recall any pressure higher than what I remember to be a 20f start after a 12hour cold soak,it pegged the 100psi gauge at 2000 rpm but was well off 100psi in minutes.

The 5W20 oil is dictated by bearing clearances.  All-aluminum engines need tighter main bearing clearances so that when the engine gets hot, it doesn't lose significant oil pressure. 

Your all-aluminum 4.6L DOHC in that 2003 Marauder probably had main bearing clearances at around .001-.0015".  If an oil with higher viscosity was used in colder climates, the bearings could be starved.

Brent I understand the logic behind this and believe me ive been told by engine builders time and time again this is the case . But im here to tell you that ive run a teksid based 4 valves with stock clearances with Royal Purple 20/50 for thousand upon thousands of laps without a single failure . Im talking hours on end at 4000 to 7500....
Of course I never had to start it in February in canada either....   
I only say this because there is no blanket rule for those....

Sure, but there’s a big difference between a factory stock engine in a Mercury that has to be all-climate, and a race engine. 

[Blueoval77]

Race engine , man I was in a class where its gotta be "Stock"..... No race engines here man.....   

[blykins]

Race engine , man I was in a class where its gotta be "Stock"..... No race engines here man.....   

Yeah I’ve seen classes like that.  An eye roll emoji is appropriate. 

[WConley]

Looking at my gauges during a test run, I see a HUGE difference in oil flow vs temperature.  On first startup, at 60 degrees or so, the flow is less than half that at 200 degrees and cold pressure is way higher at a given rpm.  We all know the pressure thing, but flow was an eye-opener for me. 

That reminds me of an old guy I once met who flew a restored P-51.  His big thing was to wait until the engine came up to full temperature before applying takeoff power.  His patience was rewarded over the years by much longer intervals between $$$ engine rebuilds.

[Joe-JDC]

My DOHC 5.7 V-8 requires 0-20W synthetic oil.  I would never consider running 10W-40, or 10W-50 in it.   My son put Royal Purple in my '86GT after I changed it to a 383W, and it used oil from that time until we changed back to 10w-30.  I will never use RP oil again.  Your experience is totally different from mine.  Joe-JDC

[Blueoval77]

Well , look at it this way , in reverse . Its August and its 102 outside  . You are about to run 100 laps just as hard as that engine will run. I know I am about to open the "Lubricity" door and all that but do you really think running water in the crank case is a good idea ? Thats what your going to end up with after 100 laps at those RPMs in the heat of summer. Engines getting a bit warm ? Well its gonna have to get over that....
I Do run the lighter oils in the street modulars I have around but if its going to the show its getting changed every week with new 20/50 royal purple.At one point I had 5 cars in the class all with similar setups and all with the same maintenance and if the planets were aligned we usually held the top 5  .
Im talking about the worst punishment in the worst environment you can think of .

I cut a hose once and lost all the water with I think it was 8 laps to go or so and I had no choice but to go .When I lifted after the checker the car just shut off. The heads didnt care for it but I used that complete bottom end in another car later on and it was nearly perfect when I tore it down....

The question here is whats the thing used for ? What I was saying is that the oil choice and not using the heavy oils is not a blanket statement.

[Blueoval77]

Absolutely Conley , getting them up to temp is of utmost importance...

[blykins]

The question here is whats the thing used for ? What I was saying is that the oil choice and not using the heavy oils is not a blanket statement.

For a modern passenger car that can see anything from Minnesota to Texas, I think it is a blanket statement.  Otherwise, the OEM manufacturer wouldn't have spent millions of dollars on bearing clearance and oil viscosity R&D.   Remember, the OEM urges the general population to start their car, give it a few seconds for oil to get to the top end, then drive off.  Long gone are the days of carefully letting a car warm-up, because now everyone is scared of emissions.

What you have described in your scenario is such an extremely narrow slice of the pie.  What Lance described is certainly because of the block material, bearing clearances, and what the manufacturers have deemed a general oil viscosity for a modern passenger car.

[Henrysnephew]

Now that the subject of oil pump function in newer design engines has come up I'd like to bring up the cover deflection issue experienced by the crank-driven design common today in many brands.  I am amazed that the covers commonly deflect enough during high rpm/demand to allow copious quantities of oil to escape the pressurized system - a Fred Flintstone relief valve?  How could this not have been considered a defect during the design process?  It shakes my confidence in modern design logic.
Randy M

[Blueoval77]

Well Brent you would be shocked at the amount of "Engine builders" that blanket the entire platform with that oil for all of those Manufacturers reasons. Fire and Brimstone will rain down on you from above if you put that 20-50 in there !!
 I figure most of what we are talking about here isnt riding down to the corner to get groceries  . If so Conley wouldnt have started this mess......

[Barry_R]

At an EMC event I was making repeated pull after pull just playing around with stuff after locking down three decent ones.  As we reached the end of the session the oil temperature was getting over 200 F.  The guy from Amsoil was looking on and commented that this was the first engine he had seem where temperature was getting into a good operating range...

[blykins]

At an EMC event I was making repeated pull after pull just playing around with stuff after locking down three decent ones.  As we reached the end of the session the oil temperature was getting over 200 F.  The guy from Amsoil was looking on and commented that this was the first engine he had seem where temperature was getting into a good operating range...

Hard to get oil hot on the dyno unless you purposely try to do it.  I know most of my dyno sessions get the oil up only to the 170-180° range.  I have gotten to 200-210°, but it has been on cam breakins during the warmer months.