Jeff Taylor believes that the stock pump is ok for any purpose running right up to 10,000rpm mini sprint cars. The archilles heel with the A series is heat and removing it from the oil. Do that and the little engine will go almost forever.
I have seen however an A series at Jeffs workshop which had an oil pump failure and it cooked the main bearings so much that they actually melted like solder and dropped the molten metal into the dry sump like ball bearings!!!
The only indication the driver had....and by the way he finished and won the race... was a rattle in the engine when he started it up to put back on the trailer after the last race!!
go the A series.

I did some tests on the standard oil pump on the weekend and checked oil pressures from idle to 8500 rpm. I run an A12 block with A14 crank, A15 head, 10.4:1 compression and efi etc etc.
Results are as follows.

idle = 50psi
2000rpm = 55psi
3000rpm = 60psi
4000rpm = 68psi
5000rpm = 70psi
6000rpm = 72psi
7000rpm = 74psi
8000rpm = 74psi
8500rpm = 74psi

Based on these tests the oil pressure is very good with the existing pump, and it looks like the relief valve is opening around 74 psi oil pressure.
I am in the middle of making a high volume oil pump out of a z series pump and an A series pump but I may put that on hold for the time being because my oil pressures are good. I might just put an oil cooler onto my car instead of finishing the high volume pump.
After doing all the tests on the weekend I tend to agree with Jeff Taylor's view that the standard oil pump in good condition is all that is needed (in my case anyway).
Interseting subject with lots to learn here. So next step for me is to find a small suitable oil cooler and all the necessary bits.

Sports 1300 racers (see pic) who used the A12 engines found that they rocker gear needed more oil for longevity at high rpm. They commonly modified the 'scallop' in the camshaft to increase the volume of oil supplied to the overhead gear, along with common oiling mods to the crank, and used the Lseries oil pump internals as described here.

Thats interesting L18_B110.
Its the reason I started to look into the High volume oil pump in the first place, I found that I had above normal wear on the rocker shaft even after machining rocker spacers to increase oiling of the rocker arms. I guess if you are running high lift cams and big valve springs at big revs then something is going to suffer. Of course roller rockers is the long term fix but my budget wont stretch that far
Thanks for the info.

wow this is very interesting.....

so... if my engine is running at cool tempratures (below half on factory gauge), then my oil shouldnt be getting too hot due to cooling the turbos???? is that a fair statement

i'd like to add a cooler also, as the extra heat from the turbos cant be too healthy on the oil,

actually just thinking would i get less blow-by and oil venting from the crank??? with cooler oil (i.e. thicker oil) as she breathes a fair bit of oil at the moment

hmmm, interesting, my only fear with adding the cooler is that along with cooling turbos and running the cooler, the pump may start to drop pressure, and i was considering making this pump to ensure it's ok, but dodgeman makes the good point that im wasting h.p. if i dont need it...

obviously the way to tell is set it all up and do test but thats a lot of effort and some cash outlay

so im wondering..... what do you guys reckon

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Micheal, keep in mind that your oil temp will most likely be different to your water temp, please clarify exactly what you are asking?

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True, and an oil cooler seems to be the standard for other members using highly strung A series. Go the way of a cooler if you are happy with your current oil pressures and volumes.

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It is most likely that your blow by will be less with a thicker oil, some guys I know run up to 60 weight oil in their older race motors to reduce blow by but it is only usually masking another problem. Remember that the hotter your oil gets the thinner it becomes (up to a point). Some of the modern synthetic oils (5w-40 for example) are very thin at room temp so they flow quickly and easily on start up, as they heat up the chemical bonds form in the oil and they thicken up to similar spec to normal 40 weight oil. This is sometimes good when you consider that most engine wear occures when your engine is cold at first crank but I'm still not a fan of synthetis oils.

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Maybe you should consider a high volume oil pump then run a thinner synthetic oil, that way you have the high volume oil being fed to wherever it is needed and the oil cooler keeps the oil temp to reasonable numbers. That way you wont have to worry about your oil thinning out and your pump dropping pressure as you oil heats.

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Yep agreed, thats what I have just been doing and its a fair bit of mucking around but the only real way for you to be certain about whats going on in your motor.

I'll keep you posted about how I get on with all the testing.

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well, i guess im saying, is how related is oil temprature to water temprature?, or can they be considered almost independant

from something i read i think here it seemed that keeping the oil cooler will help keep the engine temp (water temp really) cooler also?

why do you say your not a fan of synthetic then?

thanks for the info, good food for thought

ooops bit of overlap on posting there

thanks for pointing that out benny, so i guess that means there isnt really a loss (there will be some but negliable really?), so why the hell not do it anyway, cant hurt and would be a bit of fun to nut out

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I imagine that they are related (again up to a point) but remember that water temp is determined by different parameters and is metered to give a certain water temp when you are thrashing it. Oil temp on the other hand can and will be different because it performs a different roll in your engine and how do you tell if your oil is not performing up to its specification if you cant see the pressures and temps on a gauge - bit like flying blind so I will be looking into monitoring the oil temps from now on.

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Yes I believe there is some merit in that statement.

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Old school I guess, just my personal opinion.

D-mans stated that "higher pressure robs HP" not higher volume.........I reckons that oversupply of oil to an engine [volume] is like cheap insurance.

Benny