Conventional Fiero wisdom seems to agree that significant flaw with 2.8s is oiling? That being said, worth the time and dollars to install high volume oil pump from Fiero Store. This engine is mildly modified; Crane cam, rocker roller arms, etc. What do you guys think?

I put a HV from my parts store in my 3.4. Oil pressure is great. Runs 40 at idle.
Some said it would hurt gas mileage but I still get 35mpg hwy with a 4sp. (85GT)

I always use high volumn pumps on builds and rebuilds.
Not high pressure.

The oiling flaw in the earlier (pre-87/88) V6 engines has very little to do with the oil pump. Rather, the problem is with the size and layout of the oil galleries in the engine block itself. If you have adequate oil pressure now and your car is primarily driven on the street, you probably won't gain anything by installing a high-volume oil pump.

On the other hand, a high-volume pump will take more power to drive, which means a higher load on the distributor drive gear. If you had adequate oil pressure before, all of the additional flow from a high-volume pump is just going to be dumped through the pressure regulator bypass valve.

My 3.1 V6 (same block as the later, "improved" 2.8s) has about 30,000 miles on it. It has a standard oil pump in it, and using 5W30 synthetic motor oil the pressure at idle rpm is ~50 psi cold and ~35 psi hot. At anything above about 1200-1500 rpm the oil pressure is fully regulated at ~65 psi cold and ~50 psi hot. A high-volume oil pump would not improve anything for my engine. YMMV.

[This message has been edited by Marvin McInnis (edited 04-30-2011).]

I have one in my 3.4 pr swap and it just seemed comon sense to do it at the time. It runs about 80 PSI though and it has left wondering is that good?

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Red 88 Formula 3.4 pr 4 speed automatic
Black 86 GT 3800 SC automatic swap in progress

Marvin is right. High Volume oil pumps are not needed unless you have an upgraded engine (very upgraded) and larger oil passages. The problem lies in the amount of load it puts on your distributor drive gear. It will wear out the drive gear a lot faster, put excess load on it, and can be bad for the engine. When I had drive gears being ate, everyone I talked to asked about the oil pump.

Also, 80psi is TOO HIGH! its okay under first start, but 80 constantly is too high. you want half that when at operating temperature. I have seen high oil pressure exploding cheaper oil filters before... just boom and oil goes everywhere. Though one time I saw that it was with a car that got straight 30 instead of 5W-30, and its oil pressure on start was 180psi (yes, 180), because someone though it would be intelligent to fix a spun bearing with heavy oil. 80PSI shouldnt blow the filter, but it will put lots of strain on your distributor drive gear. the more PSI, the harder your engine has to push the oil.

bottom line:
You most likely never need a high volume oil pump. Only install one if you have larger oil passages, or some slack in your parts, and you need the extra volume to raise pressure. it harms stock engines more than it helps, and you wont notice the harm right off the bat, it will be very noticeable in the long run.

Got it.
Thanks guys.

Thanks too. It does drop down to 50-60 after its warmed up.

A little history on the high volume oil pump -

Back in the 50's and 60's you noticed a significant drop in oil pressure at about 80,000 miles due to increased bearing clearances due to wear. An easy way to boost pressure and keep the car going was the high volume oil pump. More flow - higher pressure - no need to buy a new car or have major work done.

Modern engine design leans more toward flow than pressure - the idea is to have the oil form a "hydraulic wedge" in the bearing/journal clearance to prevent metal to metal contact. The HV pump does this well - if your bearing clearances are looser than desired.

Bottom line - if your bearings are within tolerance, you don't need it and may well cause other problems, as several of our previous commentors have stated.

If you have an external filter and external cooler then a HV pump will help there.

i just put a melling high volume in mine idle is about 45psi and at 2500 rpm its around 85-90psi

My 3.4 V6 crate engine came with a beefed-up oil pump. When I installed the engine, I first ran it on 10w40. But oil pressure at startup was off the scale (it pegged the needle). After the engine warmed up, it would drop to 60-70 PSI at idle. No kidding.

Since then, I have experimented with lighter weight oils. I first switched to 10w30, which didn't seem to make much difference. Then I stepped down to 5w20. That helped a bit. Cold oil pressure is still around 80 PSI. But after the engine warms up, it drops to around 40 PSI at idle. I'm actually considering stepping down to 0w20 next.

This is a GM crate engine that came with this oil pump from the factory. Pretty crazy stuff.

I made the mistake of putting a high volume oil pump in my van. I eat through distributor gears. My oil pressure is pretty high all the time. It also didn't help that my cam is a billet steel roller cam, which defeats the cast Iron distributor gears. Other steel based gears haven't fared much better either. The only plus side is that I know my bearings will be well lubricated, just so long as the distributor gear particles don't kill them.

So, I say High Volume pumps are overrated, And in some cases a very bad thing. They do put a little more load on the engine, but it's more of a part stress then it is parasitic load.