how much is too much?

[barefootskater1200]

oil pressure.
im running a 30mm pump in my mostly stock 1641 turbo and it is not full flow.

my problem
the oil pressure bypass valve doesnt ever seem to shut. thus no oil to the cooler. and that loop is where i have my filter as well...
my gauge never drops below 50psi even after a ten mile run. i am getting oil to both the cooler and filter, just not enough.
the oil doesnt seem to be getting very hot either, judging by the temp of the dipstick and turbo feed line.
my thinking is that its stuck on full bypass due to the high pressure.

i have some time off work over the next couple weeks and im curious if its worth tearing the engine down and full flowing it...

any thoughts, ideas, experience?
i have no explanation why the oil doesnt get hot. i even have a thermostat i installed to try to correct it... but that made no difference that i can tell.

also i should mention that the engine is fresh. full rebuild finished just a couple weeks ago, and i made sure all the passages were clean but i wont disregard the possibility that i missed something or messed something up...

[Leatherneck]

Do you have a Temp gauge on it or just feeling it?

[Piledriver]

T1s originally had a 21mm pump.
T4 pumps were 26mm, but had a lot more places for the oil to go and larger bearings.
(rocker shafts grooved, more full flow to the heads via the pushrods than T1, later units had hydraulic lifters)

If your clearances are near stock, it wouldn't surprise me at all if you were pumping most of the oil back to the sump on every pass.
(Even the stock setup probably bypassed 75%+ back to the sump at cruise RPM)
What IS somewhat surprising is that your oil isn't shooting straight to 260F+ degrees.

Cool weather can make a thermostat-less ACVW run stone cold, which is far worse for it than a bit too hot in many cases.

Folks that insist (or misteakenly) use a "HD" oversize pump frequently need to use a full flow cooler setup.
It can be done with a factory cooler, but its a LOT easier going with an external.

They sell the big pumps simply because people buy them, as bigger must be better, right?
At least I think you understand how the stock oil cooler pressure based logic works, so the solution is obvious.

If you can track down a suitable autostick pump, it has a cute little turbo scavenge pump stage built in for free.

[barefootskater1200]

Well I spent all day playing with my car.
I replaced all the rubber lines going to and from the cooler and filter, cleaned the adapter out. Changed the oil, (10w30 valvoline) stuffed the advised stainless scrubber in the alt. stand. Removed the bypass valve and cleaned it and made sure it moves freely.
I also did some turbo related stuff that doesn't really pertain to this topic

Once I got it running again this is what I found.
The oil is getting hot. At least hotter. I don't have a temp gauge hooked up but my filter is too hot to grab and hold on to. Though the oil thermostat is not opening.
My engine also doesn't like full choke, but I believe this to be turbo related as well.
And I have a leak. I think it's coming out around the bottom of the alt. stand, but it's hard to tell.
This is all after a fairly aggressive 3 mile run up to 70mph, and shifts as high as 5500rpm. Ambient temps in the low 60s today.

Also my oil pressure is sitting at 33psi hot idle (1000-1100) and never exceeds 75lbs revving up to 6500.
So I think the 30mm pump is alright. Though I do have a 26mm on the way.

Should I replace the pump anyway?

[Marc]

You've probably got more pump than you need, but I wouldn't sweat changing it - the higher priority is getting rid of that "fool-flow" setup. The stock system relies upon pressure to determine when the cooler is bypassed, the added restriction of a filter inline with the cooler is enough to confuse it...adding a thermostat to that plumbing loop can only exacerbate the issue.
Get a proper full-flow filtration system on there (ideally by tapping the case for the return line, but there are alternatives) and a stock doghouse cooler/shroud...if you need additional cooling, that's when you would put a cooler in series with the filter and perhaps make use of the thermostatic bypass.

I'm assuming you have a dual-relief, large-passage case so please correct me if that's wrong. The flywheel-end control valve is designed to dump oil back to the sump at ~65psi to protect the cooler from overpressure; when the oil is cold & thick (or if the pump is 'way too big) the restriction of the drilling in the dump passage may allow pressure to exceed 65psi, even with a stock plunger & spring...but a 30mm isn't grossly oversized.

[Piledriver]

What is your hot oil pressure at say 3500 RPM (cruise)?

The reason I ask is that is the make or break issue with oil cooling, unless you drive at 6500 RPM all the time.
A short blip to redline is not the deal breaker.

The rear (front is front) pressure bypass/relief piston pees oil to the sump at (IIRC, Marc will correct me if required) at ~42-45 PSI, assuming std spring and piston. If the pump is big enough it can overwhelm the ~6-8mm drilling back to the sump at the bottom of the pulley end relief valve setup, and the smaller flywheel end relief comes into play.(w/Some aftermarket cases, hole isn't that big, apparently)

The rear (pulley end) bypass, when active ALSO bypasses the std cooler by providing a very short direct oil path to the mains.

If you have a "tight" engine, I would look at the external Hoover "HVX" mods like grooved rocker shafts (are aftermarket solid shaft setups grooved?) but that will only help a little if you didn't also modify the lifters for more oil to the heads.
The smaller pump may end up being a good plan assuming it fits properly...
...which is why I suggested a NOS or good used factory pump.(They exist)
If the new pump just slides in, beware.
(pull the pump studs when you test this, some Schadeck pumps seems to have a slightly offset hole that makes it very hard to tell)

Watch the ZDDP content of the oil you run. Most oils you grab at Wal-Mart are NOT good for flat tappet lifters, or std valve adjuster screws for that matter.
There are a few commonly available oils that are safe, this point has been beaten to death, repeatedly, elsewhere in the forums.

[barefootskater1200]

It is a dual relief case. Original to this car I'm pretty sure (73 super) and this rebuild was the first cut for the mains. What are the alternatives to drilling and tapping the case? I can't afford to split it again.

I generally cruise at 3000 rpm. Sometimes less. Though on hot runs it sees 5500. But I wasn't looking at the gauge while cruising so I'll have to watch it.

I replaced the lifters during the rebuild but just used stock replacements from cb, unmodified. And didn't change anything or modify anything in the oiling system aside from adding the 30mm pump and changing the location of the cooler. And I know my setup is far from ideal.

I don't buy oil at Walmart. I actually spent the last few years working at parts plus and have cheap access to high quality oil. Everything I've read suggests that this valvoline is up to par. But I'm not above being corrected.

[Piledriver]

Hit bobistheoilguy.com or valvolines website and lookup the zinc content of the oil you are using.
IMHO needs to be at least 1100 ppm with single springs, and I would only use 1200ppm or higher with duals or an aggressive cam.

Valvoline VR-1 (any weight ~1500 ppm zinc) and maybe the super blue 15w-40 diesel oil are OK, worth a little research.
The actual critical additive is called ZDDP, a zinc/phosphorous compound, but it shows up in the specs as zinc and phosphorous % or PPM.

The vast majority of "modern" oils (only actually rated for 2007 and later cars, read the API spec) are 900ppm zinc or less.
These days, that "modern" list includes Castrol GTX, any grade.
You have to spend more $$$ for Castrol Syntec or maybe Edge for safe levels of ZDDP.
(I no longer buy Castrol products, even if they are owned by Shell now)

I'm running Shell Rotella HD30 at the moment with dual springs. Cheap. Works.
I'm using a "defanged" Melling 28mm pump in my current T4 test victim. It does not leak, or overpressure, but took work.
(I got 3 for free, couldn't resist a challenge)
It also doesn't "fit" right like most aftermarket pumps, but with dual orings and SBC style "pressure balancing" grooves machined in it behaves.

[barefootskater1200]

My oil pressure sits right below 60 cruising in 4th at 3200. Too much?

[raygreenwood]

I'm using a "defanged" Melling 28mm pump in my current T4 test victim. It does not leak, or overpressure, but took work.
(I got 3 for free, couldn't resist a challenge)
It also doesn't "fit" right like most aftermarket pumps, but with dual orings and SBC style "pressure balancing" grooves machined in it behaves.

What did you do to defang the Melling. I picked one up back when I lived in Dallas. It has maybe 200 miles on it. Pressure was just wrong. But it sure is a nicely built pump.

I am, not far from doing rebuilds on two 26mm type 4 pumps. ....and sending parts out to be hard anodized. I had also thought about milling the melling gears down to 26mm and putting a lapped spacer in over the gears that bolts to the outer cover.
For my needs a blueprinted stock 26mm will do dandy. But it would be nice to know how to make the Mellkng work for backup. Ray

[Leatherneck]

My oil pressure sits right below 60 cruising in 4th at 3200. Too much?

After it is warmed up to what temp? Usually it is 10psi per 1000 rpms, that is not with every bodies but it is a guide to what is ok.

I also use the rotella, has what the diesels need as well as our AC VW's.

[barefootskater1200]

im not sure what temp. lower than 180 though because the thermostat is never opening

[Piledriver]

I'm using a "defanged" Melling 28mm pump in my current T4 test victim. It does not leak, or overpressure, but took work.
(I got 3 for free, couldn't resist a challenge)
It also doesn't "fit" right like most aftermarket pumps, but with dual orings and SBC style "pressure balancing" grooves machined in it behaves.

What did you do to defang the Melling. I picked one up back when I lived in Dallas. It has maybe 200 miles on it. Pressure was just wrong. But it sure is a nicely built pump.

I am, not far from doing rebuilds on two 26mm type 4 pumps. ....and sending parts out to be hard anodized. I had also thought about milling the melling gears down to 26mm and putting a lapped spacer in over the gears that bolts to the outer cover.
For my needs a blueprinted stock 26mm will do dandy. But it would be nice to know how to make the Mellkng work for backup. Ray

I have considered sticking the Melling in a mill and taking it down to 21-24mm or so for wet sump use. The flange is plenty thick.

SBC style pressure balance grooves (inner and cover) create something of a pressure variable internal leak.
...keeps the peak pressure down but the volume is still good. End play is >.002 after lapping, on a cast iron pump everything expands at the same rate. (just not the case)
One "must do" with a cast iron pump is clean, clean, clean... cast iron as machined is filthy.
Some quality time in a ultrasonic bath is worth the effort.
Never, ever just bolt one in.

I'm running HD30 Rotella (1400 PPM zinc) at the moment, T1 cooler on the T4 (with a baffle to fill the space in the cooling air outlet)
No oil temp issues even in Dallas summers. Std oiling system/clearances, only polished the pressure relief pistons to a mirror finish.

I installed orings just past the port openings and near the flange, .055 deep and .100" wide as it was a sloppy fit in the case.
(.065 oring, wider groove gave it room to sqiush)
Even considered some of the spray on rubber coatings or brazing to build up the OD, but on iron, orings are a better plan due to the case expansion delta.

I was delighted to find a VW OG pump in the T3 motor I replaced in my square, was a factory replacement shortblock from all appearances, no serial#, never cut, 10mm studs, deep #3.
The pump It will get used in a T4, as it actually fits in a case properly.
I couldn't even give away the T1 parts, so they gather dust.
I should probably spend the $$$ to have it align bored and 8mm studs and do something with it, but water ate at the inside bottom of the sump a bit.

For the record, Schadeck or Melling pumps are .004-.006" smaller than factory pump OD.
I suppose it's intended to make them "easy to install". Idiots...

[barefootskater1200]

wow. i never knew that there was so much to consider involving oil pumps...
im trying to get my hands on a doghouse setup and going to go back to a 26mm pump supplied by my local euro shop.

just to get a few things straight though
the oil pump needs to be a very tight fit?
and pressure as a guideline should be ? at idle and go up 10 psi or so for each 1k rpm?
keep in mind that i am not using an external sump and i am oiling a turbo as well...
and only running single HD springs...

[Piledriver]

The spec in the Bentley manual I have only shows oil pump bore size in the case
Spec is 70.00mm-70.03mm (2.7559"-2.7570") note those specs are in 10ths (ten thousandths)

I didn't have a mic handy, but the Schadeck pumps I have measure 2.754" (3), the Mellings I have handy measures 2.756 (2), so it is tighter than the 3 Schadecks, but it doesn't "grow" so has to be more of a crush fit.. The Schadecks fall into a fully torqued cas (with studs removed).

Both of the stock VW pumps I have measure out at 2.758-2.759, but I'm using calipers not a mic.
(plus both have been pressed in and used for years, the Schadecks and Mellings are new)

The issue is that IIRC the pump is supposed to be a .002-.005" press/interference fit, which is why it gets installed/removed with the surrounding case bolts loosened, and VW made a special oil pump puller for it. (like a gear puller) for this reason.
(This fit spec might be found in VWs "Without Guesswork" but I can't find mine)

VW supposedly had the oil pumps "binned" for size as the holes in the case actually varied somewhat, don't know if that was just at the factory or at the dealer level back in the day.

If the pump slides in/out of the hole (with the studs pulled) with your bare hands, it will suck air and leak oil pressure around the pump body.
This is likely the main why "big" pumps exist... compensation for crummy tolerances.