Oil Pump spec's

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Dear Mel,

On a cold morning ( in southern California... probably 40F to 50F ) the STOCK pump can burst a stock oil filter canister, which is rated at 200psi. Running a blueprinted pump, your start-up pressure can exceed 300 psi.

Which tells you why you need a by-pass valve. It also gives some indication of the pressure LOSS in a pump that has not been blueprinted.

But as for some table showing pressure vs the viscosity of the oil, I've never seen one.

-Bob Hoover

"Veeduber" schrieb im Newsbeitrag = news: snipped-for-privacy@z5g2000yqn.googlegroups.com...

This requires a more complex equation.

Regards,

Ralf

Well, why don't you post the equation instead of merely stating the obvious?

J.

"P.J.Berg" schrieb im Newsbeitrag news:op.uuh5k0syl5ult0@cm-84.208.86.10.getinternet.no...

Maybe I'm answering only the question about a table that's shows pressure vs. viscosity.

Regards,

Ralf

Hey, P.J. and Ralf and all you other guys... Wanna have some fun? Build yourself a VW Oil Pump Tester. Seriously. It's easiest if you've got a lathe & milling machine but you can make a suitable holder out of WOOD and some Bondo.

The idea is to make a bench-top VW oil pump HOLDER. You drill the inlet & outlet holes first... then bolt them together with a bolt passing through both pieces. Bolted up like that, use your milling machine or the lathe to turn the hole to the ddiameter of the pump- body MINUS about three through. You will need to rig a slotted DRIVER. A piece of 3/4" shafting will do, turned down to accept 1/2" drive v-belt pulleys. Use 3/4" collars.

The handy thing here is that you can make up any kind of pump cover you want... or you can buy some of that blister-pak'd crap. Put a gauge in the circuit and rig an input hose, you can do all manner of interesting tests. But you'll need about 2 hp on your input... and a double-sheave pulley to get enough power to it.

An engine builder who taught me a lot of stuff about racing engines had a rig similar to the above that he used to test blue-printed pumps, long-gear pumps and so forth. The experiments he was working on at the time of his death had to do with a centrifugal oil filter -- a belt-driven jobbie that ran at 2x crankshaft speed to power the 6" dia. 'filter plate'.

If you happen to have an aero-space industry handy you can pick-up new- surplus aluminum billets, tooling plate and so forth at bargain prices. Or, you can try making your own castings.

I suppose the point of all this is that when you can't find the data you need, you can always create a few simple experiments and develop the data yourself. such as using about one-quart MORE oil than recommended... and giving the engine a chance to fill all your lube- oil devices & plumbing before you put the hammer down. By that time the extra quart will have vanished, taken up by the hosing & pipes supplying your cooler, pre-luber, filter and so forth. With AIRPLANES you need to establish the sump's capacity with the engine at various ANGLES. Overlook that particular data and you can eat an engine because the angle sez you've got too much oil in the sump when in fact you may not have enough.

All of this is just common-sense stuff; the sort of thing everyone eventually figures out... after losing an engine or two.

-Bob Hoover

cool, we could hire Mario to make it... probably wouldn't cost more than

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Dear Joey,

If you've got a seriously blown engine around the place, something that poked a hole in the case down around the #3 cylinder, you can use that case as your pump-holder. Just saw it off just aft of the middle bearing web. You can pull the oil pick-up tube and install something more suitable. Or you can leave the tube in place but add a length of hydraulic hose.

When blueprinting a pump what you're looking for is a set of gears that are .001 OR LESS in radial clearance in a pump body that is NOT scored on the bottom. Then you use a surface grinder to bring the pump body AND the cover-plate to a ..001 COMBINED clearance. These are a steel-to-steel interface but the aluminum pump body will take care of that, expanding enough to give the gears sufficient clearance so as not to score the cover plate.

When making a test stand keep the pump's rotation in mind. I know it sounds like one of those trik questions but it's not. In fact, I know a guy named Bob who got everything all set to drive a pump directly with a 1hp electric motor... except he forgot the pump is driven ANTI-clockwise... and the motor spins the other way.

-Bob

Hahah... was just a joke since it involved bondo, Mario would be the man for the job!... anywho, if anyone was serious about making a setup like this, I do, in fact, have a blown engine.... I could donate a 1971 AE case that has a cracked main bearing saddle...