piston squirter installation

ajwans · 02-02-2010, 06:22 PM

Are the piston squirters installed on any angle or directly orthogonal
to the parting line of the case? I will have a machinist with a bridgeport
to install them but not being intimate with Porsche cases directions
would be appreciated.

andy

cgarr · cgarr's Garage

Is this for a case with no squirters now? If so you can also mill a groove in the connecting rod to accomplish pretty much the same thing.

ajwans · 02-02-2010, 06:52 PM

I saw the Costa Mesa clip showing this. Struck me that it would cost oil
pressure at idle and I wondered if enough oil squeezed past the bearings
that way.

Is it just a way of directing the flick of oil off the crank as it spins? I really
don't get how it works, but I would like to be educated.

andy

my1st911 · my1st911's Garage

It squirts oil under the piston to cool it. Whether its from a squirter, or from the rod, it will do the same thing, and have the same "loss of oil pressure" Not enough to even notice though

ajwans · 02-02-2010, 09:29 PM

Quote:

Originally Posted by my1st911

It squirts oil under the piston to cool it. Whether its from a squirter, or from the rod, it will do the same thing, and have the same "loss of oil pressure" Not enough to even notice though

The squirters only open up when there is 2 bar pressure behind them.

Here's a link to a video of the conrod squirter version: YouTube - Porsche 911 Connecting Rod Oil Squirter Mod

I can't even work out how the oil gets past the bearings and into that
groove to be spat out at the piston bottoms.

andy

gestalt1 · 02-03-2010, 05:41 AM

so, even if you have nikasil cylinders on an early aluminum case you can just have the rods grooved and not bother with adding the squirters? on a race engine would you add the groove in the rod and the squirters for more oil cooling on the piston? it would seem easier to modify the rods than mod the case for squirters.

gestalt1 · 02-03-2010, 06:00 AM

i would also think that cross drilling the crank would be nessesary for getting enough oil to the rods for this to work well.

gestalt1 · 02-06-2010, 06:50 AM

anyone else have any opinions on this?

m42racer · 02-07-2010, 01:53 PM

Looking at the mod done to the Rod, I too have a misunderstand of this. The Oil sent to the Rod bearing via the Crank journal would be compromised, both pressure and volume. I suppose the relief valve will compensate some, but the volume will surely be less. Would not the bearing shell also need to be modified. How does the Oil get up to the Pistons? Seems like one of those mods that has not been thought out very well.

Just have the squirters fitted to your case. I know this is done alot. There is some cross drilling required. Down through the through bolt holes and cross from the webbing. Some are fitted through the front and staked and some go in from the back side. This is not a hard machining process.

I also think crossdrilling is not a good thing to do. All this does is take oil away from the side the Oil should be directed to. This extra hole can create a "vacuum" or some sort of hydrodynamic condition that pulls the oil away from the galley that should be getting then Oil.
Ask any engine engineer and I bet they will tell you this but in more depth. This seems to be an engine assemblers theory that is not backed up with any sort of engineering data.

jcge · 02-07-2010, 03:28 PM

My guess as to its' operation....

The groove just accumulates oil as it leaks from the edge of the journal in the usual fashion. At this point the oil has done its job in lubricating the journal and is effectively on its return path to the sump.

As the rod/journal passes TDC, the centrifugal force simply flicks the accumulated oil toward the underside of the piston. Not a "squirt" under oil pressure in the "piston squirter" sense, but just "accumulate" over the course of the revolution, and "flick" at TDC, over and over.

John

gestalt1 · 02-07-2010, 03:45 PM

i think you are right John, the oil has to come out at the edge of the rod bearing and the groove directs it to the bottom of the piston. oil squirters were added when nikasil cylinders were introduced. i also think it helps that the porsche is a flat engine, on a V or inline the oil needs to go up so a pressurized squirter is needed.