964 blocked oil rail crankshaft

[Porsche_Jek]

Hi felow pelicans

My 964 crankshaft no 4 connecting rod bearing are totaly worn out see picture. All other bearings are totaly fine. After inspecting I noticed the crankshaft oil rail for no 4 are blocked by some kind of steel ball so I suspect this is the reason. I've tried to drill out this ball but it's of too hard alloy . What to do? Anyone else have experienced this?

[Tom_in_NH]

I don't have a solution for you, but it is probably a piston squirter check ball. Were they replaced? If so, one of them got away........

[Catorce]

Almost certainly a check ball from the squirter. I make rebuildable piston squirters and have seen all kinds of squirter failures. However, i have NEVER seen a ball get loose from a factory squirter and to be honest I don't know how that is even possible.

You need to not drill it out. You need to drill out the main oil gallery plug, then dislodge the ball with a drift pin, push it back into the main oil gallery, and then make sure you recover the ball.

If you try to drill it out you will ruin the case by drilling the soft aluminum while the hard ball remains unaffected.

Either way you might just be looking at a new case!

[racing97]

Look at the path of the individual oil path through the crank specifically on the journal in question. They are adjacent to the crank pin in the center they are on both sides.
Those passage ways have a ball type seal I can't remember the trade mark name at this time.
If the ball comes out you will loose pressure at that crank pin.

regards

[Walt Fricke]

How about a picture of the location of this ball? Is it in the case, and not the crank?

Your pictures are of a rod which suffered an oiling failure, I suppose. Bearing mushed, and journal scored? What are the #6 and #7 main bearings like?

But the rod bearings are oiled via the #1 and #8 main bearings, through passageways internal to the crank. 964s are the same as their predecessors in this regard, aren't they? #4 is close to the #8 main, so unlikely to starve the way the #5 does.

Is this ball to be found blocking the oiling hole in the crank for this bearing?

If Catorce has never seen a squirter check ball get loose backward down its passage, against the pressure of the oil, much less find its way into the #8 bearing oil supply, and thence through the crank to the first rod bearing hole, then the squirter seems an unlikely culprit. You can easily check to see if all your squirters are in their proper places in the case, and are working.

The chain tensioners have ball check valves, but, if one of those pops off, the ball would have to circulate through the scavenge pump screen, and the oil filter, that seems unlikely.

[Porsche_Jek]

Thanks for feedback guys, please see picture of ball. I've checked my piston squirter check ball but this is located inside of block and can't be accessed. The blockage ball are of bigger size then the squirter outlet hole. Any other ideas for where this ball can come from?

[racing97]

look on the counterweight adjacent to the crank journal you will see a missing plug it is probably made by this company
https://www.sfckoenig.com/

[tocobill]

Almost looks like one of the ball plug for the cam tower.