Dougs951S

Hey guys, changed the oil on my NA today and found a chunk of metal stuck to the magnetic plug. I included a picture of it next to a US dime for size comparison. The chunk is magnetic. It sort of looks like a chunk of a rod bearing to me, but it's awfully large to be that I think.

To investigate further, I cut open the oil filter and ripped out all the folded carboard/cotton filter media off the center perforated cartridge. I found essentially no metal in the filter, not even minute particles.

Oil pressure is great, and the motor sounds and runs fine. Thoughts? I don't think a chunk that large could just break off a bearing and end up in the oil pan intact since the clearance between rod journal and crank is so tight.

V2Rocket

My first thought would be to pull the cam tower and see if there are any broken lifters/springs/valve keepers.

Dougs951S

Upon closer inspection, the material is obviously steel sandwiched between a later of non metallic substance on both sides. I believe it's a chunk of head gasket material that made it's way down into the pan when I did the HG recently. This is the first time I've changed the oil since then. I guess in the end, the oil filter doesn't lie. If there is nothing in the filter, than there is nothing to worry about.

FWIW, here is a quick chart I made up today of oil pressure vs rpm, with 20w50 oil at operating temp. I believe my pressure gauge is wonky which is why I'm maxing out at 4.5 BAR from ~2100 rpm all the way to redline. The sender unit is brand new.

FRporscheman

I also see about 4.5 bars max on all of my cars. Either the gauge wonkiness is endemic, or 4.5 bar is the pressure set by the relief valve.

V2Rocket

Over the years on my car and the ones I've worked on, cold idle pegs the gauge at 5 bar, warm/hot idle the gauge is 2.5-3.5bar, and much RPM over 1500-2000 makes the gauge hit 5 bar again, using regular dinosaur 20W50 filled allll the way up.

Classic low oil pressure gauge reading symptom is that you are a quart low...

ddombrowski

We used to peg the gauge on our car at 5 bar with the stock oil/water cooler setup. Then, we went to a turbo oil cooler setup that had a sender on it already.

I wanted to use the same sender we already had so as to be consistent, but somehow I must have broken it because when I put the whole thing back together (with the new oil cooler), the gauge read 0. I used the extra sender and the car now pegs 4.5 and doesn't go any higher.

I changed too many variables to know for sure what happened. Could have been my re-seat of the OPRV, could be the sender, who knows? I'm now in the 4.5 club.

FRporscheman

BTW, when I first read the title and scrolled down, I thought you found a dime in your oil. So many jokes you could make with that...

Talk about getting nickel and dimed
We told you not to throw money at it
There's an oil CHANGE for ya

StoogeMoe

The car stops on that dime.

Dougs951S

Well, confirmed today that the gauge isn't wonky. The car gets 5 BAR on a cold start, but it takes a few seconds to build that last .5 BAR up. The gauge will read 4.5 BAR at startup, then creep up to 5 BAR over the next 2 or 3 seconds. 10 minutes into a normal drive, my pressure is starting to drop at idle to ~4 BAR. By 15 minutes into a drive I'm at steady state temperature and pressure, which is 4.5 BAR above 2000 rpm and 2 BAR at 950 rpm idle.

Sound like a cracked pickup tube or rod bearings?

odonnell

My car idles around 2 bar on M1 15W-50 full syn. Rod bearings are healthy. Wouldn't worry about it