the_vetman

tikicaca, to my non-expert ears your engine sounds normal.

paradigm79

Been a while since I updated and I hate finding dead end threads so i wanted to close this out. I believe this is now solved with a simple fix...remove the LN Engineering spin on adapter and NAPA Gold 1042 filter they suggest and put the stock Porsche oil filter back on.

I ended up rebuilding both heads, replacing soft lifters, etc. among many others things I didn't document in this thread and nothing made a difference. Once I returned to the stock filter the noise stopped right away. I also immediately noticed an increase in both cold and hot oil pressure, and I cut open the 1042 filter and found signs on collapse, presumably from over pressurization. Based on this I have no doubt the 1042 is more restrictive than the stock filter and some effect on this weird noise manifesting.

Why everyone with this adapter doesn't experience the same effect I don't know, but I have met one other person with the same engine and exact same symptoms, his also went away with switching back to the stock filter. Hope this helps someone out there.

LexVan

Glad to hear you have fixed this. How did you measure the cold and hot oil pressures? We don't have that gauge on the 987. Thanks.

paradigm79

I removed the useless stop watch in the sport chrono pod and installed my own full sweep electric OP gauge. It reads from an unused port in the heads, same exact location as the factory OP reads from, but on the other cylinder bank. It also give way more resolution and response than any factory gauge that are often highly damped.

There are plenty out there to choose from, here's the one I used.
http://www.propartsllc.com/product.a...categoryid=16#

pp000830

Sounds like a valve tapping. Could be just a little carbon in the valve seat. Don't look for love too hard on this one, just enjoy the car!
You know the line, “accept the things I should not fix, have courage to fix the things I must and have the wisdom to know the difference”
Andy:-)

paradigm79

I agree. I went through everything reasonable and maybe a little beyond. Ever since I've just been driving it as it was intended and enjoying every howling minute of it.

Britjunkie

Paradigm 79, you are the MAN. Thanks to you I can sleep at nite again. Just as you found out, some of the spin on oil filters must be sensitive to the pulses in oil pressure at idle. I'm speculating that the oil bypass in some filters "tick/rattle" at idle and might be ones with a lower bypass PSI, perhaps the filters with the sheet steel spring vs. the coil spring. Anyway, I replaced the LN spin on adapter and filter with the stock Porsche housing and filter. Once again, nice normal engine sounds. No more banging my head against the wall

paradigm79

You're welcome, although I can't say I agree with your theory on exactly what's going on because many spin on oil filters including the 1042 I was using based on LN's recommendation don't have an internal bypass valve. Those filters were designed for engines that have the filter bypass integrated into the engine block, ours does not, therefore a valve that's not present can't be making noise

I think the noise emanates from the valve train or chain tensioner/ chain. Either way, no doubt a few of us afflicted have turned off the noise by sticking with the factory filter.

Britjunkie

Well, I did some more investigation into the 1042 and other spin on cross reference filters and they all have internal bypass valves.
I'm suggesting that the type of bypass, bent steel, coil steel spring, and top loaded bypass valves and their various bypass pressures may be the source of the noise.
You might be confusing the engine's pressure relief valve with the bypass in the oil filter. Anyway, there aren't many other moving parts in the cartridge filter vs. the spin on that could create noise thus my speculation.
At this point I'm wondering why I replaced the stock system with the spin on in the first place. I'm just damn glad you found out the source for whatever reason!

paradigm79

Possibly for the same reason I did...I bought into what LN was "selling" which was 100% filtration due specifically to the lack of filter bypass valve. After I discovered the pressure reduction I cut mine open and there is no bypass valve and a collapsed element to boot. (There is an anti drain back valve, however that serves a different function.) No doubt there is an oil pump PRV, I'm not confusing that.
My goal is not to argue that point so much as to say that I'm fairly confident that while the oil filter makes it manifest, the actual source of the noise is from the heads or chain tensioner being effected by the change in oil flow/pressure conditions. This means you probably need a combination of things (like a sick lifter, etc. ) present for this result, which helps explain how their can be hundreds running LN spin on adapters yet very few of us with this result. You can also make this noise better or worse not only through oil weight changes but brand changes within the same nominal weight, which to me further indicates it relates to the specific oil flow/pressure condition, and not exactly the filter only. While not claiming to be a professional engine builder I have rebuilt a few of these M96/7 engines now, and what must be appreciated is the level at which lube oil now serves the role of hydraulic actuation fluid (true of most modern engines) where filling and leak down rates of cam phasers, lifters, chain tensioners, etc. become very important. (I know at least Ford and BMW have had similar noise issues with their cam phasers.)

If I wasn't concerned with ground clearance I think trying a much larger spin on filter such that the pressure drop across the element was equal or less than the OEM filter would be worth a shot. Perhaps this is ultimately the reason LN started recommending the stainless mesh filter instead later on. The engineer me still wants to understand it, but thankfully the driver me won and I've been happily driving it instead of being under it anymore.

Cheers!

Britjunkie

"like a sick lifter, etc." Now you've done it, well at least I had 2 good nights sleep

Rob VN

At one time I ran the LN mesh filter on my 987. It made a whistling tone. Going back to the 1042 the noise went away.