rockhouse66

I agree. I used the white Scotchbrite - not sure which is less abrasive, the gray or the white, but I know it is very fine and not like the green stuff. I used it to remove the dark specks that remained after scraping, but I no doubt could have just left those and it would seal fine. And it is easy to knick the surface with the razor blade so you have to go slowly and keep the blade laid back almost horizontal.

Slakker

Getting ready to install a deep sump and the DIY I read said to use a brass brush. Any thoughts?

RngTrtl

brass is softer than Al so no worries.

mayday1

Dropped the oil pan tonight, found more plastic bits, and the pieces
are bigger than those trapped in the oil filter, which tells me the plastic
didn't come from the oil filter. All the plastic pieces were located near
the oil pickup area (inside the black plastic windage enclosure. Looking
around all the plastic pieces in the sump area, I didn't see any damage,
but saw a tiny hole in the black plastic windage baffle. It didn't look
chipped, it was nice and smooth so I don't know if it was there by design,
or a small chunk of it broke. Found a couple pieces stuck in the metal
screen of the oil pickup.

Do I need to disassemble all the plastic bits to check for internal damage?
Externally I saw nothing obvious, but black plastic coated in dirty oil
makes it hard to see.

Some pics:

Ahsai

You may want to use Durametric to check the cam deviations. If they are far out or not steady, it's even more reason to replace the variocam pads sooner rather than later. Since your plastic bits are black, I think they came from the main chain (between crank amd cams) rails.

mayday1

hi ahsai,

I'm new to porsche (owner for exactly one week), so your message is
a bit like greek to me. Where is the variocam pad and is it replaceable
without taking apart the engine?

thanks

dgjks6

This is more than you need but this gives some idea what you are in for

https://rennlist.com/forums/996-foru...y-project.html

docmirror

OK, you took a risk on a no-PPI deal and have not picked the brass ring. So, you've got some work ahead of you(or larger checks). Now you know more of what you know, but you still don't know what you don't know. That is - you don't know which piece of plastic is going bad. Or, if this is a cumulative deal from multiple. The short answer here is that all of them should be replaced. The cam chain guides can all be replaced without removing the engine, but it's a lot easier with the engine out.

Alternately you can just 'go drive' until it comes apart eventually, and we'll have another roller chassis avail on the market. Meh - I guess valve-piston interference isn't fatal to the whole engine, but it sure is a lot more expensive than doing the guides now.

Another option since no one knows you on here is to put it back together, have it shipped to Chicago, or maybe Miami, and sell it there, then try again with another 996 and get a proper PPI(note - this is not a recommendation, but an option).

mayday1

My current thinking is that the plastic bits have been there
a) since a week ago when I first drove it,
b) since last oil change (I'm guessing a couple thousand miles, a year
or two).
c) several years, through several oil changes.

If it is b) or c), I'm not too worried about a catastrophic chain failure
for the next few hundred miles.

If it is a), I should drop everything else and attend to it right away.

But I have no way to tell if it is a), b), or c), so I'm not going to drop
the engine now and waste a good driving season :-)

So I should button it back up and drive it, and dissect the oil filter
every few hundred miles to see if there are further plastic
bits (cheap insurance).

Now to reassemble:
Do I need loctite for these small bolts that attach the plastic parts
to the inside of the engine? The torque on these bolts are low since
otherwise they'll crush the plastic, but they are subject to heavy
vibration inside the crankcase. If I need loctite, what type do I
need that can cure in the presence of motor oil?

Slakker

Order new bolts and loctite 5900. I just got mine in today from rmeuropean. The new bolts have thread lock already on them. Torque them to 7.5 lbs.

You didn't ask my opinion, but this is RL, so here it is anyways. I think you are a fool. You could easily cost yourself 10-15k by sticking your head in the sand and continuing to drive your car. There are also some high end rebuilders that you will not be able to use when it fails because they don't work with people that don't take of their cars. But don't worry, MBM will still take your money when you're ready. Best of luck.

docmirror

I'm not a nervous nelly by any means, but your engine is SCREAMING at you that something is wrong. I consider the scenario where the PO did an oil change(or had it changed) and found bits of plastic in the filter, then sent it to the detail shop, and put the 'for sale' sign up. But- you are right that we don't know how long the engine has been shedding phenolic bits. All we know for certain is that it IS currently shedding phenolic bits, and it's not supposed to do that. We also know that you didn't have a full flow filter on the engine so a certain amount of bits have gone through the oil pump screen, pump, and into the oil galleries to the bearings. And now - the whole world knows that as well.

Lets say you find an indie shop that will do the cam tensioners for $3k(I really have no idea of the cost, but a fair guess). At the same time, you put in the later model baffles, deep sump, full flow filter, and new cam cover and COP seals, maybe adds another $800. You've got a nice running engine, with a secure valve train for under $4k. The price of a valve interference can easily double that. The price of a catastrophic failure can triple that and way more. BTW, I was just kidding about buttoning it up and sending it to Miami for sale. In case that didn't come across well.

5CHN3LL

The smaller ones are the ones that have been through the oil pump. What's going to happen if a larger chunk breaks off that isn't small enough to get chewed up by the chains? Or you get enough to effectively block the pickup?

mayday1

Is the oil filter on the intake or on the output side of the oil pump?
I assume it is on the output side of the pump. So plastic bits flowed
into the sump, some of them are small enough to go through
the wire screen and into the pump. The pump grinds them up
and spits them out into smaller bits, these bits then go into
the dirty side of the filter and get trapped by the filter, so
ideally we shouldn't have plastic bits clogging the oil passages.

But if the oil filter bypass valve was opened, then the bits can get
everywhere inside the engine. This is my worst case scenario.
(OK, the worst case scenario is soon after I fixed this problem, one of the
other 19 failure cases materialises and I have to fix it again).

My best case scenario is there was no bypass, so the oil passages are
fine. The question then is will the chain guide/pad continue to
shed plastic bits, or once the defective part broke off, the rest
of the plastic continue to function normally, and slowly wear away
like in a normal engine.

Fortunately I don't depend on this car, my daily driver is a FIAT so
I can still drive all over the place to chase parts :-)

docmirror

More likely is a chain tooth jump when the vario switches the guide, and if it jumps one tooth maybe ok, just the check engine light. two teeth, maybe ok, maybe not, three tooth jump and head rebuild, plus chains, and sprockets(crack cases), plus guides.

5CHN3LL

For those of us who remember the Fiats of the 60's and 70's, depending on your Fix It Again, Tony as your daily driver is funny indeed.