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Security nuts on the DME - Boxster 986 S / worn bearings?

Stoo.c

Well-known member
Joined
7 Apr 2014
Messages
205
Morning all. Decided to finally get round to removing the engine on my 986 S (havent driven the car since getting it about a year and a half ago) yesterday.

Dropped the gearbox out and came to unplug the harness from the DME in the boot and there is a little metal shield covering the top DME plugs with some security nuts.

Is there a knack to removing these or am I better off just cutting them free and replacing with normal nuts?

Untitled by Stuart Crump, on Flickr

Many thanks
Stuart
 
Thanks very much - I did try the hammer and chisel approach but no sign of movement. I'll just break them free and replace.

Many thanks
 
Tried again with the hammer and chisel method and it worked perfectly. Shame the engine's scrap though after all that.
 
I'm probably being a bit dramatic as the engine actually ran fine other than pressurising the coolant. I was removing the engine to pressure test the heads and do the head gaskets however upon dropping the oil and filter as part of the removal process, the filter was full of non magnetic metal grains which came as a shock and to me points at bearings which is crazy given the engine sounded and performed fine other than the cooling issue.

So I'm fairly sure the engine is rebuildable without a doubt however its whether or not is worth it to me at the moment. I bought the car knowing there was an overheat issue - ok so I was hoping it wouldnt be a cracked head or failed gasket but such is life. If I pay somebody to rebuild the bottom end, I'm likely looking at 2k plus and I simply dont think I have the time to do it myself particularly as this would be my first Porsche bottom end rebuild.

First thing, I'll pull one of the heads regardless so I can look at the condition of the liners as this may help me make a decision. If the liners don't look too hot then I'll probably not bother with a rebuild on the engine at all.
 
If the coolant is being pressurised then i can only think of a headgasket as the cause ..

Normally and this is pretty rare the coolant gets into the cyl and you end up with D chunk .. a destroyed liner , ( ive seen a handfull in 14 years ).

A headgasket failure is again pretty rare but i cant think of anything else .. a cracked head just mixes oil/coolant and doesnt pressurise the system .

metal particles are to me a seperate issue .. if chrome then IMS and you could cheat with an IMS kit , dont tell Alex i said this , you wouldnt get a warrenty and you would have to flush out the engine but its an option .

If copper then its bearings .. to get chunks of copper metal then i would have thought there would be noises as normal wear and tear then the particles are miniscule .

If black then it could be part of the guides for the IMS .. in itself not a problem as such but with out a strip then its hard to say .

I have seen on servicing cars with metal in the filter .. these cars do keep going without any work being done to address it .

As to why some cars go for years with metal in the filter and others dont is anyones guess ... wish i new !
 
Thanks for the reply - I really appreciate the interest. I absolutely agree that the coolant pressurising and the metal flakes are completely unrelated. If it weren't for seeing them in the filter, I would be quite happy thinking new head gaskets and away we go. Regarding the coolant system, when I first got the car as an overheating runner (about 2 years ago) I checked everything else hoping it was an air lock/bleeding issue but it soon became obvious that it wasn't - probably the main reason its just sat there for so long as other things in life have taken priority but recently I decided it was time to do something about it. When removing the exhaust system, there was actually coolant drips coming out of the manifold so there has definitely been coolant getting in there (presumably when the engine gets switched off and there are no longer combustion gases forcing into the coolant system).

The bits in the filter are definitely metal and definitely non magnetic. They are very fine but there is a LOT of them - I will try and get a picture. I would say they look to be coppery but of course they could just be oil stained.

Hopefully I can do a bit more investigating this weekend and get a bit closer to finding out. On a side note, whilst I know the gauges arent exactly reliable, the oil pressure was showing absolutely fine on the dash prior to this strip down.
 
Interesting .. a couple of things .. have a look at the plugs .. any sign one or more are cleaner than the others ..

Im guessing the engine is out ? if not and the coolant system is filled then use a coolant presure tester .. leave it over night then remove the plugs .. look for coolant and perhaps turn the engine over by hand to see if any comes out the plug hole .

A borescope check or heads off should soon show your if its headgasket as one cylinder will be pretty clean .. ie very little carbon build up .

Im of the opinion its a headgasket due to the pressuring but .. ive seen X 1 996 head which cracked between the coolant and the secondary air channel .. the bit you can see when the exhaust mainifold is removed .

Its possible you have 2 problems there .. gasket and a crack .. but lets be realistic .. the odds of that .. hmm ...

You also wont get and pressurisation with this crack .

Biggest issue is the metal .. fine particles ... no obvious knocking and lets face it big ends do rattle .. and good oil pressure .. doesnt sound to me atm like a scrapper ..

trouble is we are back to square one .. with out a strip then we cant say for definate how bad the shells are .. might be normal wear and tear or might not .

Pictures of the particles if poss please .. the canister and if possible empty it onto a rag .. also cutting open the oil filter is what i would do for an inspection .

If its worth saveing then im happy to help .. undecided atm though !
 
I now have some pics - just need to upload and the plot thickens :grin:

After my initial shock, I inspected the filter a lot more last night and I'm now confident the bits are NOT copper and some of them are bigger than I gave it credit for. You're right, bits of copper this big and the engine would have been knocking about like crazy - it simply ran too well. They are 100% non magnetic so no steel in there at all however as silly as this sounds, i'm not even sure they're metal any more. I feel like I can squidge the bits between my finger nails and easily deform them but they aren't big enough to be 100% sure.

I actually have my 996 C4S being collected this morning by Archer Motorsport for a service and brake fluid change so will be giving them the boxster filter for a little look. Hopefully that may clear things up a little more. The engine is still technically in the car but completely disconnected and ready to drop this saturday. The plan is to remove both heads, inspect the bores and get the heads into the machine shop for a pressure test and then hopefully a light skim.

I'll also remove the IMS cover to check the condition of the bearing. Pictures of the filter coming shortly.

Again many thanks for the help so far.
 
Untitled by Stuart Crump, on Flickr

They certainly look metallic in the pic but almost feel rubbery and not sharp as one would expect. Once the engine is out I'll also remove the sump and have a look around.
 
I cant zoom in on that im afraid and i really would like to .. if you have a bigger piucture please post or mail me ..

[email protected]

That looks like plastic or rubber .. if you can squash the bits then its rubber ..

Are the bits green ? it kinda looks like that to me .. if so inlet mainifold gaskets are green ... other than someone dropping an old one in a cyl then im not sure how it could get in the filter though .

What im thinking atm is its some sort of silicone sealent from previous work done ... cam cover .. sump gasket etc etc ... and they used too much of it .

If it was harder then its plastic and thats chain guides .. not a major issue in its self but there is rather a lot of bits and that would be concerning .
 
Morning and again thanks for staying involved here deMort. I think we are all now in agreement (the guys from Archer as well) that this isnt in fact metal and is a rubbery material - I'm confident its not plastic - its too soft.

From what I can tell, this car was fastidiously maintained by somebody who clearly loved it a lot - loads of receipts (porsche ones mainly - ouch), service stamps etc and then suddenly it stopped a few years ago and went to a new owner and the mileage didnt really change by much at all until it ended up with me. The history of this car is too good to let it die. My guess is the overheat issue occurred and the fastidious owner decided enough is enough (as he would have probably gone to Porsche based on the other receipts) so it was sold on with an 'issue' that a few people have attempted to fix and failed until it landed at my door. I've already uncovered a few 'attempts' i.e. the thermostat was missing, the coolant appeared to have some gunk in it etc so its quite possible that something has managed to get in with the oil.

I'm now far more confident that this engine is 100% savable. I will investigate further this weekend and start pulling the heads.
 
Stoo.c said:
Untitled by Stuart Crump, on Flickr

They certainly look metallic in the pic but almost feel rubbery and not sharp as one would expect. Once the engine is out I'll also remove the sump and have a look around.

That's rubber from the cam chain tensioners..
 

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