ID this, for a slow $20
 

Okay, I was going to tear this engine down as it was in a flood and my confidence was low, however, this stock 3.6l in my '92 C2 Cabriolet ran perfectly (except for a stuck thermostat to the front oil cooler that was quickly caught before temps rose to high). Anyway, upon start up after an oil change, I heard one of those catastrophic noises from the rear of the 911. We found no tools bouncing around the engine compartment, so out came the oil and along with it this chunk or metal. YIKES, now I really do have to tear her down and split the case - a first for me!

Just for fun, I'll give the first person who can ID this chunk a $20 PayPal payment. It'll take me a couple of weeks to get the engine out and stripped down, so don't expect immediate payment. The scans below show a lot of details, except the size - which is just under 1cm (3/8"). Let's stay below 20 questions to limit the length of this post so make your questions count!

Oh yeah, if there's anyone in the Madison, WI area that wants to get their hands dirty and enjoy a beer or six, please PM me. My garage is warm and clean (as of the beginning of this project is clean). I have all the appropriate books (thanks Wayne!), but will be purchasing some tools on the fly. IT'LL BE FUN!!http://forums.pelicanparts.com/uploa...1105553064.jpg

I submit a piece of cylinder wall as my official guess and final answer.

rod failure, piece of your crank case got hit and broke off
i'm thinking part of the case below the cylinders, where the pistong squirters fit in... :

http://forums.pelicanparts.com/uploa...1105554262.jpg


just guessing here, pic's aren't big , not much detail

chunk of the case internal re-enforcing web, official and final answer

Jim

I dunno guys, I think I got it. See the cross-hatching in the first picture? :)

could be just a scratch or 2... can't see that piece (straight round edge) fit on a cyllinder ...

I am with Stijn, looks like a nice rounded bottom, my cylinders were squared off, could be machine work leaving those marks, tough without a refernce in the image for size, could be really small, could be really big.

is it magnetic or not?

all open questions

Jim

Man, you guys are making some expensive answer. Couldn't you all come up with something that is less costly...

Answer to the first question about it being magnetic... I found this 1cm metallic part on my oil plug magnet, but it is barely magnetic. It doesn't stick to steel, but will stick to a strong magnet. Weird, huh?

From the milling marks it has it looks to me like part of the cylinder (bottom) or even part of the lower piston skirt. Those are my two guesses.

easy. that is without a shadow of a doubt a piece of the left googleflange crankcam gear.

I take paypal!

slightly magnetic.... it is a piece of a Nikasil cylinder.

yep, the odds favor the cylinder, if so he will need the $20:eek:

Jim

Smestas and Doug... You are TOO late. :D

I'm gonna donate my winnings back to Don if I am right, as Jim sez, he's gonna need it. In exchange for my $20 donation he has to carve my initials inside the case. :D

Don,
I have recently relocated to Brookfield from the East Coast. I would be happy to help you out some weekend if you need it. I guess I'm a qualified Porsche technician. I rebuilt the 930 nearly two years ago and it's still running fine! ;)

Great answers with only one of the 20 questions used up. Maybe it was too easy for you pros. Anyway, I'm hoping to get the engine dropped this week and start disassembly this weekend. My PayPal should be paying out early next week. The next question will be: Why did this damage occur?

Dave\Werk-I: I'd love to have your help for removal\disassembly if you have time, however, I really would like a help with assembly and don't want to over-extend you - whatever you feel comfortable with. I'm guessing you won't be making the 1.25 hour trip to Madison in the 930!

Chris is right, but it's from cylinder number 2.

Sherwood

Sherwood? I gotta know how you hazarded that guess.. Common problem?

The cause: Most likely a failure of one end of the rod. A broken wrist pin or rod bolt, main bearing, or something on the rod allows it to move sideways and knocks out pieces of the cylinder bottoms.

common problem is #2 and #5, they are in the center of the crank so get less oil, read the thread on "center drilled crank"

Jim

I guess I should have known that... :D

Chris,
Actually a WAG. With your sharp observations of that as a piece of cylinder, I have a 1 in 6 chance of scoring. I didn't realize #2 and 5 were likely candidates, but we'll see. If there's any prize money left, please donate mine to the Tsunami relief effort.

Sherwood

You and Me have no luck, I too found major engine failure
 

Your post have a very familiar ring, I too found a major..major..major failure in my case. It's my first total rebuild and my first Porsche project as well. I LOVE IT! Look at my picture, it looks like my intermediate shaft pulverized, I found an extra distributor gear floating around near my timing chains.

Regards,

Alex :mad:

piston skirt.

I finally got the engine torn down, well at least down to the case, and Chris Streit (a.k.a. cstreit) is a winner! It was his first guess, without asking further questions, plus he answered definitively and with authority. Congratulations - I owe you $20 (will contact you via PM for your PayPal account address).

Below is a picture of opposing cylinders 3 and 6 - 6 has the chunk missing and the base of 3 is cracked. I noticed cylinder 1 has some of the surface missing so it needs replacing as well.
http://forums.pelicanparts.com/uploa...1107152777.jpg

The next mystery is what other damage did those chunks do? Peering into the oil return tubes and I can see the vanes of the oil pump (see picture).
http://forums.pelicanparts.com/uploa...1107152391.jpg

Thus, I need 3 pistons\cylinders and an oil pump at a minimum (besides the usual rebuild parts). Hmmm, maybe its time to upgrade to 3.8 liters!? Any suggestions? Does anyone have any parts lying around??

ehm.... you sure the pieces you posted are the cyllinder?
do they fit in there?

maybe there's other damage inside your case

Don,
I fear the worst. I would suggest splitting the case and taking it in for a complete checking out. You mentioned earlier that the car had suffered from water damage. Judging from the photo you provided showing the lower portion of the case, it appears there is a large amount of rust deposited on the aluminum case. I think it is safe to assume that water had entered the case over time, creating the aggravating circumstances for mechanical failure.

Don.

I'm donating my $20 prize to charity.

Namely, the "Don Settergen Engine Memorial Rebuild Fund". It's a worthy cause and I know they can use the help right now. :D

I'll second those recommendations to open the case. There has to be a good reason those pieces are broken off. Looks like rod contact - - but why? :eek:

Oh yeah, the chunk I displayed earlier fits nicely one one side of the hole on cylinder 6. Hmm a little JB Weld - just kidding.

And, oh yeah, that case has got to be cracked. The only way you can see the vanes of the oil pump would be if its housing is cracked. Anyway, at this point I'd do it just to satisfy my curiosity and to further improve my confidence in this car.

And lastly, thanks Chris for the donation and Dave thanks for the use of your tools - both have already been used!

eroded oil pump
 

Oh my god! I opened the case and found out what started all the damage - the water. Look at the pictures below and you can see a distinct water line below the crank (whew), but coving the oil pump. The oil pump eroded (its shocking that the pump still moved oil and had some pressure) and one of its alignment studs traveled around the engine meeting up between the crank and the bottom of cylinders 3 and 6. Also, water entered cylinder 1 eroding the lining a little bit (dropping the compression only about 15% compared to the other 5 cylinders). The case looks good by my eye, so it is off the machine shop that Kelly-Moss Racing uses (its in competent hands). She'll get all new bearings and seals and the whole works!

I found an oil pump, but I need some cylinders. Mine are the newer style with the gasket groove at the head surface and are stamped 95ZN6. Does anyone have any lying around or know where I can get some new or good used? Does anyone know what other cylinder revision numbers are compatible (I found some 100ZN8’s on eBay)?

Thanks as always!

http://forums.pelicanparts.com/uploa...1107362720.jpg http://forums.pelicanparts.com/uploa...1107362812.jpg

"Okay, I was going to tear this engine down as it was in a flood and my confidence was low, however, this stock 3.6l in my '92 C2 Cabriolet ran perfectly (except for a stuck thermostat to the front oil cooler that was quickly caught before temps rose to high). Anyway, upon start up after an oil change......"

Let me guess. You drained the oil tank, but there's no drain plug on engine?

What happened between, "ran perfectly" and "upon start up after an oil change..."?

Inquiring mind wants to know,

Sherwood

I took the car to some pros to check out the oil system as the pressure wasn't steady and I wasn't sure after reading all the posts what it should be. The mechanic drove the car 7 miles and noticed it getting too hot and diagnosed the oil thermostat problem. Oddly they did not notice the pressure instability caused by this oil pump problem.

As for the oil changes, I pulled all three plugs (filter, tank and case) when I changed the oil about 3 or 4 times before the oil came out clean. I assume the mechanic did the same.

Even after the casastophic noise, I was able to turn the engine over by hand without a noise. Then I cranked her with the started and tested compression and she was still good. Then, I fired her up and she ran like before - smooth, but with instable oil pressure. With no confidence in the engine I tore it down to find the problem. YIKES!

The thermostat was stuck as diagnosed (I removed it, cleaned it and tested it), but a stellar mechanic missed this oil pump problem. No worries though as she was going to need to be torn down anyway. Just an extra 2 cylinders added to the cost of a confident rebuild...

Don,
To quote a somewhat infamous politician, "I feel your pain". In case you haven't thought of this, have the shop remove the oil gallery plugs and have the cases compltely flushed out.
Did this vehicle sit through a winter of freezing temps when the flooding occured? Freezing water in confined spaces, such as an oil pump, could explain the disintegration of the sump pump. When water goes into a crystalline(sp.?) state, the forces are extremely powerful, hence the use of freeze plugs in water cooled engines.

No freezing occured as I bought the car in late fall from Maryland. Also, the engine was never run with any water in it as the car was stationary at the time of the flood. After the flood, the starter was shot so noone could have started it. The damage to the oil pump looks like errosion, possibly salt water??

Wow, can you post more pictures of the oil pump? I have *never* seen anything like that...

-Wayne

The fact that it ran with the oil pump like that is amazing. I am suprised it mananged to scavange the sump though.

As far as that cylinder goes, there are people on this board that have paid to have their cylinders notched like that.

i guess it could work , but i'de at least grind the edges , so no miniscule crack remain in the edge... that could grow under stress...

Here are pitcures of the oil pump from a couple more angles. I'mm going to clean it up and save it as the ultimate convesation piece. It is truly amazing that the engine ran smoothly. The only thing I found odd was the erratic oil pressure that peaked at only ~3-4 bar.http://forums.pelicanparts.com/uploa...1107841908.jpg
http://forums.pelicanparts.com/uploa...1107842011.jpg

The rebuild is fully underway. I started another post so you all can keep pushing (helping) me along! http://forums.pelicanparts.com/911-engine-rebuilding-forum/207873-first-time-rebuilder-gaining-momentum.html

what exactly is that stuff all over the pump? Welded on metal bits?

That's corroded material that is actually missing, not added. It seems like the material just rotted away. It's really weird because the case has some pitting (blasted clean) and one cylinder has pitting (replaced), but the pump abolutely rotted away. The pump must be made of a material the more easily reacts with water (possibly salt water). Maybe there is an electrical charge on the case that increased the reaction?