my DIY engine rebuild

[BFeller]

Originally Posted by Jamesp

The metal in the coolant passage is cause for concern, particularly since the engine appears to have had some work in the past. What does the block side of the water pump look like? Failed metal impeller water pumps are legend on this forum.

The picture does show a foil tab that seals a bottle of some sort. Maybe from the previous owner applying IMS Bearing Repair in a Can.

[flaps10]

Originally Posted by BFeller

The picture does show a foil tab that seals a bottle of some sort. Maybe from the previous owner applying IMS Bearing Repair in a Can.

Well apparently they didn't read the instructions, or didn't use enough. cough.

I didn't have time for a pic this morning as I suited up for the ride in, but I did look at the crankcase side of water pump housing. It is slightly discolored from the coolant but it is 100% "as cast" and doesn't have a mark on it.

[Jamesp]

Originally Posted by flaps10

Well apparently they didn't read the instructions, or didn't use enough. cough.

I didn't have time for a pic this morning as I suited up for the ride in, but I did look at the crankcase side of water pump housing. It is slightly discolored from the coolant but it is 100% "as cast" and doesn't have a mark on it.

That's good news. Parts are expensive, but you are in a position to turn back the clock on the parts in your engine that tend to wear. My rings had 120K on them, and while clearly worn (about 1/3 gone), they sealed fine, so I kept the $1200 (wow! price rings for anything else) but replaced the really worn parts like the bearings which were down to the steel backing. Check out Gaudin Porsche for good deals, but watch out for shipping. Also, if you are going to replace your IMS bearing do a little research on bearings in general which helps in the decision on what to put back in. I liked the Pelican bolt and seal, but not the bearing due to the seal. Keep up the great work and thanks for the post!

[flaps10]

I had a post all typed up earlier with pictures, etc of where I had managed to get to on Friday night, then had a failure to click "Submit Reply".

Well it basically contained this picture:


Since I was practiced up, removing the other cam cover, cams, lifter carrier and finally cylinder head was pretty straight forward. I had also made a comment in the post about how I've come to the conclusion that during dismantling a Porsche engine if it requires anything more than a nudge with the rubber hammer or gently prying at the pretty healthy spots the designers left you, you missed a fastener.

[sidetrip]
Back in the day I had a 75 Honda Civic 1200 and it blew a head gasket. The manual described how to get all the way down to removing the head bolts and then pointed out two (pathetic in comparison to what the M96 designers left us) locations you could pry ever so gently, but admonished that "what ever you do, don't pry at the gasket surface". (Duh). Let me tell you something, that gasket was STUCK on. I ended up devising a way to allow me to use my floor jack from under the car to push on the only spots allowed and it damn near lifted the car off the ground before the gasket came loose. Compared to that, the Porsche is a dream.
[/sidetrip]

Today's project was to get the case split. So I did.



I swear to you, that's not a crescent wrench in the back ground. It's not. Really.


Chain ramp for the IMS/crank shaft chain. On to the shopping list. The ramps for the cam chains looked much newer.

Looking over the pistons I could see some very light scoring on them, mostly between the crown of the piston and the first ring. #1 cylinder is the worst one. But the rings look damn smooth and the bores of the cylinders looked absolutely brand new in some cases, and one or two with a few very fine linear scratches. I made a point to head back after I had everything situated on my work bench to go back and wipe out those bores and really take a look

Houston, we have a problem.

I thought it was the strange way light shines on stuff that is dripping with oil but when I wiped the bore of my #5 cylinder I noticed a significant scratch. Shown under two different lighting scenarios so you can see the best. With bare fingers it is just possible to feel the scratches. I did my best to light them well for the pictures.


I had to orient myself with the way the crankcase was situated and then move to the bench to see if I could see any corresponding damage. I was worried that I would find where a wrist pin snap ring had popped out, but it seems to be secure. Looking on, it didn't take long to notice.

Here's what you see at first:

Then you zoom in:

There's supposed to be a break in the ring, but it's not supposed to be over an inch long. My guess is this is an assembly mistake, most likely the last time someone was in here. The ring material is really thin and it would not be that difficult to have snagged and got a piece crushed into the cylinder wall.

After taking the pictures here I cleaned up my tools and called it a night. Tomorrow I'll need to obtain the correct sockets for the bearing carrier and connecting rods.

Stay tuned as I dig deeper.

[flaps10]

And this, ladies and gentleman, is why you do a complete tear down when you find metal in the filter.






This is cylinder #6. The bearing even appears to have mileage on the outside (i.e. it's a spun bearing).

tick, tick, tick...boom. I read that somewhere.

The good news for today is that it appears that my crank is in pretty good shape. I believe a basic polishing of the journals and I'll be okay.


The good.


The bad. My main bearings are ugly.





So, it's apart. I'd appreciate the opinions of anyone who has actually turned wrenches themselves on a M96 engine, or at least an engine, on what I've uncovered.

I've got a couple of local shops picked out that do ultrasonic cleaning. They happen to be shops that build hot rods, so I'm assuming they can also handle polishing a crankshaft.

My wrist pins look great.

"Other than that Mrs Lincoln, how was the play?"