Rebuild #2
 

Hello fellow pelicans,

After 5 years and 25,000 miles on my first rebuild, I have to open her up again, for a rod bearing failure, most likely #2. This happened due to oil starvation, when one of the oil hoses got disconnectd due to a shoddy installation on my part...Thankfully, I did not split the case the first time, only did a top end, so now is a perfect opportunity to refresh the bottom end. The compression was good, heads are still fresh, headstuds were replaced last time, so I am hoping only the bottom end will have to be done, but I will only know for sure when I dig inside. Stay tuned.
Here is the patient, 78SC with 129,601 miles.

http://i1061.photobucket.com/albums/...qu/image-1.jpg

Re: Rebuild #2
 

Good luck.

Any exiting upgrades coming?

Will follow this and good luck :)

Sorry to hear about this - your rebuild thread was among those I subscribed to before embarking on mine:
http://forums.pelicanparts.com/porsche-911-technical-forum/729856-87-drop-top-drop-n-top-end.html
I'm doing just the top end as you did last time around.

What were the symptoms of your bearing issue? Which hose was it that you had the problem with that caused the oil starvation?

Best of luck on this one - I'll be looking for progress reports!

GK

The symptoms were a noise that first could have been mistaken to a valvetrain noise.

http://forums.pelicanparts.com/911-engine-rebuilding-forum/684493-does-sound-like-rod-knock.html

But the last time I went for a drive, this noise turned into a very loud knocking, the kind of noise that makes you turn the engine off ASAP. Then I found little bits of metal in the oil.

The hose that caused the starvation is a rubber hose I needed for backdated exhaust. Big mistake. I should have kept my old exhaust...

Have all the parts to install my SSIs except the oil lines. What was it about this particular line that caused the starvation issue?
Good luck with your overhaul!

Sorry to hear this, but the reassembly of the top end is easier the second time around!

I did not install the corrsover oil line, instead used my old one wich I cut and connected to the rubber oil line with a hose clamp. The connection eventually gave. Very very stupid idea on my part. My advice: Do not try to save money on these parts.

Aurel,
Sorry to hear about your misfortune.
I guess we are sort of in the same boat. (again)
I remember reading about your previous rebuild when I did my 3 liter...

And now I've just started the reassembly of my "New" 3.2 liter. It was installed in 2009, I think, and been running fine.
But I, -I like you, made a slight oversight during the mounting of the engine to the car.

My mistake was to not fasten the oil breather hose properly. So it jumped off. And a lot of moisture and debris had free access to the crank case. This led to premature wear on the cams, rockers, and valve guides. I actually had rust on one of the chain tensioners. Otherwise the engine is fine. I did open her up to check the wear on the crank bearings. -Like New. (Almost)

So I'm in the process of rebuilding a what will become a 3.4 liter, PMO inducted, EFI controlled goody engine. ;)
So I guess there is a silver lining at the end... (At a cost, of course) :(

Otto,

Yes I remember you started your first rebuild not long after mine. Looks like we are in the same boat again. I still have to put the engine on the stand, not sure how I managed that last time. As far as performance improvements, I am not making any plans before I open it and see the damage. If I am lucky, it should be less than $1000 in parts but if my crankshaft or cylinders are damaged, it may get a lot more expensive...Then I might consider buying a 3.2 and selling this one as a core. Who knows...

Aurelien,

WELCOME (Back) to the Forum! I guess if we all hang around long enough history is bound to repeat itself. Sorry to hear it was for a catastrophic cause vs. sheer mileage.

I have been using a 1000 pound harbor freight hydraulic table to both drop the engine and raise it to the P201. I like this better than the ATV jack which didn't have the vertical reach or the "stack of wooden blocks on the 21" rise floor jack" which I just didn't trust.

Welcome back!

Thanks for sharing and sorry your rework of the factory part gave trouble.

Aurelien - I think your avatar picture caused the oil line to fail (not your re-working of it)! :p :D

Your original rebuild was one of the threads that gave the the confidence to tackle my own. Just as an fyi, I could not quiet my ticking valve train until my rockers were rebushed. It can be hard to tell if they are in the motor as even the most minor gap can tick pretty loudly. It was hard for me to determine if the sound was valve train or something else, but since you are proceeding I can only assume you are confident that it is more than a noisy rocker.

If oil starvation was bad enough to harm #2 rod bearing, I would be concerned about every bearing in the bottom end.

Good luck with your project.

Good luck with the re rebuild. I too referred to your first build to help with mine.

Yeah I know, not the sharpest knife in the drawer kind of avatar...I might have to change it for a better rebuild ;).

I like the avatar. It reminds me of the masons on Monty Python (does anyone remember the intro to The Architect Sketch?)

BTW - what rings did you use on your rebuild #1? The Goetze rings available here at PP and other places are reasonably priced, but some of the older rebuild threads indicate that chrome rings should be used with Alusil, a few posts mention using Porsche-sourced rings (at geometrically greater cost.) I'm figuring that the Goetze rings are dimensioned for these pistons (which go with these alusil cylinders) so they should be correct for this application. Looking for some thoughts and recent experiences.
Thanks,
GK

For my drop, I used the "small drop" method, i.e., I kept the car only high enough so that I could loosen the tranny mount bolts, then used the floor jack to ease the engine down onto a rolling cart - about 3" - then jacked the car up slowly until there was enough clearance to roll the powertrain out.

I used a come-along attached to a strong point in my garage ceiling to lift the engine up onto the engine stand. The come-along is rated to nearly double the engine weight, but let's just say I didn't leave her swinging for very long before I got the weight onto the stand.

Good luck!
GK

I did use the Goetze rings and had good luck reringing my Alusils. I just did a very soft deglazing of the cylinders, which is described in the first rebuild thread.

Aurel:

Sorry to hear of this problem developing.

However, you know what to do and like some have said "it is easier the second time around."

Good luck and I look forward to your progress too!SmileWavy

Good luck with your Second rebuild project.

I will be watching to see how it goes.
I learned a lot from the excellent posts on your last projects.

Peter in Melboune

You'll want to check your rod(s) for proper big end sizing since the knock is the rod beating on the rod journal due to excessive clearance. BTDT last year when my motor let go and luckily the rod stayed on the crank (yay for Pauter rods!) and didn't see sunlight until I took the engine apart.

I have an extra set of good stock 3.0L rods for cheap. Let me know if you need a set or want to see if you can match up one if the weights work out.

Progress
 

I have removed the right cam tower. I see no scuffing on the cam lobes, which is good sign. The cylinders walls are nice too. It looks like no debris made their way into the heads. But the noise was on the other side, and I have not gotten there yet because the woodruff key in the cam is stuck. I am going to get a pair of side cutters to convince that key to let go...Then I will report my findings on the left side.

https://picasaweb.google.com/ad8588975/Rebuild2#5861581223190423730
https://picasaweb.google.com/ad8588975/Rebuild2#5861581235484162466

This does not look good
 

I have removed the cylinders now.

There is sign that one piston kissed the valve. I am assuming that is because the rod bearing under that piston was trashed.

https://picasaweb.google.com/ad8588975/Rebuild2#5861673182198894162

I also have scuff marks on 3 of the pistons, and the cylinder bases have groves that do not pass the fingernail test...

https://picasaweb.google.com/ad8588975/Rebuild2#5861673198823092850

Tough luck on valve contact. Have you worked the economics of the machine work coming your way against a replacement engine? Tough spot to be in...

Sorry to see that piston & cylinder damage. That stinks.

Could have been worse. I know that's not much consolation. Just saying that it could have been much worse. I've recently BTDT (and still "doing that")

http://forums.pelicanparts.com/911-engine-rebuilding-forum/706984-engine-bearing-failure-disassemble-heads-too.html#post6994622


The economics of a replacement engine are not in our favor. Sure you can get a used engine for around $3K to $4K. But it's of unknown condition and one's often inclined to open it up for some work before putting the engine into service. The costs start adding up fast.

Whereas collecting used replacement parts is usually much cheaper when you're DIYing it.

The good news is, if I have to replace P&Cs, I may bump my compression and displacemement a bit ;).

I have to see if the head where valve-piston contact occured is damaged. I would expect at least the valve will need replacement. What else?

What really will decide how I procceed is how the crank looks like...

Valve contact can mess up the seat if the head is cocked. Also should replace the guide since the piston would knock the valve up against it.

Any time you install a new valve(s) you should have the seats cut anyway.

Little progress
 

I removed rod#6 and was able to confirm my initial diagnosis of spun rod bearing. I measured it and it does not seem to have stretched more than 100 mircons, but I will have to measure all of them to compare. I can see the crank surface is damaged, will have to be polished at least...I havent split the case yet but I am getting there.

http://forums.pelicanparts.com/uploa...1365805925.jpg
http://forums.pelicanparts.com/uploa...1365805942.jpg

Maybe I'm not looking in the right place, but the piston scuffing could be normal piston slap?

Just curious - What are your plans regarding the oil tank? Just clean it? KTL, what did you do in your rebuild (oil tank)?

Good luck on rebuild, will follow.

I'm not going to say piston scuffing is common. But you see it a lot. Light marks on the skirt and cylinder are OK. But once you start feeling ridges on those marks, it's a problem.

Oil tank can be cleaned. It needs to be ultrasonically cleaned to get any bearing material out of the tank and its upper screen. After the oil comes in the bottom of the tank, it goes up a tube that puts it thru the filter. When it comes out of the filter, it gets dumped on the screen to de-aerate it. Point being is that the screen should be free of debris since the filter should catch everything. But when there's a bearing failure, you don't want to take any risks.

My tank is full of bearing debris because in my infinite wisdom, I used full flow (non-bypass) Canton filters. So when my engine unleashed a shiatstorm of bearing material, it clogged the filter and then collapsed the filter cartridge, allowing bearing debris into the tank too.

One of my cylinders has a ridge that I can feel all the way up, and I am concerned this may cause oil smoke, low compression, etc...Luckily, I may have found a set of Mahle P&Cs, and even the rods, for a very low price. So low that I could not pass it. I took a little gamble there, but we'll seewhat I get. Looked very nice on the pictures.

Sometimes those gambles work. I did same on a set of '85 pistons and cyls and got a nice low mileage set that had been sitting for decades after the car got wrecked. Also sourced a set of like new axles from same guy. $50 for a set of 16K mi. axles that just needed cleaning.

Let me know if the rods don't pan out for you. I have an extra set of SC rods that I got with a replacement crank. My episode was a bit worse than yours, not to mention my crank was near min. STD spec before the failure. So I decided it'd be cheaper to get a good used crank vs. having mine welded & reground back to STD

Here what my engine configuration will be once I am done. Pretty much what Wayne calls an upgraded 3.0L CIS in his book:

Large intake ports (already have)
DC 15 cams (between SC and 964, already have)
9.3:1 CIS pistons and Mahle Cs from an 82 (should be here tomorrow!)
74 backdated exhaust
Lightweight pressure plate (since I have to do a clutch job, why not?)

This should give a fun reliable street motor if I do it right...

Hope those pistons and cylinders work out well for you. I saw that you snapped those up not long after they were listed on the for sale forum.
Are those cylinders Nikasil?

According to the stamp on them, 95zn1 w16 is for Mahle Nikasil. I also counted the fins, they have 11, my KS Alusils have 10. But I could be wrong...worst case scenario I got another set of Alusils with higher compression pistons. And a set of rods.

I received my P&CS set, and they are indeed Mahle Nikasil, in very nice shape, coming from an 84,000 miles 82'SC. I measured the cylinder bores, here are the results:

1 94.98, 94.99
2 94.98, 95.00
3 94.99, 95.01
4 95.00, 95.00
5 95.00, 95.00
6 95.00, 95.00

I also measured the compression ring clearance on the pistons, and it is very tight, while on my old Alusil pistons, the clearance is over 100 microns.

Unfortunately, the set was poorly packaged, and one of the piston skirt got broken during shipping.

https://picasaweb.google.com/ad8588975/Rebuild2#5868442018078026082

So now, I must find a replacement CIS piston Mahle 95L67 9.3:1 CR. If anybody has one please let me know...

Also, the pistons and cylinders were separated, how do I figure out how which piston goes in which cylinder?

Sorry to see one of your piston skirts was damaged. That's a real kick in the junk.....

I'd not worry about the pistons being separated from the cyls, should you plan to re-ring them. Seems worthwhile to get new rings as they're not terribly expensive & you don't know which piston goes in which cyl.

Going forward, i'd take your piston measurements (skirts) & compare with cylinder diameters. Mix/match pistons & cyls to best balance the clearances per the specs.

Will definitely rering the pistons. I have several leads for a piston replacement, but the challenge is to find matching weights. If no luck, I may just buy a new set of JE pistons. But for now, the focus is on the bottom end. I had no issues removing the flywheel bolts, and have removed all the bolts, even the hidden ones, for splitting the case. Then, after reading all the threads I could, I started tapping the 4 corners to separate the cases. Second evening I try with no luck. How long is the tapping supposed to take? What are the best tools? I even read about Henry Schmidt method of hitting the yoke but I could not figure out how that would work. I just don't like beating too hard on that case...

I even found a cool video showing case splitting, seemed easy...
http://m.youtube.com/watch?v=8DtBJKUctMU&feature=relmfu