911sc Rebuild

[Soren Lorenson]

Hey there

So.. back on this thread (http://forums.pelicanparts.com/porsche-911-technical-forum/938852-chain-cover-question.html)
there was speculation about what happened after an over-rev (linkage broke).

Well, life got in the way and she sat until Jan or Feb of this year. I eventually got her over to a local place and had it taken apart.

Here was the outcome:





Yep. That was ground to bits. Literally.

[pampadori]

how high do you think it revved?
How long had you been using Mobil 1 on this motor? Just curious. i noticed your cam chain pic in the other thread and would expect it to be cleaner if you had a good syn modern oil in it. However, i think driving them like stink actually keeps them cleaner inside than anything else.

If this is your first flat 6 rebuild, get ready for the fun! its a great experience to rebuild one. Put EBS on speed dial and prepare to spend some serious change. (but totally worth it)

[theiceman]

Originally Posted by pampadori

how high do you think it revved?
How long had you been using Mobil 1 on this motor? Just curious. i noticed your cam chain pic in the other thread and would expect it to be cleaner if you had a good syn modern oil in it. However, i think driving them like stink actually keeps them cleaner inside than anything else.

If this is your first flat 6 rebuild, get ready for the fun! its a great experience to rebuild one. Put EBS on speed dial and prepare to spend some serious change. (but totally worth it)

running them like stink keeps them cleaner inside ? I'm not sure about that .. lol

as he had a shop take it apart ,it I am not sure he would do it himself.

OP is the shop recommending P and C and valve train refresh ? or do they want to split the case ?
The bottom ends of these cars are pretty robust but in your case I'm wondering what they recommend.

['76 911S 3.0]

Originally Posted by theiceman

running them like stink keeps them cleaner inside ? I'm not sure about that .. lol

as he had a shop take it apart ,it I am not sure he would do it himself.

OP is the shop recommending P and C and valve train refresh ? or do they want to split the case ?
The bottom ends of these cars are pretty robust but in your case I'm wondering what they recommend.

I would hope with that much damage and metal floating around they would absolutely recommend and complete tear down.

OP, bummer on the grenade but I'm sure she will be back together in no time!

[theiceman]

I understand , was it just one broken valve ? some of the pics are hard to see detail .

[Flat6pac]

You ll need to check for bent rod and junk through out the fuel injection too.
Bruce

[pampadori]

Originally Posted by theiceman

running them like stink keeps them cleaner inside ? I'm not sure about that .. lol

as he had a shop take it apart ,it I am not sure he would do it himself.

OP is the shop recommending P and C and valve train refresh ? or do they want to split the case ?
The bottom ends of these cars are pretty robust but in your case I'm wondering what they recommend.

Doh! I missed that OP was having a professional wrench tear it down.

However, i stand by the drive hard = clean insides. Compare a crown vic motor from a cop car that's been thoroughly thrashed to a similar engine from your aunt Clara's car she only takes to church on Sundays.

The Italian tuneup is REAL!

[Bob Kontak]

Originally Posted by theiceman

I understand , was it just one broken valve ? some of the pics are hard to see detail .

I think a piston was pureed.

If so, I did this to an early 300ZX when downshifting at speed. Sounded like breaking glass. Con rod had no problem putting holes in the engine block. Very efficient.

$500 and a used engine was at the end of my driveway on a pallet. OP cant do that.

[pmax]

OP, sorry to see the carnage.

Crankshaft and case did alright ?

[Soren Lorenson]

Yep, just one valve and the piston was turned into rubble.
Whole thing came apart, and yes the cam was fine and the case was ok. Everything got cleared out, and sent to various shops.

She was pretty unloved by the people before me so this was a good
Time to go through the whole car.

Lots of random issues found. I’ll post some more pics etc soon.

This is an over due update so everything is already done (6 months later)

Edit: yep they split the case because of all the debris

['78 SC]

You ll need to check for bent rod and junk through out the fuel injection too.
Bruce

Bruce gave me the same advice 2 years ago when I blew up my track motor. It's good advice. Apparently when a motor lets go the crankcase interior is a tornado of fumes, oil mist and metal bits which unfortunately vents to the oil tank. Here's the inside of the breather line between the crankcase and oil tank.


Here's the inside of one of the intake runners. The shiny bits are pulverized piston, cylinder, etc.



Assume your entire lubrication system (tank, coolers, thermostats, lines, etc.) is similarly contaminated. I found metal bits throughout. My oil pump housing was seriously grooved so I replaced it.

I don't mean to be the bearer of bad news, but this is your chance to head off a repeat performance resulting from an oil passage blocked by debris.

[Pazuzu]

At least you found the other parts of your piston ring!

[3rd_gear_Ted]

Assuming that is a 3.0L motor, it might be time to think 3.6L conversion.
Think 100+ HP

[theiceman]

...or at least dropping in 3.2 Ps and Cs

if you are replacing them anyway aren't 3.2s drop ins ?

[Bob Kontak]

Originally Posted by theiceman

...or at least dropping in 3.2 Ps and Cs

if you are replacing them anyway aren't 3.2s drop ins ?

Same diameter. Longer crank throw accounts for the extry 0.2 displacement in the post SC engines. But you knew that.

[Pazuzu]

Originally Posted by Bob Kontak

Same diameter. Longer crank throw accounts for the extry 0.2 displacement in the post SC engines. But you knew that.

He means a set of 98mm pistons, which gives a 3.2SS. Short stroke.

Bigger bore, same stroke. But you knew that

[Bob Kontak]

Originally Posted by Pazuzu

He means a set of 98mm pistons, which gives a 3.2SS. Short stroke.

Bigger bore, same stroke. But you knew that

I read Iceman's post differently. I came away with him suggesting using post SC P&C's. But it was after more than a couple beers.

What I don't know is are they "drop in's" even though the same bore as the SC?

New Mahle 3.2 SS set for the SC is what? Five grand? A single used P&C from a 3.2 is guessing, $250.

Gotta get a rod, too. Crank journals?

[theiceman]

yeah I was talking about the SS. To be honest I don't know a lot about upgrades but when I had my engine apart to do my stud repair someone said something about getting a used set of 3.2s machined out and putting larger pistons.
They could be " dropped in" without any machining of the spigots.

Sorry if my wording created any confusion. I am going to look into this when I pull it apart again in about another 40 years .. hmm.. wait ..

[Soren Lorenson]

So I went to ROW 3.0 and a 964 Cam.
Also was time to lose the cat, and put on SSIs and a dual in/out Dansk sport exhaust.

She sounds good now

[chrisbalich]

Originally Posted by Soren Lorenson

So I went to ROW 3.0 and a 964 Cam.
Also was time to lose the cat, and put on SSIs and a dual in/out Dansk sport exhaust.

She sounds good now

how do you like the 964 cams with the ROW 3.0?

i already have a ROW 3.0, SSIs, and 2 in/out. so cams could be a nice kick in the pants to go with my EFI & ITBs.