My engine blew! I think!

[berettafan]

neat thread though terrible circumstances.

just wanted to point out that this is precisely the point at which many so called Porsche nuts would be ruined forever thanks to a few bad decisions. No matter what you do the absolute WORST option would be to tow it to a mechanic and say 'have at it Cletus'. Far better you follow the advice given here and get educated.

[Fast Corners]

Wow...sorry to see that.

I have a couple of questions:

1) How long have you had the car?
2) Were the oil return tubes replaced before you got the car or by your mechanic?

Those oil return tubes are not the original ones to the car. They don't look like that after 30 years (that is unless the car is a trailer queen or museum piece). Since they are not the expandable tubes that means that the cam towers (at a minimum have been off of the engine). For that matter, the heads are very clean and the cylinders look pretty new too.

I'm not trying to cast aspersions but, I have never seen a failure like that ever! I'm not fond of the rod distruction theroy basically because I think the damage would be more drastic and it would not stop at the seal of the oil return tube. Additionally, the oil return tubes are below the level of the crank and more near to the level of the aux shaft.

The road damage theroy is a possibility but I would expect to see more evidence of an impact or deformation on the tube or the broken piece of the case for that matter.

The shape of the crack reminds me more of a casting defect or stress related failure. I would think if it were a casting defect the problem would have manifested itself earlier. That being said who knows when a lightbulb is going to blow?

Let me know about what work has been done to the motor and maybe I can think of something else.

[Aurel]

Something could have hit the oil return tube frontisde, causing it to break the case backside. Look for marks on the front of the tube.

[daepp]

1) weakened area due to inexperienced replacement of oil return tube?
2) driving condition/rod - he indicated he was going 20 then accelerated. Could the engine have been lugged and then snapped a rod?

[zorin]

I had the car for couple of years now. The engine was rebuilt before that by MotorMesiter. I guess they had replced the oil return tubes.

[mca]

Would over torqued head studs do this? Too much pressure between head, tube and case?

Something could have forced the return tube to lean and cracked the case at the base?

[mca]

Originally Posted by zorin

The engine was rebuilt before that by MotorMesiter

Uh oh.

How many miles have you driven it since the rebuild?

[Aurel]

Motormeister worked on that motor? Search no longer my friend

[daepp]

Motormesiter? Surely you are pulling our collective legs! Please, say in aint so...

[daepp]

Rx: 2.8 SS from Henry!!!

[Joe Bob]

Motor Scheister? "Nuff said".....

[Fast Corners]

Thanks for the info...In your 2nd photo (see below) the tube looks intact and the break looks pretty clean with no real evident signs of impact. If you look at the other (undamaged) oil return tube boss, it appears that there may be two stress cracks in it (They may be casting marks though...not really sure).

Now if you look at the base of the cylinders (especially the center one), I cant see any cylinder base gasket. So here is what I was getting at...If the motor was rebuilt and either performance modifications (omission of cylinder base gaskets, fly cutting of the heads, turning down of the cylinder height, etc...) or other machining was done the engine may be too narrow. Torquing down the heads on a narrow engine may have "locked" the oil return tube in solid. They are supposed to "float" in between the cam tower and the case. Thermal cycling of the motor may have caused a stress fracture to be induced. Of course this is speculation since I can't see the motor in person or tear into it. I'm just trying to figure out what would have caused something like this to happen.

It comes down to two things to me at this point...casting defect or incorrect assembly of the motor.

[Aurel]

"It comes down to two things to me at this point...casting defect or incorrect assembly of the motor."

My vote is for the second choice. You explained very well how Motormeister may have caused that engine to self-destruct. Could also be mismatched set of cylinders of different heights. They are known to do that too...The cam tower puts all the cylinders on the same plane, but with height differences, stresses are not the same at the bottom. It could be that the cylinder where the oil return tube broke the case is shorter.

[jjrowe]

Now if you look at the base of the cylinders (especially the center one), I cant see any cylinder base gasket. So here is what I was getting at...If the motor was rebuilt and either performance modifications (omission of cylinder base gaskets, fly cutting of the heads, turning down of the cylinder height, etc...) or other machining was done the engine may be too narrow. Torquing down the heads on a narrow engine may have "locked" the oil return tube in solid. They are supposed to "float" in between the cam tower and the case. Thermal cycling of the motor may have caused a stress fracture to be induced. Of course this is speculation since I can't see the motor in person or tear into it. I'm just trying to figure out what would have caused something like this to happen.

It comes down to two things to me at this point...casting defect or incorrect assembly of the motor.

Interesting theory, and it makes sense. I would think that the end of the tubes will show some deformation if this is true. It seems like you would have to be off quite a bit though for enough stress to break the case. The "something hitting the motor" theory is going to work our best as far as getting the car fixed. Insurance may cover it. If it is an assembly issue, I highly doubt Motormeister will own up to it. I would not take anything apart until you contact your insurance company. If it was hit or your sue motormesiter, you need a mechanic to back you up.

- Jesse

[kenikh]

That case can be welded; I've seen 930 cases welded with worse, so no worries.

The MotorMeister bit is worrisome. Even if the engine ran without losing oil, I would rebuild it based on the fact that MM did the work. As you may ascertain from further research, MM is the Typhoid Mary of Porsche shops. Better to swallow that bitter little pill now while everything is out.

[zorin]

Thanks.
So the question is should I get another engine or just another block? Parts Heaven have 3.0L engine for about $5500 (with core exchange) and $1200 for a block.
Anybody has any engine for sale?

[beepbeep]

Originally Posted by zorin

The engine was rebuilt before that by MotorMesiter.

Uhh ohh... that is not good news. Damage looks like something a loose rod would do...I believe big end rod cap got loose and knocked out a piece of case.

[Fast Corners]

Zorin, good question...I like JJRowe's advice but if money is no object.

I would have the motor disassembled and figure out what goodies are in the motor. For instance I noticed carbs on the motor...So does that mean non-CIS pistons? and/or Cams? If so, and they are good along with your crank etc. etc. I would much rather rebuild the motor than guess at the condition of another. I would say that Kenikh is correct in that the visible damage is repairable by welding and machining. But without knowing what condition the case is in (poorly machined case facing, linebore, etc.) why would you chance a rebuild with out knowing.

Basically...figure out what you have before you invest in something else.

[CBRacerX]

Pull the tube (you can crush it in the middle with a large pair of pliers to shorten it) and take a look from there. You cannot cause any more damage and you will probably learn pretty quickly what happened. Good luck!

[t951]

This thread was interesting, and as always I like to learn what I can.

Then the magic words were uttered...... "Motor meister"....

Now, the thread will follow a different course, and I am curious to see where it goes.

I would suggest taking the motor apart and documenting all the mismatched parts, etc.

Not that it will matter as I don't think you have recourse with them, but it will help you learn a lot of stuff for your rebuild / replacement.

Plus, I am sure others like me want to see what is in there!