logray

You can actually do the variocam pads with engine in car. You remove the heat shields, mufflers, and lower the engine down a little. Then you can access the cover. I think OP of this thread speedrII did it this way in fact, and I've read about others doing it without removing the engine. It is much easier with the engine removed, of course.

speed rII

You are correct, well I think that the jets prowide the lubrication to the cylinders.

Couple of my "jet's" was stuck open, so when the engine is hot and oilpressure low, the "leakage" from jet's might be too big, causing the oil starvation on the mainbearing and the rod.

My car had the symptoms all the time, I just didn't regognise those.

Well, next time (hopefully newer) that these symptoms come back I know that the engine must be diss-asembled.

Logray, no problem. I asked opinions of what may have gone wrong, and the plastic from those pad's could cause plockages in the oilsystem. If those got somehow in the small oilpassages

RPMulli

It may be a possibility then

speed rII

LINK

There are some pics that ihave taken, from various repairs to my car.

Secondrow from the bottom, there is 5 pics from lifter change. Same method can be used to change the vario pads... Just wash the engine and enginebay before you start the project.

Just calculated the parts cost for the bearing project, and I'm now at 2,7k usd, so bit more that I expected. But not bad at all...

15psi

What are the chances that oil starvation was caused by low oil pressure during hard turns or debris from the engine rebuild. These would seem more likely than the pads crumbling.

speed rII

15psi, if the oilpressure would have been low becouse hard turns, it would have affected all the bearings.
On my engine, only conrod 5 bearing and the mainbearing that delivers the oil to 5 rod was broken.
All the other bearings were in good condition, some wear but nothing serius.

15psi

I don't remember if I heard this when I was talking to techs while searching for my car or on forums, but I thought that one main bearing was more likely to fail when you lost oil pressure. The 951 engine has a similar situation that one cylinder is more prone to bearing failure with low/no oil pressure occurrences.

I know my oil pressure drops dramatically on very fast turns. And unless you are looking at the oil pressure gage during the turn, instead of the road, you have no idea. I have considered an accusump or a x51 oil return.

Do you have a pic of the bearings? And #5 on the crank?

Macster

If you have the engine open and the rail exposed and the rail has an open composite facing and that bothers you then replace the rail with one that has a closed composite facing.

Furthermore, I'm sure there are owners out that can do this work with a Swiss Army knife and a roll of duct tape and 15 cents in parts/supplies.

I don't care. I do not have any indy shop I'd trust to do this work and I'm not about to use my car as a guinea pig to find one.

Also, I do not have the time, the place to do any heavy engine work.

Even if I had the time and the place I have no desire to ever open up the engines on my Porsches.

Unless it is clear from the engine's behavior that it needs doing I'm not about to have this level of internal engine work done.

If the engine does need opening up I'll consider preventative upgrading but only if it needs doing. For instance, when I had the Boxster in for its VarioCam problem I talked to the tech about replacing the actuator chain rails (when the problem was limited to the solenoid) of the exposed actuator and then the rails of the actuator on the other side as well.

The tech told me that when we could see the actuator and its rails if the rails were worn and deemed (based on his experience) worn enough to to replace then he'd recommend doing the other side's actuator rails at the same time.

The camshaft cover came off and the actuator was exposed and I was informed and stopped in to view the engine innnards. Clearly the rails showed no signs of excessive wear which is what I expected. I would have been more surprised if they needed doing.

Now, it happened though the actuator proved to be defective and along with the new actuator it came with new rails. But the wear on the original rails didn't cause the tech to recommend replacing the other side's rails.

Anyhow, as soon as I stopped buying fixer upper cars, I haven't had to open up any of the engines in lesser cars I've owned before or while owning Porsches and I'm not about to start with my Porsches.

If you or others want to do this sort of work, believe this level of preventative maintenance necessary, then do it and more power to you.

In the meantime I'm just going to continue to drive my cars. Took the Turbo to Las Vegas and back over the weekend. Drove the car over 1K miles over 3 days of driving. Left Friday. Took two days to get there. Tired and stopped at Tehachapi for the night. Sunday left LV and drove the whole 530 miles back in one day.

There and back all I had to do was stop once in a while for gasoline. That's all the car required. That's the kind of interaction I want with my Porsches.

Sincerely,

Macster.

washington dc porsche

How many miles are on the odometer and how often did you change the oil?

Flat6 Innovations

If pad wear wasn't an issue the MFR would not have revised the materials that comprise the pads at least 3 times?

Its pretty simple.. Every time we pull cam covers on any engine we update the wear pads.. Thats the rule I have made; just like changing water pumps every 3 years no matter the mileage.

Over time direct experience and dealing with the same challenges over and over again has taught us exactly what needs to be done and when. Anyone that interfaces with these engines and actually pays attentions and documents every job would see the same things.

When the wear pads become worn the 4th and 5th timing chains suffer and so do the vario cam actuators. We have seen engines alter valve timing due to this and the direct result being a loss of fuel economy.

I have seen these wear so bad that they were removed in two pieces.. I'll be instructing another "M96 101" Engine Rebuild school tomorrow through Saturday and those wear pads will be put into the hands of my attendees along with a lot of other nice "trophies".

If someone hasn't seen these same things we see its pretty clear that they haven't worked with enough M96 powered cars to have a valid opinion~

speed rII

15psi, rodbearing was on it's bare metal, all of the softer alloys havebeen wear of.
Mainbearing was worn to the copper.
These ones looked just like mine did. Just some pic that I found on the net.


W. DC Porsche, 60k miles on the odo and I have drove about 15 of that. Oilchanges every 5k miles.
I have no servicehistory from previos owner, I only know that I'm the second owner of this car.

Jake, could you comment the oiljet's? Have you seen those fail? Or am I totally in wrong track on finding the cause?

Flat6 Innovations

Sounds like you have a situation where the oil was overheated or where hot oil + G forces created main bearing wear..

The reason the rod bearing failed is because the main bearing failed and contaminated the charge oil to the rod bearing, filling it with foreign object debris and reducing clearance..

The rod bearings are volume and pressure fed (via centrifugal force) with oil by the main bearings, when the main starts to fail the debris kills the rod bearing.

We typically see this from the main closest to the flywheel and its corresponding rod bearings. Its common. If you need a crank, we probably have one (magnafluxed, never use an M96 crank without having it magnafluxed!).. I am also developing under and over sized main and rod bearings as well as new crankshafts to solve these issues.

I know what causes the issue you have experienced, but stating it on a forum is just dramatic and leads to keyboard warriors and armchair experts shedding light from info they have "parroted" from elsewhere.

Pac996

Generally instead of something blocking an oil passage causing a spun bearing it's a case of revving when starting the engine. For instance it's cold and you want to make sure the engine doesn't cut out due to extreme cold. Revving the engine at start up even when the engine is already up to temperature is a chance to spin a bearing. Then there's the mistake of having the foot on the pedal when starting the engine and the first thing that happens is the engine revs. Bearings are not the same material as the engine block. They can be spun at initial start up due to being dry and not expanded by being heated up which helps seal things better. But the expanding should be going on after the oil has lubed them up. Another way to spin a bearing is not putting the same bearing back in the same alignment and position in a rebuilt engine when not changing the bearings. And like always there's another oh boy I didn't know that either, when engine oil gets dirty it can leave residue on the bearings that can bake on. High contaminant levels can speed up problems like that. Even parking the car for winter or longer can lead to oil caking dirty stuff on the bearing from oil slowly draining away leaving the dirt on the bearing. Longer healthier runs of the engine help cook out the acidic and other contaminants that run amuck in oil. But if parking a car for winter I'd advise changine the oil before parking and running the engine for a while. There is even ESPEACIALLY after changing the oil do not do anything but idle the engine for 5 minutes allowing the passageways to refill and surfaces to be recoated. Simple life and simple engines. Just the pains are extreme.

logray

Just curious Jake, doing some research for a possible future rebuild part 2 on my M96-01.

Do you offer magnafluxing and balancing service to go with LNE Nickasil 3.4L->3.6L bore and JE pistons (and existing hopefully "good" crankshaft and rods shipped to you)? Do you have a ballpark $ for this? Assuming using a stock flywheel.

Thanks

Flat6 Innovations

Yes. Magnaflux and our inspection is 175.00 for the crank, whether the crank is good or bad.
Dynamic Balancing with our M96 specific fixturing and profiles is 350.00 for intermediate balance tolerance and 375.00 for a race tolerance balance (Intermediate = .5 oz. in., Race = .2 oz. in.)