JFP in PA

10 hours ago, hankster66 said:

Hi JFP, is there anywhere I can find valve specs to check guide wear, install height, etc. ?

Unfortunately, Porsche never published internal specs for these engines, primarily because they did not want them serviced in the field.  Probably your best potential source is someone like Jake Raby, who along with building some of the most powerful versions of these engines, is running a school to teach proper engine assembly, has published both DVD and printed matter on the subject of engine assembly.

A lot of us out here in the real world have had to learn a lot of hard lessons on how to care for these engines through trial and error because there is no technical support available from Porsche; even the dealers do not attempt to do internal engine repairs, they get a car with bad valve guides, the owner gets a factory reman head.

Possible........

59 minutes ago, jstew039 said:

Well...I am back with the same issue. only this time the car has no power, meaning that it appears that the battery is completely dead and there is no power at all to any component (no interior lights, dash lights, power locks, etc.). However, the battery is fully charged and the anti-theft light is blinking on the radio.

 

I have been told that the Electronic Immobilizer (aka Drive Block) will only interrupt power to the coils and consumer components will still be active.

 

😞

The immobilizer, what you call drive block, shuts off power to the ignition and fuel systems when it is working properly.   That said, because of its location (under the driver's seat), it is very susceptible to being flooded when the car's drains plug up, which shorts out the system and can cause other issues.  I would pull the unit, open it up and look for signs of water damage.  These can sometimes be repaired but are often toast when this happens.

Good luck.

I would also look under the rear of the car to see if one of the axles has become disconnected.  What you described sounds like what happens when the bolts back out of the axle flange. 

23 minutes ago, Joseph Beral said:

God bless you! Thank you.

Why not consider becoming a contributing member?

3 hours ago, johnbull said:

Just yesterday, although the gear select lever goes into 'R' there is no drive, the vehicle doesn't move! Also the 'R' light on the dash is flashing. After trying a number times it eventually goes in drive with a judder. The fault is now intermittent, sometimes it goes into reverse and drives sometimes it doesn't! Any suggestions as to what is at fault? Thanks.

Get the car scanned with a Porsche specific diagnostic tool which can see Tiptronic faults. It may be something small like a single solenoid had failed, but with out diagnostics you are guessing in the dark.

31 minutes ago, A Corn said:

Can I use 16" tires on the 996 without screwing up the speed senors? 

I seriously doubt 16 inch wheel will clear the brake calipers and rotors on the car.

26 minutes ago, RJ'sGottaDrive said:

Strange that it's happing now, without any water intrusion lately. I don't even drive it in the rain and it's stored indoors.

Where is the control box located? I could check that myself.

Thank you.

 

Under the driver’s seat.

They get scattered all over the cooling system.  Best way we have found to get some of them out is to flush the cooling system components backwards from the normal flow path with copious amounts of clear water.   This will still not get every last one as some of them get wedged in tight passage areas and don’t want to come out.  Whatever you do, DO NOT apply full water line pressure to the system, it is designed for less than 20 psig pressures and will not be happy if you hit it with 60-90 psig line pressure.

If that is the case, you got lucky. 😉

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That bearing is decidedly on its way out, small amounts of ferrous particulate indicate it was already on its way to failure.  If you have not already pulled the sump cover in preparation to do the retrofit, I would do so now.  You will be looking for similar fine ferrous grit in the sump.  If you find none, you are golden, but if you find it there, it is everywhere inside the engine.

You can do the IMS with the heads off; most problems that arise during DIY IMS retrofits involve the cams jumping time, which could not happen in your case.

Please do not "bump" posts, it is against the forum rules you agreed to when you joined.

1 hour ago, j4nus said:

Dear JFP,

Yes I read the different possibilites. I tested with the PIWIS and I got the same message but I'm not sure how to investigate further and it would be interesting to know how the other members solved it concretely.

Pretty straight forward, you just follow the possible causes tree, eliminating them one at a time until you find the cause.  Even the absolute best diagnostic tools only provide a sense of direction of where to find the fault; none that I know provide a set of directions, which is where the technician's diagnostics capabilities come into play.

31 minutes ago, j4nus said:

Hi,

any solutions ? I have the same problem

Welcome to RennTech 

Loren listed all of them in his post above.

There is only one place I would send Porsche water cooled heads: Len Hoffman   Hoffman Cylinder Heads  Len will go through them and tell you what is needed, he is one of the best in the business. 

If you read what I have said about bolts, you already know where I stand on this subject.  Bolts are cheap compared to having to do the job twice.

It would not be the first new fuel pump that was a dud right out of the box, particularly if it is an aftermarket pump.

What timing procedure did you use to initially set the cam allocations? And are you sure you did not mix the cam locations (switched the cams)?

You can get a good idea of the installed heights by measuring from the spring retainer to the cylinder head surface with everything assembled.  It is not as accurate as doing it disassembled, but you are looking for an outlier rather than small incremental differences.  Sometimes you can actually see that one or more looks "different" than the others without even using a measuring tool. Installed height is determined by target valve seat pressures, but tends to be around 1.34 inches.

The only thing I can think of that you could have done during assembly is to miss enough of the actual valve timing that the cams are holding valves slightly open that should be closed at TDC.

I do not see any obvious signs of mechanical contact.

9 minutes ago, hankster66 said:

Isn't it odd though that multiple cylinders are leaking when there were no issues prior to disassembly. Assuming they're not burnt, I can see how something in the assembly process has hung them open, but again odd (although this is new to me) that multiple cylinders would be experiencing the same problem that was not pre-existing.

 

If issue is hung open, is the only remedy taking the heads off?

There is one thing in doing work on these engines that can result in valve problems: Rotating the engine, even by hand, in the opposite direction to how it runs.  Everyone thinks that if they are trying to rotate the engine to say TDC and overshoot, you can simply rotate it in the other direction.  Problem is that you should never rotate the M96/97 engines backwards as this can cause slight piston to valve contact issues, and leaking valves.  The reason I would drop an inspection camera into the bore is to look for marks on the pistons, which indicate contact has occurred. 

There are a limited number of ways a valve can leak; burnt (the mating surface is burned away), valve head is bent and will not correctly seat, and valve stem is bent, which jams the stem in the guide, holding the valve off the seat. That is why I suggested checking the valve installed height on the affected cylinders; if the stem is jammed in the guide, the installed height will be lower than the rest.  This can also be the case if a spring has failed (broken), which will have the same impact, the installed height would be off to the low side.

If it is a spring, it is possible to fix it without removing the heads, if it is any of the other candidates, you have no other choice as it would be impossible to fix with the head in place.  I'm sure this is not what you wanted to hear, but it is the case.

26 minutes ago, hankster66 said:

Yes, checked twice and rotated additional 180 degrees. Same issue on bank 2. The valves are visually closed, but obviously not entirely sealed. I had checked leakage before tear down on all cylinders; no issues. to confirm, doing this with cam cover offer, with cam tools in place.

If it were in my shop, I would borescope the questionable cylinders to look at the valves.  Only real probabilities here are bad valves (burnt or hung open), and if confirmed by inspection or checking valve heights when closed, the heads will probably have to come off.

Make sure whichever cylinder is leaking air out the exhaust is at TDC before plugging in the leak down unit.  

32 minutes ago, Alan David said:

seems like my tank is leaking.could a crack be repaired with  JBWeld or flex tape?

For about 5 min.  Replace it, and do not use aftermarket parts or you will be doing it again in about six months to a year. 😉