j_beede

The reason a high compression flat engine uses more oil is due to the fact that when the engine is stopped all the oiI that was lubricating the cylinders doesn't drain back into the oil sump because the cylinders are placed flat ( horizotal and not vertical) in the engine. As a result, this residual oil has a tendency to seep past the piston rings into the combustion chamber when thhe engine is at rest, where, at start up, it is burned off. Engines left to sit for longer periods sometimes exhibit the puff of smoke many Porsche owners experience at start up which is common and normal for these engines. The smoke is the residual oil being burned off. Every other type of engine has its cylinders either vertical, as in a straight four or six cylinder , or at an angle that allows all the oil coating the cylinders to drain back into the engine sump when the engine is turned off. Daily drivers that are driven longer distances tend to get more miles per quart of oil because consumption when the engine is warmed up and running is similar to any other straight or " V " type engines. Run it for longer periods of time between start ups and you'll use less oil per mile. While there are other issue that can contribute to excessive oil consumption in this or any other type of engine the flat engine design is a key contributor in a Porsche engine.

Not to mention the problems that boxer engines have with ring wear on the bottom side of the pistons due to the force of gravity

1 quart per 1000 km sounds excessive, I would say that is a problem. I see several manufacturers claiming that 1 quart per 1000 miles is "normal" when their cars typically use 1 quart per 5,000 miles. I suspect they are simply trying to avoid warranty work for those outliers that consume oil.

Comparing the oil consumption of a 300 HP, 7000 RPM engine designed to last 60,000 miles to an 18,000 RPM V8 designed to last 300-400 miles is unreasonable in my opinion.

Well...Here you are...It is normal.....Right from the Owner's Manual for 997's, And it is the same for 996 as well:

Let me make sure I have this right... 24 quarts of oil added between oil changes is considered "normal" per the owner's manual... You are okay with that?

1 quart per 1000 km sounds excessive, I would say that is a problem. I see several manufacturers claiming that 1 quart per 1000 miles is "normal" when their cars typically use 1 quart per 5,000 miles. I suspect they are simply trying to avoid warranty work for those outliers that consume oil.

Comparing the oil consumption of a 300 HP, 7000 RPM engine designed to last 60,000 miles to an 18,000 RPM V8 designed to last 300-400 miles is unreasonable in my opinion.

Well...Here you are...It is normal.....Right from the Owner's Manual for 997's, And it is the same for 996 as well:

Disagree. "Up to" 1.5 liters per megameter is legal language to protect the manufacturer. Two quarts of oil to make a round trip from SF to LA? May as well replace those fouled plugs too!

1 quart per 1000 km sounds excessive, I would say that is a problem. I see several manufacturers claiming that 1 quart per 1000 miles is "normal" when their cars typically use 1 quart per 5,000 miles. I suspect they are simply trying to avoid warranty work for those outliers that consume oil.

Comparing the oil consumption of a 300 HP, 7000 RPM engine designed to last 60,000 miles to an 18,000 RPM V8 designed to last 300-400 miles is unreasonable in my opinion.

I've seen this as a telltale indicator of a failing battery cell. Is there any difference in window speed with the engine running versus off?

Given the inadequate lubrication that the m96 IMSB is subjected to, I think you were wise to replace your bearing. Lucky for you that your engine was eligible for the retrofit--not all are. Did your independent mechanic do some expectation setting with you regarding the replacement bearing and its lubrication?

If your car is eligible for the LN Eng retrofit I would do it at your next clutch change. Keep in mind that the retrofit is not a cure for the inadequate lubrication that I suspect contributes to IMS bearing failure. The retrofit simply allows the bearing to be replaced without requiring engine R&R and full tear down--major savings there. Unfortunately, 996 with later model m96 or engines replaced in q4-05 or later may not be candidates for the retrofit. This is the 13mm versus 22mm IMS nut topic that you have probably heard about.

I answered this same question for you two days ago. What's the deal? Here is the same answer again.

The engine code is on the driver side of the block just below the #3 cylinder exhaust header. I find the code hard to read without putting the car on a lift. I had success using a digital camera to photograph the code and was able to read it that way.

If your engine has "AT" in the code like this: M96/04AT66***** it means your engine was replaced. Some people view this as a plus, but it usually means that you have an IMS bearing that cannot be replaced without a full engine tear down. This probably means no LN Engineering retrofit option for example.

Okay, I ended up buying a 2001 Carrera Cab earlier this year with about 85k miles on it. When I checked the motor is seemed very clean, all the way down to the nuts and bolts looking new and the wiring harness looking new. My thought it that this car has had a motor replacement done but the dealer did not have any service records for it. Is there a way to check to see if the motor was replaced? Maybe a part number revision?

David

The engine code is on the driver side of the block just below the #3 cylinder exhaust header. I find the code hard to read without putting the car on a lift. I had success using a digital camera to photograph the code and was able to read it that way.

If your engine has "AT" in the code like this: M96/04AT66***** it means your engine was replaced. Some people view this as a plus, but it usually means that you have an IMS bearing that cannot be replaced without a full engine tear down. This probably means no LN Engineering retrofit option for example.

I would find a speed shop that sells racing fuel. Some

race tracks sell racing fuel.

Aviation motors are made for lead fuel to keep them

from knocking.

Paul

FYI: Sunoco 110 racing fuel is leaded too.

Repeat: Reman engine probably means no IMSB retrofit for your car.

I can't imagine a more impressive $20,000 used car than a MY99 996! Great looking and too much fun to drive. Just keep in mind that these cars cost $60,000 to $80,000 when new and the prices for parts and service do not scale with the car's resale value. Has the engine been replaced? It was not uncommon for MY99/00 996s to have their engines replaced. The issue with the reman engines is that they are often not candidates for the LN Eng IMSB retrofit--if you care about such things.

Since the factory bearing can fail below 20,000 miles or survive beyond 100,000 miles I suspect we will find out at some point that the bearing (sealed or open race) is not the true culprit. I think others have commented on eccentricity in the IM shaft itself as the likely root cause. The LNE external retrofit doesn't address the shaft itself. I believe that Flat6 offers a more extensive retrofit if the IMS is sent to them for re-machining. I assume they take care of IMS eccentricity as part of that process.

$6,000-8,000 for a 996 with a blown motor sounds optimistic--unless it has a remarkable set of wheels, fresh tires and full fatory aero kit.

As noted... The "AT" in the engine code indicates a Porsche remanufactured engine. Yours is a 3.4L and appears to have the newer--and non-replaceable--IMSB with 22mm center nut. If that is so, there is no LN Eng retrofit opportunity for this engine per J. Raby. Many MY99/00/01 owners are pleased to find out that they have a newer replacement engine. Personally, I have avoided 996s with the M96/**AT engines because of the non-serviceable IMSB.

Pushing the car to 10 MPH then dumping the clutch after the engine seized? Sounds pretty barbaric. Were you hoping that the engine would start and your friend would drive away happily ever after? Disappointing to hear of this given the effort that was put in. I had been "on your side" up until then.

Well, well. Amazing. I can't imagine what the end of the shaft must look like. Next step... order an IMS Guardian :)

Have you been to Mesa Verde in Cortez, CO? If you go to North Rim of the Grand Canyon, Mesa Verde is worth a stop.

FYI: The last 996 engine I checked read: M96/04AT66Y6xxxx. My understanding is that the "AT" indicates a reman engine.

Don't know if it works or not. It has not be released to the public yet. I would bet it is just a fancy/hacked remote bar-b-que grill thermometer. Every bearing the I have had go bad gets hot first. But I also believe IMS failures are a small number.Just my 2 cents.

I believe it will be some sort of variation of a magnet positioned so that it accumulates ferrous metal particles in the oil between two electrodes--thus closing a circuit that makes the buzzer/light turn on. For the price he is charging I am sure that it will be more than that. I think it may be a while before it is available in volume as he seems to still be making changes to the design.

I've read alot about the ims and ems issues. Can a mechanic check the ims to see if it needs to be replaced? Would it be better to put the 1500-25oo into buying a 2002 911 turbo with 80-90000 miles?miles due to the engine being more"bomb proof"? The owner of the c2 is a friends relative so that is why the good price.

You probably know that there are multiple versions of the IMSB in m96 engines. The earlier IMSB is a candidate for IMS retrofit, it has a 13mm center nut. The later m96 such as those used as replacement engines in 996s may have the later IMSB with 22mm center nut which is not a candidate for the LN Eng IMS retrofit. Unfortunately, the transmission must be dropped to determine which IMSB you have. Has the engine been replaced in the 911 that you are considering?

No the engine has not been replaced. Can you tell by the block number?

Yes you can. A "reman" engine will have the letters "AT" in the engine code something like... M96/04ATxxxxxx

An 8.5mm camera probe is only a bit larger in diameter than a pencil. It should fit!

I've read alot about the ims and ems issues. Can a mechanic check the ims to see if it needs to be replaced? Would it be better to put the 1500-25oo into buying a 2002 911 turbo with 80-90000 miles?miles due to the engine being more"bomb proof"? The owner of the c2 is a friends relative so that is why the good price.

You probably know that there are multiple versions of the IMSB in m96 engines. The earlier IMSB is a candidate for IMS retrofit, it has a 13mm center nut. The later m96 such as those used as replacement engines in 996s may have the later IMSB with 22mm center nut which is not a candidate for the LN Eng IMS retrofit. Unfortunately, the transmission must be dropped to determine which IMSB you have. Has the engine been replaced in the 911 that you are considering?

I read that overhauled or new engines should be kept at or below 4,000 RPM for 2,000 miles. Just getting ready for my turn to fork the big bucks in a new engine (80,500 miles !)

Motor swap at 85,000 miles... sorry to hear that. Can you request an engine with a 13mm IMS bearing center nut?

Each caliper has two bleed screws and each of the bleed screws has a plastic dust protector cap.

If the cap is melted then you could have a stuck caliper piston that is causing overheating and faster wear. Best have a closer look at that caliper.

Loren, it's more like a very thin plastic film that is on the outside of the caliper. It had bubbled and wrinkled, and now part of the outside of the caliper looks faded and not bright red.

My car was in an outdoor parking lot for about a week, and it had rained and stormed. The discs, particularly the fronts, were very dirty and sort of crusted with gunk. Normally, after washing, a coating of rust will appear on the discs, but it cleans up after first braking. this time the gunk was dried and hard and causing a grinding sound when I first drove the car and used the brakes. I drove for awhile until I could get to a station with water and sprayed water on the discs. this loosened the crap and the discs then smoothed out when I drove the car and used the brakes. I dont think this would have overheated the calipers.

the plastic film is like the protectors on new appliances that protects from scratches and peels off easily once you get home. Ever hear of anything like this on C4S or turbo calipers? Cheers, jl

That would have to be some pretty high temperature plastic film to put up with caliper temperatures. Perhaps someone clear coated your calipers? What sort of material would remain stuck to a rotor after braking--yet rinses off with water? Odd. What did it look like?

...almost forgot... be sure to take along one of those Harbor Freight 20% off coupons that you find in Autoweek etc. That makes it $192!