Repair or sell recently purchased 996 with bore scoring?

After years of planning and hard work, I recently fulfilled a lifelong dream purchased a '99 Carrera black/black coupe with 71k miles. It was out of state, but I had done my homework and learned about IMS, RMS, AOS, bore scoring issues, and talked to a local mechanic who inspected the car and seemed to be aware of those issues as well. When I picked up the car, it wasn�t making any worrying noises, but just a couple weeks after bringing it home I heard a ticking sound at startup that would fade away. I took it a local Porsche specialist that looked into the cylinders with a borescope and confirmed scoring on cylinders 5 and 6. As I understand it, the only fix is to bore-out and resleeve the block - basically a complete rebuild. I�ve talked to 4 different Porsche specialist shops, and searched the internet, and can�t find a number lower than $15k to fix this. That�s almost what I paid for the car a month ago, and I�m having a tough time justifying spending $30k+ on a car that will likely end up being worth low 20s. The dream is now a nightmare. I have two questions for this forum: 1. Is there a way to fix this car for significantly less than $15k? (Doing the work myself is not an option) 2. How much is the car worth in this condition?

You might try and find someone that will pull the engine and do just the cylinders/pistons. I know I'll get some slaps from folks here but you don't have to do a complete rebuild on the engine. If the bore scoring is light, and there's no other damage then the crank and heads should be fine. This might be a way for you to get this done on a budget. Also, have you checked the Porsche junk yards for an engine?

There is a member here who ran a scored engine for multiple years before doing a rebuild. If it doesn't smoke, and it isn't gobbling oil, I am not sure what the harm is. But I am not an expert, and the experts all sell rebuilds, so it is hard not to think that they might have a certain bias. Also: factory short blocks are now very economical.

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Ouch. Sorry to hear about your situation. Bore scoring is a pretty common problem with the M96 and M97 motors. Just watch Jake Raby's Bore Scoring video on YouTube and you'll see how the problem occurs. I've read that many people have changed their oil to a heavier viscosity to squeeze out a few more miles, but the problem won't go away of course. Aside from a full rebuild, you could always try to find a suitable used engine or just sell it as-is and move on with life. Rebuild or used engine... either way, it's going to mean a lot of money.

Did he take pics of the scoring? To bad a proper PPI wasn't done before purchase.

I would second the motion of getting a Porsche short block. I think it is $6k?

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One of the shops I talked to offered to go that route, which would still be close to $10k. And once you have the engine out and in pieces, you have to be willing to spend up to $17 if they start to find it needs the full treatment. In fact it ends up being more expensive than sending it out to a rebuilder specialist in the first place, as an indy shop can't do a full rebuild as economically as a shop that does them all the time.

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I have spent a lot of time beating myself up about pre-purchase due diligence. However, none of the shops I talked to would have done a borescope as part of the PPI. PPI+borescope = $1k inspection. Do that on a couple of sub-$20k cars and you've eaten up a bunch of your budget. It's risk analysis. I took a riskier route and got (very) unlucky.

99 not sure I'd bother with it. A roller is worth 5-10k based on condition and model since this is a 99 I can't see it more the 5k. The factory short block is probably the cheapest way to go but then you should probably keep it for 5 years to get your monies worth. I drove my 02 C4S for 40k miles with scoring until it got bad enough that I was worried about a 2 hour drive and having to check the oil and top it up. At the end of the day when I did rebuild, scoring was not deep but getting close near the top. It was just a matter of time. Over the period of time the tick tuned into a loud slap as it got worse so I think the scoring got worse over time. This is my 4.5.6 before and after

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A couple of people here have mentioned a factory short block. I can't find anything resembling that for less than $10k, but I fully admit I might be searching for the wrong term. Any links would be greatly appreciated.

I think it was on sale at the dealer for 6k when that was posted, not sure it is anymore. Also if your do decide to keep driving it and it starts burning oil. Best to decat it or change the cats to at least a 200 cell as the oem cats will get backed up with all the oil it has to burn off and will eventually break apart.

Short block: part number 996100996TX https://www.sunsetporscheparts.com/o...4l-996100996tx Sale Price:$6,902.00 Core Charge:$2,513.04

If it's the car you want to keep long term I would go for the Short Block from Porsche. If you just want to get out from it, check the Porsche dismantlers across the country. Either way expect to spend at least $9-12K. Can you pull and install the motor yourself?

Where are you located? Tell us more about the cat and how it is optioned.

You have plenty of time to determine what to do with your car. I would just drive it right now and consider your options. As many had said, a short block from Porsche would be a great option. Relax and sit back for a while. Go drive the car, have some fun. Nothing should break because of it.

I know it's tough to swallow, but 30K for a 996 is par for the course. I think I've even seen a quote somewhere along the line of it's a $30K car, pay now or pay later. Many of us, myself included, are well beyond that even net of wear items. There's no point in just dumping the car right now. Move to heavier weight oil with more frequent intervals and drive it. You'll get the same roller price in 1 year or 3 years. I know it looms in your mind, but these cars in constant need of maintenance so you just get used to it. On my list is the catalytic converter, lubing the pivot bearing in the transmission, frunk struts, something clunking in the suspension, cup holder. I'll be happy if I can get 3 months of not having to do anything.

My car has been knocking like bore scoring since 60k miles January 2017. I've taken all precautions with 3k oil changes, BG oil flush, Ceratec additive oil analysis at each oil change. I don't drive WOT much and rarely go over 5k RPMs. I am just trying to push off the rebuild another year. I now have 87k miles and it's been almost two years since I first noticed the symptoms. The car burns a quart of oil every 1400 miles and it very rarely smokes at startup. Since I will just buy a rebuilt engine, I am not even wasting money on replacing my original IMSB. if I need a clutch, I would do it. I understand that the specifics of why one car quickly goes from bore scoring discovered to car is not running anymore and another car just knocks for several years probably depends on many unique conditions for each car.

LS Swap!!! Drive it until you collect the parts. There are stand alone management systems available now that make it pretty plug and play if you dont have to deal with emissions where youre located. The factory short block option would be the best bet for it to return to driver status while you keep up with all the other parts failing on it as mentioned previously and its the most "plug and play" of all but you'll have to pay someone some $$$ do the swap also. Dont sell the car because of this little issue. Use a thicker oil and/or additive to keep it trucking see how long it lasts

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Have you even priced an LS swap?

I watched the Rennvision vid on bore scoring. Can anyone tell me how the piston skirt coating starts to flake off, and why it�s more prevalent on bank 2?

I thought it had to do with hot spots (thus using a lower T-stat) in the head and poor lubing/oil pressure when cold. I could be wrong...Conrod and piston angle has been mentioned as well.

I also think the power stroke on the right side loads the top part of the cylinder wall. Which is the area that gets less cooling and less lubrication as stated above.

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I understand how you feel but forget what its worth because most people who have older cars are into them for more then they are worth. Drive it as is for now, maybe years, then replace the engine. At the end of the day you will be into a car for 30k or less that is far more exciting to drive than almost every other car you see out there on a daily basis.

I'd get a second opinion on the borescore rare for 3.4 usually 3.6 or 3.8, can get tappet rattle and tensioner noise on cold starts , did they go in from the top as usually you need to go in through the sump underneath to properly diagnose a bore score??

What it's worth? Think about the folks who paid $80-$90k for a brand new 996 and have only driven it 10,000 miles... Talk about "under water". A little bore scoring in one cylinder doesn't mean the engine is toast (yet). There are plenty of options but suffice it to say that none of them are inexpensive. Do your due diligence and then decide how much you like/love the car and for how long you want to keep it. Only then will you be able to make a well informed/intelligent decision. Good luck

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I�m in the Chicago area, so my labor prices are likely higher than other places. Car is a black/black coupe, manual. Options: LSD, power memory seats, 18� twisty wheels, rear wiper. Mods: 19� black mesh wheels, short shifter, silicone intake tube, muffler bypass exhaust, and tinted windows. Car looks fantastic from 5 feet and draws lots of positive reaction. Up close, paint has a fair number of blemishes.

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They went in through the spark plug openings and took photos. Cylinders 5 and 6 are striped.

For those recommending the factory short block: that might be a cost effective option for folks who can do the work themselves, but shops here tell me that the extra labor will make it cost as much as a rebuilt engine, which will have more new parts and a warranty.

My story is quite similar and I feel your frustration. Although I have a 2005 3.8L 997.1 C2S. Mild to severe bore scoring was found on four cylinders using a bore scope. What made me check it out was that the oil consumption was getting very high (1L oil per 1,000km). I have no significant noise coming from the engine though and it doesn�t smoke much, only a small puff under hard acceleration. But, the rear end of the car is usually covered in a light film of �oil dust� as I call it and sooty black exhaust tips. Where I�m located in BC, an engine rebuild with the upgrades, costs the equivalent of $20k USD. The car is worth about $35k USD, which makes it difficult to justify the rebuild. I drive it still, but my plan is to sell it in the Spring. Hopefully it keeps running as well as it is and doesn�t calf before then. As far as your car goes, used or rebuilt 3.4 and 3.6 engines are almost half the cost of 3.8 and there are a few on eBay. If the problem doesn�t get much worse, just keep driving it and enjoying it.

Drive it! start a little savings fund on the side for the time when the engine goes. If you put 5k miles a year on the car you may get another 5 or even 10 years out of the engine before it goes. and, btw, if the engine goes, a nicely optioned lower mileage 99 with a non-running bad engine will bring closer to $7500 or even more if you are willing to wait on the right buyer.

What actually causes the bore scoring? How can it be prevented?

Take a look at the engine guide here, these guys are the go to for engine rebuilds in the UK where I originated from. It’s a 74 page document but very detailed! https://www.hartech.org/

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Not correct, or misinformation/confusion. The Factory short block will have all new parts. There will be less labor involved in installing a short block simply because the whole bottom end will be ready to go, no disassembly/reassembly, no machine work ect. Just have the heads rebuilt and installed and the accessories and thats it.. As far as cost go's , the "rebuild" would depend on the damage/mileage/desired outcome, so even with more labor cost, it could be less than a short block or much much more than a short block.

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I've read about many theories on what is the main contributing cause for the phenomena called "Cylinder Bore Scoring". Some argue it can been caused by the pistons expanding faster than the block during warm up in colder climates and with extreme factory tolerances, the pistons begin to rub against the cylinder walls. Others argue it's from "fuel washing" from ethanol gasoline which have poor lubricity chemistry. And, even metal contaminated oils... on and on it goes. Raby uploaded a video showing scored cylinders on a 2002 C4S. He demonstrates how deteriorating iron based piston skirts severely etch into the cylinder walls. Over time, it develops a clear case of scored cylinders. Just search "996 Bore Scoring" in YouTube.

I suggest just driving it until it dies. No reason to worry about it and it's probably not worth putting the work and money needed to fix it.

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I kind of agree here. You can buy another cheap 996 for the same cost of a rebuild...These cars at these prices are disposable...Part out the old one and get some money back!

That's why I made the Porsche YouTube videos. Hoping to help educate people on the possible issues when it comes to these cars. If the car is still running, I would just drive it. Not worth trying to fix one issue when so many others are possible.

OP, what did you end up doing with this car? Engine rebuild? Sell it?

I'm curious how this ended up as well. What is the cost to have the engine re sleeved with L&N? Specifically the process itself assuming the engine was removed and taken apart down to whatever level they'd need to do the work?