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Porsche Cylinder Bore Scoring

How do you repair a Porsche engine with cylinder bore scoring?

Unfortunately, many Boxster, Cayman, 911, Cayenne, Panamera, and Macan engines with Alusil or Lokasil engine blocks will suffer cylinder bore scoring.

The Porsche engines we most commonly see with cylinder bore scoring that are sent to us for repair include the M96.03/M96.05 3.6 and M97.01 3.8 Porsche 911 996.2 and 997 engines as well as with the M97.21/M97.22 3.4 engine used in Cayman S and late Boxster S models. To a lesser extent, we also see M96.01/M96.02/M96.04 3.4 996.1 engines with bore scoring. On a positive note, Boxster and Cayman models with the 2.5, 2.7, or 3.2 engine are unlikely to suffer from cylinder bore scoring, however any M96 or M97 engine can suffer from cylinder cracking or d-chunk failures that will require the engine block to be sleeved to correct for these problems.

Porsche Cylinder Bore ScoringOften, customers are told that they have bad lifters and that is the source of the tapping or ticking noise their engine is making. However, in most cases, that noise has nothing to do with your lifters and is in fact piston slap caused by excessive piston to cylinder clearance, a key indicator of scored bores, as well as having one sooty tail pipe and elevated wear metal levels in your Porsche's engine oil. (Read more about this and other M96 and M97 engine problems and failures) As bore scoring progresses, oil consumption will increase as ring seal is compromised. For reference, a healthy factory M96 or M97 engine with a stock AOS should have a manometer reading of 4-6 inches of water column.

A diagnosis of scored bores doesn’t immediately mean your engine is dead. We see more and more engines being identified with bore scoring before symptoms have even manifested. This frequently happens when engines are bore scoped as part of the IMS pre-qualification procedure and through the use of used oil analysis to track iron, silicon, and aluminum wear levels in your Porsche’s engine oil.

We’ve seen many owners nurse an engine by switching to a thicker viscosity oil like Driven’s FR50 5w50 that also has increased moly levels allowing them to continue to drive their cars for months or even years until the symptoms become bad enough to require an engine rebuild or replacement as long as you don't have any underlying conditions like a bad fuel injector or vacuum leak that is making the problem worse.
 

Should I rebuild or replace my engine?

Although Porsche does offer engine shortblocks from the factory for Boxster, Cayman, and 911 models, these replacements do not address any of the inherent flaws associated with the factory Lokasil and Alusil cylinders and still require your shop to pull your existing cylinder heads, have them rebuilt, and then finish assembly of the engine to make it into a complete longblock.

That said, for the same price or less, you can get additional value by rebuilding your existing engine rather than replacing it with another one from the factory that doesn't address any of the known problems with the M96/M97 engine. One such option is to use LN Engineering’s Nickies. Although there are cheaper options like direct Nikasil plating of the cylinder bores or installation or wet or dry steel sleeves, none of these options address all known cylinder issues. With thousands of blocks successfully repaired since 2002, no other cylinder solution for M96 or M97 engines have the proven track record of LN Engineering Nickies Porsche engine conversions for Porsche Boxster, Cayman, and 911 engine rebuilds.

It is equally important that the most common trouble items are taken care of when rebuilding any M96 or M97 engine. Be sure to take a look at our article covering Porsche M96/M97 Engine Failures so that you can educate yourself with what is required to correctly overhaul and upgrade these engines. Beware there are many shops out there advertising rebuilt engines that don't address any of the inherent issues with these engines or that cut corners to keep costs down at the risk of subsequent engine failure.

LN Engineering and Flat 6 Innovations Porsche Bore Scoring Repair Solutions
 

Who can rebuild my Porsche Boxster, Cayman, or 911 engine?

The first step would be to find a shop that is familiar with rebuilding the M96 or M97 engine unless you decide to tackle the rebuild yourself. A good resource would be one of the many IMS Solution Certified Installers, as most of them have completed hands on training with Jake Raby at The Knowledge Gruppe.

If the shop that services your Porsche cannot rebuild your Porsche engine, RND Engines offers stock replacement M96/M97 Porsche longblock engine rebuilds available exclusively through one of our Certified Installers.

Flat 6 Innovations offers performance Porsche engine rebuilds through their own national network of Certified Installers.

Alternatively, if you are a do it yourselfer and choose to do a DIY rebuild of your Porsche M96 or M97 engine, check out Rennvision’s Focus On: M9X Engine Assembly DVD series. This should be the first thing you purchase and watch before taking the next step. You might also want to check out their Porsche Torque Spec Book and M9X Engine Assembly Workbook as both enthusiasts and professionals alike will find these resource immensely valuable when it comes time to reassemble the engine. We would also recommend that you check out Rennlist's 996 Forum as we have helped many Rennlisters carry out their DIY Porsche Boxster, Cayman, and 911 engine rebuilds.
 

What are my options for rebuilding the M96 or M97 engine from my Boxster, Cayman, or 911?

Once you’ve chosen who is going to do the rebuild, the first step is to drop the engine and disassemble it. The engine block would then be shipped to us for our Porsche engine conversion featuring the Nickies sleeving process. To make this easy, LN offers a pre-paid block shipping option where we ship you a custom box with molded inserts to ensure your case halves doesn’t get damaged in transit.

We machine every M96/M97 block for Nickies sleeves, which replaces the cast-in Lokasil liner with a billet aluminum nickel silicon carbide plated bores. At the same time, our Porsche engine conversion process increases the bore size, which allow for an increase in displacement and performance. We include matching JE, CP, or Mahle Motorsports pistons. Our most popular Nickies Porsche engine conversions include:

Porsche Boxster 986 2.5 -> 2.7

Porsche Boxster/Cayman 986/987 2.7 -> 2.9

Porsche Boxster 986/987 3.2 -> 3.8

Porsche 911 996 / Cayman S 987 (including 07-08 Boxster S) 3.4 -> 3.8

Porsche 911 996/997 3.6 -> 4.0

Porsche 911 997 3.8 -> 4.0

Where some other shops might offer slightly larger options using steel sleeves, our aluminum Nickies sleeves keep the engine running cooler and the NSC-plated bores, like those coated with Nikasil, reduce friction, all resulting in more horsepower through increased efficiency.

During the reconditioning process, the block deck gets surface ground and depending on how much is required to straighten the case, custom MLS head gaskets in the correct thickness are provided. Vapor blasting is also available for M96 and M97 engine cases which can be used to restore the external appearance of an engine block to near new condition.
 

Why does LN Engineering prefer an open deck configuration for its Nickies cylinder sleeves?

Porsche has used an open deck configuration for its watercooled engines for decades, as have many other manufacturers with their all-aluminum engines. An open deck provides better cooling than a closed deck which is advantageous for high performance engines. The only downside to an open deck is an increased risk of cylinder wall distortion and reduced rigidity, which has led to numerous issues with the M96 engine. However, the LN Engineering Nickies Porsche engine conversion sleeving process retains an open deck configuration in bore sizes up to 101mm without compromising strength, longevity, or reliability through the use of our billet aluminum Nickies sleeves that are made out of a specialty aluminum alloy that has significantly higher strength and thermal conductivity than the factory cast aluminum cylinders.

Our Nickies cylinder liner sleeves overcome the inherent deficiencies of the factory open deck configuration with a proven track record extending almost twenty years, with nearly 250 engines sleeved per year using our exclusive Porsche engine conversion process. It is worth noting that almost all of the Porsche blocks sleeved by LN Engineering with our Nickies have been oversizes, not stock bore sizes, reflecting the success of our process, even when increasing engine displacement and output significantly over that of a stock Porsche engine. LN Engineering's Nickies big bore Porsche engine conversions have been used exclusively by Flat 6 Innovations for all Porsche Boxster, Cayman, and 911 996 and 997 performance engine builds from day 1.
 

Does LN Engineering offer closed deck Porsche engine conversions?

LN Engineering does indeed offer Porsche closed deck engine conversions for Boxster, Cayman, and 911 996 and 997 models. Although most customers prefer with our standard open deck Nickies Porsche engine conversions that allow for displacements up to 4.1 liters, there are certain instances where the reduction in cooling can is an acceptable tradeoff to gain increased cylinder rigidity. Turbo Porsche engine conversions are an example where a closed deck does have benefit with the M96 or M97 engine. We normally recommend limiting the bore size to 99mm when fitting Nickies to Boxster, Cayman, and 911 engines that are supercharged or turbocharged, however with our closed deck conversion larger bores sizes up to 101mm are available that are optimized for use in forced induction applications. Also, for normally aspirated applications with bore sizes larger than 102mm, we will also provide closed deck Porsche engine conversions to ensure we are not trading off any strength or durability.
 

What is the typical turnaround to have my Porsche engine block sleeved?

Typical turnaround time from start to finish is 3-4 months and that includes time for whomever you choose to rebuild your engine to disassemble it and send us the block and IMS for reconditioning. Typical turnaround is 6-8 weeks for us to machine and install Nickies sleeves in your block as part of our Porsche engine conversion process, with the majority of that time required for the Nikasil plating process.
 

I see engine builders offering Nikasil cylinders for less than LN Engineering's Nickies. What is the difference?

We often hear of customers that say their rebuilt Porsche Boxster, Cayman, or 911 996 or 997 engine has Nikasil cylinders, but not Nickies. The difference is that with LN Engineering's Nickies Porsche engine conversions, we machine out the original cast in cylinder liners and fit our billet Aluminum Nickies sleeves. Although it is technically possible to have the original cast-in stock cylinders Nikasil plated, this does not address the known cylinder issues and can result in subsequent cylinder cracking, d-chunk, or slipped sleeve failures. The original cast-in cylinders in M96 and M97 engines are also notorious for going out of round and having excessive taper. Although direct Nikasil plating the block will restore the cylinders back to round, in our experience the cylinders have memory and will return to being out of round or having excessive taper very quickly because the parent metal the Nikasil plating is applied to is flawed. If you bore out the original cylinders to increase the displacement, that only increases your chances of having an engine failure that much more. The only way to proper rebuild an M96 or M97 engine block is to fit Nickies cylinder liner sleeves as part of the reconditioning process.
 

Is it possible to only repair a single cracked or scored cylinder?

Although other shops will indeed sleeve a single cracked or scored cylinder, all too often we receive engine blocks that have suffered a subsequent failure where an adjacent cylinder has cracked or sleeved.
 

Why does LN Engineering not use cast iron, ductile, or steel sleeves in M96 or M97 engines?

Shops that use cast iron, ductile, or steel sleeves when repairing Porsche Boxster, Cayman, or 911 996 or 997 engines often do so because they are cheap, easy, and the sleeving process can be done very quickly.

There are two styles of sleeves often used - dry and wet cylinder liner sleeves. With dry sleeves, the existing cylinder is retained and is bored out, then a thin wall iron or steel sleeve is pressed in. We see many M96 and M97 blocks that come through our door that have one or more dry sleeves fitted to fix cylinders that had suffered from cylinder bore scoring. With wet sleeves, the original cylinders are machined out, much like what is done with our Nickies Porsche engine conversion process, but a cast iron, ductile, or steel sleeve is then fit to the engine block.

About 10% of all the M96 and M97 engine blocks we receive on an annual basis come to us already fitted with dry or wet cylinder sleeves and have subsequently failed and are shipped to us to be correctly reconditioned using our Nickies. The leading cause for failures on Porsche engines fitted with cast iron, ductile or steel sleeves is intermix. We have never seen any steel sleeved M96 or M97 block pass pressure testing. We often find that the sleeves have moved in operation due to dissimilar material expansion rates, allow coolant and oil to intermix, and can result in blown cylinder head gaskets. In some instances, the required interference fit required to keep the cylinder sleeves or liners from moving or leaking ends up cracking the engine block, requiring replacement or extensive repairs.

Outside of these issues, using cast iron, ductile, or steel sleeves severely reduces the ability of the engine to cool properly, especially if displacement is increased. This negatively affects the engine's longevity, durability, and performance. Manufacturers have gone to great length to eliminate iron or steel liners or sleeves in their aluminum engines for these reasons exactly.

If you want to learn more about repair and sleeving of aluminum engine blocks, we recommend reading Introduction to Reconditioning Engine Blocks.
 

What do I need to do about the IMS bearing while rebuilding my engine?

While the engine is apart, addressing the IMS issue is also a must. LN Engineering offers an intermediate shaft reconditioning service. This allows us to inspect the bearing housing bore for runout and also to pin the main drive sprocket, which can slip and cause a failure. We will also fit an IMS Retrofit (ceramic hybrid ball bearing or cylindrical roller bearing) or IMS Solution depending on what replacement ims bearing you want to go with. If your engine has suffered scored bores and was already fitted with an IMS Retrofit, the bearing should be replaced at time of rebuild. However, if your engine was fitted with an IMS Solution, you should be able to reuse it during the reassembly process.
 

What upgrades are available for my Porsche engine?

As part of our Nickies Porsche engine conversions, for a street engine, we would also recommend a 160F low temperature thermostat to help keep the engine cool and ARP rod bolts to replace the weak factory rod bolts. This provides a solid and reliable foundation for a reliable engine for your Porsche Boxster, Cayman, or 911.

If you ever plan on autocrossing or tracking your Porsche, additional upgrades need to be made to address other weaknesses inherent to the M96/M97 engine as part of any Porsche engine conversion. These upgrades include:

Carrillo or K1 Connecting Rods

Billet Tensioner Paddle

Billet Oil Pump Drive

2 Quart Deep Sump

Coated Connecting Rod and Main Bearings

ARP Crankshaft Carrier and Cylinder Head Bolts

By replacing the above components during your engine rebuild, you are addressing the known issues associated with the Porsche M96 and M97 engine used in 1997-2008 Porsche Boxster, Cayman, and 911 models and will have a track ready engine that should give you years of reliable service with proper maintenance.
 

Is an engine rebuild kit available for my Porsche engine?

Yes! To simplify the reassembly process, LN Engineering offers engine rebuild kits for Porsche M96 and M97 engines including M96.01, M96.02, M96.04, M96.03, M96.05, M97.01, and M97.21 engine designations with everything we recommend replacing. We can also assist with cylinder head rebuilding and porting or anything else you might need when it comes to rebuilding your Porsche’s engine.

Above our standard Porsche engine rebuild kits, the RND Premium and Deluxe Engine Kits also include many more items that are highly recommended to be changed out rather than reused. Components that are normally reused and not included in these kits should be evaluated, qualified, and replaced if necessary.
 

How do you recondition your Porsche crankshaft and M96/M97 crankshaft carrier/cradle?

Assuming your Porsche engine did not suffer a catastrophic failure, there is little to be done to the crankshaft and carrier. There are to published technical specifications for crankshaft connecting rod and main journal diameters or tolerances with wear limits. If there is wear or damage to the crankshaft, we recommend replacing both the crankshaft and carrier as a matched set. We only use Genuine Porsche bearings which are available only in standard size, so turning of crankshaft journals or line honing the carrier are not an option. We recommend upgrading to our coated Porsche bearings and ARP crankshaft carrier bolts on all rebuilds and having the crankshaft magnafluxed to check for cracks and the crankshaft journals polished.
 

Will I need to gap my new piston rings or have my Porsche engine components balanced prior to assembly?

Most aftermarket piston rings are supplied as file to fit sets. This requires you to file or grind the piston rings to ensure you have the correct end gap. Typical piston ring end gaps for an M96 or M97 engine with aftermarket pistons and rings and Nickies cylinders are .015" for the top ring, .016" for the second ring, and a minimum of .015" for the oil control rings. To gap the piston rings, you'll want a piston ring filer.

Although the aftermarket pistons and connecting rods we supply are balanced out of the box (in fact often better than the original factory parts) and the dual mass flywheel provides significant dampening that makes up for imbalances, we do recommend at bare minimum static balancing all components. However, dynamic balancing of the rotating assembly is money well spent for any engine and recommended if you plan on tracking your car.

LN Engineering offers both a Porsche piston ring end gapping service as well as a Porsche engine balancing service to further simplify the reassembly process when rebuilding Boxster, Cayman, and 911 996 or 997 engines.
 

Who can rebuild my Porsche cylinder heads?

LN Engineering's Porsche cylinder head rebuilding and porting service is available only to customers with qualifying purchase of Nickies cylinders, Nickies block sleeving, or Nickies Lite cylinder reconditioning services. Our rebuilt Porsche cylinder heads benefit from years of experience with thousands of Porsche heads rebuilt by our specialists to date. 100% of components are tested, reconditioned, or replaced and feature multi-angle Serdi valve job, Viton valve stem seals, and critical surfaces are diamond milled, exceeding original manufacturer specifications. All components are inspected and replaced if worn. Additionally Porsche Boxster, Cayman, and 911 M96/M97 cylinder heads are always pressure tested and crack checked. All cylinder heads are vacuum tested after final assembly as part of our standard quality control checks so all you need to do is bolt them onto your engine.

Although cylinder head porting is available, in our experience most customers don't need to as the Porsche did a great job on these heads and they already flow too much for the stock displacement. By bumping up displacement, you're actually optimizing the engine and you'll feel and see the performance increase through a wider, flatter torque curve that provides higher average HP and torque across the whole power band. If you are looking to get every last bit of power out of your rebuild, porting will help the top end, especially when paired with an IPD competition plenum and GT3 throttle body.

Unlike aircooled Porsche cylinder heads where they can benefit from larger intake or exhaust valves, performance valve springs, and lightweight retainers, M96 and M97 cylinders heads come from the factory configured very well, even for track use. In the event that new valves, springs, or retainers are needed, we use Genuine Porsche or OEM replacements unless otherwise specified or requested.

Likewise, the factory camshaft profiles are excellent even with increased displacement and we rarely see any wear on camshaft lobes requiring repair or replacement. The X51 power package added high flow heads, intake plenum, oil system upgrades, and performance camshafts to the 3.6 and 3.8 engine, of which it is possible to purchase this kit or the cams from Porsche separately or you have your original 3.6 or 3.8 camshafts reground to an X51 profile by someone like Webcam Camshafts or you can purchase upgraded camshafts from Schrick (LN Engineering is an Authorized Schrick dealer).
 

What engine rebuild options does LN Engineering offer?

LN Engineering's close partnership with Jake Raby's Flat 6 Innovations delivers turnkey proven M96 and M97 performance engines for owners of Porsche Boxster, Cayman, and 911 models featuring all our improvements including Nickies Porsche engine conversions, IMS Solution, and countless other upgrades co-developed by the LN/FSI team.

Unfortunately, there are simply more engines that need rebuilding than Flat 6 Innovations and RND Engines can rebuild. We recommend taking a look at the IMS Solution Certified Installer list as most, if not all, of the shops listed have been extensively trained by Jake Raby including on how to properly rebuild the M96 and M97 engine. A proper rebuild for a Porsche engine typically starts at around $20k and can go higher if you are planning on doing additional performance upgrades. What many do not factor into the cost is engine R&R (removal and reinstallation) as well as replacing worn ancillaries that are often overlooked by most shops when estimating these jobs. Please keep this in mind when budgeting for your engine build.
 

What do I do if my 2009 and later Boxster, Cayman, or 911 with the 9A1 or MA1 engine suffers bore scoring?

Unfortunately, any engine with a hypereutectic engine block can suffer from cylinder bore scoring, not just the M96/M97 engine used in Porsche Boxster, Cayman, and 911 models. LN Engineering offers Cylinder Bore Scoring Solutions for Porsche MA1/9A1 engines with Alusil Engine Blocks. Using a similar process, LN Engineering can repair any Porsche Alusil engine block with cylinder bore scoring including those used in Porsche 944, 928, Cayenne, Panamera, and Macan models.
 

Do you have any additional information about cylinder bore scoring and on how to properly rebuild my Porsche engine?

LN Engineering provides educational resources, training, and guidelines at no charge to its aircooled and watercooled Porsche customers. Be sure to check out our education library with dozens of free downloads and sign up for our valuable newsletters that offer original technical content that we think every Porsche owner should know. We've highlighted information specific to rebuilding and maintaining your Porsche Boxster, Cayman, and 911 with the M96 or M97 engine to supplement The Knowledge Gruppe's Focus on M9X Engine Assembly DVD, Workbook, and Torque Spec books.

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