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You bet!

Using a gapless ring does eliminate the path for the gasses which is reflected in very low leakdown numbers.

@@lnengineeringllc I see there are many variables i.e. compression, stroke, etc. I found many production stock engines are running -.2 to -.6inH2O hot idle in the crankcase, the result is carboned Oil Rings and eventually burning oil. Just curious how much the gapless ring would lessen the issue roughly. Thanks

Assuming you are using a Genuine Porsche AOS and conventional piston rings, it should read between 4-6 inches of water column.

Always a safe bet. Coolant pipes are the biggest issue on these models but easily addressed through preventative maintenance.

I'd recommend removing the drive belt to see if the noise goes away. That would be the first step. The drive belt rollers seem to be failing now do to age, so it could be as simple as that.

Sorry to hear that. Thanks for letting us know.

Glad it was helpful!

Yes, for example a stock 97-08 Boxster, Cayman, or 911 M96/M97 engine should have 4-6" of water column if fitted with a Genuine Porsche AOS and if measured when fully warmed up.

@@lnengineeringllc In my case -15.0 inches of water column in my 991.1. I got a reading of -14.91 inches of water column using a Porsche oil cap that I modified and my manometer. It is something I will check from time to time.

@@lnengineeringllc I've been looking into what other manufacturers run for vac in the crankcase and most run at least 1 - 2 inHg, Audi went from 2.5 to 2.9. Honda/Acura is at .2 to .4 hot idle up to 2 to 4 inH2O run up and have problems with carbon buildup in the ring pack. Do you see any Porsche with this carbon problem? Just curious, Thanks.

It's currently around $6k to recondition an M96/M97 block including sleeving and resurfacing as well as new pistons, rings, pins, and clips. This includes our standard QC checks for ovality, taper, surface finish, and pressure testing. lnengineering.com/products/watercooled-porsche-cylinders-sleeves-and-pistons/porsche-cylinder-bore-scoring.html

If you have an engine with a Lokasil or Alusil cylinders, the silicon is likely coming from the cylinders. I would also expect increases in iron and aluminum. It is unlikely to be from the air filter as long as you are using a paper filter. We see this incorrectly referenced in oil analysis reports from labs that do not know Porsche engines as well as we do.

We do not have much experience with Panamera models, but from what we have been told, the Audi derived 2.9 and 3.0 turbo engines shouldn't suffer from bore scoring, but only time will tell.

After we machine out the original cast-in sleeves we then o-ring the engine block, but both operations are done in the same setup.

@@lnengineeringllc what do you guys charge for that service on Honda h22 open deck block?

We have not applied our process to a Honda block to date, but it would be similar to sleeving a Porsche 944 block: lnengineering.com/products/watercooled-porsche-cylinders-sleeves-and-pistons/porsche-944-944t-968/porsche-944-968-104mm-engine-block-reconditioning-inc-nickies-sleeves-no-pistons-or-rings-included.html

We would recommend having someone check the surface finish with a profilometer to make sure it's correct Second, you'll want to make sure the engine isn't run too rich which washes down the cylinder bores of critical lubrication.

Great idea to run a complete fuel system cleaner with PEA (polyetheramine) at least every 2-3k miles, even if you run a Top Tier fuel. I personally run one bottle of Injector Defender every other fill-up.

I'm assuming you have a base model with the 2.7 liter engine. If so, base model Boxsters and Caymans don't suffer from bore scoring, so often the ticking comes from a lazy lifter, exhaust leak, or noisy injectors. You might simply try changing your oil, especially if you are running a 0w40- I've seen that quiet up lifters in the past when switching to a 5w40 like Driven DT40.

Good choice to use Shell fuels. Redline SI-1 is one of the few fuel additives that are worth using. Chevron Complete Fuel System Treatment (the more expensive one) would also be suitable, although I'm partial to Driven Injector Defender. You might want to consider Driven's LS30. You are likely to see it holds its viscosity much better and I would expect lower wear levels. For comparison, we have the same issue with the factory Porsche fill which shears from a 40 to a 30 grade sometimes in as little as 1000 miles.

@@lnengineeringllc Thanks for the info on those products; I'll definitely check out the fuel additive. I'm going to go with a fill of Redline 5W-30 at my next oil change and then run a used oil analysis after 3k miles and see where it's at on the wear metals. I had run Motul 300V 5W-40 for 3k miles but had disappointingly high levels of iron, with everything else perfect. If the Redline doesn't pan out I'll definitely try the Driven oil.

Yes, based on information from Mahle the coating applied to the original pistons would not be compatible with the steel liner. We would highly recommend against sleeving just one cylinder as well as we have seen countless engines fail months later with another cylinder issue in one of the other unsleeved bores.

Yes, we can indeed recondition and repair a Mercedes Alusil block. It would be no different from what we do with Cayenne engines. The most cost effective option is to slightly overbore the block, say 1mm, Nikasil plate it, and then fit it with new aftermarket pistons. To do this we would need a sample piston (or two, if they are bank specific) so we can use this for a reference when building the new replacement pistons.

Yes, we have worked closely with Lake Speed Jr. for years and now Total Seal for piston rings for our Nikasil plated cylinders. We mostly do aircooled and watercooled Porsche cylinders, but we do some Rotax 912 and aircooled VW Type 1 and VW Type 4 cylinders as well.

You can actually nurse an engine with bore scoring for quite some time. We recommend switching to Driven FR50 5w50 oil as it has high anti-wear and friction modifier levels that along with the increased viscosity will help slow down the wear associated with bore scoring. Unfortunately, high oil consumption will lead to lots of carbon buildup in the chambers and can lead to detonation that can damage the rod bearings. Also the increased soot loading of the oil will cause increased wear in the engine and chain stretch. Again, some of this can be addressed with shorter oil change intervals, but it for sure won't go forever that way.

The Knowledge Gruppe does offer access to recordings of some of its online courses. I do believe more courses are in the works.

Soon they all be electrical and I don't have to lust over them any more. good and bad. haha

Porsche did go to SUMEbore coated cylinder bores with the 991.2 and 718, so we hope cylinder issues are a thing of the past. Fingers crossed!

I daily drive my 981 and maintain it frequently as preventive but I don’t have any fear of bore score, not a problem with these engines unless owner neglects the car or doesn’t drive it frequently or overheats it. These 9a1 are great engines, nothing like the m9x nightmares of the past. Read and follow the owners manual, change your fluids more frequently than recommended and your 9a1 should be super reliable and free of scoring.

Correct. The higher pitch ticking is from the injectors.

You got it. We often get blocks in that have been steel sleeved where the blocks have cracked when sleeves are fitted with interference fit. The block parent metal is easily compromised. Once the sleeves are fitted, they are cured and receive a final bake to get full strength out of the adhesive. The adhesive is rated to 450F, but if it ever gets that hot, you have bigger problems! The sleeves aren't going anywhere - in fact they are next to impossible to remove without machining them out after we've completed the process.

We do sometimes see marks or discolorations in the bores, but in this case, I think that's actually a spot that is scuffed but hasn't become deep scoring.

@@lnengineeringllc Are such abrasions on a smaller scale dangerous, or can they continue to be used with proper maintenance?

Usually when you do see them higher in the bores you'll find that below the piston at BDC there will be significantly more damage. That said we have seen people switch to DT40 (or DT50 if a thicker oil is desired or DI40/DI50 for direct injected applications) and slow down the progression of bore scoring. However it won't get any better, that's for sure and won't go indefinitely, even with a better oil. @@worldsinsider

@@lnengineeringllc Thanks for answers! Thank God my cylinders are all right 😅, I was just interested in this moment.

Glad you could make it out. Lots of noises there.

Thank you. It is always our intention to try to educate others about this topic so that people can make informed decisions.

As you have a factory replacement engine, the Porsche dealership should be able to tell you what IMS bearing the engine has based off the engine number. That data we do not have access to unfortunately. The engine would have whatever bearing was currently being used by Porsche during the model year it was manufactured. If the engine was built in or after model year 2006, it will more than likely have the larger, non-serviceable IMS bearing.

Happy to help!

Very unfortunate to be the case. Something all owners or future owners need to be aware of.

As you have a factory replacement engine, the Porsche dealership should be able to tell you what IMS bearing the engine has based off the engine number. That data we do not have access to unfortunately. The engine would have whatever bearing was currently being used by Porsche during the model year it was manufactured. If the engine was built in or after model year 2006, it will more than likely have the larger, non-serviceable IMS bearing.

thank you @@lnengineeringllc

Glad you found this video informative! Thanks for watching.

Spot on. The clunk is the piston slap caused by the increase in piston to cylinder clearance once bore scoring has progressed significantly.

The sleeve ends up sandwiched between the head and bottom of the water jacket, so it's can't necessarily fall or slip, and is o-ringed to provide positive sealing. The proprietary gluing process is not shown in the video, but this is done rather than using a press-fit for the sleeves.

It starts as a tick tick tick that sounds just like a bad lifter. As scoring progresses, the piston to cylinder clearance increases and eventually the engine will have a knock like an old diesel engine. Hopefully that clarifies things!

@@lnengineeringllc thank you 👍🏻

The Honda S2000 is a great car! It has a similar hypereutectic engine block, but Honda did a great job on these starting with the NSX and Prelude - they don't suffer from the same cylinder bore scoring as we see on European engines with Alusil or Lokasil engine blocks.

@@lnengineeringllc I hear that! I sincerely want a Porsche 911 but the 993 is way out of my range and this bore scoring on the 997.1 and .2 is just too much to handle. I’m going to keep on enjoying the S2k, which is a blast to drive.

@@DonBMW Bore scoring rarely occurs on base model Cayman 2.7 as well as Base and S model Boxsters with the 2.5, 2.7, or 3.2 engine through 2008. All you really have to worry about on those cars is the IMS. Might be worth looking into.

Yup! And it only ticks louder on the Gen 2 models with direct fuel injection. This model has port injection, but the injector noise is still audible.

Is the knocking the lower frequency noise?

Awesome. That's great to hear. FSI might be more expensive than going with another builder, but as you have experienced, there is a huge difference with the end result when going with one of Jake's Porsche engine rebuilds.