That car’s fine, consumes no oil runs good, just was a little confused as to why Porsche is affected a lot more than other brands with the same tech.
Cylinder wall treatment for Porsche?
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By the time the Vega engine went into production the engine problems had nothing to do with the block alloy. GM’s process for honing and etching the bores was a mature process and was the best thing about that engine. It had other design flaws that caused it to overheat and that was what killed public perception of the model. Even those were subsequently corrected but by then it was too late and sales were doomed.
A lot of people think the problem was the all-aluminum block but it was not.
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The Intermediate shaft bearing would be a tough one for sure. I would more than likely take it to the shop and bend over for the full day of labor to install. Just looking at the M96/97 engine it looks like at least 10 hours or more in shop time alone.
Actually it is far more possible to "re-hone" an Alusil block since Alusil is an alloy whereas Nikasil is a coating. Unlike a coating the material properties of Alusil are uniform throughout the material, but it must be properly processed after boring.
I'd say 10-15 for your first time depending on your experience level and ability to follow directions. That's on the M96. The M97 is simple: all you can do is drop the trans, clutch, and flywheel to remove the outer seal. Anything further requires splitting the cases.
Bore score in M96 is caused by cylinder ovality. I'm not sure what causes it to begin in the Cayenne.
sport bikes been using coated cylinders a long time without issues. it saves little weight as well as spacer + heat transfer is superior. yes it costs more done right + cheap manufacturers like Hardly use outdated steel liners. guessing some newer coatings are being TRIED to save $$$, as usual buyers are the real testers!!
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I thought they were a spray coating like Ford? It's only X deep, so if you need a re-bore you are down past the coating and thus will need to sleeve it.
This is an old article but it’s one of the best I’ve seen with a fairly detailed explanation:
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Page Not Found | Porsche Club of America
www.pca.org
To repair scored cylinder walls?Thought this was interesting but I would use Archoil 9100 over Ceratec.Page Not Found | Porsche Club of America
How-TO: Hone Alusil Blocks
Believe it or not these engines can be saved! If you experience excessive oil burning, alot of times it's caused by a bad pcv or bad valves seals, or even bad valve guides in conjunction. That is not ALWAYS the case however. The Audi aluminum engines are made of an alloy known as AluSil...
www.audizine.com
These guys made a little custom setup using Sunnen AN-30 paste and basically burn it into the cylinder wall. Apparently Sunnen were the first cook to this stuff up for the Vega way back in the day.
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That seems to support what I was thinking. You aren't punching those engines 30-over, as you'll be removing the material entirely. Obviously if you aren't in the position to have to do that, you have more flexibility.
Well no you can't remove the coating with Alusil since it's a property of the entire alloy. But you do need to somehow etch, hone or otherwise treat the surface after boring so the silica particles are exposed and presented properly (however it is done). With Nikasil you would have to replace the coating since once it's gone you just have a normal aluminum surface.
I think though that unless something catastrophic happens neither Nikasil, Alusil or any of the other materials are going to be the point of failure. I tend to side with what rooflessVW said above that it is something else wrong with the engine. On my ancient old BMW the engine mechanicals are the best part of that vehicle, compression is excellent (too much trouble to perform a leakdown test on it) and it uses less than a quart of oil in an OCI of about 8000 to 8500 miles. I love the M60 engine, I wish there was a way to keep it when I scrap the vehicle soon due to rust problems. Maybe I'll keep it in the bedroom next to the bed, I'll ask my wife
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Well no you can't remove the coating with Alusil since it's a property of the entire alloy. But you do need to somehow etch, hone or otherwise treat the surface after boring so the silica particles are exposed and presented properly (however it is done). With Nikasil you would have to replace the coating since once it's gone you just have a normal aluminum surface.
I think though that unless something catastrophic happens neither Nikasil, Alusil or any of the other materials are going to be the point of failure. I tend to side with what rooflessVW said above that it is something else wrong with the engine. On my ancient old BMW the engine mechanicals are the best part of that vehicle, compression is excellent (too much trouble to perform a leakdown test on it) and it uses less than a quart of oil in an OCI of about 8000 to 8500 miles. I love the M60 engine, I wish there was a way to keep it when I scrap the vehicle soon due to rust problems. Maybe I'll keep it in the bedroom next to the bed, I'll ask my wife
It appears in terms of Ford, I was thinking of the plasma spray process they used on the GT500
Honing Aluminum Blocks - Engine Builder Magazine
Manufacturers who produce “linerless” hypereutectic aluminum blocks today include Audi, BMW, Honda, Mercedes, Porsche, Volkswagen, Volvo, and Yamaha. Most late-model engines have aluminum blocks to save weight, including most of the familiar domestic V8s such as Chevy LS, Ford 4.6L modular and...
www.enginebuildermag.com
One of the 2 or 3 gentlemen stateside that builds these engines suspects it is a case of overlapping tolerances, resulting in a too-large cylinder to piston clearance. This allows piston rock then slap then scoring. He also suggests that colds starts (where the clearance is largest) combined with excessive idling (fuel washing cylinders) before driving off is an influence, as a higher percentage of damaged engines come from up north.Well no you can't remove the coating with Alusil since it's a property of the entire alloy. But you do need to somehow etch, hone or otherwise treat the surface after boring so the silica particles are exposed and presented properly (however it is done). With Nikasil you would have to replace the coating since once it's gone you just have a normal aluminum surface.
I think though that unless something catastrophic happens neither Nikasil, Alusil or any of the other materials are going to be the point of failure. I tend to side with what rooflessVW said above that it is something else wrong with the engine. On my ancient old BMW the engine mechanicals are the best part of that vehicle, compression is excellent (too much trouble to perform a leakdown test on it) and it uses less than a quart of oil in an OCI of about 8000 to 8500 miles. I love the M60 engine, I wish there was a way to keep it when I scrap the vehicle soon due to rust problems. Maybe I'll keep it in the bedroom next to the bed, I'll ask my wife
It is also suggested that the honing procedure was updated in late '08 and it did result in increased reliability, as he has only done a few engines past that date.
It wasn't the aluminum block cylinders that had the issue, it was an under designed radiator (tiny size !) and once the engine was badly over heated it had issues. I had a 1974 Vega GT and never had any issues with it because I made sure it never over heated. If GM would have spent $2 more per car and put in a larger radiator they would have saved themselves lots of troubles.
ZeeOSix you’re right! I had a ’73 Vega and drove it 60k trouble free miles before trading it in on a Camaro. Never used oil.
I’ve only used XADO in an automatic transmission (and it worked great), but it alleges to do what you’re looking for
There is some credence to the use of LM Ceratec, however it won't restore compression or reverse bore scoring.
The cylinder blocks in the Cayenne V8 as well as Panamera and Macan models are cast from Alusil. The bores are basically raw aluminum and they undergo a process that exposes the silicon particles. There is no plating on the bores. What happens is that when too many of the silicon particles fracture, the oil tribofilm can no longer be supported and you get scoring. This also can occur if the iron clad piston skirt coating fails, resulting in aluminum to aluminum contact with metal transfer and galling.
Ceratec as well as LM's MoS2 additive contain moly. Moly can bind to the aluminum where ZDDP cannot. Porsche approved oils have little to no moly, even Liqui-moly's A40 approved oils, so you have to add an additive or use a non-approved oil that has high moly levels. Driven DT40 and Millers Nano 5w40 are two such oils with high moly levels that are beneficial to protecting against bore scoring.
You do bring up a good point as to older Porsche models and other makes that also have used Alusil blocks. Kolbenschmidt changed the manufacturing process in the late 90s to use a mechanical exposure process rather than a chemical one which can result in fractured silicon particles. Also the piston manufacturers went away from iron clad piston platings to coatings that are nowhere near as durable. There are other contributing factors as well. For those curious, I spent years researching this issue as it also pertains to Boxster, Cayman, and 911 models with Lokasil engine blocks:
FREE DOWNLOAD: Understanding Bore Scoring in Al-Si Cylinder Systems by Charles Navarro
Since 2002, LN has delivered precision performance parts and services for Porsche engines including Nickies cylinder and piston sets and ims bearing kits.
lnengineering.com
Thanks, from a happy 996 & 986 customer!There is some credence to the use of LM Ceratec, however it won't restore compression or reverse bore scoring.
The cylinder blocks in the Cayenne V8 as well as Panamera and Macan models are cast from Alusil. The bores are basically raw aluminum and they undergo a process that exposes the silicon particles. There is no plating on the bores. What happens is that when too many of the silicon particles fracture, the oil tribofilm can no longer be supported and you get scoring. This also can occur if the iron clad piston skirt coating fails, resulting in aluminum to aluminum contact with metal transfer and galling.
Ceratec as well as LM's MoS2 additive contain moly. Moly can bind to the aluminum where ZDDP cannot. Porsche approved oils have little to no moly, even Liqui-moly's A40 approved oils, so you have to add an additive or use a non-approved oil that has high moly levels. Driven DT40 and Millers Nano 5w40 are two such oils with high moly levels that are beneficial to protecting against bore scoring.
You do bring up a good point as to older Porsche models and other makes that also have used Alusil blocks. Kolbenschmidt changed the manufacturing process in the late 90s to use a mechanical exposure process rather than a chemical one which can result in fractured silicon particles. Also the piston manufacturers went away from iron clad piston platings to coatings that are nowhere near as durable. There are other contributing factors as well. For those curious, I spent years researching this issue as it also pertains to Boxster, Cayman, and 911 models with Lokasil engine blocks:
FREE DOWNLOAD: Understanding Bore Scoring in Al-Si Cylinder Systems by Charles Navarro
Since 2002, LN has delivered precision performance parts and services for Porsche engines including Nickies cylinder and piston sets and ims bearing kits.
