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I run these JE forged ones. They are for a reconditioned 97.5mm bore. I got engine damage and needed to rebore because of the taper. It was at about 0.05mm. I currently have about 5000km on these and so far I'm happy.
I run these JE forged ones. They are for a reconditioned 97.5mm bore. I got engine damage and needed to rebore because of the taper. It was at about 0.05mm. I currently have about 5000km on these and so far I'm happy.
Still trying to understand how the piston/cylinder wall are still talking to each other. This opens the door to great possibilities for a rebuild but many concerns still with the compatability. You have 5000km on them so they are clearly working out for you and that's great.
How hard do you drive your car ? Any type of racing ?
Still trying to understand how the piston/cylinder wall are still talking to each other. This opens the door to great possibilities for a rebuild but many concerns still with the compatability. You have 5000km on them so they are clearly working out for you and that's great.
How hard do you drive your car ? Any type of racing ?
I don't race the car, there are just no drag strips in Belgium. I hoped to go to this race http://www.race-1000.com/ in Germany but due to the pandemic the borders were closed.
My engine is not over stressed at the moment, currently I'm running LTH, RaceIQ cams and a 76mm pulley. However I'm dreaming of a 3l whipple supercharger and it is build for that.
Many people are convinced that the coating on the pistons is there to protect the bores. But I'm not convinced. I destroyed a piston and consequently a bore. During the disassembly of my engine the other bores looked really good even though the coating on the pistons was gone due to millage. I only have a picture of the damaged bore but even that is looking reasonably well. If I really wanted I could have slapped another piston in it and sell the car. I've read a lot of thing about AluSil and some people believe the trick to making it work is in the ring and I can believe that.I included some pictures of my claims and a picture of the re balanced crank wich also shows the reconditioned bores at 97.5mm.
The damaged piston the damaged bore Pistons without coating Other side of the pistons without coating modified crank and bores
I run these JE forged ones. They are for a reconditioned 97.5mm bore. I got engine damage and needed to rebore because of the taper. It was at about 0.05mm. I currently have about 5000km on these and so far I'm happy.
so, that’s mean the engine block wall can be honed, am I right🤔
coz I heard from someone, they said that the engine block wall can’t be honed as there is some coating on the surface of the block wall
Those pistons you show (oem) ARE still coated. That costing is ferrous. Meaning iron based. Or tin and iron. So they are not bare aluminum and and on a micro level, the iron is what touched the aluminum on the bores.
I am so glad your engine in your configuration is working.
However across Porsche, Mercedes, and Audi, people have tried breaking through this issue and it simply is 1) Real and 2) Detailed
Rings are indeed important. Chromoly faces rings is one thing I recall but....
Alusil is NOT a coating. It is an aluminum alloy. It has over 14% silicon in it, and an “alusil” bore is what is defined as the bore surface when it has been “lapped” to allow the crystal structure of silicon (not silicone) to stand proud. Simple as that. Fragile but somehow long wearing.
The pistons for millions, possibly billions of miles across the German automakers who use alusil are coated in a Ferous material. This is what works.
There is a possibility that the black coating has enough Teflon or molly in it work for the pistons that you put in. 5000km is not a lot, I’m sorry.
The bored can be honed. But then, after final sizing to pistons, they must be lapped with a paste. That paste does not materially change dimensions. But it prepares the surface for the rings and ferrous piston coating.
06-04-2020, 01:50 AM
