Engine rebuild, new rings, what prep??
02-08-2005, 11:15 AM
#16
Instructor
Thread Starter
Join Date: Jul 2004
Location: Bournemouth, South coast, England
Posts: 215
Likes: 0
Received 0 Likes
on
0 Posts
Cool Danno.
Thats what I was looking for.
It seems like it would not be ecconomical to use these liners, due to the amount of machining and detail work that would be needed. I was just wondering if it would be easier in cases where a scored bore or worn bore would normally require new pistons. But now it would look like it would be easier to buy new pistons and have the block bored and steps 1 to 4 carried out.
Whats MMC?
So, if the bores look good and measure out as good... is there any benefit from performing step 4 to prepare the bores for fresh rings, just to polish back any of the aluminium between the crystals to compensate for any wear on the crystals (even if it cant be measured?)
Thats what I was looking for.
It seems like it would not be ecconomical to use these liners, due to the amount of machining and detail work that would be needed. I was just wondering if it would be easier in cases where a scored bore or worn bore would normally require new pistons. But now it would look like it would be easier to buy new pistons and have the block bored and steps 1 to 4 carried out.
Whats MMC?
So, if the bores look good and measure out as good... is there any benefit from performing step 4 to prepare the bores for fresh rings, just to polish back any of the aluminium between the crystals to compensate for any wear on the crystals (even if it cant be measured?)
02-08-2005, 04:32 PM
#17
Race Director
Most economial solution to badly scored cylinders would be to just bore it out and install a steel/iron liner. This has been done for decades and numerous shops can handle it. You can then bore it back out to stock 100mm size and use the same piston (if in good condition).
MMC = metal matrix composite. A materials that's not a homogenous alloy, but is an amalgamation of distinct materials. An example is fibreglass/carbon-fibre which is a composite of structural fibre fixed in a binding epoxy matrix. Problem is the binding epoxy is relatively low-strength. There have been experimental materials with using aluminium as the binding material on carbon-fibre. The layup is the same with a layer of carbon-fibre then a layer of aluminium foil, then carbon-fibre, then foil, etc. Then the whole thing was pressed with high force and temperature to melt the aluminium around the carbon-fibre. Super strong and light weight compared to normal carbon-fibre, but not economical to manufacture.
So the idea went the other way with introducing solid fibres into the molten aluminium during casting. One of the first commercial retail applications was the M2 mountain-bike from Specialized over 10-years ago. The frame was about 2-3 lbs lighter than previous alloy frames of the same strength. This MMC was made from embedding silicon-carbide particles in the alloy. Manufacturing problem was they had to make new presses and rollers that can work with the harder materials.
Our Alusil blocks are an MMC as well since it has silicon crystals embedded in it. The resultant material has properties that's different from normal aluminium alloys. Heat-conductivity is slightly lower, thermal expansion is lower, strength is up somewhat. The main benefit is having the tough silicon surface in the cylinder bores.
Honda's blocks are a MMC that's particularly well-engineered. The cylinders are first constructed of a porous ceramic mesh, like a bird-cage. They are held in place in the mold as molten aluminium is poured in, which is then wicked into and through the ceramic mesh. After everything's cooled, you have a super-strong cylinder with embedded fibres. Pure science fiction!
MMC = metal matrix composite. A materials that's not a homogenous alloy, but is an amalgamation of distinct materials. An example is fibreglass/carbon-fibre which is a composite of structural fibre fixed in a binding epoxy matrix. Problem is the binding epoxy is relatively low-strength. There have been experimental materials with using aluminium as the binding material on carbon-fibre. The layup is the same with a layer of carbon-fibre then a layer of aluminium foil, then carbon-fibre, then foil, etc. Then the whole thing was pressed with high force and temperature to melt the aluminium around the carbon-fibre. Super strong and light weight compared to normal carbon-fibre, but not economical to manufacture.
So the idea went the other way with introducing solid fibres into the molten aluminium during casting. One of the first commercial retail applications was the M2 mountain-bike from Specialized over 10-years ago. The frame was about 2-3 lbs lighter than previous alloy frames of the same strength. This MMC was made from embedding silicon-carbide particles in the alloy. Manufacturing problem was they had to make new presses and rollers that can work with the harder materials.
Our Alusil blocks are an MMC as well since it has silicon crystals embedded in it. The resultant material has properties that's different from normal aluminium alloys. Heat-conductivity is slightly lower, thermal expansion is lower, strength is up somewhat. The main benefit is having the tough silicon surface in the cylinder bores.
Honda's blocks are a MMC that's particularly well-engineered. The cylinders are first constructed of a porous ceramic mesh, like a bird-cage. They are held in place in the mold as molten aluminium is poured in, which is then wicked into and through the ceramic mesh. After everything's cooled, you have a super-strong cylinder with embedded fibres. Pure science fiction!
