Piston Rings?
11-14-2007, 05:27 PM
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Piston Rings?
I just purchased some chrome moly hastings rings for my b16 turbo (10psi). Well they came I found that all the rings seem to be cast iron. I know that oem rings would probably be the best but what do you guys think about the hasting rings and should I try to return them for the right ones. I have searched the part number and cant find anything saying that they are cast iron. I did find one site that said they were chrome moly but couldnt really confirm this. I will be calling hastings in the mourning but just let me know what you guys think. What would be the best for this application every search has revealed that people believe hasting or npr work fine but i dont know. Thanks
11-15-2007, 06:17 AM
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Re: (Sr420Det)
why not use just the original rings that the manufacturer supplies.
"Piston rings are subject to wear as they rub up and down the cylinder bore. To minimize this, they are made of wear resistant materials (cast irons and steels) and coated or treated to enhance the wear resistance. Typically top and oil control rings will be coated with Chromium, or Nitrided_ possibly plasma sprayed _or have a PVD (physical vapour deposit) ceramic coating. "
would yours not then be chromium coated iron? ^
"Piston rings are subject to wear as they rub up and down the cylinder bore. To minimize this, they are made of wear resistant materials (cast irons and steels) and coated or treated to enhance the wear resistance. Typically top and oil control rings will be coated with Chromium, or Nitrided_ possibly plasma sprayed _or have a PVD (physical vapour deposit) ceramic coating. "
would yours not then be chromium coated iron? ^
11-15-2007, 02:38 PM
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Re: (agrn93ls)
Originally Posted by http://www.automotiverebuilder.com
one area where we're going to see big changes is in ring coatings," said Wilkinson. "Back in the 1950s, chrome was the most common type of facing material for rings. Moly was introduced in the 1960s, followed by plasma spray moly coatings in the 1970s. We think chrome plating will be going away because of environmental reasons.
The Japanese use nitriding to increase the wear resistance of their ring sets. Nitriding does not have the scuff resistance of plasma spray moly, but it gets rid of the chrome. We're developing nitrided oil rings now for some OEM applications," said Wilkinson.
Gas nitriding, which should not be confused with the black phosphate coating that is currently used on most rings to prevent rust during shipping and storage, is a heat treatment process that impregnates the surface of the metal with nitrogen in order to harden the surface of the metal. This makes the rings very hard about 68 on the Rockwell C scale for improved wear resistance.
"One of the advantage of the plasma spray process is that different materials such as chrome carbide can be mixed with the moly powder to produce different ring characteristics," said Wilkinson....
"We can manufacture rings that don't wear (themselves), but they wear the cylinder bore. So we have to balance ring and bore wear to come up with the best overall solution."....
The increased demands on today's engines means more OEMs are using ductile and steel top compression rings. As mentioned earlier, these tougher materials are needed to withstand the pounding and heat.
Gray cast iron is an adequate ring material for most older passenger car applications. But the change to thinner low tension rings in newer engines, and the relocation of the top ring closer to the top of the piston, has dictated the use of ductile iron or steel top compression rings in many applications.
Gray cast iron is a brittle material that can easily break if mishandled. Rings made of this material may also break if the engine experiences heavy detonation.
Ductile iron (also called "nodular" iron), on the other hand, has a different microstructure with rounded grains instead of rectangular grains. This allows the metal to bend without breaking , so it can withstand detonation in high load engines. It also makes the metal about twice as strong as gray cast iron.
Chrome or moly faced ductile iron 1.5mm top compression rings have been used since the early 1980s in many turbocharged engines, and are now used in many late model domestic engines with the new piston and ring configurations. Gray cast iron rings are still common in aftermarket ring sets, but many premium ring sets now have ductile iron top rings.
Another ring material that is seeing greater use in new engines is steel. Twice as strong as ductile iron and four times as strong as gray cast iron, steel can provide the durability and toughness needed for the most demanding top ring applications. Steel rings have a tensile strength in the range of 240,000 psi, which compares to 180,000 psi for ductile iron and 45,000 psi for gray cast iron. Hardness can vary depending on the alloy and heat treatment, but is generally in the 44 to 53 HRC range compared to 38-40 HRC for ductile iron and 22-23 HRC for gray cast iron.
Like ductile iron, steel is not compatible with cast iron cylinder walls so it must be coated with either chrome or moly, or nitrided. Most of the steel rings currently in production have a width of 1.0 to 1.2mm....Steel rings are usually barrel faced, having contoured outside diameters which give the ring a center contact with the cylinder wall.
Though the best advice here is to follow the OEM lead and replace ring sets with ones made of the same material (or better), several ring manufacturers said steel and ductile iron rings are virtually interchangeable. If a steel replacement ring is not available for a certain application that uses steel as original equipment, a ring set with ductile iron top rings can be substituted.
Federal-Mogul's Gabrielson says there are even some instances where the OEMs have gotten away from steel and gone back to gray cast iron. The use of knock sensors and more precise engine control systems on these engines has reduced the risk of detonation to the point where the added durability of steel is no longer necessary.
one area where we're going to see big changes is in ring coatings," said Wilkinson. "Back in the 1950s, chrome was the most common type of facing material for rings. Moly was introduced in the 1960s, followed by plasma spray moly coatings in the 1970s. We think chrome plating will be going away because of environmental reasons.
The Japanese use nitriding to increase the wear resistance of their ring sets. Nitriding does not have the scuff resistance of plasma spray moly, but it gets rid of the chrome. We're developing nitrided oil rings now for some OEM applications," said Wilkinson.
Gas nitriding, which should not be confused with the black phosphate coating that is currently used on most rings to prevent rust during shipping and storage, is a heat treatment process that impregnates the surface of the metal with nitrogen in order to harden the surface of the metal. This makes the rings very hard about 68 on the Rockwell C scale for improved wear resistance.
"One of the advantage of the plasma spray process is that different materials such as chrome carbide can be mixed with the moly powder to produce different ring characteristics," said Wilkinson....
"We can manufacture rings that don't wear (themselves), but they wear the cylinder bore. So we have to balance ring and bore wear to come up with the best overall solution."....
The increased demands on today's engines means more OEMs are using ductile and steel top compression rings. As mentioned earlier, these tougher materials are needed to withstand the pounding and heat.
Gray cast iron is an adequate ring material for most older passenger car applications. But the change to thinner low tension rings in newer engines, and the relocation of the top ring closer to the top of the piston, has dictated the use of ductile iron or steel top compression rings in many applications.
Gray cast iron is a brittle material that can easily break if mishandled. Rings made of this material may also break if the engine experiences heavy detonation.
Ductile iron (also called "nodular" iron), on the other hand, has a different microstructure with rounded grains instead of rectangular grains. This allows the metal to bend without breaking , so it can withstand detonation in high load engines. It also makes the metal about twice as strong as gray cast iron.
Chrome or moly faced ductile iron 1.5mm top compression rings have been used since the early 1980s in many turbocharged engines, and are now used in many late model domestic engines with the new piston and ring configurations. Gray cast iron rings are still common in aftermarket ring sets, but many premium ring sets now have ductile iron top rings.
Another ring material that is seeing greater use in new engines is steel. Twice as strong as ductile iron and four times as strong as gray cast iron, steel can provide the durability and toughness needed for the most demanding top ring applications. Steel rings have a tensile strength in the range of 240,000 psi, which compares to 180,000 psi for ductile iron and 45,000 psi for gray cast iron. Hardness can vary depending on the alloy and heat treatment, but is generally in the 44 to 53 HRC range compared to 38-40 HRC for ductile iron and 22-23 HRC for gray cast iron.
Like ductile iron, steel is not compatible with cast iron cylinder walls so it must be coated with either chrome or moly, or nitrided. Most of the steel rings currently in production have a width of 1.0 to 1.2mm....Steel rings are usually barrel faced, having contoured outside diameters which give the ring a center contact with the cylinder wall.
Though the best advice here is to follow the OEM lead and replace ring sets with ones made of the same material (or better), several ring manufacturers said steel and ductile iron rings are virtually interchangeable. If a steel replacement ring is not available for a certain application that uses steel as original equipment, a ring set with ductile iron top rings can be substituted.
Federal-Mogul's Gabrielson says there are even some instances where the OEMs have gotten away from steel and gone back to gray cast iron. The use of knock sensors and more precise engine control systems on these engines has reduced the risk of detonation to the point where the added durability of steel is no longer necessary.
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