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Stardate 4/24/2012 captains log ......
Made a few firm decisions over the last week and got a new shipment of more parts today . Supertech sent me my oversized inconel exhaust valves and nitrided intake valves . These are some real works of art .
A small piece of useless information I found out from speaking to supertech and doing some research - the inconel alloy comes in a few different flavours (This I didn't know ) , these valves are made from X-750 alloy containing the following elements :-
carbon , titanium , Chromium , aluminium , Niobium , Cobalt , Nickel , manganese , Silicon , Sulfur , Copper and Iron . this mixture in the right combinations makes a super alloy has a tensile strength of 170,000 psi and a yield strengt of over 120,000 psi.
apparently Alloy x-750 Inconel is similar to alloy 600 but is hardenable due to the addition of Ti and Al. In addition to good corrosion and oxidation resistance it also has high tensile strength and creep properties to around 700° C. Its resistance to relaxation makes it suitable for high temperature springs and it is also used in rocket engines, nuclear reactors, aircraft, tooling and pressure vessels.
But the question is - will it be up to the job in my RB26 ?
The Intake valves are Black Nitrided , supertechs website sayes this about them :-
Nitriding is a hardening treatment that even though it is not widely used as the chrome coating, it has several benefits and is becoming very popular, mainly for European and Japanese applications. The microhardness is higher than the stainless steel base material, keeping good ductility beneath the hard nitrided layer (microhardness is 800HV minimum).Surface finish is smoother than with chromed stems, having less friction between stem and guide.
Valve seat surface is harder with the nitrided layer, lasting longer with lead free fuels, alcohols, nitro or other "explosive" mixes. Matches any kind of seats (nodular iron seats, steel powder metal seats, hard aluminum-copper seats or beryllium copper seats).Higher rpm's engines take full advantage of all previous features. The higher the engine speed the bigger the power loss due to internal engine friction! The black nitride layer reduces this power loss due to less valve-guide friction.
The nitrided layer is adhered to the base material at a microscopic level, so does not "flake" or break when the valves bend due to impacts with the pistons.
I also bought a new set of Nissan OEM valve collets as the ones in the head might have been stressed from the heads last interference problem (valves hitting pistons) , and also grabbed respective manganese bronze valve guides from supertech to match the valves.
I spoke to the guys at Brian Crower and ended up ordering a set of titanium valve retainers . They will pefectly complement the HKS step 2 springs that i have .
And the Tomei cam wheels need no introduction - pretty common purchase for rb26 owners these days . I would have prefered the HKS ones but the tomei do the same job and were $100 cheaper .
Here's a pic for those of you that can't read --- or just like part pron
Made a few firm decisions over the last week and got a new shipment of more parts today . Supertech sent me my oversized inconel exhaust valves and nitrided intake valves . These are some real works of art .
A small piece of useless information I found out from speaking to supertech and doing some research - the inconel alloy comes in a few different flavours (This I didn't know ) , these valves are made from X-750 alloy containing the following elements :-
carbon , titanium , Chromium , aluminium , Niobium , Cobalt , Nickel , manganese , Silicon , Sulfur , Copper and Iron . this mixture in the right combinations makes a super alloy has a tensile strength of 170,000 psi and a yield strengt of over 120,000 psi.
apparently Alloy x-750 Inconel is similar to alloy 600 but is hardenable due to the addition of Ti and Al. In addition to good corrosion and oxidation resistance it also has high tensile strength and creep properties to around 700° C. Its resistance to relaxation makes it suitable for high temperature springs and it is also used in rocket engines, nuclear reactors, aircraft, tooling and pressure vessels.
But the question is - will it be up to the job in my RB26 ?
The Intake valves are Black Nitrided , supertechs website sayes this about them :-
Nitriding is a hardening treatment that even though it is not widely used as the chrome coating, it has several benefits and is becoming very popular, mainly for European and Japanese applications. The microhardness is higher than the stainless steel base material, keeping good ductility beneath the hard nitrided layer (microhardness is 800HV minimum).Surface finish is smoother than with chromed stems, having less friction between stem and guide.
Valve seat surface is harder with the nitrided layer, lasting longer with lead free fuels, alcohols, nitro or other "explosive" mixes. Matches any kind of seats (nodular iron seats, steel powder metal seats, hard aluminum-copper seats or beryllium copper seats).Higher rpm's engines take full advantage of all previous features. The higher the engine speed the bigger the power loss due to internal engine friction! The black nitride layer reduces this power loss due to less valve-guide friction.
The nitrided layer is adhered to the base material at a microscopic level, so does not "flake" or break when the valves bend due to impacts with the pistons.
I also bought a new set of Nissan OEM valve collets as the ones in the head might have been stressed from the heads last interference problem (valves hitting pistons) , and also grabbed respective manganese bronze valve guides from supertech to match the valves.
I spoke to the guys at Brian Crower and ended up ordering a set of titanium valve retainers . They will pefectly complement the HKS step 2 springs that i have .
And the Tomei cam wheels need no introduction - pretty common purchase for rb26 owners these days . I would have prefered the HKS ones but the tomei do the same job and were $100 cheaper .
Here's a pic for those of you that can't read --- or just like part pron
. Can't wait for the update
wil be doing something about that soon ) .
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