sad day for my 968 motor :(
02-05-2002, 12:31 AM
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sad day for my 968 motor :(
So I am dissasembling my engine for a preinspection before it goes into it's new home in my 944. I get the valve cover (rocker box for you europeaners) off and what do i see? Two of the cam chain teeth on one of the camshafts are busted right off 
. Needless to say this put a big damper on things for me.
Anyone know why this would happen? The little plastic guides on the variocam assembley looked ok. Maybe the chain stretched? the motor has 85k on it.
Anyway I kept going and pulled the head off and everything else looks real good so far, actually everything is suprisingley clean.
So now I have to figure out what my options are. New from Porsche (I'm thinking big $$$), used set. Anyone know if maybe it could be repaired via. welding and grinding (Jon Millege maybe?)?
Anyone have any input or maybe a set of 968 cams, please let me know.
waiting for my card - Rennlist member
. Needless to say this put a big damper on things for me. Anyone know why this would happen? The little plastic guides on the variocam assembley looked ok. Maybe the chain stretched? the motor has 85k on it.
Anyway I kept going and pulled the head off and everything else looks real good so far, actually everything is suprisingley clean.
So now I have to figure out what my options are. New from Porsche (I'm thinking big $$$), used set. Anyone know if maybe it could be repaired via. welding and grinding (Jon Millege maybe?)?
Anyone have any input or maybe a set of 968 cams, please let me know.
waiting for my card - Rennlist member
02-05-2002, 02:30 AM
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I payed $750.00 for two used cams years ago, new ones were $740.00 each.
There is a process, at least that's what I was told by a machinist freind, to repair, but you must bring the cams up to temp, in stages, weld them, with rods that he didn't have, (Inkanel, I think) VERY EXPENSIVE for a small quantity, and cooled in a similar process.
Therefore he recommended, that I purchase the used cams...
There is a process, at least that's what I was told by a machinist freind, to repair, but you must bring the cams up to temp, in stages, weld them, with rods that he didn't have, (Inkanel, I think) VERY EXPENSIVE for a small quantity, and cooled in a similar process.
Therefore he recommended, that I purchase the used cams...
02-05-2002, 12:45 PM
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<a href="http://webcaminc.com/porsche-auto.html#9" target="_blank">944S2 & 968 Cams</a>
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02-05-2002, 11:55 PM
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Thanks for your input guys!
I made a bunch of phone calls today to cam grinders, everybody said it could not be welded because of the heat being being centered in the cam and the amount of it, and it would likely warp. Then I called the guys from the web cam link (thanks Michael) and they directed me to a company called partswerks and told me they were just about the only guys in the country who could fix it. After a long conversation with this guy Jay over there he explained the process to me. What he is proposing to do for me is machine (grind?) the old sprocket off and "cold weld" a new one on. He says he sends them out for the "cold welding" as it requires some pretty specialized machines. He says he's done quite a few as it is a common problem which he said was likely caused by the chain being stretched. He told me $295 ea. and even though only one of the cams is broken he reccomends sending him both to at least have the other magnafluxed.
So what do you all think? Should I give it a shot? I think I will inquire a little more about any kind of warranty (our conversation kinda got cut off towards the end), but I think I may go for it. Be way cheaper than new ones and probably used ones (It's a shot in the dark with used ones anyway, I may get junk, plus finding them) and mine look real nice, hardly any wear to begin with.
Thanks
Peter
INCONEL® 600
A nickel-chromium alloy with good oxidation resistance at higher temperatures. With good resistance in carburizing and chloride containing environments.
Alloy 600 is a nickel-chromium alloy designed for use from cryogenic to elevated temperatures in the range of 2000 deg F(1093 deg C). The high nickel content of the alloy enables it to retain considerable resistance under reducing conditions and makes it resistant to corrosion by a number of organic and inorganic compounds. The nickel content gives it excellent resistance to chloride-ion stress-corrosion cracking and also provides excellent resistance to alkaline solutions.
Its chromium content gives the alloy resistance to sulfur compounds and various oxidizing environments. The chromium content of the alloy makes it superior to commercially pure nickel under oxidizing conditions. In strong oxidizing solutions like hot, concentrated nitric acid, 600 has poor resistance. Alloy 600 is relatively un-attacked by the majority of neutral and alkaline salt solutions and is used in some caustic environments. The alloy resists steam and mixtures of steam, air and carbon dioxide.
Alloy 600 is non-magnetic, has excellent mechanical properties and a combination of high strength and good workability and is readily weldable. Alloy 600 exhibits cold forming characteristics normally associated with chromium-nickel stainless steels.
Typical corrosion applications include titanium dioxide production (chloride route), perchlorethylene syntheses, vinyl chloride monomer (VCM), and magnesium chloride. Alloy 600 is used in chemical and food processing, heat treating, phenol condensers, soap manufacture, vegetable and fatty acid vessels and many more.
Specifications
CHARACTERISTICS
Resistant to a wide range of corrosive media. The chromium content gives better resistance than Alloy 200 and 201 under oxidizing conditions, at the same time the high nickel gives good resistance to reducing conditions.
Virtually immune to chlorine ion stress corrosion cracking.
Demonstrates adequate resistance to organic acids such as acetic, formic and stearic.
Excellent resistance to high purity water used in primary and secondary circuits of pressurized nuclear reactors.
Little or no attack occurs at room and elevated temperatures in dry gases, such as chlorine or hydrogen chloride. At temperatures up to 550C in these media, this alloy has been shown to be one of the most resistant of the common alloys.
At elevated temperatures the annealed and solution annealed alloy shows good resistance to scaling and has high strength.
The alloy also resists ammonia bearing atmospheres, as well as nitrogen and carburizing gases.
Under alternating oxidizing and reducing conditions the alloy may suffer from selective oxidation.
APPLICATIONS
Thermocouple sheaths.
Ethylene dichloride (EDC) cracking tubes.
Conversion of uranium dioxide to tetrafluoride in contact with hydrofluoric acid.
Production of caustic alkalis particularly in the presence of sulfur compounds.
Reactor vessels and heat exchanger tubing used in the production of vinyl chloride.
Process equipment used in the production of chlorinated and fluorinated hydrocarbons.
In nuclear reactors uses are for such components as control rod inlet stub tubes, reactor vessel components and seals, steam dryers and d separators in boiling water reactors. In pressurized water reactors it is used for control rod guide tubes and steam generator baffle plates etc.
Furnace retort seals, fans and fixtures.
Roller hearths and radiant tubes, in carbon nitriding processes especially
I don't know that inconel would be necessary as a filler if it were to be welded, first of all I don't think Porsche made the cams from it and welding 2 that dissimalar metals would probably not be good. Probably just a high wear air hardening tool steel would be best if anything.
Disclaimer: just my $00.02, please do not try to weld your cams at home
I made a bunch of phone calls today to cam grinders, everybody said it could not be welded because of the heat being being centered in the cam and the amount of it, and it would likely warp. Then I called the guys from the web cam link (thanks Michael) and they directed me to a company called partswerks and told me they were just about the only guys in the country who could fix it. After a long conversation with this guy Jay over there he explained the process to me. What he is proposing to do for me is machine (grind?) the old sprocket off and "cold weld" a new one on. He says he sends them out for the "cold welding" as it requires some pretty specialized machines. He says he's done quite a few as it is a common problem which he said was likely caused by the chain being stretched. He told me $295 ea. and even though only one of the cams is broken he reccomends sending him both to at least have the other magnafluxed.
So what do you all think? Should I give it a shot? I think I will inquire a little more about any kind of warranty (our conversation kinda got cut off towards the end), but I think I may go for it. Be way cheaper than new ones and probably used ones (It's a shot in the dark with used ones anyway, I may get junk, plus finding them) and mine look real nice, hardly any wear to begin with.
Thanks
Peter
INCONEL® 600
A nickel-chromium alloy with good oxidation resistance at higher temperatures. With good resistance in carburizing and chloride containing environments.
Alloy 600 is a nickel-chromium alloy designed for use from cryogenic to elevated temperatures in the range of 2000 deg F(1093 deg C). The high nickel content of the alloy enables it to retain considerable resistance under reducing conditions and makes it resistant to corrosion by a number of organic and inorganic compounds. The nickel content gives it excellent resistance to chloride-ion stress-corrosion cracking and also provides excellent resistance to alkaline solutions.
Its chromium content gives the alloy resistance to sulfur compounds and various oxidizing environments. The chromium content of the alloy makes it superior to commercially pure nickel under oxidizing conditions. In strong oxidizing solutions like hot, concentrated nitric acid, 600 has poor resistance. Alloy 600 is relatively un-attacked by the majority of neutral and alkaline salt solutions and is used in some caustic environments. The alloy resists steam and mixtures of steam, air and carbon dioxide.
Alloy 600 is non-magnetic, has excellent mechanical properties and a combination of high strength and good workability and is readily weldable. Alloy 600 exhibits cold forming characteristics normally associated with chromium-nickel stainless steels.
Typical corrosion applications include titanium dioxide production (chloride route), perchlorethylene syntheses, vinyl chloride monomer (VCM), and magnesium chloride. Alloy 600 is used in chemical and food processing, heat treating, phenol condensers, soap manufacture, vegetable and fatty acid vessels and many more.
Specifications
CHARACTERISTICS
Resistant to a wide range of corrosive media. The chromium content gives better resistance than Alloy 200 and 201 under oxidizing conditions, at the same time the high nickel gives good resistance to reducing conditions.
Virtually immune to chlorine ion stress corrosion cracking.
Demonstrates adequate resistance to organic acids such as acetic, formic and stearic.
Excellent resistance to high purity water used in primary and secondary circuits of pressurized nuclear reactors.
Little or no attack occurs at room and elevated temperatures in dry gases, such as chlorine or hydrogen chloride. At temperatures up to 550C in these media, this alloy has been shown to be one of the most resistant of the common alloys.
At elevated temperatures the annealed and solution annealed alloy shows good resistance to scaling and has high strength.
The alloy also resists ammonia bearing atmospheres, as well as nitrogen and carburizing gases.
Under alternating oxidizing and reducing conditions the alloy may suffer from selective oxidation.
APPLICATIONS
Thermocouple sheaths.
Ethylene dichloride (EDC) cracking tubes.
Conversion of uranium dioxide to tetrafluoride in contact with hydrofluoric acid.
Production of caustic alkalis particularly in the presence of sulfur compounds.
Reactor vessels and heat exchanger tubing used in the production of vinyl chloride.
Process equipment used in the production of chlorinated and fluorinated hydrocarbons.
In nuclear reactors uses are for such components as control rod inlet stub tubes, reactor vessel components and seals, steam dryers and d separators in boiling water reactors. In pressurized water reactors it is used for control rod guide tubes and steam generator baffle plates etc.
Furnace retort seals, fans and fixtures.
Roller hearths and radiant tubes, in carbon nitriding processes especially
I don't know that inconel would be necessary as a filler if it were to be welded, first of all I don't think Porsche made the cams from it and welding 2 that dissimalar metals would probably not be good. Probably just a high wear air hardening tool steel would be best if anything.
Disclaimer: just my $00.02, please do not try to weld your cams at home
