i think andrew already mentioned the galvanic corrosion? or some sort of chemical reaction between the copper and aluminum? i have always been told to use something BESIDES copper anti-seize on aluminum, or anywhere that a part will come in contact with aluminum. ive never personally seen a case of copper anti seize eating aluminum, but ive never questioned it either.
Zinc is such a natural anti-rust agent, I've never used anything but it on iron/steel. That's why "below the belt line" all OEM's use zinc clad steel sheets now for the body panels... at least here in NAFTA.
Thanks for all the replies...it looks like it might be personal preference?
http://www.kraftindustrialsupply.com/My%20Scans/ZINCAS-EN.pdfLoctite ® Zinc Anti-Seize (formerly C-638) is a smooth, homogenous mixture of zinc dust and petrolatum. It prevents seizing during assembly or disassembly of threaded or unthreaded metal joints--particuarly if these metal joints involve aluminum or aluminum alloys. Zinc Anti-Seize also provides corrosion protection for both aluminum and ferrous metal (iron Base) components. Within a metal threaded connection, it acts like an “internal galvanize” using the electrochemical properties of the zinc dust to protect iron surfaces.
Or.....
http://www.permatex.com/products/Automotive/lubricants/specialty_lubricants/Permatex_Copper_Anti-Seize_Lubricant_b.htmA premium quality copper anti-seize and thread lubricant that may be used to prevent seizing, corrosion and galling where high temperature conditions exist. Contains a high percentage of micro-fine copper flakes in a semi-synthetic grease carrier and is fortified with high quality rust and corrosion inhibitors. Temperature range: -30°F to 1800°F (-34°C to 982°C). Provides good electrical conductivity. Meets Mil Spec #907E.
Suggested Applications: Spark plug threads installed in aluminum, exhaust manifold bolts, engine bolts, oxygen sensors, knock sensors, thermostat housing bolts, fuel filter fittings, and battery cable connections
So after all that …what is/was the VW factory practice injector instalation?
You'd want to look into galvanic corrosion to understand. When zinc and aluminum come into contact with an electrolyte between them, the zinc is sacrificed and oxidized. When copper and aluminum come into contact with an electrolyte between them, aluminum is sacrificed and oxidized and the reaction happens 3 times faster than it does between zinc an aluminum.
If you google "aluminum boat anode" somewhere you'll see what they use to protect the aluminum engine from dissolving in the salt waters :-D Hint, its not copper.
Thank You Gentleman
that sure seems to clear things up
Zinc it is ......
You'd want to look into galvanic corrosion to understand. When zinc and aluminum come into contact with an electrolyte between them, the zinc is sacrificed and oxidized. When copper and aluminum come into contact with an electrolyte between them, aluminum is sacrificed and oxidized and the reaction happens 3 times faster than it does between zinc an aluminum.
If you google "aluminum boat anode" somewhere you'll see what they use to protect the aluminum engine from dissolving in the salt waters :-D Hint, its not copper.
just think of this, we build the entire damn boat out of aluminum, we put a couple zincs on all our boats usually. all boats that roll out of the shop get zincs.
and salt water will still corrode an aluminum engine block over time if you dont flush them out regularly. and an automotive engine in a boat never lasts that long either, head gaskets are different material. boat engines get stainless ringed head gaskets.
You'd want to look into galvanic corrosion to understand. When zinc and aluminum come into contact with an electrolyte between them, the zinc is sacrificed and oxidized. When copper and aluminum come into contact with an electrolyte between them, aluminum is sacrificed and oxidized and the reaction happens 3 times faster than it does between zinc an aluminum.
If you google "aluminum boat anode" somewhere you'll see what they use to protect the aluminum engine from dissolving in the salt waters :-D Hint, its not copper.
just think of this, we build the entire damn boat out of aluminum, we put a couple zincs on all our boats usually. all boats that roll out of the shop get zincs.
and salt water will still corrode an aluminum engine block over time if you dont flush them out regularly. and an automotive engine in a boat never lasts that long either, head gaskets are different material. boat engines get stainless ringed head gaskets.
Yep, and how long will the boat or engine last w/o any zinc ?
Posted by: Mark(The Miser)UK
After all, the seal is your 'brand new' heat shield which doesn't leak . If they are expected to leak, then why not use 'recallibrated' heatshields.
None of my diesel books from VW or Bentley recomend pastes on the threads. I think if you want anything, PTFE is the way to go. 51 lbft dry, according to book.
and salt water will still corrode an aluminum engine block over time if you dont flush them out regularly. and an automotive engine in a boat never lasts that long either, head gaskets are different material. boat engines get stainless ringed head gaskets.
No kidding... I learn so much here...
. If they are expected to leak, then why not use 'recallibrated' heatshields. 