Monty

A recent thread motivated me to do a little research into assembly lubes related to turbo applications. Obviously, turbo systems operate at higher temperatures than NA components, with temps reaching 1600F in high-performance applications, and 1300-1400F being common.

I have always made it a habit to use the proper assembly lubes, anti-seize, thread sealers, thread-locker, etc. In the case of the turbo system, I initially assumed moly based assembly lubes and anti-seizes would be acceptable, but realized that it loses it's effectiveness at around 700F, and the moly actually becomes corrosive at 1000F, well within the normal operating range of a turbo application.

I recently found some copper-based Loctite C-5A anti-seize which is rated up to 1800F. I thought that was a good solution but found out that at elevated temperatures, the copper-based antiseize could actually become corrosive to stainless steel.

Further research indicated that a nickel based anti-seize/lubricant is more appropriate, especially with stainless steel fasteners. The nickel-based formulas offer protection up to 2400F, well beyond the range of applicable turbo applications. Besides being the appropriate anti-seize for a fastener on the hot side of the turbo system, it is also appropriate for the wastegate puck lubrication.

Monty

The one I found is made by Loctite, here's the Technical Data Sheet for it. I found it at a local industrial supply warehouse.


Something else I just read that I didn't know:

A stainless steel must contain at least 12% chromium, but lean chromium steels can still show rust on the surface. Using 18% chromium will make a more rust resisting stainless steel.

Exposing any stainless steel to oxygen at temperatures above 1200F will cause the chromium to join oxygen and therefore leave the surface depleted in chromium - if it falls below 12% the surface will show rust.


[Modified by Monty, 10:19 AM 1/25/2003]

Twin_Turbo

Thanks for the very usefull info

Marck

74vetteman

I'm in the pipeline business, and we use large jet engines to turn our compressors. The hot section on the jets run 24/7 at 600 degrees celsius+. They run thousands of hours in this state, and when it comes time to remove/service the engine, heat corrosion is a major problem on the stainless steel fasteners.
The best anti-sieze that we have found is "Rock 'n Roll" by Walter. It is a ceramic based lubricant designed for stainless (and other) fasteners and resists temperatures up to 1400C (or 2500F). The ceramic particles act like tiny ball bearings upon dis-assembly. The label states "especially suited for stainless steel components in very high temperature, or very wet and corrosive applications". It is made in Germany, but is readily available in the industrial supply stores around here. Their US address is: J. Walter Company, 141 Locust Street, Hartford CT, 06114-1504. Web site is http://www.walter.com
I use it on my O2 bungs on my headers, and never have any galling. The only caveat I have is that it is pure white, and it somehow manages to get everywhere.

WashingtonRacer

okay so a note to self when putting the engine together make sure to use either a nickel based sealent, or a ceramic based.