Questions about copper washers.

At the oil pan plug it's 'intended' for one time use, (I routinely get two or three) not sure about fuel lines I would suspect the same??

Others will know more...I don't car if my OIL drips, fuel would be a different decision...LOL!

 

You are better off replacing them.

BUT, if you are one of those frugal types (like me), you can take a torch to them, get them cherry red, quench them in water, and reuse them.

It reanneals the washers.

 

Plain flat copper washers are reuseable.

Copper crush washers are designed to seal with a given force against the mating surfaces. They are one-shot and replaced new with each use.

Crush washers are expensive as things go, being just under a dollar each, but trying to achieve a seal without replacing them can be more expensive in the long run.

 

They look good to me, id re-use them.

 

To reuse properly just heat them with a propane torch until they glow. Then just let them cool, do not drop them in cold water. No problem to do this 2-3 times, but eventually they will wear and leak.

 

With an acetylene torch; Blacken them with soot using no O2, just acetylene, then heat them enough to burn off the soot. Do not quench.

 

These are DIN 7603 sealing washers (DIN 7603A to be more exact in this case). After use (when they've been crushed and strain-hardened), they will not be as soft as when new (when they are in a fully-annealed condition), so their resealing characteristics won't be as good (although they often work OK for reuse if the corresponding surfaces they are contacting are flat/parallel/no scratches).

Manual reannealing can work, but they should really be heated and cooled in a non-oxidizing environment -- not exactly something a DIYer has laying around .

The sizes used on a carb are not exotic. If you do an internet search on "DIN 7603A washers" that should give you several sources, or, if you do a search on "Global Metrics" (a supplier that's been mentioned here before), that should get some prior threads.

PS You guys need to look up the properties Copper. The post-heating condition of Copper does not depend on the cooling rate -- doesn't matter if they are liquid-quenched, or not, after heating:

http://en.wikipedia.org/wiki/Annealing_(metallurgy) -- see the 2nd paragraph.

 

STEVE,

LOL +101
Copper does not quench harden....... why?
It does not change crystalline phase when heated.
(For,, it is not Carbon Steel.)




Edwardo
Materials Engineer

 

Thanks for the info. I posted what I was taught.
This makes sense as plumbers inadvertently quench copper pipes every time they are wiped after a joint is soldered, without consequence.
My lesson for today.

 

Sorry if I came across as being too critical Ross, and for large flat parts (like copper head gaskets) the "do not quench" rule (i.e., using air cooling) is a good one because you can't make a mistake using the air cooling method. Liquid cooling can be used, but the gasket needs to inserted vertically into the water so both sides cool at equal rates to prevent warping. If you put a hot copper head gasket flat-wise into a pan of water, it will warp significantly. Anyway, just trying to give an explanation why the meaning of "rules" from knowledgable people sometimes need a little more underlying explanation, or an understanding of the application, to follow the reasoning behind the rule.

 

I've reused the CU crush seal on my Porsche 10 times at least. I anneal it each time then remove the oxide with emery cloth. That takes all of 5 minutes including cool down time in air. It have never leaked a drop at that seal. I cannot remember when I replaced the CU oil pan seal on my 328. I have another vehicle that uses an aluminum seal. It too has been used several times with no leaks yet.

 

I had no idea that the copper crush washers should be changed after each use.

I have used the same ones for the last three years, the ones that act as sealers at the drain plugs and gear oil plugs on a 348.

So far no leaks, but after reading this thread I will start using new ones each year.

 

Yeah, but I won't work for $3/hour

For me, the decison to reuse, or not, gets down to risk. On an oil drain plug, a little oil weeping (if it happens) is no big deal; on a K/KE-Jet system with (very thin) fuel at 75 psi, it's just too risky not to use a fresh one -- JMO.

 

For the drain pan plugs, I bought a whole bunch at once (I think 25?...) with a parts order several years ago. Every oil change, I have a fresh gasket at hand.

Plus 20 or so of used gaskets waiting to be re-annealed for future use. That means I have close to a 50 year supply of copper gaskets!

 

+1!

Id reuse it and if it leaks, it leaks. Replace it then!

 

Looks like you are rebuilding a carb which is a labor intensive project. Probably more than one since it's a Ferrari. Since new copper washers are readily available why would you even consider not replacing them, particularly since the cost is insignificant. Why risk doing it over again because the old washer failed. Just my $0.02.

 

Because I have to go out and purchase them and that is an inconvenience. I've been reusing them for over 25 years and have yet to have one leak. I began doing this with the Mercedes I owned back in the early 80's. When, upon my judgment which seems to be impeccable when it comes to reusing washers, they become too used I replace them. I firmly believe that most people over tighten them vastly shortening their usable life. I also firmly believe that Ferrari owners seem to get a 'charge' out of unnecessary spending on their cars. And lastly, I have two good friends who are have graduate degrees in metallurgy.

 

Im with you mate.

 

So did this guy...
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touche

 

I do a fair amount of wrenching on Bosch K-Jet fuel injection systems (Volvo 244 Turbo), and reuse the copper washers throughout, without any failures.

The fuel is under considerable pressure, and has never leaked.

In reusing them, I don't re-anneal them; instead, I smooth them a bit using emery paper.

So far, so good.

 

RIP

 

That's why I "Only" use Ferrari Copper Washers. They come placed in a little bag, by Italian women, with a Cavalino on it. See...! I could maybe part with 1,,, for $ 1,000,000,000.00 usa

PM me
Ha.

Edwardo
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