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  • ditchdigger

    Feb. 1, 2012 8:50 p.m. ditchdigger Dork

    I wound up with a few fiat gaskets today. One of them being a 1.5mm thick solid copper unit. One of these actually

    I have heard a million stories over the years about solid copper gaskets. They used to coat them with silver spray paint in the 50's and 60's. Some say don't coat 'em with anything others say a bead of silicone around the oil and water passages is critical.

    Some folks say they are infinitely reusable, some say 3 times max and some say only use once.

    Some say they are unsuitable for a street car, others say are the best thing ever.

    I know they are old technology and pretty much obsolete, but for older motors without MLS options it does sound promising.

    Should I treat it as an interesting artifact, polish it and frame it or install the sucker and turn the boost back up to 20psi?

  • Feb. 1, 2012 9:17 p.m. Knurled Dork

    A lot of it depends on application - not just type of induction/compression but also block/head materials. You probably won't have as much luck with an aluminum head/iron block as you would with an all-iron or all-aluminum engine where the materials grow at the same rate.

    If you've o-ringed the block or head, I wouldn't reuse the gasket. Lots people say you must O-ring for copper gaskets, too...

    Regarding special sauces: Copper-Kote. It's made for sealing copper head gaskets.

  • oldeskewltoy

    Feb. 1, 2012 9:44 p.m. oldeskewltoy HalfDork

    My favorite coating would be Hylomar

    SCE gasket has been making copper gaskets for years. You might ask them some of these questions..... http://www.scegaskets.com/

  • triumphcorvair

    Feb. 2, 2012 8:41 a.m. triumphcorvair New Reader

    Here's another good source of information on copper head gaskets.

    http://www.headgasket.com/

  • Brett_Murphy

    Feb. 2, 2012 9:45 a.m. Brett_Murphy Dork

    There is a tube of Hylomar in the picture. Hylomar is fantastic stuff.

  • Taiden

    Feb. 2, 2012 9:49 a.m. Taiden SuperDork

    You can anneal copper in the home shop, although something that large may not be trivial.

    The clamping forces should work harden the copper. I would be skeptical to reuse it unless it was annealed again.

    motoiq had an article about annealing copper banjo fitting seals, if I recall correctly.

    People use copper orings to seal chambers individually, why not an entire headgasket?

    That said, it would make an awesome ornament.

    Would make a better ornament if you blew the engine to smitherines and the headgasket remained perfect. Would make a nice wall of shame piece.

  • Curmudgeon

    Feb. 2, 2012 9:59 a.m. Curmudgeon SuperDork

    The biggest concern I would have is the surface finish of the two parts. For a copper HG to work they have to be mirror smooth (I forget what it's called in microinches). Even that won't guarantee it will seal around coolant and oil and for those areas yes the Hylomar would be a good choice, better than CopperCoat. (Blasphemy! )

    O ringing: what it does is 'crimp' the copper HG tightly with a steel ring. I was sort of a proponent of this till I took apart a couple of engines with the copper sandwich (copper sheet with asbestos or whatever in the middle) and saw no indication of HG failure. I would think that in reasonable applications (say 11:-1 compression, reasonable boost and proper A/F ratio) there would be no reason to O ring anything.

  • Feb. 2, 2012 10:12 a.m. Kram New Reader

    I restored Brit bikes for a while professionally and never any troubles with copper head gaskets as long as some sort of sealant such as the supplied Hylomar you have or best imo, Threebond Grey. Trick is to not go crazy with it, just a smear on each side and let it air dry for a while first.

    On rougher surfaces, let air dry then apply another smear then asemble immediately - this should never apply to head gasket surfaces though.

    Do yourself a big favour and buy new head bolts if you can and are applicable (not studs).

  • Feb. 2, 2012 10:23 a.m. Kram New Reader

    triumphcorvair wrote:

    Here's another good source of information on copper head gaskets.

    http://www.headgasket.com/

    Just had a read, good info for a change and the "Yamabond" they recommend is actually made by and the same as the Threebond I recommend - but Threebond is half the price!

  • Curmudgeon

    Feb. 2, 2012 11:44 a.m. Curmudgeon SuperDork

    Something else about dead soft copper head gaskets: the 'composite' gaskets rely on a steel ring (the 'fire ring') with a sheet metal cover to contain combustion pressure. That's maybe 1/16" of metal at the most.

    On a dead soft copper, the whole gasket acts as a reinforcement for the 'fire ring' because it's all one piece of metal. In particular the area between the cylinders is all metal unlike a composite gasket. Multi layer steel is similar to a copper HG this way.

    Copper also conducts heat well, the composite gaskets don't.

  • Conquest351

    Feb. 2, 2012 11:53 a.m. Conquest351 Dork

    The only thing we ever did differently at Motion Dynamics was to retorque the head studs (bolts) after the first warm up of the engine. Get it to operating temps and then shut her down, pull the VC, and retorque. That was it. This was in a 2.5L stroker from a 2.3 in an SVO with a BIG turbo and about 35 lbs of boost. It put about 450 to the rear tires and never had any HG problems.

    EDIT: Wer did put some sealant around the coolant and oil passages. Forgot about that. I can't remember exactly what it was though. Seems there's 2 good, experienced ideas on this thread already about that.

  • ditchdigger

    Feb. 2, 2012 12:35 p.m. ditchdigger Dork

    If I use it it would be on my block that was recently resurfaced to an almost polished finish and would be with a fresh head, oversized ARP hardware and no o-ringing. Boost would be under 20psi and with the thicker head gasket it would put my CR in the 9:1 range.

    850's are known to have an insatiable appetite for head gaskets and these have been the best/worst option depending on who you ask for 40 years or so. So far I think I might have forced more boost into one than anyone else on the planet.

    On of the other gaskets I picked up was an actual NOS abarth copper fiber sandwich type gasket.

  • BAMF

    Feb. 2, 2012 12:47 p.m. BAMF Reader

    I made one for a friend several months ago out of some copper sheet using our CNC router at work. It went on an air cooled Benelli single (250cc 4 stroke). After I cut it, my buddy got out a torch and annealed it and bolted the thing up. I was surprised at how well it worked.

  • 44Dwarf

    Feb. 2, 2012 12:59 p.m. 44Dwarf Dork

    Who here remembers when oil cans had lids... We used to cut out the tops and make THIN head gaskets for two strokes to tighten up the squish area.

 
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