Posted February 8, 200421 yr comment_67582 I've just pulled the head off my sisters 2L sigma to change the head gasket. Now what I am wondering is, what is the best way to clean up the surfaces in preparation for the new head gasket?Also, what's the best way stop any of the old head gasket gunk getting down into the bores while cleaning it?Thanks,Justin Link to comment https://www.classiczcars.com/forums/topic/10094-changing-head-gasket-cleaning-the-mateing-surfaces/ Share on other sites More sharing options...
February 8, 200421 yr comment_67598 I've always purchased a glass scraper for that job. Be careful not to score the aluminum too deeply. Link to comment https://www.classiczcars.com/forums/topic/10094-changing-head-gasket-cleaning-the-mateing-surfaces/#findComment-67598 Share on other sites More sharing options...
February 8, 200421 yr comment_67601 Justin,They make a gasket scraper which doesn't work any different than the glass scraper that mike said so take your pic and maybe you've got one kicking around. As far as how to stop it from going into the cylinders... not a whole lot you can do. Just take your time... the good thing is the cylinders are closed off by the pistons so when you're down grap a shop vac and kinda suck any of the crap out that got down there.Did the motor overheat when the gasket blew? If it did you should check to see if the head is warped. Also remember to use new head bolts.Have fun,NateP.S. What's a sigma? Link to comment https://www.classiczcars.com/forums/topic/10094-changing-head-gasket-cleaning-the-mateing-surfaces/#findComment-67601 Share on other sites More sharing options...
February 8, 200421 yr Author comment_67639 CoastGuardZ: Mitsubishi Sigma. Maybe was a Crysler Sigma over in the US, as they are actually a crysler (AFAIK).Wouldn't I only need new head bolts if they were torque to yield head bolts?Thanks guys. Link to comment https://www.classiczcars.com/forums/topic/10094-changing-head-gasket-cleaning-the-mateing-surfaces/#findComment-67639 Share on other sites More sharing options...
February 8, 200421 yr comment_67647 Ahhh, one of those Diamond Star Motor deals? I found pics of both a Chrysler and Mitsu Sigmas online and they were both Aussie cars, I don't think they ever sold them in the states, not 100% though. On the headbolts... You make the call then. I haven't been around the block too many times yet but in my past experiences it has been "required", suggested and then done eventually. Torque to yield? Aren't all headbolts torque to yield? By this you mean that they have a certain psi to be tightened to correct? Every head bolt I know of has to, but I could be wrong. Have fun and before you fire it up, make sure you have all your tools! Nate Link to comment https://www.classiczcars.com/forums/topic/10094-changing-head-gasket-cleaning-the-mateing-surfaces/#findComment-67647 Share on other sites More sharing options...
February 9, 200421 yr Author comment_67660 They will all have a particular torque to which they must be tightened. Torque to yield is where you increase the tension past the yield point of the bolt. That's that stress at which the bolt will go into plastic deformation (as a pose to elastic), i.e. it will not go back to it's original shape. Hopefully have it back together this avo, with no nuts and bolts left over.....and all my tools still accounted for. Link to comment https://www.classiczcars.com/forums/topic/10094-changing-head-gasket-cleaning-the-mateing-surfaces/#findComment-67660 Share on other sites More sharing options...
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