Head gaskets.
in [Aussie Drivers]
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From: Clocky on 9 Aug 2010 00:43 F Murtz wrote: > Noddy wrote: >> "F Murtz"<haggisz(a)hotmail.com> wrote in message >> news:4c5e955d$1(a)dnews.tpgi.com.au... >> >>> What are current day thoughts on head gasket coating? (none, plain >>> grease, copper coat grease or spray,nickel anti seize,etc? >>> The old man 60 years ago swore by grease as he was trained by the >>> air force. >> >> Grease would be one of the best things to use on any head gasket >> that you *didn't* want to seal, as would any other non adhesive, non >> compressible solid that's main purpose in life is to act as a >> lubricant. I used to know an old guy, who was pretty old school, and he >> also >> swore by grease for use on head gaskets. When I shook my head and >> asked him why, he said "because it made the gaskets easy to remove". >> He used to be into Valiants, and not surprisingly he used to go >> through head gaskets on a pretty regular basis and could never put >> two and two together despite me and a few other people telling him >> that the use of grease is what was actually causing his problems. >> >> Still, he was one of those guys who had his "ways", and couldn't be >> told. His idea of a good valve job was to remove the head, take off >> the springs, coat the underside of the valve head in heavy lapping >> paste and stick it back in the head and then place the part of the >> stem protruding from the top of the guide in an electric drill chuck >> and give it a decent spin while pulling on the drill as hard as he >> could :) The best thing to use on any gasket, including head gaskets, is >> what >> the engine and/or gasket manufacturer recommends. >> >> Most head gaskets these days are of a composite material that come >> pre-coated with an adhesive which requires nothing other than the >> mating surfaces to be in a suitable condition for a new gasket to be >> used (clean and free from damage or blemishes in other words) and >> the parts assembled and tightened in the correct manner (which the >> gasket manufacturer usually advises). For gaskets that don't come >> with an adhesive bonding agent, which these days would be limited to >> old stock items or plain copper sheet, there are specific head >> gasket sealants such as Hylomar or VHT's Copper Coat which are >> aerosol based that work particularly well with a *light* even coat >> that will promote an effective seal. The most important part of any head >> gasket seal, apart from the >> gasket itself, is the finish of the mating surfaces on the block and >> head. If they're not clean and smooth, then the best gaskets and >> glue that money can buy isn't going to do diddly squat. >> >> -- >> Regards, >> Noddy. >> >> > > > It appears my first alternative is correct, none. > It is amazing the differing opinions that abound if you research the > subject including my long dead father who was trained by the air force > as a fitter driver motor transport (fitter D.M.T.)I think they must > have put grease on all gaskets 70 years ago although I seem to > remember something called gasket goo for some water gaskets. I know people put grease on gaskets, but not head gaskets. There was a time when silver paint was used on headgaskets, probably copper gaskets and that GM bolt sealant that was like molasses. I remember doing some when I first started my apprenticeship in the late 80's. Gasket goo was good stuff, and still available AFAIK, I think it's similar as that black aviation sealant that came in the bottle with a little brush attached to the lid. I still have a bottle in the shed and it works very well.
From: Clocky on 9 Aug 2010 00:48 Jason James wrote: > "Milton" <millame23(a)yahoo.com> wrote in message > news:4c5f0fc7$0$28656$c3e8da3(a)news.astraweb.com... >> >> "F Murtz" <haggisz(a)hotmail.com> wrote in message >> news:4c5e955d$1(a)dnews.tpgi.com.au... >>> What are current day thoughts on head gasket coating? (none, plain >>> grease, copper coat grease or spray,nickel anti seize,etc? >>> The old man 60 years ago swore by grease as he was trained by the >>> air force. >> >> Probably 60 years ago, they didn't know better. No way would I be >> putting grease anywhere near a head gasket. > > Indeed,..more than one person has recommended grease to me over the > years.. You'd think it would eventually turn to carbon. The idea of > any coating, is to provide a medium to fill any unevenness between > the block and head, and to provide an extra gas-seal. I have used > grease in the "old days" without any repercussions, but then again > those old engines didnt do much work without them needing stripping > down due some other problem. > Head Gaskets today are already coated >> with a sealant that works once the two surfaces are heated by the >> engine. > > That makes sense, altho the rings of blue seem to be silicone in > nature? >> Correct procedure is to ensure both surfaces are perfectly flat, >> ultra clean and then tighten the head bolts as per recommended >> method. > > The rule of thumb was> one thou per inch of head/deck measured with a > steel rule laid across the surface. > > I personally >> believe it's a good idea to retighten them to the recommended torque >> settings after you've driven a couple of hundred klms althought this >> old fashioned method doesn't appear to be popular anymore. > > In every case I've found the head-bolts will retorque after as little > as 300 ks. In every case where the headbolts are NOT torque to yield you mean, which excludes just about every engine made in the last decade. You don't want to retorque torque-to-yield bolts so if the tightening procedure involves torqueing in stages of angles rather then just a tension wrench you shouldn't touch them again.
From: atec77 on 9 Aug 2010 01:56 On 9/08/2010 9:27 AM, Jason James wrote: > "Noddy"<me(a)home.com> wrote in message > news:4c5eacdf$0$34570$c30e37c6(a)exi-reader.telstra.net... >> >> "F Murtz"<haggisz(a)hotmail.com> wrote in message >> news:4c5e955d$1(a)dnews.tpgi.com.au... >> >>> What are current day thoughts on head gasket coating? (none, plain >>> grease, copper coat grease or spray,nickel anti seize,etc? >>> The old man 60 years ago swore by grease as he was trained by the air >>> force. >> >> Grease would be one of the best things to use on any head gasket that you >> *didn't* want to seal, as would any other non adhesive, non compressible >> solid that's main purpose in life is to act as a lubricant. >> >> I used to know an old guy, who was pretty old school, and he also swore by >> grease for use on head gaskets. When I shook my head and asked him why, he >> said "because it made the gaskets easy to remove". He used to be into >> Valiants, and not surprisingly he used to go through head gaskets on a >> pretty regular basis and could never put two and two together despite me >> and a few other people telling him that the use of grease is what was >> actually causing his problems. >> >> Still, he was one of those guys who had his "ways", and couldn't be told. >> His idea of a good valve job was to remove the head, take off the springs, >> coat the underside of the valve head in heavy lapping paste and stick it >> back in the head and then place the part of the stem protruding from the >> top of the guide in an electric drill chuck and give it a decent spin >> while pulling on the drill as hard as he could :) >> >> The best thing to use on any gasket, including head gaskets, is what the >> engine and/or gasket manufacturer recommends. >> >> Most head gaskets these days are of a composite material that come >> pre-coated with an adhesive which requires nothing other than the mating >> surfaces to be in a suitable condition for a new gasket to be used (clean >> and free from damage or blemishes in other words) and the parts assembled >> and tightened in the correct manner (which the gasket manufacturer usually >> advises). For gaskets that don't come with an adhesive bonding agent, >> which these days would be limited to old stock items or plain copper >> sheet, there are specific head gasket sealants such as Hylomar or VHT's >> Copper Coat which are aerosol based that work particularly well with a >> *light* even coat that will promote an effective seal. >> >> The most important part of any head gasket seal, apart from the gasket >> itself, is the finish of the mating surfaces on the block and head. If >> they're not clean and smooth, then the best gaskets and glue that money >> can buy isn't going to do diddly squat. > > At work, the mechanic used to use "Rolls Royce" which came in hardening and > non-hardening bottles. I cant remember which one he used for head-gaskets. > In the POS Passat engine, I used non-hardening "Gasket Goo" which worked OK. > There was also a gasket cement made by Ford. > > Jason > > That was the blue Hylimar ? looked like the blue used in machine shops but very thick ? -- X-No-Archive: Yes
From: F Murtz on 9 Aug 2010 02:40 Clocky wrote: > F Murtz wrote: >> What are current day thoughts on head gasket coating? (none, plain >> grease, copper coat grease or spray,nickel anti seize,etc? >> The old man 60 years ago swore by grease as he was trained by the air >> force. > > None, they come ready to fit generally. Head gasket on what? > > 7M-GE, notorious for head and gasket problems,
From: Jason James on 9 Aug 2010 02:41
"Clocky" <notgonn(a)happen.com> wrote in message news:4c5f8873$0$11126$c3e8da3(a)news.astraweb.com... > Jason James wrote: >> >> In every case I've found the head-bolts will retorque after as little >> as 300 ks. > > In every case where the headbolts are NOT torque to yield you mean, which > excludes just about every engine made in the last decade. > > You don't want to retorque torque-to-yield bolts so if the tightening > procedure involves torqueing in stages of angles rather then just a > tension wrench you shouldn't touch them again. Yeah,..I'm talking about re-usuable head-bolt situations. However,..I cant see how torque to yield h/bolts installations are going to be any different. I know you cant retorque them, otherwise they might snap. So why do headbolts lose tension? Dirty threads and perhaps the gasket loses it squash? Jason |