pinky Posted January 23, 2017 Report Share Posted January 23, 2017 Hi, I spent a few hours on the car today, I did a compression test Her are the results, I believe this confirms it is the head or valves What do you think no3 is way down 1 180 (Front of car ) 2 195 3 125 4 205 Cheers pink Quote Link to post Share on other sites
Motorsport Mickey Posted January 23, 2017 Report Share Posted January 23, 2017 How did the cylinder head retorque go ? If you've not done it yet retorque it and then repeat the test. Don't forget to UNDO the nuts 1 flat before retorquing it back up otherwise you will not likely get an accurate figure on the torque wrench. Micky Quote Link to post Share on other sites
john.r.davies Posted January 23, 2017 Report Share Posted January 23, 2017 If it were a head gasket you would expect two cylinders to bve down. Rings or valve? Do it again with teaspoon of oil down the plug hole. That will raise thee pressure asvthevrings seal better but not if a valve leaks. John Quote Link to post Share on other sites
Hamish Posted January 23, 2017 Report Share Posted January 23, 2017 (edited) Could be just one cyl especially if it's 2 or 3 into the central waterway ? Mine was the smallest breach that wouldn't torque out. The wet test is a good idea. Edited January 23, 2017 by Hamish Quote Link to post Share on other sites
pinky Posted January 24, 2017 Author Report Share Posted January 24, 2017 Thank you for your suggestions, Today I took the head of, didn't take to long, Copper gasket looked ok Turned head over and filled it up with white spirit No 3 leaked like a sieve all the others held the fluid So I presume for a quick fix, I need to relap no 3 valve so it sits nice Pink xxxx Quote Link to post Share on other sites
foster461 Posted January 24, 2017 Report Share Posted January 24, 2017 Thank you for your suggestions, Today I took the head of, didn't take to long, Copper gasket looked ok Turned head over and filled it up with white spirit No 3 leaked like a sieve all the others held the fluid So I presume for a quick fix, I need to relap no 3 valve so it sits nice Pink xxxx Inlet or exhaust Pink ?. If it is the exhaust and the seat looks badly worn/pitted the others may be in a similar state and need new inserts. Stan Quote Link to post Share on other sites
pinky Posted January 24, 2017 Author Report Share Posted January 24, 2017 hi Stan, haven't stript them out yet, I shall take them out and inspect them cheers pink Quote Link to post Share on other sites
ChrisR-4A Posted January 25, 2017 Report Share Posted January 25, 2017 Hi Pink, for sure whilst the heads off take all the valves out and check, clean and re lap. Copper head gasket needs annealing before reuse I think? Chris Quote Link to post Share on other sites
DaveR Posted January 25, 2017 Report Share Posted January 25, 2017 . Rings or valve? Do it again with teaspoon of oil down the plug hole. That will raise thee pressure asvthevrings seal better but not if a valve leaks. John I agree with John. Do the test. Dave Quote Link to post Share on other sites
Lebro Posted January 25, 2017 Report Share Posted January 25, 2017 Too late for that he's got the head off ! Bob. Quote Link to post Share on other sites
john.r.davies Posted January 25, 2017 Report Share Posted January 25, 2017 Too late! But Pink says a valve leaks when paraffin left in chamber, No.3 which was down in compression, so that fits. Relapping the valve seats will lose any "lead memory", but may only be important if pink has a leaden right foot! John Quote Link to post Share on other sites
pinky Posted January 27, 2017 Author Report Share Posted January 27, 2017 Too late! But Pink says a valve leaks when paraffin left in chamber, No.3 which was down in compression, so that fits. Relapping the valve seats will lose any "lead memory", but may only be important if pink has a leaden right foot! John Hi john, not sure what is lead memory Is it the carbon that forms around the valve helping to seal it ? Also what is a leaden right foot I need to heat treat the coper gasket I believe I have to heat it to it is red hot, and let it cool down slowly making the metal softer Should I re grind all the valves or just the one that is leaking ? Bearing in mind that at the end of the summer it is coming in for a full refit Thanks for your help pink Quote Link to post Share on other sites
Ian Vincent Posted January 27, 2017 Report Share Posted January 27, 2017 Lead memory is the lead that has effectively hardened the surface of the valve seat over the years and protects it against valve seat recession caused by unleaded fuels. The solution is hardened valve seats suitable for modern lead free fuels but if you only do limited mileage and are going to strip the engine fully soon, that won't be an issue. For the time it takes and peace of mind, I would remove and check all the valves and lightly re lap them. Rgds Ian Quote Link to post Share on other sites
RogerH Posted January 27, 2017 Report Share Posted January 27, 2017 Hi Pinky, Leaden right foot = a heavy foot that presses the pedal hard Once you have got the head gasket red hot you can cool it either by dunking in water or simply hang it up to air cool. For the small amount of work it must be worth removing all valves to ensure the are OK for the Summer. lap them in if necessary. Lead memory doesn't actually 'harden' the valve seat but it has that effect. It puts a barrier between the valve and seat and it stops the valve sticking to the valve seat and pulling metal off the seat - it is similar to 'Galling' Roger Quote Link to post Share on other sites
pinky Posted January 27, 2017 Author Report Share Posted January 27, 2017 Hi roger, Thank you for answering my question However what is gailing, god I must be thick Pink Quote Link to post Share on other sites
stuart Posted January 27, 2017 Report Share Posted January 27, 2017 You cant really re-use a composite gasket Pink only a solid copper one. Stuart. Quote Link to post Share on other sites
john.r.davies Posted January 27, 2017 Report Share Posted January 27, 2017 Wotthey said about lead. Does copper need to be red hot to anneal? Is the appearance of typical green copper tinge in the flame enough to anneal it? Means copper ions being striped off the surface. John Quote Link to post Share on other sites
RogerH Posted January 27, 2017 Report Share Posted January 27, 2017 (edited) Hi Pinky, you are not thick. You are simply not a metallurgist (neither am I but I dabble). Galling is when you rub or impact two metals together and one transfers metal to the other in lumps of various sizes - usually very small. It is almost as though parts of one metal body stick (or weld) to another metal body and when they separate metal gets torn from one and stays on the other. A thin layer of contamination such as the lead film can stop this. Hi John, you need to get the copper up to a certain temp in order to anneal. This temp is close to red hot. If you cant measure the temp then get it red hot and you are sorted. With metals such as Ali Alloys the old trick is to rub soap on the back face of the sheet needing annealing; heat the other side and wait til the soap turns brown. The Ali Alloy will not be soft (ish). Doing it without the soap or a temp sensor results in a puddle of All alloy. Roger PS -m as Stuart states you can only anneal a solid copper gasket - not the composite. Edited January 27, 2017 by RogerH Quote Link to post Share on other sites
ianc Posted January 27, 2017 Report Share Posted January 27, 2017 Website wikihow.com/Anneal-Copper has a useful guide to annealing solid copper sheet. As mentioned, ONLY APPLICABLE TO SOLID COPPER HEAD GASKET. 1 - Use a blue-coloured flame (so as not to melt the copper) 2- Get the copper to cherry red 3 - Pick up the sheet with pliers and place in large bucket of cold water 4 - When cooled, the copper will have been softened and the gasket can be re-used. Ian Cornish Quote Link to post Share on other sites
Alec Pringle Posted January 27, 2017 Report Share Posted January 27, 2017 The real problem here is to achieve the cherry red heating evenly of the whole gasket - which requires a large torch. The gasket should then be placed, horizontally, into a flat tray of water . . . . . not just dropped into a bucket of water, which will simply result in unequal annealing from one end of the gasket to the other. A mistaken course of action which I once learned the hard way . . . . . !! Cheers Alec Quote Link to post Share on other sites
RogerH Posted January 27, 2017 Report Share Posted January 27, 2017 Hi Folks, you do not have to cool it in water. It can be cool slowly in the air for the same effect. As Alec states uniform heating is required. Roger Quote Link to post Share on other sites
Waldi Posted January 27, 2017 Report Share Posted January 27, 2017 Or not run the risk of varying hardness oacross the gasket and buy a new gasket? Quote Link to post Share on other sites
Alec Pringle Posted January 27, 2017 Report Share Posted January 27, 2017 Hard to know why anyone would want to use a solid copper gasket on a normal road engine . . . . . probably six times the cost of a traditional standard spec copper sandwich gasket, and to what potential benefit ? Cheers Alec Quote Link to post Share on other sites
Waldi Posted January 27, 2017 Report Share Posted January 27, 2017 Maybe there is a parallel with gasket technology in the (petro)chemical industry: Solid metal gaskets on items like heat exchangers, piping, reactors etc. are replaced often by envelope -, corrugated - or KAM profile designs, that have prooven to be more reliable. The "memory" (springrate) of a soft gasket like a sandwich of metal and a composite (or graphite) in between may also be an advantage in head gaskets. Quote Link to post Share on other sites
john.r.davies Posted January 27, 2017 Report Share Posted January 27, 2017 Thanks, Roger! Knew of the soap trick, wondered if there was one for copper, like the green J Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.