Alright here is the question I recently pulled my heads off my 1969 buick riviera. It has a 430 with headers and intake and carb along with a very mild cam. Anways it was a suspected blown head gasket but because I didnt let it run to long after it overheated im not the oil wasnt too discolored. so I took of the head and by the way I could hear water dripping into the hot header and sizzling with engine off. The gasket isnt perfect but its not horrible. could I have cracked my head or warped it what shouls I do? Back to the topic what is magnafluxing and were can I have it done. If the heads are good im gonna put it back together and see what happens there are no visible cracks, p.s. those shorty headers are nice because you can pull them off with the heads same with installing. thanks, willy
Magnaflux MAGNAFLUX is a trade name for the magnetic particle inspection process. This is a highly accurate and reliable method of detecting cracks in materials that are of iron or steel. A magnetic field is produced in the material either by an electromagnet or a permenant magnet. Then a solution of iron metal particles is sprayed on the part. When there is a crack, it will show up under ultraviolet light. Works great but should be done by an experience person whith the right euipment. Check your YELLOW PAGES under testing labs. Also, some well set up machine shops and motor rebuilders have this equipment. Good luck. Ed
Magnafluxing Willy- As a machinist apprentice, I magnaflux daily. Ed covered the basics pretty good. Any reputable machine shop should be able to magnaflux your head. Altough to magnaflux, the metal must be clean. When I say clean it needs to be thourghly cleaned by either hot tank or sand blast. In your case, I'd recomend a Pressure test over a mag. again any good engine shop should be able to do for about 100 bucks. A pressure test can be done to any head, or block for that matter regardless of how dirty it is. what happens in a PT, is the head is mounted upside down in a jig, by the valve cover lip. A metal plate, with holes for the chambers, and a thick rubber gasket is used for sealing purpose. this plate is clamped against the head in order to block the water jackets, which keeps the air from escaping. all other water ports are blocked, except for one that will be blocked with an air fitting. 45-50 PSI of air is pumped into the water jackets. with all the water outlets blocked, this pressurizes the head, and their should be no leaks. soapy water is sprayed all over the head, and if it bubbles out anywhere, the head is cracked. Presure testing is an extremly accurate way of finding cracks. I almost prefer it over magnafluxing since it can more easily find cracks deep in ports and things of the like. Remember, a proper cooling system should not exceed 17 PSI, so a blast of 45 PSI is like a fail safe. If you have any questions about it, just ask. If you opt to go the Mag route, the head will have to be torn down and degreased, which can make for extra costs. If you plan to PT, save your self a buck by cleaning the head surface. A quick 5 minute job with a Wire wheel will be fine. I'd have them throw a mag on the surface of the head, since PT cannot pick up surface cracks. All this should cost about or less than a 100 bucks. have them check the surface for warpage too. Good Luck, Joe
Re: Magnafluxing Joe, have you ever used a dye penetrant to inspect for cracks? It consists of spray cans of cleaner, a dye, and a developer. Should cost about $25 from an industrial supplier like McMaster-Carr. I used this method on some vacuum-pumping equipment, and was VERY impressed with how well it worked.....I wanted to know how it compares to magnafluxing.....
Walt- we don't use the Dye. It does work well, but it can be difficult to detect smaller cracks. It's not very cost effective either, not to mention it is time consuming as well. Joe
Magnaflux Willy, I have used MAGNAFLUX and Penetrants for many years in the aviation business (as well as Eddy Current, Ultrasonics and X-Ray). Both inspection methods have their advantages and disadvantages. For your use the recomendation to use pressure testing is a very valid one that I too would recommend. If you do go with a MAGNAFLUX inspection be sure to not use a cleaning process that upsets the metal surface as it will lay over the metal surface and seal up the cracks. A good chemical bath cleaning or hot tanking works great. The penetrant works well but does not detect cracks or inclusions below the metals surface that MAGNAFLUX will find. Penetrants also, if of the visual type (the old blood on snow stuff)are corrosive and must be well cleaned after inspection. In closing, as this is getting long winded, the world of NDT requires an operator who is well trained and experienced. False indications of cracks can cost you as well as those who look but don't see the cracks because of inexperience. Good luck on your heads.:beer Ed
