iron cylinder head repair

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Customer brought in a super charged 3.8 GM motor already disassembled. It wiped out one rod bearing and trashed one rod and crank .Magged the heads and one had two cracks. Called customer he said he had two more heads which I magged and both were cracked. Now I had a cpuple heads to "play with", cut one open to have an idea of what it looked like. Usually a crack that deep in a automotive head reaches the water jacket. These heads are thicker than usual and the cracks were not through. If the crack was more shallow I could have counterbored and install seat inserts. The cracked area was about .5" thick with the crack going .4" deep. Gouged cracks on the best casting, preheated, spray welded with ni powder, post heated, pressure tested, machined, reassembled. Job done dun.Peter Attached ImagesEquipment:2  old paws2  eyes (that don't look so good)1  bad back
Reply:more pics Attached ImagesEquipment:2  old paws2  eyes (that don't look so good)1  bad back
Reply:sweet repair, you do very nice work!miller... 225g, s32p, 250x, 304, 12vs, MSW41     victor o/a thermal dynamics cutmaster 50 lenco panel spotter        hobart hf-boxG3 Farms.....raising cattle, hay, kids and hell, ...oh yeah I'm a fire sprinkler contractor by trade.
Reply:Originally Posted by G3farmssweet repair, you do very nice work!
Reply:Nice detailed work !!!
Reply:Another awesome job Peter.  I trust you're staying busy.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:Very nice repair Peter.
Reply:Very nice job, methodical thorough approach and first class repair and machining, I can only dream about such skill that you always bring to those difficult castings.Lincoln SP-170 MigHypertherm powermax 45Lorch T220 AC/DC TigButters FM 215 synergic MigKemppi 180 adaptive mig RULES ARE FOR THE OBEDIENCE OF FOOLS AND THE  GUIDANCE OF WISE MEN.
Reply:Originally Posted by a1998z3Nice detailed work !!!
Reply:Great looking repair, looks just like a new one!"The reason we are here is that we are not all there"SA 200Idealarc TM 300 300MM 200MM 25130a SpoolgunPrecision Tig 375Invertec V350 ProSC-32 CS 12 Wire FeederOxweld/Purox O/AArcAirHypertherm Powermax 85LN25
Reply:Very interesting. I looked into doing head welding several years ago, as my engine guy asked me about it. At the time what I found were mostly dated documents on doing it. Most were calling it recasting or furnace welding and was was more similar to OA welding than stick, or spray welding. I didn't realize you could use spray/powdered metal welding o do this type of repair. Is this the go to method now for cylinder head repair? What are its limitations when welding on heads?
Reply:Always happy to see your posts and thanks for sharing!Much of the knowledge shared here is stuff that you used to have to sweep floors, then grind welds for weeks, months and years to learn!I was wondering what your device was in the first couple pictures then saw the one where it said "contour probe"  never heard of one, now I'll have to look it up!
Reply:Originally Posted by pedaldudeAlways happy to see your posts and thanks for sharing!Much of the knowledge shared here is stuff that you used to have to sweep floors, then grind welds for weeks, months and years to learn!I was wondering what your device was in the first couple pictures then saw the one where it said "contour probe"  never heard of one, now I'll have to look it up!
Reply:I would guess it is a strong electro magnet, used together with magnetic powder to check for cracks in iron. Magnaflux testing...Edit: Too slow...
Reply:Originally Posted by noriteGreat looking repair, looks just like a new one!
Reply:Great pictures and information, Peter; thanks for sharing!  Also, I wonder if the high-nickel alloy now deposited in that area will tend to help reduce similar cracking from recurring (compared to say, if it were repaired in an oven and using a cast iron filler rod.)Also, your observation about cast iron heads getting larger after being heated and cooled in an oven is interesting, and also a bit curious.  Any thoughts on why this happens?  (Maybe trapped internal stresses inside the original castings are somehow causing this enlargement?)Last edited by jakeru; 11-18-2012 at 02:47 PM.
Reply:Another good job Peter!! Could you possibly explain the machining end of this? I have always been courious about rebuilding heads.  Thanks,Chris
Reply:Its more common to find heads off these motors WITH cracks, then without. Most of the time they are not large enough cracks to reach the valve seat, and cracks in these heads really don't hurt performance because the cracks are so minor. Almost rare to find a set of these without cracks.
Reply:Very nice rice repair work Castweld.  The finish on the seats look ground, did you use a form cutter to get the seat roughed in and then finished with stones due to hard spots at the edge of the weld?  Or is it not as noticeable with spray weld? Originally Posted by jakeruGreat pictures and information, Peter; thanks for sharing!  Also, I wonder if the high-nickel alloy now deposited in that area will tend to help reduce similar cracking from recurring (compared to say, if it were repaired in an oven and using a cast iron filler rod.)Also, your observation about cast iron heads getting larger after being heated and cooled in an oven is interesting, and also a bit curious.  Any thoughts on why this happens?  (Maybe trapped internal stresses inside the original castings are somehow causing this enlargement?)
Reply:Originally Posted by jakeruGreat pictures and information, Peter; thanks for sharing!  Also, I wonder if the high-nickel alloy now deposited in that area will tend to help reduce similar cracking from recurring (compared to say, if it were repaired in an oven and using a cast iron filler rod.)To be honest I have not tested the two processes against each other. I guess I would have to do each process on a pair of v heads on same engine and be sure each bank would over heat equally. That would be a tall order for my shop. If I were operating in a school setting it would be an interesting test though. In other words I do not get paid to do that.In the 12 years I have been repairing by spray I have had several over heat again, most with only gasket failure. Pressure testing and surfacing them was required to put them back in service. a few heads cracked again in a new area and one cracked in several places including repaired area. I am not tracking 100 percent of the heads though.Also, your observation about cast iron heads getting larger after being heated and cooled in an oven is interesting, and also a bit curious.  Any thoughts on why this happens?  (Maybe trapped internal stresses inside the original castings are somehow causing this enlargement?)
Reply:I was talking about machining the head in general and making sure the seats are right. Thanks,Chris
Reply:Great job..can you also do alum. Luckly i was just idling. had a timing chain set that was miss marked. Attached Images
Reply:Wholly $hit batman....That blows.TA Arcmaster 300CM3XMT 304S22P12 suitcase feederX-Treme 12VSOptima pulserTA161SMaxstar 150STLHypertherm PM45OP setupStihl 020AVP, 039, 066 Magnum
Reply:Nice work Peter..Done a few of them myself and they all crack in the same place..a1998z3..Bet it was not running all that good either but have no fear..That can be repaired with minimal amount of B/S if you know what you are doing..Been there done that TOO many times..I can't find the pics but I repaired a 351C head that lost the intake valve at around 8000 RPM...What a mess....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Originally Posted by a1998z3Great job..can you also do alum. Luckly i was just idling. had a timing chain set that was miss marked.Originally Posted by duaneb55z3,I've personally seen Peter in action and his work and have no doubt your head would be a routine repair for him.  Do a serach of his threads and you'll see jobs such as this . . .http://weldingweb.com/vbb/showthread.php?t=29696. . . and this . . .http://weldingweb.com/vbb/showthread.php?t=50729. . . which only scratch the surface.
Reply:Originally Posted by Tamper84I was talking about machining the head in general and making sure the seats are right. Thanks,Chris
Reply:Originally Posted by a1998z3Great job..can you also do alum. Luckly i was just idling. had a timing chain set that was miss marked.
Reply:Originally Posted by castweldHead machining, I am using a Bridgeport vert mill with column spacer and home made roll over fixture. Mira tooling gets seats installed and cut, along with Sioux seat grinding tools. I use tooling from Regis for installing guides including guide liners. Head surfacing, two machines will get best results I use a Rottler, but Sunnen will do same quality job. Last shop I was running we purchased a large Serdi with lots of tooling about $58k. If you have the volume it will pay for itself.Peter
Reply:Another nice example from an old hand, nice job peter! That head design maybe is not GM's best attempt... or is it the raised temps caused by the turbo + fuel charge?It's pretty hard to overstate the convenience and usefulness of the powder brazing, the self-fluxing part makes it almost boob-proof. you can get the filler in rod form from people like Wallcolmonoy for less money but it's not quite as easy to use.RE; Originally Posted by walkerVery interesting. I looked into doing head welding several years ago, as my engine guy asked me about it. At the time what I found were mostly dated documents on doing it. Most were calling it recasting or furnace welding and was was more similar to OA welding than stick, or spray welding. I didn't realize you could use spray/powdered metal welding o do this type of repair. Is this the go to method now for cylinder head repair? What are its limitations when welding on heads?