Amc 360 Heads Crack Missed by Machine Shop ?

djaponi3

Just Got my 360 Fired for the First time only to find coolant leaking externally near front outer headbolt area appears to be a hairline crack just above headbolt ! Torqued em down in steps and in sequence guess that wasnt good enough ! is it common for these heads ? They where magnafluxed but I think the machine shop missed it I Suspect the Crack opens up only when Heads are Torqued Down Got a Ton of Money in these heads and Just Disgusted !

tufcj

If they were magnafluxed and inspected, even a crack that only opens under tension should have been revealed. Either they missed it on inspection, or it cracked during installation. Since you installed them, you're going to have a hard time convincing a shop that they missed it. A reputable shop might give you a break on repair. It is common for AMC V-8 heads to crack around the outer corner bolt holes. I have seen lots of them successfully pinned and welded for these cracks. Bob tufcj

djaponi3

tufcj;132363 wrote
If they were magnafluxed and inspected, even a crack that only opens under tension should have been revealed. Either they missed it on inspection, or it cracked during installation. Since you installed them, you're going to have a hard time convincing a shop that they missed it. A reputable shop might give you a break on repair. It is common for AMC V-8 heads to crack around the outer corner bolt holes. I have seen lots of them successfully pinned and welded for these cracks.

Bob
tufcj

They are 502 heads ! I See Bulltear offers 2 different heads used and checked ! are they compatible part numbers ? Looking to buy 1 Head and Have it Machined and all the Goodies Transfered ! Not Interested in Repairing cast Iron ! 25 Years in the Auto Repair Field Tells Me Thats an Iffy Road I Would Rather Not Go Down ! I am Sure the Shop Missed this and I'm Not Interested in Any Pi##ing Contest ! Signed, I Still Love My AMC V8 !!!

mrtazwrench

I would not want repaired junk after seeing the pics of your project, it would be different if it were something like my old plow truck being pieced together quick and cheap.

djaponi3

Thanks mrtazwrench !!! I Bolted Both Heads together W/head gaskets and Blocked off the Coolant Passages on intake Ports to Pressure test Both Heads Found that this Crack Spreads dead Center Corner of 90 degree Machined head bolt boss Around to Front of Head about 1 inch .Tried Cold weld I.E. Hammer and Punch in an attempt to Smash Cracked ends together While under Pressure "Fugging Futile Attempt" Tried Drilling 1/16 npt Holes for pipe Plugs and Realized Just How Thin these AMC Castings Are !!! Less Than 1/16 of an inch of cast Iron ! Found AMC's Weak Point on This Particular Cylinder head Part Number Ending 502 ??? UGH Need Another Cylinder Head !!! Still Love My AMC V8's Regardless of Lost Hair and Sleep !!!

tufcj

Unless you're dead set on the casting numbers matching, all the bridged rocker heads from 74-up are about the same. 502, 503, 475, or 344 heads are all suitable replacements. Bob tufcj

djaponi3

Lucked out and found a local boneyard with a 344 in stock 50 bucks delivered off to the Machine shop with my heads to share my Newfound Knowledge on where to check these heads for cracks ! Thanks for the Help !!!