The Stovebolt Site Forums The Shop Area Engine Shop Another cracked 235 head

Help! Has anybody had good luck with crack repair on 235,261? I had my 261 repaired about 9 years ago, but it has cracked on the weld again.
The gentlmen who did the repair has passed away and I can't find anybody in San Diego that will try to repair it. I read online about Muggyweld special 72-77 rod for cast iron repair
has anybody ever used this?
Thanks Dave

Dave... look into Marine diesel engine repair companies. They do a lot of what is called Sticth Welding it involves grinding out the crack and installing steel studs and then pre heat before welding and post heat after the weld is completed to releive the tension caused by welding...you can try and weld it yourself as there are many great welding products out there but make sure you pick a machinable product as a high nickle content filler metal will make it impossible to machine. You can use your oven at home for the pre and post heat
400 degrees for three hours or as long as the head is 400 degrees all the way through...cold welding can also be done grind out the crack and weld for very short periods if you can't touch it without being burned then you stop and wait until its cooled to the touch...takes a long time and a lot of cleaning between welds and still needs a post heat treatment.... good luck! Steve

In my experience with cast iron repair,I have found it usually can not be repaired successful a second time. There seems to be plenty on 235 heads around so I would just go get another head. Most peole want to run a 235head on the 261 motors.

Thanks guys. I have tried 3 235 head so far @ $48.a pop to have them clean and maged Not to mention the cost of the head. If anybody in San Diego area reads this and has a good head Please let me know.
Thanks Dave

Dave Kuhn,

Interesting. I have always considered the 235 as a 'crack free' engine, head included. Are these items you are finding busted in the same place every time? SOP around my neck of the wood would be drill and plug for a crack...welding wouldn't even be on the shopping list.

To my knowledge, the higher the nickel content of the welding rod (cast iron/arc) the more machinable the weld will be. :confused:

Stuart

Cast iron rods have various componets included in their make up and they are classified as machinable and non-machinable so you have to take a bit of care in your selection as they are also polarity and position sensitive. I have welded many an exhaust manifold and have also use brazing in head related repairs to great success. Preperation of the weldement is most important but a good repair is possible....my question is why is it cracking therein lies the root of a problem. Steve

Dave - sorry I can't help you, ebayed my last good one a few mo. ago. You know about the annual Big 3 swap meet in a few weeks @ Qualcomm I trust. I ran one that had been welded for about 100 K mi. Was still good when I sold the motor. I have another here but it is cracked. Doug

Steve - I think the C. I. likes to move around a bit after some heating/cooling cycles. Thats why we have to 'line bore' the mains on blocks. Sometimes even the cam bores need line boring. If you just put a good machinists straight edge across a lot of our blocks you'll see the trouble. Running a indicator over them on a mill table is a better way. Exhaust man. crack, same deal. Some years of motors are notorious for that until the factories correct their castings. Thats why industrial inlines are commonly made w/one head for 2 (only) cylinders. Doug

Desertdog....YEP...in my granfather's balcksmith's shop they would lay the heads on a piece of 1/2" thick glass sheet to see if they were warped. The cooling and heating cycles(thermal stress)are very tough on an engine. On steam locomotives the problem is so bad that you leave them hot for as long as you can when they cool everything will loosen up and leak. I would say that a head check on a granite surface block with an indicator would be in order. Perhaps a bit of milling and a good copper head gasket might solve the problem...Where is the swap meet? Here in CA the big one is at Pleasenton, CA twice a year....I'm headed for Death Valley in a few weeks anything going on in Quartzsite.....Steve

Hi - Check out Big3 and Q\'site Doug

Thanks everyone. Ya Iam going to the big three. After many hours of thinging about what to do I pretty sure am going to put the 270 Jimmy in my 50 Chevy 1/2 ton and slide a sbc in the 48 panel I built for the GMC. I have been driven my 50 for 32 years with the 216. And had hoped to build a sweet 261 for it( the 261 is in the GMC) but needs to be rebuilt also. So if am lucky at the big 3 and find a do- able 261-235 head it would save me mucho time and money. Both truck have open drive lines. Panel has a 5 speed,1/2 ton has 3 speed with OD.
Thanks for the help.