Block and head repair question?

I was just watching a video on youtube of some people repairing heads and blocks and all that stuff . I saw one bit where this guy was repairing an alloy head and one large portion of the corner of this head was gone and yet the guy repaired it and you could not tell one bit that it was repaired , you could of mistaken it for new . So my question is now that video amased me I hear alot of talk about people having stuff repaired and I guess it depends on whether its worth fixing or buying another but after seeing just what they can repair in that video it got me wondering how do you know when something is unrepairable , how do you guys determine whether somethings junk or fixable . I am only asking out of curiosity .

 

can u post a link to that vid. thx

 

Heres the video , I got it a bit wrong as to what part of the video they repair what but the damage they repair is quite amasing .

http://www.youtube.com/watch?v=JBkgJNEStxo

 

Head Repair

I used to do head and block repair quite a bit and basically I had the attitude that everything is repairable. It just depends on how many fixtures you need to build to hold everything together and how many hours you spend on laying weld. I had people bring me stuff that had broken chunks off and as long as you have the pieces to put back in, it can be repaired fairly fast. If the piece is missing you have to basically re-cast the piece with weld. Once the welding is done the machine work is just like working on a new casting. I had done enough of it so I was able to estimate it pretty close and the customer made the final decision if they wanted to repair or replace.


my 2 cents
Corey

 

William, aluminium is one of the easier metals to work with, notice that head was completely stripped out, once welded can also be sent for reheat treating prior to grinding, machining fitting of guides & seats etc.

Did you know we have some very cleaver guys here too, all of that shown on that vid is done here often.

Cost for the customer is what determins whether it gets fixed.

I did see an Aston Martin head repaired at a Hamilton shop, cost not an issue as there wasnt another available, the repair was undetecable.

 

Cool . Its amasing what people can fix . Would be an awesome but tricky skill to learn .

 

Head Repair

I got my welding ticket in 1991, and I'm still learning how to do it. The hard part is not the welding itself, its selecting the correct filler material and then keeping everything straight.


Corey

 

What do guys think about heat treating aluminum? Does it change your answer if its a cast alum piece or billet?

We've never had any of our heads reheat treated after welding.

 

welding

If you use the correct welding rod I don't think heat treating will get you any better.

If you use 5356 rod on combustion chambers, it gives you sufficient hardness to live in any environment. When you machine a 5356 weld it comes out like a mirror, looks exactly like a brand new head.

For welds that are not in the combustion chamber go with 4043 rod and it give you good ductility, but its difficult to machine because it is alot softer (balls up in the cutters).

Heat treating may get you to the exact hardness you want but it costs way more and IMO using the two rods I mentioned in the right places will get you so close its not worth it.


Corey

 

Corey, (Everything is repairable. It just depends on how many fixtures you need to build to hold everything together and how many hours you spend on laying weld.)

Thats pretty much what we live by here, we are a maintenance machine and weld shop for the steel mill industry, and they could break an anvil.

Except there saying is (Just torch your way in and weld your way back out.)