9N cracked block

[Denis in MI]

I have a 9N with a cracked block it has a crack running from each each side of the drain plug hole. Has anyone tried to repair these kinds of cracks and have they had any luck.

Thanks in advance,
Denis

 

[981demo]

have the same proble with one in my NAA and am taking it to the blacksmith's shop this week to have it repaired, they said no problem, SO I am going to try this before I replace the block, I noticed it after sandblasting for a paint job, but it hadn't lost any antifreeze.

 

[Denis in MI]

I haven't filled it with coolant yet to see if mine leaks but I am afraid it will or it will start leaking after I get it running and painted

 

[redleg]

All this talk about welding cast lately reminds me of my grandpas story. Always use to here about his welding job on his 394 Olds' cracked water jacket using the battery while stranded on the side of the road. Supposedly, he drove it that way for 7 years before selling it and the guy that bought it got at least a couple more years out of it.


Don in Luther

 

[jimNCal]

I have a correct NAA block IF yours comes back as "unrepairable".

jim

 

[DollarBill]

Yes, I had mine repaired at my machine shop with a process called metal stitching. They drill a series of holes along the crack and fill them with threaded, cast iron plugs. The process has been around for years as I remember seeing it done when I was hot-rodding in my high school days. Here's a photo of a repair in progress.

 

[Denis in MI]

my worry is about the crack going ino the threaded hole for the block drain. I don't know how well it would take the repair because the crack runs right into the hole on both sides

 

[trucker40]

What do you have to weld with?Here is how I would fix it.Drill a small hole at the ends of the crack to stop it from getting longer.Not even all the way through,but deep,maybe 1/8 inch.V it out but dont go all the way through,just get a good v on it.Then weld not more than an inch at a time with either MIG or 7018.Weld an inch,clean slag,grind surface clean,weld another inch,until done.If it doesnt crack you are done.If it does crack fix it right then,grind a v and weld it the same way.Usually if it cracks it will be right beside the weld.
If you arent a good welder you might want to get somebody that is a good welder to do it.You could try 6011 also.You would want to weld short welds and 6011 has to have every bit of slag cleaned off of it before you weld again.Just use a grinder instead of a chipping hammer.I would just try and get a pass on it with 6011,grind the slag off and cover it with 7018.6011 is a deep penetrating rod,but it can crack which is why I would cover it with 7018.7018 is strong and not as prone to crack as 6011.It can crack though.The main thing is to not weld real hot.Whatever the rod burns good at and no hotter.
If you have a MIG then its a little easier to weld it.I would weld,grind,weld until it was full,and maybe put another pass on the outside with Mig.It doesnt crack as bad with MIG,but it still can crack so you want to use short welds,grind between welds, and not stop until you are done.
I would try those ways.If I wasnt a good welder I would probably cover it with JB Weld too.If I was a good welder I would just leave it alone.It could still crack.It might last a real long time too.If it didnt work I would look for another block or a welding shop that could heat it up in an oven and weld it like that.
Also I like to grind my weld on top smooth when I weld cast.I think it helps keep it from cracking.
As for where that fitting is for the drain,I would stay out of the threads but weld as close as possible.You would want to screw the fitting in loosely before you weld I think.
If the crack is real long,or its real cold when you are working on it,I would heat it up with a torch before welding and as I welded on a long weld.Also after done welding it wouldnt hurt to hit it with a torch a little too to slow it down from cooling real fast.

 

[weaveman01]

I'm not an expert- but brazing it might be a good option. Since it's not load bearing you don't necessarily need the strength of arc welding, you're just making sure it doesn't leak. And there is alot less chance of really screwing it up.

 

[DollarBill]

[color=darkred:8a47b87149]my worry is about the crack going ino the threaded hole for the block drain [/color:8a47b87149]

The machinist will know what to do - He will likely extend the plugs into the block drain hole and then re-thread it to receive the petcock. As someone else mentioned, this is a low stress point and can be fixed quite easily.

Let us know what you decide.