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Cracked Block! - How To Repair?
https://slantsix.org/forum/viewtopic.php?t=40186		 Page 1 of 1
Author:  63Dart [ Tue May 11, 2010 8:23 am ]
Post subject:  Cracked Block! - How To Repair?
Hi All,

I haven't posted in years (since the engine has been running like a dream for years)!

Here's the scoop - I live in NorCal, and I have a really nice engine that was built by Doug Dutra several years ago. He did an awesome job, and the engine still runs well. I kind of let the engine go a little bit, since I was busy for several years with some personal issues. Like all slants, it just kept running, so I didn't really do much to it other than change the oil and plugs, and adjust the valves when needed.

I recently replaced a bad freeze plug, and after I flushed out the engine, I discovered a crack in the block right below the casting number on the driver's side. It is about 3 inches long, and only appears to weep coolant only when the engine is under load.

I'd like to repair the crack without pulling the headers (or especially pulling the engine). I did some research, and it looks like JB Weld might do the trick. Does anyone have any experience fixing cracked blocks this way? Any tips? Thanks in advance!!!!!

p.s. - it's also good to be back - I really enjoyed this forum when I used to post here several years ago!!!

Image
Author:  Fopar [ Tue May 11, 2010 9:07 am ]
Post subject: 
Best old school way is drill and tap an overlaping line of screwed in brass or soft steel plugs. Start ahead of the crack, drill and tap hole insert screw in first hole flushcut it. Then drill next hole overlaping that plug following the crack with same process until you are past the end of crack.
Author:  Doc [ Tue May 11, 2010 9:22 am ]
Post subject: 
Lock-n-stitch makes the items needed for the "pin repair" discribed above.
http://www.locknstitch.com

An epoxy repair may work for a short time but usually the crack / hot coolent will work thru the epoxy (crack or lift it) over time.
DD
Author:  Aggressive Ted [ Tue May 11, 2010 9:56 am ]
Post subject: 
I have run the Prestone sealer in the past with good results. It doesn't have any fillers and is all liquid so it won't plug your radiator or heater core. On a crack like that it will last about 6 months or so.
Author:  Evilsizer [ Tue May 18, 2010 7:51 am ]
Post subject: 
what would have caused it to crack?
Author:  63Dart [ Tue May 18, 2010 10:31 am ]
Post subject: 
Doug is going to HATE me!!!!

:oops:

I drove it for about two years with what I thought was a defective temp gauge. Ummmm. . . .

It was actually a badly gunked up radiator.

I'm pretty sure that had something to do with it.

This would have KILLED most other motors, BTW. . .
Quote:
what would have caused it to crack?
Author:  carlherrnstein [ Tue May 18, 2010 10:34 am ]
Post subject: 
If you are just scabbing it by until you can fix it proper then i would suggest water glass (sodium silicate). I saw it work an a 318 industrial with a cracked head and it sealed up with no leaks, till #4 rod bearing came apart then it was leaking everything.... anyway we took the heater core lines off and connected them together. Then the same thing for the radiator, we used a piece of pipe to join them. the fill the engine with a solution of water glass and warm water. Clamp the hose you used to fill it up then start it up let it warm up, but watch the temp gauge! when it gets warmer than it should be SHUT IT OFF let it cool, and see if you still have a leak if so start it up and continue this procedure. It will eventually seal up in to a semi permeant fix.

good luck
Author:  Doc [ Tue May 18, 2010 11:25 am ]
Post subject: 
Quote:
Doug is going to HATE me!!!!

:oops: :cry: ....
Overheating would have KILLED most other motors, BTW. . .
Quote:
what would have caused it to crack?
No... "hate" would mean hating myself... seeing that I have done my share of "over-sights" that cost me an engine or few.

Anyway... I can always re- rebuild your engine, by installing all the current parts into a different block... it's just time & $$$. :wink: :roll:
DD
Author:  63Dart [ Tue May 18, 2010 12:03 pm ]
Post subject: 
LOL - it's been so long since I posted here that I forgot "Doc" was you!!!

Well, I'll shoot you a PM, but if you are willing - I'd be happy to "upgrade" - I'm thinking about souping it up a tiny bit more. . . I've driven the car now for 10 years as a daily driver, and it's actually amazing how little $$$ I have put into it, so some more motor work would be well-deserved for the car!!!

:D
Quote:
Quote:
Doug is going to HATE me!!!!

:oops: :cry: ....
Overheating would have KILLED most other motors, BTW. . .
Quote:
what would have caused it to crack?
No... "hate" would mean hating myself... seeing that I have done my share of "over-sights" that cost me an engine or few.

Anyway... I can always re- rebuild your engine, by installing all the current parts into a different block... it's just time & $$$. :wink: :roll:
DD
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