Selling crack on the block

[Dane]

Howdy Folks,

I’ve been tearing down my m10 with plans on rebuilding it, I recently started on the engine block and when I removed the lower timing chain cover I noticed 2 sizable cracks, huge bummer, I plan on taking both my head and block to a machinist soon but wanted to get some opinions from the FAQ on how likely it is my block is salvageable , I’m also curious to know what the plug is that the cracks are located around is ? I believe it was over torqued which is what caused the cracking. I will add that prior to tearing the motor apart it did run without any issues so I’m hoping that’s a promising sign.
Any help is appreciated, Thanks ! 

[visionaut]

It’s hard to tell since the depth of the cracks isn’t known…

 

Was there any coolant or oil seepage found around them?

 

AFAIK that’s not a stressed area - the big bolt head in the pic is just a screw plug, but others may know more about what it’s function is.

 

See Realoem diagram -  (upside down cuz your pics have the block upside down, lol)

 

Maybe they were there since casting?

 

Tom

 

 

Edited February 9 by visionaut

[Dudeland]

The question is why did it crack.  It may or may not be a stressed member, but what is going on.   

 

That is certainly no bueno.  Sorry. 

 

[jimk]

I believe it opens to the water jacket and most likely needed for the block casting core.

[sczapiga]

For what it’s worth, I just bought a second spare block to bring to my machinist after finding cracks in my first one I was going to use. It’s a bummer but they’re cheap and easy to come by so I’d recommend just finding another one if that one doesn’t mag out. It’s worth having your machine shop mag it. Could just be casting like others have said. I payed $200 for a block the other day and it ended up needing to be taken up to .040 to clean up the bores. Just find one with the matched main caps and it’ll save some line boring cash. 

[visionaut]

19 minutes ago, jimk said:

I believe it opens to the water jacket and most likely needed for the block casting core.

Given what Jim says above - a possible (?) source of the cracking could be if the water froze in the block…

[Preyupy]

I was going to say that is from freezing.  I suspect that is not the only  place in the block that is cracked.  Find another block, that one is now a boat anchor. 

[Mike Self]

+1 on replacement.  If it were a Type 35 Bugatti or Model J Duesenberg block, there are places that can repair those cracks properly.  But so long as good blocks aare plentiful--and you're not concerned about matching numbers between block and body, get a replacement--and have it checked to make sure it isn't cracked.

 

mike

[tzei]

Feds will be smirking on this one.

 

get better block

 

drucks are bad mkay

[conkitchen]

At first I thought perhaps you were advertising a for sale ad in your hood to fund the project.  

 

 

[Mike Self]

2 minutes ago, conkitchen said:

At first I thought perhaps you were advertising a for sale ad in your hood to fund the project.  

Yeah, but that's the kind of crack no one wants to buy, except maybe the scrapyards...

[conkitchen]

1 minute ago, Mike Self said:

..... except maybe the scrapyards...

That's no way to refer to the area where the original poster lives. 

[tech71]

 Eeww, I'm with the "find another block" crowd, even if it mag checks ok.

Where are you? I have a block with matched caps/standard bore you can have for $20 (lunch) if you come get it.

Edited February 9 by tech71

[Vicleonardo1]

I would say on your next block drink a few beers and....

Engine Myth: Urinating on Cylinder Block Improves Durability - EngineLabs

WWW.ENGINELABS.COM

---

There's an old legend about BMW Formula 1 engineers urinating on cylinder blocks to help "season" the iron casting before race prepping. The survived 1,500 horsepower, so did the trick work? Check out the story!

 

[Son of Marty]

Nitrating which is the active ingredient here is a surface hardening method and would do nothing to help stabilizing blocks but their selection of used blocks and letting them sit out in the weather for a year or more does work internal stress out of the casting. In 1970 I was lucky enough to tour the Volvo factory and they had fields of 4 and 6 cyl blocks stacked on pallets the guide said they left them out in the weather for 18 months before machining them and their engines of those years were indestructible.