I recently bought a used motor from a car that was involved in a collision. After further inspection, it appears to have spider web like cracks on the block. Does this mean that the engine block is cracked, or is there another explanation for this?

 

Have you looked at your other block to see if it looked the same?

 

Yes. It has a spot or two that look similar, just smaller. However, the engine is no good, therefore, in my opinion it's a bad reference point....

 

Pretty much all of the older VQ motors look like that. If the motor is bad, it has nothing to do with those markings.

 

Maybe some kind of cracked coating on it from age, and not a real crack through the whole thing.

 

Completely normal, just the amount of dirt on it makes it more visible. Every aluminum engine block looks like that.

 

You just made my day! I thought I bought a cracked engine block. Thank you SO much for your response!!

 

Awesome! I am so stoked to hear that. Thanks for your help!

 

I would recommend that you have the block and heads checked for cracks.

https://groups.google.com/forum/#!to...ng/dmLb7JepyG4

I have wasted a lot of time building and rebuilding engines only to discover they're cracked.
.

 

doesn't look serious imo

 

From looking at the photos, I'm 99% sure those are crack-like markings, not cracks, which caused by the surface deterioration of the tool die in the casting process. The correct metallurgical term of this deterioration is called "heat checking". Guys who owned 350Z Nismo diff cover probably see these crack-like markings before.



Here are crack-like markings on other engine blocks as well,