So...in hindsight...
What would you do differently on a used engine that was “running fine”?
What would you inspect?
How far to tear down?
Etc...

Thanks for sharing some great Tech info.

Take a look at this article.
I couldn’t remember where I had seen it.
Ran across it this evening.

https://www.corral.net/threads/must-read-psa-for-windsor-roller-block-guys.1352369/

Which cam bearings failed?

I would have the block Mangafluxed to be sure there are no cracks you cannot see with the naked eye.  If it passes have everything else checked (deck surface flat and true to crank axis, line hone for straightness, bores for size and out of round/taper).

I think the crack through the block thing was quite rare.  We've all heard of it, and maybe a handful of us have actually seen one, but its still pretty rare.  I also tend to agree that it was some form of casting defect rather than stemming from another cause. 

This was my reply to that exact thread.  it was not well received but I stand by it.

Daze post as DazeCars on the 5th page of that thread wrote:

as important and informitive as this post is I think the concern has been overblown and a little perspecitive would help.

There are two separate issues here. The first is if you are building a high power engine than this block cracked or not is not your best choice. I totally agree that Strokeme totally made the correct decision in not rebuilding these blocks. For my business personally I would never let anything but the best go out to a customer as its my reputation on the line. I also think that letting people know about this crack is good info to get out there so those building a performance 351 know what to look for. 

With that said I think this post has become more than was intended. In this thread Strokeme states that he has never seen one of these fail, in other words all the engine blocks he has seen like this came into the shop had nothing more than a crack. Also Strokeme made the statement that a lot of builders probably wouldn't even notice the crack as it is not a normal place to check so there are probably a lot of 351s out there built up that have that crack. I spent a lot of time on-line looking, and I could not find a singe instance where this crack ran and caused issues, not one. People talk about 302s coming apart and most of those cases can be attributed to boring the block out further than they should, the 302 is also a much weaker block than the 351 from the factory and is being pushed higher than it should be IMHO.

Another way to look at it, two things cause cracks on a running engine the first is heat/thermal cycle and the second is stress from combustion. Being in the center of the block heat is obviously not the cause as the center of the engine will cool slower than any other part of the engine and the hottest parts will be at the cylinders and especially at the top of the block and the heads. As far as combustion stress again the stress points are going to be at the mains and the cylinder walls not the top of the cam journal where the lifter valley and the cam journals meet. In fact that part of the block probably has a better strength to stress ratio than anywhere else in the block. I do not see any way that either of these causes would apply in this case.

"When you have eliminated the impossible, whatever remains, however improbable, must be the truth"

That leaves the obvious cause being related to the machining, so it happened at the factory. An EFI engine can easily last 200K to 300K miles. Just to be safe lets say 200K miles per engine. That means for every 5 of these engines that are cracked thats a million miles of engine life. Strokeme said 1/10 blocks have this crack. I don't know the production numbers but at 1 out of only 10 only 50,000 of these blocks would need to be produced to have over a billion miles on cracked blocks. Again I could not find one instance of a a failure. 

I think this crack is something to be aware of especially if you are building a performance 351 but based on real world data I do not believe this crack is much to worry about in most applications.

I ran into a similar situation when researching Jag IRS for my Mustang. The upright hubs are cast aluminum and quite a few hubs were showing up with a crack in the lower webbing. It was always in the same spot and had a lot people worried about the parts. After a lot of research and panic from the Jaguar community (like the 351 not one failure documented) the general consensus was that the crack happened at the factory and was not a big deal, something to be aware of so you could make an informed decision. I was thankfull that neither of my hubs were cracked and I don't think I would have risked it had there been a crack given th performance nature of my appliation, but the same thing happened there that has happened in regards to the 351 crack, a lot of concern for a minimal issue. 

The info is here so people can make an educated decision that will best suit their needs, but unfortunately IMHO it has become a a decision forced upon them due to fear and panic.

Interesting, I have a 60k Lightning F4TE shortblock in my garage. Gonna go pop the cam bearings out at some point to check. I hear what you are saying, but I am in the camp of "no way in hell I will run something with a crack".

TKOPerformance wrote:

Daze wrote:

TKOPerformance wrote:

I would have the block Mangafluxed to be sure there are no cracks you cannot see with the naked eye. 

As I said a few posts up it went to the machine shop yesterday to be hot tanked and magnafluxed.  I did some basic tests before it went in and everything seamed strait and true.  The compression was good before I pulled it apart so I am going to put it back together with new gaskets and bearings.  Haven't decided on the rings yet, I may get a ball hone and replace the rings or I may just put it back together with the rings that came out.  
 

I would let the machine shop inspect the bores and decide whether or not it should be honed or bored.  I get that it seems like a waste of money because it had good compression, but ring seal is the only thing in an engine that really matters.  To do all this work and have even slightly less than optimal ring seal would IMO be the definition of false economy. 

Good point!!..............At the very least check the bores for excess taper before    " ball honing and replace the rings".  IF that checks out then ....hone away!!
6sal6
 

Good call. Glad its moving forward again. 

I discovered the roller blocks had a cracking issue when I first started to look into building a stroker and found mixed opinions on using a roller block.  So I ended up getting a non roller block which now sits in my garage because I found a great deal on a 418 and it is not a factory roller block.

If I was to build a mild 351W and I had a roller block I would use it.  if it had a crack then things would change.

What about drilling a hole at the end of the crack?  Stopping it from cracking more in the future!
6sally6