Engine Block Crack in one cylinder! Typical Problem????

[Anonymous]

Hey,

when I bought my mustang it had a broken engine. Noone knew what the problem was so I tried to find it out. What I found was a crack in one cylinder. I mean, it was a real big crack with some imprints that looked like they were caused by a screw.
Is that a typical problem of the inline 6 mustang 200cid engines cause a lot other 200cid mustang that broke down had also a crack in the engine block.
I´ll try to get some pictures today, then you can see the problem. It´s hard to describe cause I´ve never seen something like that before.

 

[CobraSix]

Generally, if a block cracks, it's usually on only one cylinder. That's because it blows up after that before any other cracks form.

Is it a problem for the 200s? Not that I've heard. Biggest reason for failure on any old engine block is blocked cooling passages from years of rust and sediment. I'd be willing to bet just as common on V-8s.

I.E. my 1991 explorer grenaded it's original engine at 120k miles because of a blocked cooling passage around #6 cylinder (V-6). Pure dumb luck. the coolant never overheated. No sign of problems until all of a sudden the car lots lots of power and stalled on the highway.

Slade

 

[JackFish]

it was a real big crack with some imprints that looked like they were caused by a screw.
Is that a typical problem

I think a screw in the chamber would be a problem for any engine!
It happens. A screw can easily vibrate loose off, say, a choke plate in the carb.

 

[Anonymous]

I finally got the photos taken. I hope you can see what I meant:

First picture is the cylinder from above where you can see the screw imprints best:



Second is where you can see the crack best:



Third is the block as a whole:




What do you say?

 

[FLSHBCK]

That had to make some fun noises when it happened...

 

[Anonymous]

That had to make some fun noises when it happened...

Fortunately that happened to the pre-owner and not to me. But when I asked him about that he said it really made some quite noises, damn strange noises.

 

[CobraSix]

Looks like the bolt caused localized overheating due to predetonation and cracked the cylinder.

It's a fluke, but you'll need another engine block.

Slade

 

[Does10s]

That was a huge bolt! Header bolt perhaps! There's not a single bolt in a carb that uses threads that big.
What's the bottom of the head look like?

That cyl. can be sleeved, but I think I'd just buy a new motor!

Will

 

[Anonymous]

Looks like the bolt caused localized overheating due to predetonation and cracked the cylinder.

It's a fluke, but you'll need another engine block.

Slade

New engine already ordered. It should arrive soon.
Isn´t it possible to sleeve the block?

 

[Bort62]

that looks like 1/4-20 thread. I would bet it was the stud that holds on the aircleaner.

oops.

 

[fordconvert]

Ian beat me too it, air cleaner stud.

 

[woodbutcher]

Me too.Air cleaner housing bolt.BUT it begs the question.WHERE did it go???????????????????And yes.The block is sleaveable.
Leo

 

[fordconvert]

If it was a low grade/quality part like an air cleaner stud I could imagine it breaking up enough to get spit out. I have an engine that has one hole sleeved, it was not cracked but it sat outside under a tarp one winter and I guess there was one exhaust valve open so it was full of water for several years. The rest cleaned up nice at 30 but that hole was not even close so I let them do the sleeve. You have to look real close from the bottom to tell so I dont think its going to be a problem.

 

[Anonymous]

Is there any way to prevent a bolt from getting into the block again?
Because I don´t wanna change the engine that soon once more ^^ Did anyone else experience the same problem? 8)

 

[Bort62]

I dropped a valve into a cylinder once It sort of looked like that.

The way to prevent that happening is to make sure you tighten everything properly. If you are really uptight, you might be able to put a screen between your carb and the intake. But I woudn't worry about it.

Just pay attention when you are putting stuff together. This is a fairly uncommon problem

 

[addo]

I would not be so comfortable with a regular sleeve in there. They rely on integrity of the original casting - even when bored to accept the sleeve.

A thickwall (wet) sleeve would probably be OK, but what is available? If it were a rare engine, you'd do whatever is needed - maybe furnace brazing in a custom wet sleeve - but in a common motor it's cheaper and simpler to replace the block.

Regards, Adam.

 

[fordconvert]

On mine the air cleaner bolt is attached to a oversize wing nut thing that would be hard to fit down the throat of the carb. My guess is that someone lost the orignal and put a bolt or stud up from the bottom and used a regular nut or wing nut on the top and it just worked itself loose and fell in. Get the right parts and it wont be a problem.

 

[Anonymous]

I'm wondering how long that bolt laid around in the intake log until it finally made it's way through the #5 intake valve.
From the size of it, it would have had to make a heck of a 90-degree turn at the intake port to get through. And, it made it past the #4 intake by the carb and went further down to number 5.
Could have been in there for many miles before the damage occured.

Mike.

 

[Bort62]

Yeah, getting stud the size of that past the intake valve would be interesting too.

Any damage to the valve or seat?

 

[CobraSix]

New engine already ordered. It should arrive soon.
Isn´t it possible to sleeve the block?

It is...but honestly resleeving isn't usually a great option. As cheap as a 200 block can be found, it's not really worth it.

Generally you don't think about resleeving until you get into the $5000 block range (just block price) for large diesels (trucks and marine). Otherwise it's cheaper to replace the block.

Slade