How serious is this?

I just got the head back from the machine shop and my mechanic went to clean the block prior to install and found this...





Mechanic says the walls are shiny with a lack of crosshatch and that he can feel the pits with his finger...

Does the block need just a rehone? Or does it need to be bored out too?

 

How did it run before? Any piston slap noise? And is that the thrust side ("front" of the cylinder) or the back side?

In all reality. It doesn't look terrible. I'd run it. With the fresh head, you'll probable get some more blow by though..

 

Up until i pulled the head the car drove normal under normal driving. Seemed like it was hitting fuel cut during full throttle though ehich is why i checked the head and found the leaky valves.

No abnormal noise from what i could tell but my car makes all kinds of noises so i really don't know.

Car has 40,000 miles on it. Evo 9 running ethanol for about 20k miles.

 

If you can JUST BARLEY feel those with your nail, you'll be completely fine. Nothing to worry about. Doesn't seem like they are very deep.

You can do light honing if you are capable (not very difficult, you can find video's on it as well). Either way, you'll be completely fine.

 

@letsgetthisdone

The shiny spot is toward the back side of the cylinder so pointing toward the firewall.

 

How does the other side (thrust side) look? The thrust side will typically show more wear...

And don't do any honing unless you plan in completely disassembling the engine. There is no way to keep all of the filings it will generate from getting into the engine. And since it's assembled you won't be able to clean it either..

 

Lack of crosshatching is going to cause lubrication problems that will make this worse. Hard to say without measurements if a rehone or boring is called for.

 

I can see cross hatching in the pictures. It's just that one spot...

 

Yah if I'm going to do anything the whole block is coming out. I don't do these sorts of things half assed.

So it's either leave it be and wait to build the bottom end or just take the hit. But that hit will cost me near 3k after i just spent 2k on the head

 

Well FWIW if it was my engine i wouldnt put it back together looking like that. Do it once, do it right.

 

Lol, you say that like a quick head job can turn into a full engine rebuild with just a little more work. It's an engine, not a human body, it can handle certain imperfections. Slap the head back on and run it. If you're really worried, do a leak down test once you get the head on, before you install the cams. Just make sure the piston is at TDC on the cylinder you're testing. If it checks out ok, button it up and ship it. If it doesn't, you've only wasted a $50 head gasket...

 

Your mentality belongs in the realm of echono boxes that you would want to spend as little as possible to keep on the road. You cant compare a machine to the human body. If you scrape your arm it will heal, not so much an engine. Furthermore what OP is seeing in these pictures is a problem, but its also a symptom of another problem. What is being seen is not normal wear.

 

It's actually not.
Is it worn? Yes. Is it worn out? Not really. Is there an issue? Yes. Is it terminal? Not immediately.

The problem you see here is not very likely to cause a catastrophic failure, nor is it indicative of a piston that's ready to come apart. It's simply cylinder wear, and it's mid stroke.

It would be different if it was apart, and a simple hone only partially cleaned it up, and you were debating going with oversized pistons. But its not apart. He just has the head off, and the motor is still in the car.

 

It seems like you arent even addressing the OP's question. He didn't ask if he could slap this back together and run it. He asked if it needed to be honed or rebored/honed. Could OP slap it back together and get more miles out of it, probably. It would also always be in the back of his mind that his engine has a problem and is potentially a ticking time bomb. I don't believe in cutting corners, doing so always seems to come back to bite you in the *** later.

 

His first question is, "how serious is this?" To me, that reads, "can I run this engine longer or does it need to come apart?"

If it was mine, I'd run it. Car is very low mileage, probably had some rust build up in that cylinder from sitting, and this is what's left behind after piston cleaned it up.

OP, what does the front (radiator) side look like?