Black spot on cylinder wall…dingleball hone or worse?

[TexasRoadRunner68]

First off, it’s not a mopar engine. I got this used as a junkyard pullout to put in a jeep pickup. I have broken down a couple of motors now, some with actual rust putting in cylinders. What is this black spot? Coolant sat in the cylinder?

I had intended to do this on the cheap end. Bearings, rings, arp hardware etc. I hadn’t planned on having the block machined.

Think this will come out with a dingleball hone? Or is this likely a block that needs to be bored?

 

[Black_Sheep]

Is it rough and pitted or just discolored?

 

[blue69runner]

Looks like the block sat with that piston down and you have that mark in there. If no means of seeing it indented or scored you should be fine.

 

[Fran Blacker]

Certainly going to need an over bore. You should see if .060 or less will will clean it up. Willthe block take a .060 over? Boring and pistons cost money!

 

[gtx6970]

I would make a couple passes with a bar hone, see if the mark goes away. If not bore and pistons are in its future

 

[4mulas]

Certainly going to need an over bore. You should see if .060 or less will will clean it up. Willthe block take a .060 over? Boring and pistons cost money!

If it even needs a bore why go straight t0 .060?

start with a single ball hone and see. If that doesn’t do it then you’ll know where you stand

 

[Rusty knuckles]

If I wasn't building anything crazy I don't even think I'd hone it. Depends what the fingernail test says but I'd probably brake clean and scotchbrite pad it a little yo clean it up and run it as long as it's smooth.

 

[snakeoil24]

Bore it

 

[Fran Blacker]

If it even needs a bore why go straight t0 .060?

start with a single ball and see. If that doesn’t do it then you’ll know where you stand

You missed the or less after the .060. Boring .060 your only taking .030 a side. He needs to know how much of an over on that cylinder.

 

[lewtot184]

Hot antifreeze will do that with a head gasket leak.

 

[70bigblockdodge]

No bad fingernail catch, scotch brite it a little. If it cleans off at all, run a hone on it and never think about it again. Hell even a decent pit or two will make no difference on a regular daily.

 

[blue69runner]

Would run a mike down the hole and see if you have too much taper in the cylinders.

 

[toolmanmike]

A dingle ball hone is just a glaze breaker. It won't do anything more than sandpaper or Scotch Brite would. If there's damage to the bore, it will still be there whether you scuff the black off or not. It won't take enough material out to make the cylinder round or take out taper. If you can catch your fingernail in it the rings will have a hard time sealing. It's up to you how "good" you want it to be.

 

[4mulas]

You missed the or less after the .060. Boring .060 your only taking .030 a side. He needs to know how much of an over on that cylinder.

Pretty sure you’re not thinking about this correctly Fran. .030 over bore is the total oversize. Oe: if a cylinder is 4” bore and you go thirty over the new bore diameter is 4.030

I’ve never heard of anyone ever referring to it as taking .015 off ‘each side‘ for a total of 30 thou over

if you took .060 of ‘each side’ it would be .120 over. Don’t know of too many engines that can handle that. 60 thou over is generally a max for most mills but not desirable for most people..

 

[Fran Blacker]

Probably could have worded in better. That dark area looks rough. Question is how deep that is, hope OP posts results.

 

[Thrashingcows]

You guys would have cried at the condition of the cylinders on the 440 in my 68 T/C wagon....there is even a small chunk of cylinder wall missing the size of a pea and quite deep. Been running this worn and high mile motor for over a decade with no issues. Never touched the short block other than a new RV cam and double roller chain, then new gaskets and seals and a fresh set of heads...with a cast spread bore intake and a tuned T-Quad I was getting 15/16mpg.

Having said that just clean it up with a ball hone and run it!

 

[threewood]

I've seen staining like that before. If it doesn't catch a nail or feel rough and you are not building a race engine I say run it.

 

[blue69runner]

Was able to get a block that only needed to be bored 20 over size. My original motor would have had to be over 30. Front main bearing register was loose on my old block. Found the Unbored block on E bay 383 motor.

 

[Don Frelier]

Try the ball hone if you get 80% or more just put it back together

 

[Cranky]

Pretty sure you’re not thinking about this correctly Fran. .030 over bore is the total oversize. Oe: if a cylinder is 4” bore and you go thirty over the new bore diameter is 4.030

I’ve never heard of anyone ever referring to it as taking .015 off ‘each side‘ for a total of 30 thou over

if you took .060 of ‘each side’ it would be .120 over. Don’t know of too many engines that can handle that. 60 thou over is generally a max for most mills but not desirable for most people..

Yup, .030 over is .030 over but Fran is right....you take off .015 to the side which means if the 'mess' is deeper than .015", you have to go to the next size which is .040 over (if pistons are available) or go .060 over which means taking off .030 to the side. Machinists understand that thinking pretty well.