Black spot on cylinder wall…dingleball hone or worse?

[Hemirunner]

It’s an LS. Bolt the head back on and run it.

 

[sam dupont]

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..

My Uncle's Anglia had a 283 bored out .060 making what they called a 301. Going from 3.875 to 4.00, the bore of a 327. It was good for drag racing only as the thin water jackets couldn't be cooled.

 

[4mulas]

My Uncle's Anglia had a 283 bored out .060 making what they called a 301. Going from 3.875 to 4.00, the bore of a 327. It was good for drag racing only as the thin water jackets couldn't be cooled.

Isn’t that .125 over , not 60

 

[Hemirunner]

Isn’t that .125 over , not 60

It would technically be .120 over. The terms are in reference to bore diameter, not radius so .030 over is .015 removed from each side, .060 over is .030 removed from each side, not that circles have sides but that’s common terminology.

 

[sam dupont]

Isn’t that .125 over , not 60

yep, brain hiccup. Before 327's existed it was some 4 inch piston in a sacrificially bored screamer. They'll make more

 

[toolmanmike]

Yep, a 301 is .120 over.

 

[4mulas]

It would technically be .120 over. The terms are in reference to bore diameter, not radius so .030 over is .015 removed from each side, .060 over is .030 removed from each side, not that circles have sides but that’s common terminology.

4.00 - 3.875 = .125

 

[Hemirunner]

4.00 - 3.875 = .125

yeah, I didn’t do the math, just saw the .060 and went from there...

 

[EmitRDetsaw]

Coming from a motorcycle background - and two-strokes, no less - I've cleaned stained cylinders such as that with - prepare thine selves - muriatic acid. The stuff you get at a pool supply store. Wear gloves and use in a well-ventilated area. Wipe on, wipe off. Neutralize with a baking soda smoothie, and hose off with brake cleaner.

Bring the hate.

 

[eldubb440]

phosphoric acid might do it, and you live to tell about it .....don't allow the acid vapors in your shop

 

[Jeff Peterson]

Coming from a motorcycle background - and two-strokes, no less - I've cleaned stained cylinders such as that with - prepare thine selves - muriatic acid. The stuff you get at a pool supply store. Wear gloves and use in a well-ventilated area. Wipe on, wipe off. Neutralize with a baking soda smoothie, and hose off with brake cleaner.

Bring the hate.

I too, spent many a year with 2 strokes, the acid was to remove the melted/smeared aluminum off the cylinder walls after a piston sieze, it could actually make stains like this, if not cleaned and oiled quickly.

 

[blue69runner]

I don't get it. If I want to take a bore 20 over stock size bore, then that is what it is. Splitting hairs on what is taken off the entire bore. The metal that is removed from the bore is what the machinist decides to take out when boring. I leave this up to the machine shop. Now when I mike a jug from top to bottom so I can see how much taper it has in it. This allows me to know how much should be taken out during boring to make a straight cylinder. We all know older motors will be sometimes egg shaped from piston slap in the bottom of the cylinder. Sometimes there is scratches in the walls also in old motors. Now day's some builders sleeve the motors, but I am not fond of that. Cutting too close the water jackets can cause over heating in the motor. I did buy a motor that was able to be 20 over stock and am happy with that. A good machine shop can do the proper job for you and most of us do not have the motor bore machine that we would only use once. So just to say build it like you want it and drive the wheels off it.