Nick in the cylinder wall

[2000gt]

hey guys, Well I was lucky enough to find a 70 440 block for my 70 cuda but my luck went South tonight.  Was taking the egine apart so I can take it in to be cleaned, checked, etc and the pistons were being real stubborn.  To make a long story short I put 2 little nicks in one of the cylinders as I was tapping the pistons out and the bar i was using slipped.  The largest of the two is about 2 mm long and maybe 1 mm deep.  So I guess what I'm wondering is how much material is taken off when you bore the cylinders, enough to cover up my mistake or is the engine toas?   I only wanted to go 30 over but I guess I could go more???  I guess I'll have to take it in to the machine shop to know for sure but that will be a few days away so just wondering what you guys thought.  thanks for the input.

[nivvy]

   at worst you can sleeve it if you have to...there are as good as anything....

[MyMopar]

To make a long story short I put 2 little nicks in one of the cylinders as I was tapping the pistons out and the bar i was using slipped. 

   This is the reason why you need to use a plastic mallet, piece of PVC pipe or a length of wood.  Lesson learned the hard way but maybe someone else will come upon this thread and think twice.

As far as boring, I believe the most you can go safely is .060 over.  I don't know what the equates to in mm no wait I do.  If my math is right 1 mm = .03936996 so if I'm right and you're right about the depth of the scratch, a .060 over bore will take care of it, I'm not sure if you can do a number between .030 and .060, but if you can do a .045, I'd do that before going all the way out to .060.

[ChallengerHK]

 

If you're doing a .060 overbore, isn't that .030 on each side of the bore? In other words, you're cutting away .030 all the way around to make the bore .060 wider, right?

[quagmire]

No, if it is bored .030 over the entire bore's size increases by .030. 

[ChallengerHK]

I think that's what I'm saying.

If this is the bore:

          :---------------4.00"---------------------:   

and you bore .060 over, you're doing this:

   :.030:-----------------------------------------:.030:

so that the total bore is .060 bigger, by removing .030 from either side of center.

[ntstlgl1970]

Unless the size of the nick/scratch is not reduced after a rebore/hone (is your block standard?) I wouldn't worry about it. Once the block is bored and honed you probably won't be able to tell where the nick was anyway.

both Quagmire and ChallengerHK are right .030 = .030 over or .015 per side

[2000gt]

Yeah, I know it was my bonehead move - it was a very akward engine to get apart as it was so seized it wouldn't turn over at all.  I usually use a soft piece of brass, but couldn't find it, got impatient and used a drift and of course it slipped...  Oh well, I took it into the shop, they are going to rough bore it to just shy of 30 over and see what it looks like, if its still no good I'll probably just sleeve that cylinder. 

[MyMopar]

If you're doing a .060 overbore, isn't that .030 on each side of the bore? In other words, you're cutting away .030 all the way around to make the bore .060 wider, right?

Good catch there, I was spacing.

[ChallengerHK]

Ultimately it probably doesn't matter; I think ntstlgl1970 was right about boring and checking it then deciding whether or not it needs a sleeve.. I just wanted to make sure that I wasn't missing something.