hone

Remember I own an automotive machine shop so I am going to lean on the safe side….

That being said, you really can’t tell the condition of a bore just by looking for a ridge at the top. They can be out of round, tapered, oversized etc… You really should at the minimum check for those conditions before you do anything.

IMO there is no substitute for a Job done on equipment that can make the bore round and straight.

If and only If the bores meet the above you can use a flex-hone on them IMO.

 

I would sugest a three stone hone at least. I dont like those bead hones cause you realy cant see any imperfections in the cylinder. At least with the three stone you will see larger imperfections, and posibly correct minor ones.

 

One thing with the dingle berry hones. The up & down motion isn't as critical to get the correct cross hatch pattern as with the stone type. I've used both, run at @350rpm with a 1/2" drill & slow steady up & down motion. Most 1/2" drills have a 350 rpm speed max limit.

 

Have to agree with K-Star ^^^ Using a hone or BRM deal is okay so long as you understand bore finish. Some guys swear by a light rub with just paper and no hone on re-ring. You really need to understand what it is the hone is doing for you, or more specifically, your ring to bore interface. There is plenty of information/debate pertaining to bore finish and rings used too.

 

Thanks for all the info so far. I understand that a ball hone is basically going to remove the glaze produced by the old rings and add some crosshatching so the new rings will have a better chance of sealing. That's pretty much all I'm looking for. I know it's not removing any material (well, probably nothing of any significance).

Here's the deal with the engine. It's an AMC 390 I got it in a parts buy. It looked pretty clean (the surface rust is from sitting in my garage), so I took it to the machine shop to have it checked out. He noticed the fixed cracks and two sleeved cylinders (see pics below) and also noticed two freeze plugs missing, so he said I should try to find another block (not real easy being an AMC 390, but I was successful). Since I have basically nothing into it, I was going to just install some new freeze plugs, put the motor together, run it and see how it goes. I decided to check out the bearings and noticed some of them had some copper "lines" in them, so I figured I'd throw some bearings in while it was apart. That's when I decided to pull the pistons and throw in some new rings as well. The cylinders are standard, but the crank is already .030/.030, although it looks to be very clean with no issues. I'm now thinking I may pick up a bore gauge and see what shape the cylinders are in. If OK, I could just re-ring it. I might take it back to the machine shop and see if they'll check it out to see what it needs, but I'm trying to do this cheap as I already have a bunch of other engine projects going and sucking up my money.

K-star- Since you're "in the biz", what are you're thoughts on this?

Thanks again for all the comments and keep 'em coming!

 

Oh, one last thing. When I pulled the pistons, I looked for the mark that shows if they're aiming forward. The only thing I found was on one side of the piston where the pin is, on both sides of the pin is a big F. I take it this is for FRONT or FORWARD. Problem is, there was no rhyme or reason to which way the pistons were facing! Some had the F toward the front, while others were facing the back of the block. AMC uses offset rods, so I can't just turn the rod and pistons that are facing the wrong way around. ARGH!!! I did note, though, that all the stampings on the big end of the rods (to keep the right cap with the right rod) were all on the same side, so I'm assuming it's just the pistons were hung on the rods incorrectly. Clearly not a high dollar rebuild.

This being the case, I might end up having to have the block honed or bored and buy some new pistons anyway. I reeeeally didn't want to have to do this, but it seems it might be the case.

This is a dumb question, I'm sure, but what issues would arise from running the pistons the wrong direction?

Lastly, in the bottom picture above, you'll note the bolt hole looks a little rusty. Yes, I'm going to chase all the threads as well as remove any surface rust and thoroughly clean all the parts (block, rods and pistons, crank, etc.). I'm not THAT stoopid!

 

Some pistons will go either direction. Post a pic of a piston top (full view).

 

Lastly, in the bottom picture above, you'll note the bolt hole looks a little rusty...
...the surface rust is from sitting in my garage

What does the rest of that block deck look like??? Post some more pics, also of these other things you talk about.

 

I did a similar job recently on a SBC and my machinist said cast rings are more forgiving for out-of-round, etc than the moly.

 

yes, cast rings are the best to use if your not boring the cylinders.. they are often reffered to as " Rebuilders Rings " for that reason

 

block

Again, what i would do and what you can "get away with" are worlds apart.

The very first thing i would do with that block is hot tank it and mag every square inch of it..

Sleeves,welded deck, missing freeze plugs.....all adds up to a block that was frozen one time, and probably hard...

Keith

 

After seeing those pics I would do exacly what K-star says, or find a different block. I hate to see you try the cheap way out to save a buck just to find out it will cost you more time and money in the end.. :sweat:

I have found out th ehard way that the easiest way is never the right way.

 

After weighing all my options, I've decided to do as suggested. I'm going to take the block to the machine shop and have it checked out. For a couple hundred bucks, I can have the piece of mind knowing whether it's OK or not.

Thanks again for all the comments and suggestions. :thumbup: