440 Advice

[Tom68]

25ys ago I got a frozen 68 440 HP.  Finally got around to taking it apart.

Its a 68 date code block with a date consistent with my 68 chargers manufacture date.  So I'd like to use the block.  Not planning to build a lot of HP, just mildly above stock.

Three pistons rusted and took a lot of WD-40 and firm tapping to break them loose.  Took scotch bright pads and scotch bright wheel on my drill and somewhat cleaned the cylinders.  I probably won't start the motor rebuild for another year or so.  At that time I'd have a machinist do the block right.

I was thinking of using a stone hone tool to just try to see if it will clean out the rust.  Just as a first pass guess on whether the block will be usable or trash.
My question: is this advisable?  Any guesses on whether this block is trash or not?

Also what is the max oversize bore?  Seems to be a controversy.  Some say .020 some .030 some more.

Thanks

[Kern Dog]

I've heard of people going .060 over.
Mopar blocks are hard. The amount of nickle  in the iron is higher so the cylinders do not wear as fast as others like GM and Ford. Machine shops should only bore to the size they need to get all the taper out and to get past any rust spots or scratches. If it cleans up at .020 and you can find .020 over pistons, that is where you stop. The .030 number is a typical goal for many shops though. Going further than .040 ? Some advise a sonic check to determine the thickness of the cylinder walls, especially on the "thrust" side where the pistons push as much to the sides of the cylinders as up and down. This is the header side of the 2468 cylinders and the lifter valley side of the 1357 cylinders.

[BSB67]

Why do you think it might not be usable?

[Challenger340]

Some advise a sonic check to determine the thickness of the cylinder walls, especially on the "thrust" side where the pistons push as much to the sides of the cylinders as up and down. This is the valley side of the 2468 side and the header side of the 1357 cylinders.

Excellent rationale as to why sonic testing can allow 'adjustments' to be made prior to Boring the Cylinders.... or identifying a Block that shouldn't be used.
Nonetheless it's the other ther way around.... the major thrust on the 2-4-6-8 passenger side bank is the header side, and on 1-3-5-7 driver's side bank it's the valley side.  
Engine rotates 'clockwise' as seen from the front, when the power stroke loads those walls the hardest.

.060" over is usually doable and usable for all except the most demanding applications, given the extremely good angularity of Mopar BB's.   Stroker app's can be a different ball game.

[b5blue]

I had to go .060 and all is well.

[Kern Dog]

Excellent rationale as to why sonic testing can allow 'adjustments' to be made prior to Boring the Cylinders.... or identifying a Block that shouldn't be used.
Nonetheless it's the other way around.... the major thrust on the 2-4-6-8 passenger side bank is the header side, and on 1-3-5-7 driver's side bank it's the valley side.  

Thank you. It seemed right when I wrote it but I see the mistake now. I'm going to edit that now.

[Tom68]

Thanks for the thoughts.  What do you guys think of giving it a quick hone?  My intent is to not only satisfy my curiosity but also its seems like if I can take off most of the rust and put a layer assembly lube it'll stop the rusting until I can get to having the motor rebuilt (which may be a while).

BSB67 - I'm just not sure how deep the rust goes and how much it'll take to make the wall smooth and usable.

[Challenger340]

Thanks for the thoughts.  What do you guys think of giving it a quick hone?  My intent is to not only satisfy my curiosity but also its seems like if I can take off most of the rust and put a layer assembly lube it'll stop the rusting until I can get to having the motor rebuilt (which may be a while).

BSB67 - I'm just not sure how deep the rust goes and how much it'll take to make the wall smooth and usable.

You could try cleaning up the Cylinder rust a bit before taking to Machine Shop for a REAL laterally controlled Stone holder Hone process, because I doubt you 'stone hone' would have the capability to remove very much at all ?

Is your 'stone hone' one of those "floppy" shoe'd deglazer things with just the one center mount for each stone ? or is it an actual laterally maintained stone holder type I mentioned above ?
The reason I ask is your can do more damage with creating 'taper' in the Cylinders with the former than any rust removal ?

Either way,
any pitting remaining at all... even microscopic ? will undoubtedly return and continue ?

I had thought initially your intention was to remove the rust to see if the Block was able to be Bored/re-used/at the machine Shop  ?
However,
in your last post you seem to elude to re-honing/de-glazing for re-use 'as is' when you say I'm just not sure how deep the rust goes and how much it'll take to make the wall smooth and usable

Which is it ?
A.) are you trying to remove rust to see if the Block is usable for the Machine Shop to Bore/Hone/Fit new Pistons ?
or
B.) trying to remove rust enough to see if the Block and cylinders can be re-used 'as is' ?

If the answer is "B"..... go get yourself a 240 Grit BALL DEGLAZER..... and do what's typically called a 'Chicken ball' re-hone
see here;
https://www.summitracing.com/parts/brh-gbd41224
and be careful because they can remove alot of material if you are not careful and are planning to use the Block 'as is' without reboring !

[Tom68]

Sorry if I've been confusing.  I am not considering honing for use.  I am hoping I can do some light honing and the see most of the rust taken off.  Then I'll have warm fuzzies that the block MAY be usable.  I also think removing the thick areas of rust and greasing to protect will help keep if from deteriorating too much more if it takes me a couple of years before get it to a machinist.

It is kept in a heated insulated garage, not exposed to any weather.

BUT, I don't want to damage the block.  But it just seems that leaving that much rust alone for a year or two is not the right thing to do.

Oh, and the hone I have is one of those spring loaded with the three stone pads.

[Challenger340]

Sorry if I've been confusing.  I am not considering honing for use.  I am hoping I can do some light honing and the see most of the rust taken off.  Then I'll have warm fuzzies that the block MAY be usable.  I also think removing the thick areas of rust and creasing to protect will help keep if from deteriorating too much more if it takes me a couple of years before get it to a machinist.

It is kept in a heated insulated garage, not exposed to any weather.

BUT, I don't want to damage the block.  But it just seems that leaving that much rust alone for a year or two is not the right thing to do.

Oh, and the hone I have is one of those spring loaded with the three stone pads.

Any remaining rust "pitting' in the Cylinder wall is the enemy.... and will continue to propagate deeper unabated unless physically cut out by Boring(removed down to fresh cast iron) or neutralized by sand blasting and muriatic acid for example, etc.....
which in either case then requires protection of the now raw/exposed Cast Iron from any new moisture/oxidization to begin anew.

FORGET the spring loaded with the three stone pads. style de-glazer, throw it in the garbage.... because you are likely to do more damage(taper) to the cylinder than good as they provide no lateral stone control.

We've Bored LOTS of rusty cylinder Blocks.... and then let them sit protected even well Oiled as core stocks in a temperature controlled shop and thinking we got it all(rust).... only to find out a year later we missed some microscopic rust pitting that was coming back to our surprise.

Pictures would help in assessing what it is you are up against here ?
But IMO..... and without seeing anything..... your best bet is the Chicken Ball I forwarded the link to earlier ?
see here: https://www.summitracing.com/parts/brh-gbd41224
That's what we use on rusty cylinders first to cleanup and assess Cylinders before the Sonic Testing/Boring process

[Tom68]

Thanks, I'll look into the chicken ball.
I understand that if I don't remove it all, it'll keep working back.  But doing nothing is worse.  And rebuilding right now is not feasible.
Just trying to limit the damage.

Thanks for all the info.

[70 sublime]

I have often thought about just submersing a block for later use in a barrel filled with oil

Would that work to keep the rust away or getting any worse ?

We have lots of used motor oil around

[c00nhunterjoe]

Wow, thats one way to do it. Lol. Sure, to stop rust, you must stop moisture and oxygen. Submerged in oil would do that.

[b5blue]

Sorry if I've been confusing.  I am not considering honing for use.  I am hoping I can do some light honing and the see most of the rust taken off.  Then I'll have warm fuzzies that the block MAY be usable.  I also think removing the thick areas of rust and creasing to protect will help keep if from deteriorating too much more if it takes me a couple of years before get it to a machinist.

It is kept in a heated insulated garage, not exposed to any weather.

BUT, I don't want to damage the block.  But it just seems that leaving that much rust alone for a year or two is not the right thing to do.

Oh, and the hone I have is one of those spring loaded with the three stone pads.

Exactly why I had to go to .060 on a block that had never been bored prior.

Any remaining rust "pitting' in the Cylinder wall is the enemy.... and will continue to propagate deeper unabated unless physically cut out by Boring(removed down to fresh cast iron) or neutralized by sand blasting and muriatic acid for example, etc.....
which in either case then requires protection of the now raw/exposed Cast Iron from any new moisture/oxidization to begin anew.

FORGET the spring loaded with the three stone pads. style de-glazer, throw it in the garbage.... because you are likely to do more damage(taper) to the cylinder than good as they provide no lateral stone control.

We've Bored LOTS of rusty cylinder Blocks.... and then let them sit protected even well Oiled as core stocks in a temperature controlled shop and thinking we got it all(rust).... only to find out a year later we missed some microscopic rust pitting that was coming back to our surprise.

Pictures would help in assessing what it is you are up against here ?
But IMO..... and without seeing anything..... your best bet is the Chicken Ball I forwarded the link to earlier ?
see here: https://www.summitracing.com/parts/brh-gbd41224
That's what we use on rusty cylinders first to cleanup and assess Cylinders before the Sonic Testing/Boring process