This is a Mega Block, the area in question is between #2 and #3, that area should be solid!

I would measure the piston skirts and bores before buying pistons, seeing the top ring means nothing to me as that part of the piston is smaller. From what I see is it possible the head gasket was seeping when the car sat, or do you see a crack for sure? If it was seeping with the rusting and the white corrosion I think you found your problem, rings are ruined. If that is a crack, and that block is siamese, you had better magnaflux at least that bore,and the bore beside it. I would do them all.

I'm thinking you must really mean 2 and 4. Or maybe 3 and 5.

Given the odd pattern of corrosion I wonder if the bores were straight from the get go. Although we will never know the answer, It's safe to say they're not going to be straight now. If the corrosion got to the rings, looks like there is a good chance of that, then safe to assume they're gone.

I suggest check ring side clearance and overall condition of the ring grooves before putting pistons up for sale or deciding selling price, (to avoid angry future customers). Good chance they are still OK but never hurts to make sure.

7.10 rod and 4.50 stroke is probably the path of least resistance in terms of not only known decent rod ratio (Same as a Pontiac 455, can't get much more conservative than that) and relatively quick/easy parts availability.

LOL, yes it is #2 and #4

As for needing longer rods to keep the scirt of the piston from coming out of the bore, How much improvement do you think it will make over this?
I also see a good crosshatch at the bottom of the bore, so I don’t think sideloading wore out the bottom of the bore.

I am also trying to identify the block and date of casting. The casting date appears to be 0815?

A good machine shop should get you squared away, also the 4.5 stroke should not be a factor...

Good chance I got it wrong but I believe it could be the 15th week of 2008.

The "MC" inside a shield indicates Motor Castings foundry.

Darned if I can remember the location of the stamped in machining code (not a direct date), but MP never required Cummins Recon to document it or provide the decoder ring for it anyway. The Cummins markings were for the most part useless during my time working with these gems.

After the megablock went away casting date wasn't tracked on the block any longer, only the machining date was tracked by a stamping in the front.

Thanks for the replies. Yes I think a GOOD bore/hone and new pistons will square it away. #2 wall will either clean up or be sleeved. I have an appointment to pressure test to be sure that it is not a crack.
The history on the short block is quite interesting and I have paperwork to prove most of it.
I bought the short block from a gentleman who grew up in Detroit. He bought the block as soon as Mancini had several to choose from. This one sonic tested the best.
The crank with standard Mopar journals was in a shipment from Callies to Scott Karlita. Not having the “special” journal size, Scott sold it.
The whole short block was sent to Diamond (early this century) where pistons were provided, Manley rods were purchased (standard Mopar length, journal and pin as they were on sale). The bore and finish hone and balance (Mallory metal) was done by none other than Butch Elkins before he passed away and Diamond closed the machine shop. This is reportedly one of the last engines that Butch did.

Found the problem, no wonder it used oil street driving! The oil rail is through the wristpin hole. Useless for a street engine!
I find this is common for a 4.5” stroke. So, a Callies 4340 billet crank balanced with Mallory metal, Diamond 3.50” pistons 10.8 cr at 0 deck, are all up for grabs.

A little history here, this was one of the last assembly’s done at the now defunct Diamond Racing. Crank is standard Mopar journals.
Fine for a race engine, this one was originally intended for boost, but not what I want for a street engine.

I've run the ring around the wrist pin many times. That's not why it's using oil. Unless I'm missing something, there is no reason to think that the oil ring passing around the wrist pin will cause an engine to use oil.

I'd keep looking.

Until you get everything measured properly there's no way of knowing what you have.

Right now my money is on you were sold a bill of goods.

Kevin

Granted, the bores are not what they should be but I have always understood that unsupported oil ring is a no no for the street. Even Rich in his blook says to stay away from it.

I'm sure it's said to stay away from it. Sometimes you can't. But oil consumption because the oil ring isn't supported 100% by aluminum but is supported 90% or even 80% by aluminum and the rest by steel doesn't affect oil control as I've seen it.

The biggest things for oil control are bore geometry, crankcase pressure and second ring design.

To me, oil ring placement is like connecting rod side clearance. It's been taught wrong for decades and sometimes still is. I suspect long after I'm dead someone will still go berserk because the side clearance was over .024 or some silly number such as that.

I'd hate to see you spend a bunch of time and money and not fix the issue. IMHO, your problem isn't in oil ring placement.

But I've been wrong before. Just ask my wife.


EDIT: I should add the biggest oil burner I've seen was a customer who did his own engine assembly. The engine was a mosquito killer and the blame went to me for my honing procedure.

When the customer finally got tired of bitching about how crappy my cylinder honing was, he pulled the engine to take it apart so it could have the bores "touched up" by a "real machinist" who understood "how to run an F'ing hone".

The bad thing was...once it was apart, he realized HE didn't install the oil ring spacer.

Of course, he didn't go back to the track for 4 consecutive weeks and tell everyone who would listen how stupid the engine assembler was.

I post that because 1. It's damn funny and 2. Because stuff happens. It's not always what is blatantly obvious that is the issue.

Nope, that's not why you're burning oil. That ring setup is NOT a no-no for the street. My hemi is like that and uses no oil.

Many(most?) 1.320 c/h pistons used in low deck 451/470/511 builds have the pin bore in the oil ring groove.

Same with lots of SBC stroker combos.

If the oil is coming past the rings(especially that much oil), the perimeter of the piston tops should be pretty much completely clean.

Try mesuring oil ring tension with a fish scale. Take top and second ring off piston. Install it upside down and pull it out with fish scale,you my do this a couple times to get a feel for it. Also you may find it to be ok tension wise,good luck.

All the low deck pump gas stroker motors I build have the wrist pin in the oil ring groove, no problem on any of them so far on oil consumption Those pistons come with a tool steel oil ring spacer to keep the oil ring seated against the spacer so the rings will rotate without getting hung up in the wrist pin bores, I'm assuming Maybe not
Knock on wood now so I don't jinxed myself

The picture the OP posted shows the spacer rail installed.

Again, that isn't the OP's issue and I hope he keeps looking so he doesn't go through this again.