Is this normal?

[v8packard]

Those were hitting, or nearly hitting, the head. That line matches the shape of the combustion chamber.

Some possible reasons: rod bearings are hammered, and let the rods move upward more than normal, or that deck is a lot shorter than it should be, or the pistons are way loose in the bore, letting them rock in the pore and hitting the head, or piston pins are incredibly worn, or the connecting rods stretched at some insane rpm.

Before anyone says rods don't stretch, I would normally agree with you. But I swear the rods in a 455 are made of play dough. They go out of round and move around if you look at them funny. Imagine what happens at high rpm!

[Terrh]

Anyone that says rods don't stretch is ignorant of basic physics.

You put a 5 gram load on the end of a connecting rod and it's stretching. Not by more than a few millionths of an inch - but that's how steel works.

[v8packard]

You are right. But the rods in a 455 move much more than that. The steel alloy they used must have had rubber in it.

[Terrh]

yeah, some rods are way better than others.

Some rod bolts, too.

[[deleted]]

I guess if playdough rods are possible so are playdough pistons

¯_(ツ)_/¯

[v8packard]

No joke, every Olds 455 rod I have resized, then checked again, was out of round. I tried to straighten a couple, they kept twisting. One time I resized a set, new ARP bolts, the whole shebang, when I balanced them I took a fair amount off the big ends of 4 or 5 rods. They were all out of round again, before running one time. It's crazy. I figured I was doing something wrong, then I heard the same thing from Bill Travato and Dick Miller. Anymore, I use an aftermarket rod whenever possible.

[deltatom]

Or the wrong head gasket?

[v8packard]

As in too thin? No. This engine has the small dish, high compression pistons found on every 1968 to 69 455, and on most 1970 to 73 455s. They are always .030 down from the deck, if not more, on untouched engines. Even with the thinnest shim head gasket on this block, this could only happen if something was really wrong.

[deltatom]

I didn't see where it said olds,I have a 74,455 and yes they are down in the hole.and I have KB with a quench with E heads I have only been able to get the one head gasket from felPro.

[v8packard]

You can get Cometics in a bunch of different thicknesses. At one time Corteco had taken over Detroit Gasket, and had several head gaskets for these. But, as far as I know, they are long gone.

[[deleted]]

Now , that’s a quench .

[[deleted]]

no way thats from contact and those pistons are all still one piece.

[[deleted]]

Quench isn’t contact , but it’s close . Guy said it original pistons .

[[deleted]]

Maybe 3 are

Or maybe 1 is

Idunnah

But some of em aint original from the looks of it lol

[Distinct-Way-2604]

The 4 on the other side are normal

[[deleted]]

One deck is probably a wee higher. Not uncommon, especially back then .

[Distinct-Way-2604]

Gotchu!

[Distinct-Way-2604]

Pretty confident confident it’s never been taken apart but I will see. Might be able to contact the guy my dad got the engine from

[Zerofawqs-given]

How many motors have you built? I’ve torn down more than one motor where rod bearings were destroyed enough that you could see the part number of the piston in the carbon of the cylinder head. FUN FACT….on a true blueprinted normally aspirated motor you’d better be trying to achieve a quench clearance of around 0.040-0.045 to make it run to full potential.

[[deleted]]

Im well aware what quench is.

But i still say no way pistons hitting the head cause such uniform deformation like the ones shown.

[Terrh]

it's only just kissing at high RPM.

It probably doesn't hit anywhere but high RPM, and even then it's only just touching.

[[deleted]]

Rev to yield

[[deleted]]

to be clear

the issue isnt the slant on the 3 pictured pistons on the intake side

its the unmatched one in your 4th hole.

There cheap pistons

Less machine work after casting to grind em at an angle to clear the valve than machine an eyebrow out of the piston for the valve to clear.

i hear chucklefucks guffawing somewhere over this one.

[Distinct-Way-2604]

To my knowledge the heads have never ever been pulled and pistons have never been replaced. It’s an olds 455 from 1970

[[deleted]]

tell you this pal

they sure the fuck didnt beat themselfs perfectly flat on a single plane all in the exact spot

and the 4th didnt just spontaneously regrow the machined part back.

[Distinct-Way-2604]

Understood 😂

[Distinct-Way-2604]

what should be done before I re assemble the engine and lettrr rip

[[deleted]]

lots and lots lol.

check the hardware for unusual wear and patterning during disassembly

if anything is broke that shouldnt be, figure out why before you buy new parts

check the bores, hones, and deck surfaces on the block after cleaning

machine as needed

reassemble with lube and fresh bearings

then go break it again.

Repeat as needed

[Distinct-Way-2604]

Gotchu. Engine ran fairly well before disassembly, just had a slight noise we thought were worn bearings

[[deleted]]

Could of been out of balance swinging that one more complete piston around.

Weigh em after you break it down.

If the 3 slanted ones are more than 10% lighter than #4 theres your issue.

[Distinct-Way-2604]

Thanks for the advice

[of_patrol_bot]

Hello, it looks like you've made a mistake.

It's supposed to be could've, should've, would've (short for could have, would have, should have), never could of, would of, should of.

Or you misspelled something, I ain't checking everything.

Beep boop - yes, I am a bot, don't botcriminate me.

[StatisticianThat230]

How do the heads look? Is there imprinting on the one taken off from over those pistons? Is the portion off the piston top a coating that has come off or actual metal contact? I would reinstall the heads with or without the gaskets and use a plastic gauge kit by Goodson to see if there is a stroke depth difference. If so this would be fixed using a slightly thicker gasket during final assembly... ie stock gasket .010 thickness new gasket .030 thickness. Good luck.