Hi all, I'm currently in the process of rebuilding a 455 for my 71 Delta and I noticed the small pin holes shown here near the bulge for one of the front main bolts. I'm pretty sure these holes are due to a piece of metal from the bearings that spun. Not sure how to go about this repair if it is even possible. My main concerns are how thin the metal is at those spots and the fact that repair has to hold oil pressure. Any advice would be greatly appreciated.

Outside hole

Light shining through can be seen on left side near the main

Inside hole

 

If it were me, it's time for a new block. If the metal is thin there it's also thin in other spots. If it's not and you want to chance it, then have someone weld the holes.

 

Looks like the bolt holes were drilled into the main web before they were tapped during factory machining. Or something in the hole the last time the mains were torqued.

 

I have seen those holes in other blocks. It appears to me the drill for the main cap bolts just barely broke thru the casting. Maybe the machine at the factory was set to drill just a little too deep, maybe the casting was a little thin there. Remember, these blocks were cast and machined long before all the fancy equipment today.

Unless someone more knowledgeable than me suggest otherwise, I would think it’s ok.

 

I missed the pic of the light shining thru the main web casting. Definitely thin casting!! But not nearly as thin as the windowed main webs of the 403.

Is this a later model block? While I don’t buy the theory of different metallurgy for certain blocks, it wouldn’t surprise me if the castings got sloppier the later the production run life. Just a fact of life that as the molds used at the foundry get older, they would need repairs. The repairs might effect casting thickness.

 

Don’t worry about it, most are like that.

it’s inside the engine and just the bottom of the hole where nothing is going on.

many of the main cap bolt holes in the block are through holes

 

Clean it up and put some JB Weld in it and put the engine back together.

 

Take a look down the other main cap threaded holes in the block..tell me if you see through the bottom?

🤣🤣🤣

 

That simply is not a problem. Probably 75% of Chevy blocks are like that. The drill just went too far or the casting was a little off at that point. It actually makes it easier to clean the bolt threads out. Stop worrying about it and keep going. Think about it . . . its been that way for almost 50 years and hasn't caused a problem yet.

 

Disregard what I posted earlier, I thought those holes were something else.

 

Yep.

 

The machinery used on the Oldsmobile engine line was among the most advanced in the world when the engine plant went online for the new Oldsmobile V8 production 1948-49, and as I understand from personal accounts and reading, was in use to the end of V-8 production. Breaks my heart to think the lines would have been scrapped when the plant was demolished, would like to think the machining line at least could have been moved and continued in service. Today it might have been packed off to China as so much has in industry.

Video exists of the plant in operation, including live views of the Ingersoll equipment in machining including the bottom side main bearing tapping with all main bolt holes tapped in the same operation at moderately high speed, boring operations, men accomplishing select fit assembly picking, etc. Also, the 1951 engine plant stereo slide sets have excellent sharp views of all operations including crankshaft forging. BTW I never saw anything like this for the Northstar/Aurora V8, either Mercury Marine or GM, hope a visual record exists for those.

Since it seems all were drilled and tapped in the same operation, if that hole were found to be excessively deep, one guesses all might be likewise check deep. Otherwise, I agree completely, use the block. Castings vary and it passed inspection when new.

 

That is nothing to be concerned with, most OE Olds blocks will have that, and if they don't........ that area will be paper thin. It will not cause any problems at all to use that block "as is"

 

Think about it. There is no oil pressure in the crankcase, just oil splashing around. There is no oil pressure under the cap bolts. So it's a hole internally between the crankcase and the inside of the main bolt threads. So your main bolt threads will be oiled. Why is that a problem? I agree with the others, do nothing. Just finish the build and enjoy it.

 

The Chrysler transmission plant I work at up until fairly recently had some equipment that was first used with the aluminum Torqueflight trans from the early 1960s. The machine I ran was first used on the 3 speed fwd transmission. Just because something is old, doesn’t mean it’s junk. A lot of the old equestrian just runs better.

Id like to see those videos your referring to.

 

Some of the machinery and tooling was specially built and couldn't be replaced. Consider gang drilling and tapping all the main bearing bolt ho;es and oil pan rail holes at the same time. Same for head bolt holes, transmissions and differential cover holes. A CNC machine could never do it as fast as the "old technology" machines.

 

EDIT: I'll look at the plant slides tomorrow or when I can. I can't recall where I saw the machining on the mains just now.


FF thru corny stuff:


This one vanished from YT. I uploaded now so you can view it - Gleep it if you can as it may get knocked off due to copyrights of some kind:

 

Reference: Futuramic OLDSMOBILE Triple Dimension Theater slides:

These show only more deck machining, no mains:

EDIT: Having studied this under magnification I now think the main bolts are being worked in the shot on the right.

 

Did the Big 3 all paint their machining equipment the same colors?! Some of the really old machines here at the Chrysler Kokomo Transmission Plant (the ones dating back to the old cast iron Torqueflight transmission) are painted the exact same green color.

A old timer here told me you could tell the decade the machines were installed by the color. This plant was built in 1956, some of the machines still used from the beginning are that same green. Then in the 60-70s the used dark blue, then the 80-90s a lighter blue. Now, everything is white.

 

Machinery comes in the color that the manufacturer uses as part of their "identification". BUT, if you are purchasing a new machine to be built or a specialty machine, you can specify the color of your choice. Consider it like ordering a car, or buying one off the lot.
I worked one place many years ago that painted all the machinery in the same building the same color. Imagine "Sky blue", "Mint Green", "Tangerine", "Sunshine Yellow", "Dark Green", "Industrial Gray", etc. Sometimes the walls were painted a complimentary shade of the same color.
I think its highly possible that the different decades used different colors if requested, most machinery manufacturers had their "signature color". And we should remember that there are "Industrial Decorators" to make your work surroundings pleasant.
Olds engines were painted different colors over the years also.