[steve25]

In the great and very informative Pontiac made film that can be found on You tube titled “455 casting and machining for original production in 1970” it’s stated that Pontiac made its cast iron at that point in time by the electro arc method as opposed to the Crucible method.
The electro arc method produces a better quality cast iron .

My question going out here is does anyone know when Pontiac changed over to this to this better production method?

It’s also stated in this film that when the factory applies the the final balance job to each motor that the result is a motor balanced to within 1 1/2 inch Oz.
Pretty darn good you have to admit!


If you watch this 11 minute long video note that at one point the audio drops out for some two minutes, so it’s not on your end.

On a side note here I just finished porting a set of AMC 390 heads and in all my decades of grinding on cast iron I have flat out never encountered a head that ground so easy, surprisingly soft cast iron !

[PAUL K]

Didn't watch the video but those AMC heads move some air. Those were the first heads I worked on that had the coat hanger stuck in the water jacket. The Wenzlers were the second. I didn't figure out what their purpose was until Frank from AP explained it because they caused an issue with a batch of their blocks during the casting process.

[steve25]

Yup found out about the so called coat hanger sand core holder on a straight 6 head so darn long ago that I don’t even recall what the heck brand it was from!

Flow wise, yes the AMC head has a as cast intake throat size that’s a very large percentage for its valve size used.
In the high lift range they flow right in the ball park of what the post 1970 455 HO heads do ( at least on the intake side) ,but with a fair amount smaller port volume.
In fact to me a volume just right for a every day street 390 motor.

[Greg Reid]

Interesting video. Was that the Super Duty valve cover sticker on that engine visible in the last few seconds? Here's the link-
https://youtu.be/9LuXf6gJ-jg?si=WEgzZyLLg1_ETqRa

[johnta1]

It's interesting that the video is still up. It used to be when it (and the others in the series) were on, it seemed to be taken down. Not sure if it was Pontiac at that time or GM.


I have most of the videos downloaded. (when it was easier to download)


It's a very cool video, need to see the others in the series.

[Stuart]

Originally Posted by Greg Reid

Interesting video. Was that the Super Duty valve cover sticker on that engine visible in the last few seconds? Here's the link-
https://youtu.be/9LuXf6gJ-jg?si=WEgzZyLLg1_ETqRa

POCI also has it posted on their channel: https://www.youtube.com/watch?v=gMVEXmjxxWs

[steve25]

Yes, I thought I saw that same thing on the valve cover, but this is 1970 .

But then again what do know now is that the SD455 was in the works before the round port 455 HO motors, so maybe that was one of the preproduction test motors for the engineering dept.

[Ram Air IV Jack]

Originally Posted by steve25

In the great and very informative Pontiac made film that can be found on You tube titled “455 casting and machining for original production in 1970” it’s stated that Pontiac made its cast iron at that point in time by the electro arc method as opposed to the Crucible method.
The electro arc method produces a better quality cast iron .

My question going out here is does anyone know when Pontiac changed over to this to this better production method?

It’s also stated in this film that when the factory applies the the final balance job to each motor that the result is a motor balanced to within 1 1/2 inch Oz.
Pretty darn good you have to admit!


If you watch this 11 minute long video note that at one point the audio drops out for some two minutes, so it’s not on your end.

On a side note here I just finished porting a set of AMC 390 heads and in all my decades of grinding on cast iron I have flat out never encountered a head that ground so easy, surprisingly soft cast iron !

Lots of information out there but it is difficult to determine if it was true or not. I've heard over the years that the Pontiac RAIV blocks had a higher nickel content which made them stronger than other blocks. That has never been confirmed through reliable sources, but it is still talked about. Great to read and watch this stuff but be careful on what you believe!! As far as the AMC 390 engine, very good and I owned one in a Javelin years ago. It scooted along fine but the R&D at AMC couldn't match GM and the others, but I loved the AMX!

[Greg Reid]

After watching another one popped up focusing on Fisher Body. I haven't finished watching but also very interesting.

[Shiny]

Thanks for the link.

I don't have any idea when they would have changed their cast iron process but I enjoyed watching the video. Very cool to see the scale of that operation.

Even though my education was in metallurgy, I'm kind of glad I didn't work in primary metals beyond a couple summer jobs. That's a rough world.

It's sad that so much manufacturing is gone, though.

On the other hand, I cringed watching the workers man-handle crucibles of molten iron and breathing all the crap. This is a great example of hazards that probably led to OSHA regulations. I'm sure those jobs paid well, but IMO nobody got paid enough to take that risk... but the world back then was different.

[hurryinhoosier62]

Originally Posted by steve25

In the great and very informative Pontiac made film that can be found on You tube titled “455 casting and machining for original production in 1970” it’s stated that Pontiac made its cast iron at that point in time by the electro arc method as opposed to the Crucible method.
The electro arc method produces a better quality cast iron .

My question going out here is does anyone know when Pontiac changed over to this to this better production method?

It’s also stated in this film that when the factory applies the the final balance job to each motor that the result is a motor balanced to within 1 1/2 inch Oz.
Pretty darn good you have to admit!


If you watch this 11 minute long video note that at one point the audio drops out for some two minutes, so it’s not on your end.

On a side note here I just finished porting a set of AMC 390 heads and in all my decades of grinding on cast iron I have flat out never encountered a head that ground so easy, surprisingly soft cast iron !

How do you figure that 1.5 ounces is “pretty close” when we shot for three grams difference in piston balance in aircraft recip engines? 1.5 ounces is 42.5 grams….

[Keith Seymore]

Originally Posted by hurryinhoosier62

How do you figure that 1.5 ounces is “pretty close” when we shot for three grams difference in piston balance in aircraft recip engines? 1.5 ounces is 42.5 grams….

Just an observation, but "inch ounces" is a torque measurement; "grams" is a straight mass measurement.

K

[Burgess]

Originally Posted by Greg Reid

After watching another one popped up focusing on Fisher Body. I haven't finished watching but also very interesting.

I just watched this one about Fisher Body, also very interesting. There are several sections featuring the Firebird and G/P design.

https://www.youtube.com/watch?v=yYgxgGlN8CM

[hurryinhoosier62]

Originally Posted by Keith Seymore

Just an observation, but "inch ounces" is a torque measurement; "grams" is a straight mass measurement.

K

Keith, they say 1.5 ounces. That is still 42.5 grams. I don’t know about you, but 42.5 grams out of balance is a non starter for me. I went back an re-read the OP’s post. Yes, 1.5 inch ounces would be a very low breakaway point in an engine.

[steve25]

I will go back and watch it again and listen more closely, maybe it was stated as 1/2 a inch Oz.

Jack to help answer your block strength question here is a copy of the 1970 production specs.

Note that the block material on all the engines is listed as being the same.

When you look at my other page shot next to the Crank listing you will see that only the 4 bolt main caps are speced as being the better more ductile Armasteel cast iron.

If the RA4 blocks where made of better cast iron I would expect that they would have a notation as being made by this better formulation of iron.

[hurryinhoosier62]

Originally Posted by steve25

I will go back and watch it again and listen more closely, maybe it was stated as 1/2 a inch Oz.

Jack to help answer your block strength question here is a copy of the 1970 production specs.

Note that the block material on all the engines is listed as being the same.

When you look at my other page shot next to the Crank listing you will see that only the 4 bolt main caps are speced as being the better more ductile Armasteel cast iron.

If the RA4 blocks where made of better cast iron I would expect that they would have a notation as being made by this better formulation of iron.

1.5 inch ounce equates to .01 ft/lb. I priced an inch ounce torque wrench last night; nearly $400.

[Schurkey]

I have not watched that video for a few months.

The way I remember it, they say the balance is within 1 1/2 ounces, but NOT "inch-ounces". They don't specify if that's 1.5 ounces at the front of the crank, and 1.5 ounces at the rear, or 1.5 ounces total, or something else.

What they say...is almost totally meaningless in terms of balance (except that by aftermarket standards, there's no way to interpret it that their 1.5 ounces of imbalance doesn't SUCK. The only saving grace is that most of those engines never saw 5000 rpm. Maybe never saw 3500 rpm.)


"Nickle" in the iron of engine blocks and cylinder heads seems to be a myth that won't die. There's a hundred formulations of cast iron, plus heat-treatment including "lack" of heat--cryogenics. When Chevy wanted a higher-quality block, they added--and advertised--TIN, not nickle.

Pretty-much every one of the GM "sister divisions" has enthusiasts that brag-up the quality of the iron in their blocks and they always claim that their brand uses "nickle" in the iron...except Chevy with their mostly-soft iron, heavy bore wear and seat recession. Same with Ford "Fairlane" "90 Degree" "Small-blocks". Garbage iron.

[hurryinhoosier62]

Originally Posted by Schurkey

I have not watched that video for a few months.

The way I remember it, they say the balance is within 1 1/2 ounces, but NOT "inch-ounces". They don't specify if that's 1.5 ounces at the front of the crank, and 1.5 ounces at the rear, or 1.5 ounces total, or something else.

What they say...is almost totally meaningless in terms of balance (except that by aftermarket standards, there's no way to interpret it that their 1.5 ounces of imbalance doesn't SUCK. The only saving grace is that most of those engines never saw 5000 rpm. Maybe never saw 3500 rpm.)


"Nickle" in the iron of engine blocks and cylinder heads seems to be a myth that won't die. There's a hundred formulations of cast iron, plus heat-treatment including "lack" of heat--cryogenics. When Chevy wanted a higher-quality block, they added--and advertised--TIN, not nickle.

Pretty-much every one of the GM "sister divisions" has enthusiasts that brag-up the quality of the iron in their blocks and they always claim that their brand uses "nickle" in the iron...except Chevy with their mostly-soft iron, heavy bore wear and seat recession. Same with Ford "Fairlane" "90 Degree" "Small-blocks". Garbage iron.

That’s what I was thinking! 1.5 ounces is 43.5 grams. I don’t care what engine you’re talking about; that is huge amount to be out of balance.

[steve25]

When you read up on the arc melting process just like what’s stated in the video it produces a cleaner iron with less impurities then the old crucible method at the get go.

So does this not make for a better cast iron?

My main reason for this post was to see if for instance the change over to the electro arc method may have came about at the same time in 55 with the first V8s showing up, or if it was later.

[Dragncar]

When Mike Lewis balanced my rotating assembly he told me not to mix up my pins with the pistons.
Whatever the tiny amount of difference it was it was calculated in the balance job.
Its good to have a detail nut as your machinist.