Iron v. Aluminum

[patrickt]

I was just glancing at some of the costs for the fully machined aluminum blocks and thinking... does anybody subscribe to the old "seasoned block is better" line of thinking? At one time, many years ago, we used to think that an old block that had seen a number of heat cycles, that of course still passed all the tests, was better than a new block -- whether it be iron or aluminum. Now of course there is that weight thing. But how is the feeling around here on old quality iron versus aluminum?

[RodKnock]

I think Pond and Shelby have proven that their blocks are reliable. Depending on what you're ultimately looking for in terms of either a replica of the original sideoiler (Pond) or the even more beefier CSX block, I eschewed using an older block because: a) very hard to find a good unrepaired one, b) if you do find a good one, they're as expensive as a new aluminum block and 3) losing 100-125 lbs from the front of the car is, as Jamo would say, "muy goodo."

[RodKnock]

When they start making "affordable", complete and reliable aluminum SOHC engines, which from the August 2009 Hot Rod article, uses an aluminum Pond block for its base, my 482 will be for sale, though I may be farting dust at that point.

[lineslinger]

For what its worth, my machinist is building a Cammer to drop in a street ride Galaxy. He has quite a few 427 blocks in good shape. He has chosen a Pond aluminum block for this build.

[ken swart]

reminds me of the BMW turbo F1 engines of the 80s. 1000 hp 4 cylinder seasoned street blocks

[Jamo]

Originally Posted by RodKnock

I think Pond and Shelby have proven that their blocks are reliable. Depending on what you're ultimately looking for in terms of either a replica of the original sideoiler (Pond) or the even more beefier CSX block, I eschewed using an older block because: a) very hard to find a good unrepaired one, b) if you do find a good one, they're as expensive as a new aluminum block and 3) losing 100-125 lbs from the front of the car is, as Jamo would say, "muy goodo."

Well hell, you took the words right out of my mouth.

Isn't the real question...do you want an old sleeved iron block or a new sleeved arruminum block?

[RICK LAKE]

patrickt Pat this was more for 1/4 and roadrace motors. The best racing blocks where 100k miles on them. They had little to no core movement from so many heat cycles. We would leave these blocks out in the weather for a year in the sun and cold to also help cure them after machine work. IMO a new iron block would sit outside in cosmoline for a year before doing any machine work. The nascar guys vibrate blocks for the relief on possible stress issues in the core. Takes 10-20 hours, not sure on price. I know the shelby mblock cost the most and if you are not looking for a perfect 100 point cobra, this is a winner. I have 2 blocks. With the right machinist that knows the problems with this block and correcting them, It's a winner. The engineering is SO over done on this block. 2,000+ HP and looking at the 2,500 range. The other blocks will be save with 1,200 hp to maybe 1,500 hp I would go any farther than that. The first 50 blocks needed alot of work, the new ones just need touchup. The other issue is wieght. You can build a 482-527 monster with a 495 pound wieght limit for your car. Iron motor is in the 640 range. My car is 2705 with 1/2 tank of gas. How heavy do you want to be? I did leave out that alot of the old season blocks where filled to the bottom of the water pump outlets with blockcrete for more stable core and strength.
I still think that a good sonic check on a 40+ year old block is needed. A also think they used better material back then and added a little extra instead of running on the ragged limit mixture like today. Nickle would be one of the materials. You see WW2 merlin motors with 70 years on OEM blocks flying around at 400+ mph. There are alot more moving parts in that motor than an FE. These parts DO have there limitations like any thing else. Rick L. Ps if you want or like iron, than get one. Just have a good check out of the block before you bug it. Magnaflux for cracks, pressure test to 125 psi for 8 hours, and sonic test. The rest will depend on if there is any core shift in the block and how much machine work will be needed. Rick L.

[Dominik]

I agree on seasoned blocks for ultra-high horsepower engines.
Here you want to avoid that any tolerances shift during a race after the block has been machined.

As stated earlier 1,5l 1.000hp... So once you aim to produce 5.000hp from your 450+ cui you want a seasoned block. Of course, I exaggerate a bit, but you get the picture.

Also, I wouldn't know if aluminium shifts as bad as cast iron under racing use.

I would buy a new block.

Dom

[Barry_R]

Aluminum shifts and moves more than iron under heat and stress. I am in the apparent minority here - but I really prefer iron blocks. Not old busted up ones though.

[patrickt]

Originally Posted by Barry_R

Aluminum shifts and moves more than iron under heat and stress. I am in the apparent minority here - but I really prefer iron blocks. Not old busted up ones though.

My truly smart friends, who are clearly a minority of people that I know, feel the same way. FWIW, I went with a nice clean 428 CJ block .025 over. Eventually though, aluminum will be the only reasonable cost alternative.

[RodKnock]

Barry, there's absolutely nothing wrong with being in the minority, but I'm not sure you are. One of the issues floating around in my small brain is that I bought a Cobra to have a light car. The Kirkhams went through all the trouble to put their car on a diet by using billet aluminum this and that (saves money too). So, it seemed inconsistent to my thinking to use an expensive heavy iron block, assuming you can find a good one, when the Cobra is light. That's why I'm using the QT bellhousing, aluminum rear end, etc. and why I want magnesium wheels and so on and so on.

Now, the Shelby block is about 25 lbs heavier than the Pond, so I believe it has more beef to it and that's why I went with it. Having a replica SO was not a priority for me.

I looked at several vintage iron blocks, but I just couldn't wait around to find a good one and then spend as much or more than if I got an aluminum one. There are people running the Genesis iron block, but I hear Genesis is having and/or has had problems.

Everyone is different, but those are my thoughts.

[patrickt]

Originally Posted by Barry_R

Aluminum shifts and moves more than iron under heat and stress. I am in the apparent minority here - but I really prefer iron blocks. Not old busted up ones though.

Barry, can an aluminum block suffer core shift from the repeated heat and stress cycles from hard running? Or is core shift limited solely to the foundry? For example, could we see a sonic test of an aluminum block look like this one with obvious CS (granted this is a Buick 455) if it originally came from the foundry with good sonic testing numbers?

[RICK LAKE]

Barry_R Barry in some cases, it's all about the application and useage of the motor. I have an iron block in my shed. It's a 390 block with 428 crank. For street driving I may have stayed withthat setup. I wanted to use my car for autocross and roadracing. Iron was not the answer for this. I want a lite car. Aluminum every where I could. Heads, Intake, Block, timing cover, valve covers, even the spacer on the crank. With your kit I came in at 508 pounds. Over 600ft of torque and 540 HP at the crank. Small block weight and good power. You know how hard it is to find an old FE core for building. I am gald Mike Lefevers got CS to build their heads and blocks. Over heating with aluminum was an issue but now is fixed. 8 years on the 452 motor now 3 with the 482 kit. this is with the same block. Alot of abuse and some upgrades in the block from helicoils to timecerts in all the holes. Given the flexability of aluminum or iron and the fact you can repair it alot easier, I like it for racing.
Iron for a street car or 1/4 car with the water jckets fill to the bottom of the water pump holes is better IMO that an aluminum block. Some of this also depends on aluminum or iron heads and intake.
With all this being said, how is the cammer motor going to be run? Can we hope for the 800HP level to get reached? Rick L.

[RICK LAKE]

patrickt Looks like 3 sleeves is needed for that 455 block. Looks like the bores where done off center on 2,4,6,. Must be a monday morning or friday night special or the boring bar was worn with play. Sun is out go, get the paper Rick

[patrickt]

Originally Posted by RICK LAKE

patrickt -- Sun is out go, get the paper Rick

That's exactly what I'm about to do! Then I'll get my cup of coffee and head to the library.

[Barry_R]

The aluminum wont show funky numbers on a sonic cuz the measurement will only reflect sleeve thickness due to the material change.

I can understand the road race advantages of 100 lbs less weight. I still like iron.

The Cammer needs to run first before I make power estimates. Right now it's pushing my checkbook so hard I need to keep it in the freezer to prevent spontaneous ignition....