What's the appeal of an aluminum engine block?

[patrickt]

Originally Posted by blykins

Happy Thanksgiving all....I'm taking a few days vacation.

Well, that was a definitive posting. Just pm your login password and I'll keep posting in your stead, and piss them off way better than you ever could....

[RodKnock]

Originally Posted by blykins

That's fine Dave, it's an accepted fact by engine builders that doesn't need to be argued here.

More global statements, speaking for all engine builders. And it can't be argued?

You're making the Pond and Shelby blocks sound like Pepsi/Coke cans. People use aluminum pistons, rods, cylinder heads, intakes, rocker arms, etc. Until I see at least a good statistical sample of equally built FE engines, built with both cast iron and aluminum blocks, I call BS.

I know we live in a "post truth" or "truthiness" society now, but I need factual data sampling. And you line up 10 engine builders to post here on this thread that agree with you, but it's all hot air until I see real DATA!

It says right on the Shelby website:

"Strong enough to support over 1500 horsepower outputs."

"Shelby's FE alloy block delivers superior bottom end stability at high rpm."

[undy]

Thanks for the detailed explanation Brent. I understand now.

It would seem that ALL FE aluminum blocks suffer from inherent structural design deficiencies. Other alloy OEM blocks (not sure about aftermarket) don't suffer from this at all.

I pulled my heads on my 88K mile LS7 (Z06) engine and the ring sealing/pattern was perfect. That was at elevated HP levels too. It has zero oil consumption and very little, if any, blow-by.

[blykins]

Ok, pot-stirrer....

I didn't say it can't be argued. I said it didn't need to be argued here because that's not what the thread is about.

I'm also not speaking for all engine builders, as I have not talked to every single engine builder in the greater US, but I would take it as a general consensus.

What do you think Shelby's ad is going to say? "Our block squirms around at high horsepower...."

I'm also not on Club Cobra to specifically meet your needs.

[RodKnock]

Originally Posted by blykins

Ok, some data I found from the FE forum since I don't have any dyno sheets to prove my point.

From Dave Shoe (speaking to Robert Pond):

"The horsepower differences between iron nand aluminum blocks have been repeatedly characterized by Robert Pond, though I am necessarily distorting his claims because I lack sufficient experience to fully comprehend all his findings. He has been particularly interested in horsepower gains as small as a single horsepower, as his Stock Eliminator racing engines are constrained in the modifications which are allowed. I've spoken to Robert a little bit about "free horsepower", and he strongly contends that the block, all by itself, can provide dozens of free horsepower between the 600 to 1000 horsepower levels, just by its cylinder rigidity characteristics."

From Barry R, speaking of his Federal Mogul days:

"Well - - I can add a little fuel to the fire.
I supply rings and bearings to a large percentage of Pro Stock, Cup, and fastest street car competitors. In virtually 100% of situations where the weight is not critical (meaning that they would have to add ballast to offset any weight benefit from aluminum to meet a mandated minimum) these competitors ALL run an iron block of some sort.

Iron blocks simply make more power. Every time. The commonly bandied about number is somewhere between 15 and 30 - depending on the power level and the particular engine in question. Big beefy billet caps on aluminum blocks are kinda like a super strong steel lid on a cardboard box - when they're stronger than the parent material the value is limited. Ultimate power handling potential is not an issue - both materials have been proven at levels beyond anything feasable in an FE (I have seen numbers near 3000HP).

When properly prepped and designed, neither material will show bearing issues - but aluminum does require tighter cold clearances. Fuel motors don't count - - repairability is more important than the nominal power difference when you're at that level. The sole benefits to an aluminum block are identical to those of aluminum heads - weight ease of modification and repairability."

Data please! A good statistical sampling too.

All this BS for "dozens of HP" or "15-30 HP"? Oy vey. OMG!

I'd say lose 25 lbs of fat and stop eating the Havarti cheese, unless it's my favorite, cottage. And see what kind of 1/4 mile times folks can do.

[patrickt]

Personally, I think Brent has posted compelling evidence that iron blocks are superior to aluminum ones.

[RodKnock]

Originally Posted by patrickt

Personally, I think Brent has posted compelling evidence that iron blocks are superior to aluminum ones.

Really? As a lawyer, an Internet post is "compelling evidence"? Again, OMG. I'll never hire you.

Maybe, if I had a dispute over a neighbor's tree or something, but no serious legal matters.

[patrickt]

Yep, I think you've lost. Even if you had the popular vote, you still lost.

[blykins]

Unsubscribing.....

[ERANJ]

I think RodKnock has made many global statements...if you don't agree with my position you're wrong or submit until you see it my way.

[RodKnock]

Originally Posted by ERANJ

I think RodKnock has made many global statements...if you don't agree with my position you're wrong or submit until you see it my way.

All I'm asking for is to see evidence of the HP difference. We all know the weight difference between a cast iron and alloy block. That's 125 lbs.

And all this discussion over 15-30 HP or "dozens of HP."

And from what Brent and others have said, aluminum shifts around, expands, squirms or whatever, which means that it leaks more? Alloy engines are rebuilt more often? They lose compression because of expansion? How much compression? Does an alloy block engine lose .1 pt, .2 pt, .3 pt, etc. of compression?

Pond and Shelby have been selling blocks for at least 10 years. How many consumers have posted here and complained about their alloy block? Certainly the 8 (or more) alloy block purchasers that have posted here on this thread have not complained about loss of power, lack of reliability and/or quality. Any alloy block consumers feel their alloy blocks are fickle? Seriously, I'm always interested in consumer feedback about various products. I subscribe to Consumer Reports.

[moore_rb]

Originally Posted by blykins

Unsubscribing.....

Nice... Look what you guys have done- you've chased off the thread's original poster....

Me too- I'm unsubscribing. This is the first engine related thread where Brent Lykins and I agree 100%, so I'm pulling my chips off the table, and hitting the Cashier's window on my way out of the casino.

Happy Thanksgiving everyone...

[Jac Mac]

Originally Posted by RodKnock

And from what Brent and others have said, aluminum shifts around, expands, squirms or whatever, which means that it leaks more? Alloy engines are rebuilt more often? They lose compression because of expansion? How much compression? Does an alloy block engine lose .1 pt, .2 pt, .3 pt, etc. of compression?

BBM website.. Alloy block comes with nominal block height of 10.153", Iron 10.170", so Alloy block growth is ~0.017". With factory 1.73" rocker ratio that will cause an increase in valve lash of ~0.029". Thats the block alone without any further increase from alloy heads etc, obviously a problem for any solid cam with recommended hot lash of ~0.022" and would require block heater or similar to start up.

Iron 427 with 11/1 comp ratio will drop to ~10.6/1 in alloy block with same specs, so ~.4 drop in compression.

Brent would be better to simply add a hefty premium to every alloy block build and not waste his time trying to explain cause and effect to those clients.

[patrickt]

Originally Posted by Jac Mac

Brent would be better to simply add a hefty premium to every alloy block build and not waste his time trying to explain cause and effect to those clients.[/b]

Uhhhh, that's what I said in my first reply way back on page one of this thread.

[RodKnock]

Originally Posted by patrickt

Uhhhh, that's what I said in my first reply way back on page one of this thread.

Yes, but Brent answered:

Originally Posted by blykins

Yeah, in a perfect world, that's how it is.

However, there are certain things called warranties. IMO, the customer should not have to incur damages because of a manufacturing defect either....flat tappet camshaft, aluminum block, bad crank, etc.

I like how you think though....

Also can't just raise my prices to cover things that "might" happen. I would price myself out of every engine build if I had to do that.

[patrickt]

OK, so you're in agreement now that iron blocks are superior to aluminum ones?

[Three Peaks]

And the silly season is upon us...... no, wait, the election is over..... I guess we haven't gotten it out of our systems yet.

Carry on, or whatever it is that this thread has become.......

[fordracing65]

Most of the new Cammers I see being built are aluminum blocks. There are like 7 for sale on eBay. Just by Brent and Barry alone I will take them for what their word is and they both agree iron is superior when it comes to FE blocks. I don't have to hear it from anyone else. I take their words as gospel when it comes to FE engines.

[RodKnock]

Originally Posted by patrickt

OK, so you're in agreement now that iron blocks are superior to aluminum ones?

if, and only if:

1. The weight savings of 125 lbs is not meaningful,
2. The extra cost of the alloy block is meaningful,
3. Bling is not your thing,
4. 15-30 HP or "dozens of HP" is meaningful,
5. Steering and nimbleness in corners/turns is not meaningful,
6. greater fuel efficiency, due to less weight is not meaningful.

Under those conditions, yes, cast iron blocks are superior. But only if those 6 conditions have been met.

And, if the argument is that you would never feel the difference of 125 lbs (5 1/2% of my Kirkham's weight), then I don't see how you could argue that the extra 15-30 HP of a cast iron block would be noticed either. You can compensate for the reduced HP of the alloy block by adding compression, changing the cam, intake, etc., but it's mighty difficult to toss out or lose 125 lbs in a Cobra, unless Google or Tesla installs a driverless computer application.

[rodneym]

I'd like to go on the record as stating that my next FE will be iron.

It will be a 332ci with 240HP. That way Pat can keep up