What's the appeal of an aluminum engine block?

[blykins]

I've always wondered why a lot of my customers requested aluminum blocks for their FE builds. I have asked one or two of my patrons the reasons for their choice and the answers usually revolved around weight.

Is that the most common reason?

Or is just the exotic-ness (is that a word?) of having an "all-aluminum engine"?

Here's my side of it....

At the quantity level that aftermarket FE blocks are manufactured, the quality will always be a variable. If the blocks were made by a big name manufacturer, such as Ford Racing, Dart, World Products, etc., where the quality could be nailed down, it may be a different story.

Now, I will say that the manufacturers that I work with are top notch on customer service and will usually fix or reimburse for any problems that come up. However, the downtime and hassle simply aggravate me.

I've never had an issue with any aftermarket cast iron block but I've experienced quite a few casting flaws on aluminum blocks that would have induced severe internal water leaks if they had not been discovered before-hand. These are usually caught on a pressure test before machine work begins but will still set a build back by a few weeks at the least.

The sleeves can also cause issues. It is nice to have a block that can essentially have the cylinders replaced at will, but it does make for a hairy situation at the beginning as all the sleeves have to be set. This involves the use of an oven and a torque plate to push the sleeves down as far as they will go, so they will not drop when the assembled engine is running and has heat in it.

Aluminum blocks just don't make the same horsepower that a cast iron block will make with an equivilent build. The blocks expand, move around, etc., which can reduce ring seal and the amount of power that's made. Due to the expansion rate of aluminum, main bearing clearances have to be adjusted while assembling, to allow for the clearances opening up under operating temperature.

On the positive side of things, the aluminum blocks are lighter. However, this doesn't really mean much for the average Cobra owner. If you are racing, this may be a concern, but for the regular street car build, I personally see no benefit.

So, the motive behind my long-winded post was actually two-fold. The first motive was just to poll the Club Cobra crowd to see what the consumer level of thinking was behind the aluminum blocks. The second motive was just to vent a little bit. I have made the decision to not accept any more all-aluminum FE build orders. Not sure if I will retract that decision later on down the road, but to me, the pros just don't outweigh the cons and if an issue occurs on a build, the builder is always the one to incur the cost.

As some of you know, aftermarket FE blocks have been non-existent this year. I've been waiting on blocks since February and still have not received any. Foundries have changed, designs have changed, and until things settle down, I just have to go with my gut.

[Blue66]

I call them cool guy parts in the Buick turbo world. Bragging rights Now in the COBRA world I felt better with it because of all the 427s we had in the 60/70s that guys blew up.. Trying to find a really nice cast iron block could be challenging. On the good side less weight on the nose. Really haven't beat on it bad. Still have little V6 Turbo's if I want a hell ride. Plus we have a lot of parts from hoarding

[moore_rb]

Originally Posted by Blue66

I call them cool guy parts in the Buick turbo world. Bragging rights

I'm with this guy...- Most dudes are going to tell you they want aluminum instead of iron for both the reasons you mentioned - Weight, and for the "cool factor"

But my personal opinion is that these 2 reasons mask the real rationale, which is technical ignorance, augmented by a fat checkbook...

"A fool, and his money, are soon parted"
- Benjamin Franklin.

It's the same reason that guys are coming to you asking for a 700hp solid roller, for a car that they put 500 miles a year on, driving around to car shows and parking lot meets.

Bench racing is fun, without being nearly as scary, or time consuming, as the real thing...

[Phx Mike]

Originally Posted by moore_rb

I'm with this guy...- Most dudes are going to tell you they want aluminum instead of iron for both the reasons you mentioned - Weight, and for the "cool factor"

But my personal opinion is that these 2 reasons mask the real rationale, which is technical ignorance, augmented by a fat checkbook...

"A fool, and his money, are soon parted"
- Benjamin Franklin.

It's the same reason that guys are coming to you asking for a 700hp solid roller, for a car that they put 500 miles a year on, driving around to car shows and parking lot meets.

Bench racing is fun, without being nearly as scary, or time consuming, as the real thing...

Not sure why you would say it is technical ignorance. The aluminum block weighs about 60 lbs less than the iron block. That's not insignificant if you care about weight. And if you choose an iron block and aluminum heads you have to consider the thermal expansion differences and what issues that may or may not create. Going with the iron heads adds more weight.

I made a very conscientious decision to choose aluminum for the engine block in my car due to the resale value and because it is in keeping with the "technology" and low weight focus of the Kirkham product design (billet suspension components etc). I don't think that makes me a "fool" or a "bench racer".

There is no question that aluminum sand castings have more porosity issues than cast iron components - this is a problem in the aerospace parts world also and the associated casting yield gets built into the cost of the parts. There are ways to help mitigate it such as hipping, mold and core design, mold heat and pouring technique but none are foolproof nor inexpensive and certainly not approaches that are well suited to low volume production.

It will be interesting to see 3D printed parts when the additive manufacturing machines get large enough to make them.

[blykins]

I know it probably wasn't meant to sound that way, but this is not an engine builder experience issue. I've built more all-aluminum FE's than I can remember right now.

When you get a fresh block out of the box and it doesn't pass a pressure test, there's really not any experience that needs to be involved there....unless it involves going with another block manufacturer. However, there have been issues with all of them at one time or another.

What it comes down to for me is that I'm really not willing to be a guinea pig for new foundries or new block manufacturers, especially when I've had issues in the past. I understand that cast iron blocks are probably cast using the same foundries, but as the others have pointed out, the aluminum blocks have more of a chance for porosity.

[fordracing65]

Originally Posted by Phx Mike

Not sure why you would say it is technical ignorance. The aluminum block weighs about 60 lbs less than the iron block. That's not insignificant if you care about weight. And if you choose an iron block and aluminum heads you have to consider the thermal expansion differences and what issues that may or may not create. Going with the iron heads adds more weight.

I made a very conscientious decision to choose aluminum for the engine block in my car due to the resale value and because it is in keeping with the "technology" and low weight focus of the Kirkham product design (billet suspension components etc). I don't think that makes me a "fool" or a "bench racer".

There is no question that aluminum sand castings have more porosity issues than cast iron components - this is a problem in the aerospace parts world also and the associated casting yield gets built into the cost of the parts. There are ways to help mitigate it such as hipping, mold and core design, mold heat and pouring technique but none are foolproof nor inexpensive and certainly not approaches that are well suited to low volume production.

It will be interesting to see 3D printed parts when the additive manufacturing machines get large enough to make them.

Pond website. Iron fe block 285lbs. Aluminum fe block 135lbs. That's a 150lbs difference. You're about 90lbs off.

[Phx Mike]

Originally Posted by fordracing65

Pond website. Iron fe block 285lbs. Aluminum fe block 135lbs. That's a 150lbs difference. You're about 90lbs off.

It says the weight of the original iron block was 195 lb which is what I was using as a reference.

[moore_rb]

Originally Posted by Phx Mike

Not sure why you would say it is technical ignorance. ....

I made a very conscientious decision to choose aluminum for the engine block in my car due to the resale value and because it is in keeping with the "technology" and low weight focus of the Kirkham product design (billet suspension components etc). I don't think that makes me a "fool" or a "bench racer"

I wasn't talking about you... I already knew why you chose an aluminum engine for your car... It fits a theme with your car's overall styling- I get that.

But Brent's original points are very valid- aluminum makes perfect performance sense for cylinder heads... but not engine blocks; unless weight is the most important factor to you (which it clearly must be to many, many guys out there)

- Not knockin, just sayin...

And yes- Until your car has a time slip from a drag strip, or a road course (or has generated a fist full of cash from an illegal Saturday night out on some road in boonies, sorry to say- You're a bench-racer.

But that's ok- I'm a bench racer, too... My best days throwing a car around a track are probably behind me... I can tell whenever I get a little punchy in my Cobra that my eyesight and my reflexes aren't what they were 15 years ago....

And I never said bench-racing wasn't fun

[fordracing65]

Originally Posted by moore_rb

I wasn't talking about you... I already knew why you chose an aluminum engine for your car... It fits a theme with your car's overall styling- I get that.

But Brent's original points are very valid- aluminum makes perfect performance sense for cylinder heads... but not engine blocks; unless weight is the most important factor to you (which it clearly must be to many, many guys out there)

- Not knockin, just sayin...

And yes- Until your car has a time slip from a drag strip, or a road course (or has generated a fist full of cash from an illegal Saturday night out on some road in boonies, sorry to say- You're a bench-racer.

But that's ok- I'm a bench racer, too... My best days throwing a car around a track are probably behind me... I can tell whenever I get a little punchy in my Cobra that my eyesight and my reflexes aren't what they were 15 years ago....

And I never said bench-racing wasn't fun

Not true. Brent does not like FE blocks because of the consistency in casting them. Every other aluminum block is fine. OEM blocks go over 100,000 miles easy with no problems. 90 percent of daily drivers use them. It's the quality of the FE blocks.

[patrickt]

Originally Posted by blykins

I have made the decision to not accept any more all-aluminum FE build orders. Not sure if I will retract that decision later on down the road, but to me, the pros just don't outweigh the cons and if an issue occurs on a build, the builder is always the one to incur the cost.

Bad idea. Remember, you are a not a physician; you have no duty to "do no harm." Rather, you inform your customer with your professional opinion, if the customer wants to be informed. But then you build what you are paid to build. Just inform the customer on all the down sides, and if that's what the customer wants, then that's what the customer gets. Think of yourself as a tattoo artist -- if the customer wants it, and the customer pays for it, then the customer gets it... even if you think it's a bad idea.

[blykins]

Wrong.

What happens if a sleeve drops (had that happen once) and you don't find out until you get ready to pull it off the dyno and pull the valve covers to do an inspection?

You think the customer pays for that?

What happens if there's a pin hole leak in a lifter bore that wasn't caught until it's on the dyno and running? You don't just fix that stuff without tearing the engine completely down to bare bones.

I don't give prices only to have to take $1000 profit out of it at the end because of a manufacturing defect.

It would be simple if there were no risks to the builder and all I had to do was present the pros/cons to the customer. However, it doesn't work that way.

Why do you think there are regular street build aluminum FE blocks running around with lifter bore bushings? That's something that's not necessary unless we've gone to a .904" lifter, etc. However, there have been pin hole leaks in lifter bores and the fix is either to snag a new block or put lifter bore bushings in. That stuff ain't free.

[patrickt]

Then you restructure your pricing to reflect those prospective risks. You do not just "close the door" on risky builds. Rather, you price them accordingly and clearly, and plainly, convey the risk to the buyer. There are a lot of professions were the professional does not "guaranty their success." They simply pledge to do their best. Breaking in a SFT cam is a good example. If you do your best, and it goes south, the cost should be on me, not you.

[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]

Originally Posted by blykins

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.

Well, I don't know enough about the engine building business to know how far you can successfully "hedge your risk." You know a certain percentage of a certain type of build will incur problems. If you hedged all of those builds, with a surcharge, that charge, combined, could cover the costs of fixing the occasional crapper. That's how you do it in most markets. But from a business perspective, you don't turn down business. Instead, adopt this mantra: If you throw enough money at me, I will do it. I might not succeed, but I will do it.

EDIT: and more often than not, you will succeed.

[RodKnock]

Originally Posted by patrickt

Well, I don't know enough about the engine building business to know how far you can successfully "hedge your risk." You know a certain percentage of a certain type of build will incur problems. If you hedged all of those builds, with a surcharge, that charge, combined, could cover the costs of fixing the occasional crapper. That's how you do it in most markets. But from a business perspective, you don't turn down business. Instead, adopt this mantra: If you throw enough money at me, I will do it. I might not succeed, but I will do it.

EDIT: and more often than not, you will succeed.

Engine building doesn't have actuarial tables with thousands of customers ranging from the age of 1-100. Nothing wrong with managing risk as a business person. If alloy blocks have issues and cause Brent warranty problems, and he'll sleep better at night, then I have no problem telling customers that he won't build any more engines with alloy blocks until further notice. He'll suffer a loss of business, but then he's backed up anyway.

These engines are $20,000-ish +/-, so having a few go bad, could bankrupt a person.

[patrickt]

Originally Posted by RodKnock

... and he'll sleep better at night, then I have no problem telling customers that he won't build any more engines with alloy blocks until further notice. He'll suffer a loss of business, but then he's backed up anyway.

Well, alright. I just hate to see a dollar slip through his hands. That's just my nature.

[RodKnock]

Originally Posted by patrickt

Well, alright. I just hate to see a dollar slip through his hands. That's just my nature.

A lot of folks can wait a year for their ERA or KMP to be built. I have a sense that when it's time to build an engine, buyers don't want to wait a year or whatever for their engine to be built. So, it's probable that Brent would lose those customers anyway since he's backed up now anyway and there's an alloy block shortage.

Brent, BTW, not too long ago, BBM had no blocks available. I remember a CC member inquiring here in a thread. Are they available for immediate purchase now?

[blykins]

Nah, I look at it like this: if there's a higher than normal chance that it's going to be a pain in my butt, I'm not going to do it. There's a very high chance that a cast Eagle FE crank is going to break off at the front rod journal. Now, should I use that crank, upcharge for it, or should I avoid it altogether so I don't have to incur any damages, risks, or time setbacks?

I have a backlog of builds right now. It's just me doing it. Stopping everyone else's build because of a build with issues absolutely ruins my day.

Ok, so who's going to answer the question without trying to give me business tips?

[DanEC]

It's your business and bottom profit line. If someone has a serious enough thing about an aluminum block they will find someone else to build it.

Personally, if it were my business I would like to think I had a higher standard than the average tattoo artist.

[RockBit]

I chose an aluminum block for my build simply because of weight savings. I didn't want the car to be nose heavy. I was not aware that using an aluminum block posed additional risk to the engine builder.