Made by Crosley in the 1940s. Check it out, interesting reading.
http://www.ggw.org/~cac/Mighty_Tin.html
http://www.ggw.org/~cac/Mighty_Tin.html
Stamped steel engine block
- Thread starter Matt_S
- Start date
- Status
Kestas
Staff member
Considering all the requirements of a high-volume production engine, it's hard to beat cast iron, even after 100+ years. We're trying with cast aluminum, but even that has a lot of drawbacks.
I hope nothing serious with cast aluminum blocks
. I have one in my 2002 F-150 with the 4.6L V-8.
Whimsey
Whimsey
Kestas
Staff member
Whimsey, the problem isn't for the owner, but for the manufacturer. Aluminum is more expensive, weaker, more difficult to cast, more difficult to machine, less stiff (bends during machining), has higher thermal expansion (can't hold tolerances), cannot tolerate high temperatures (more prone to warpage), galls (problems with threaded holes), and has less noise-damping characteristics. The aluminum block needs a complete redesign to overcome its shortcomings when compared with gray iron. And it's not as easily recyclable because of the cast iron liner inserts used for the cylinder walls.
In my opinion, it's just not worth the weight savings (one of only a few advantages) you get with an aluminum block for high-volume production.
In my opinion, it's just not worth the weight savings (one of only a few advantages) you get with an aluminum block for high-volume production.
Which modern aluminum non-North American car engines still use iron liners?
Kestas
Staff member
Better yet, tell me which one's don't! The only one I know of is one of the high-end Mercedes (600?) engines.
Some technologies - I don't know if they found their way into production - incorporate hypereutectic Al-Si alloy cylinder liners in regular cast aluminum.
As for Ford aluminum blocks, only time will tell. Who knows, we may be pleasantly surprised with the longevity of these blocks. One can only hope that Ford properly took into account all the shortcomings with aluminum when designing the block.
I believe it was warpage that was the downfall of the aluminum Vega block.
What I've heard of the aluminum Mercedes blocks is that because of the high primary silicon content there is virtually no wear on the cylinder surfaces for (conceivably) over 500,000 miles. The down side is that these cylinder walls either cannot be repaired or are extremely difficult to repair. So you can imagine the critical importance of making sure that engine is oiled properly!
I'm going to try and get this tread back on topic. These were disposible engines based on wartime need to conserve materials and minimize wieght for airlift. 35hp for 1200 hours is non-remarkable even for back then. The idea of using the same engine design for very cheap cars in the immediate post-war frenzy of pentup demand made sense for a short time. Real-world durability just wasnt there.
Only the first 12 of 283 Mooney Mite airplanes were originally built with 25hp Crosley engines. The were all replaced with 65hp Lycomings at no charge to the customer.
Only the first 12 of 283 Mooney Mite airplanes were originally built with 25hp Crosley engines. The were all replaced with 65hp Lycomings at no charge to the customer.
Most problems from aluminum blocks came from floating liners, not enough threads in bolt holes, and corrosion issues. Most of these problems have been addressed and are no longer an issue.
Ford used an aluminum block on older DOHC Colbras, but when they went to a supercharged engine they switched to an cast iron block for strength and durability. So I'd say it's safe to say that the aluminum 4.6 isn't the strongest engine, but an aluminum block doesn't necesarilly make and engine weak.
GM's ecotec makes 145hp in stock form, but GM has made it produce 750hp on a stock, aluminum block. And up to 1000hp after resleaving it.
-T
Ford used an aluminum block on older DOHC Colbras, but when they went to a supercharged engine they switched to an cast iron block for strength and durability. So I'd say it's safe to say that the aluminum 4.6 isn't the strongest engine, but an aluminum block doesn't necesarilly make and engine weak.
GM's ecotec makes 145hp in stock form, but GM has made it produce 750hp on a stock, aluminum block. And up to 1000hp after resleaving it.
-T
The Vega was one of the early cars to use the high silicon alloys. I head at the time that they used the same alloy as Porsche, but Porsche did it right. I doubt the Mercedes alloy is a lot different.
For 2002 and 2003 F-150's with the 4.6 V-8 used aluminum blocks. Previous to 2002 and 2004 and up F-150's use the iron block. Kestas, now I'm real uncomfortable with the truck after reading your postquote:
Originally posted by T-Keith:
I believe all F-150s have a cast-iron block.quote:
Originally posted by Whimsey:
I hope nothing serious with cast aluminum blocks. I have one in my 2002 F-150 with the 4.6L V-8.
Whimsey
-T
Hopefully the engine never has to be touched other than for normal maintenance. It sounds so fragile
Whimsey
Kestas
Staff member
True. For all aluminum blocks without cast iron liners, hypereutectic silicon is the alloy of choice for the cylinder walls (or the whole block for that matter). After the bores are final machined, the walls are lightly etched to remove the aluminum matrix and the hard silicon particles stand proud on the surface. The pistons and rings ride on this hard surface while the depressed areas between the silicon hold oil needed for lubrication, just as a honed cast iron surface does.
Done right, aluminum can be a good (but expensive) performer.
Done right, aluminum can be a good (but expensive) performer.
I'm hoping expense is the reason Ford dropped the aluminum block for the 4.6L in their trucks and not reliability problems
Whimsey
Nikasil coatings are also another way to make aluminum work. It's used a lot on motorcycle engines, don't know if it has filtered down to any car companies yet.
BMW has tried Nikasil with mixed results. They wont risk it in North America yet (still use iron blocks) until the sulfur content of our fuels comes down.
- Status
