Iron VS Aluminum heads
#31
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I have thought about going to iron heads just because salt water eats the living **** out of aluminum. Who wants to spend 10 grand on heads every 5 years?
#32
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There are literally hundreds of aluminum head choices on the market these days and they go from basic stock replacement design levels, to raised runner, spread port full competition heads. The only draw backs I see to iron is 1) the weight, and 2) there isn't the selection and performance design upgrade choices available like the aluminum heads, but they're getting better. I've heard a few people mention "CNC" options for aluminum heads. Well CNC machining is not limited to aluminum. Any port can be digitized and CNC machined in any head. There are lots of iron heads out there with CNC machining done. If you start looking into some racing classes that have iron-only head rules you'll start seeing some pretty darn nice iron heads with a lot of time and effort into their development. The EQ320 is a good head to start with for the BB Chev. The Dart Iron Eagle 330 is a fully CNC ported iron head. There are some aftermarket BB Ford iron heads that are some very serious competition heads. The shapes and designs of the ports and chambers are what really matters, not the material. One of the design "flaws" in the BB Chev conventional head is the size of the chamber, not only in volume, but also surface area. It transfers way too much heat and making the head out of aluminum only makes things worse. The real benefit the aluminum chamber has over most iron heads is it's design and shape which up until just recent years was a huge improvement over OEM iron heads. It wasn't the material that made it better.
#34
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There are literally hundreds of aluminum head choices on the market these days and they go from basic stock replacement design levels, to raised runner, spread port full competition heads. The only draw backs I see to iron is 1) the weight, and 2) there isn't the selection and performance design upgrade choices available like the aluminum heads, but they're getting better. I've heard a few people mention "CNC" options for aluminum heads. Well CNC machining is not limited to aluminum. Any port can be digitized and CNC machined in any head. There are lots of iron heads out there with CNC machining done. If you start looking into some racing classes that have iron-only head rules you'll start seeing some pretty darn nice iron heads with a lot of time and effort into their development. The EQ320 is a good head to start with for the BB Chev. The Dart Iron Eagle 330 is a fully CNC ported iron head. There are some aftermarket BB Ford iron heads that are some very serious competition heads. The shapes and designs of the ports and chambers are what really matters, not the material. One of the design "flaws" in the BB Chev conventional head is the size of the chamber, not only in volume, but also surface area. It transfers way too much heat and making the head out of aluminum only makes things worse. The real benefit the aluminum chamber has over most iron heads is it's design and shape which up until just recent years was a huge improvement over OEM iron heads. It wasn't the material that made it better.
#35
Coating the pistons other than the skirts ever notice the underside of the piston crown. What is that browish build up ..burnt oil. Have experimented with coating that side with a heat barrier which reduced oil temps. Have also painted my aluminum heads to help retain some heat. Some clam just pant the front and rear cylinder areas and not the center cylinders to keep heat temps more even between middle and end cylinders.
BBC has issues with the combustion chamber width vs the bore size they were really designed for a 5.00 bore back in the 427 days.
Some engines iron factory heads ported will flow better than some of the aftermarket stuff.
BBC has issues with the combustion chamber width vs the bore size they were really designed for a 5.00 bore back in the 427 days.
Some engines iron factory heads ported will flow better than some of the aftermarket stuff.
#37
Not an expert, what effect does fuel have on this debate? The reason for my question, I have some old small block chevy stuff I will be throwing together for a drive around fun car, and have debated old good iron heads versus aluminum. If running e85, does that make the fuel burn cooler? Taking some of the heat detonation problems away? I've heard you can run more compression on e85.
#38
Not an expert, what effect does fuel have on this debate? The reason for my question, I have some old small block chevy stuff I will be throwing together for a drive around fun car, and have debated old good iron heads versus aluminum. If running e85, does that make the fuel burn cooler? Taking some of the heat detonation problems away? I've heard you can run more compression on e85.
I would imagine ethanol would burn cooler though?
Last edited by MILD THUNDER; 01-20-2016 at 12:09 PM.
#39
I like the weight savings of an aluminum head, but one thing I think about is the expansion rates of aluminum on an iron block vs iron on iron. I have no idea what issues it causes but the rate of expansion between the two are huge, could be a non issue, just throwing it out there. What does it do to head gaskets with the differential?
#40
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WAG - less rpm (less power strokes per minute and more valve on the seat time), smaller valves, less cam duration (more time on the seat), etc,etc ???
I don't know diesels well, thus the WAG.
I don't know diesels well, thus the WAG.