Iron VS Aluminum heads
01-20-2016 | 12:30 PM
#41
Registered
Joined: Aug 2006
Posts: 1,026
Likes: 16
From: Renton, Wa
I believe the D-Max has aluminum heads and that's why it's so quiet.
01-20-2016 | 12:32 PM
#42
Registered
Joined: Jan 2006
Posts: 688
Likes: 0
From: wisconsin
Just throwing this out there, If you want more heat to stay in the head. Then why do so many guys run their water temps so cold?
01-20-2016 | 12:48 PM
#43
Registered
Joined: May 2012
Posts: 1,465
Likes: 9
You want as much heat to stay in the combustion chamber during the power cycle, which cools as the gases expand and the piston goes down, more heat and pressure at the beginning, more power.
After the power cycle, exhaust, and then compression, you want the combustion chamber cool enough that hot spots don't preingnite the compressing charge. Having the block cooler helps with this. There is a boundary layer at the surface of the metal, whether it is aluminum or iron that keeps the searing hot combustion gases from melting or burning away the metal. Aluminum passes more heat than iron as it is thermally more conductive and therefore is less likely to get those hot spots.
After the power cycle, exhaust, and then compression, you want the combustion chamber cool enough that hot spots don't preingnite the compressing charge. Having the block cooler helps with this. There is a boundary layer at the surface of the metal, whether it is aluminum or iron that keeps the searing hot combustion gases from melting or burning away the metal. Aluminum passes more heat than iron as it is thermally more conductive and therefore is less likely to get those hot spots.
01-20-2016 | 01:01 PM
#44
Registered
Joined: Oct 2013
Posts: 2,888
Likes: 148
From: SF Bay Area
A bit of a segue, but would it be feasible to put a small blower like a B&M 250 on a 9.5:1, forged internals on a 502, and 91 octane pump gas? Would aluminum (Edelbrock Oval Performers) let you get away with that much CR under boost?
01-20-2016 | 01:02 PM
#45
Frank's Marine Service
Joined: Sep 2002
Posts: 11,959
Likes: 142
From: Elkton, MD
I ran Iron heads on my blower engines for years and it wasn't terrible. However the boost was low (6-7lbs).
Almost all Mercury's forced induction and high performance engines now have aluminum heads. I think the last time Mercury put an Iron head on a blower engine was the 800SC?
Not saying iron is bad... I kept mine for years because I was running in salt water. However, having switched over to aluminum and running them on a few other engines, I'm a believer.
Almost all Mercury's forced induction and high performance engines now have aluminum heads. I think the last time Mercury put an Iron head on a blower engine was the 800SC?
Not saying iron is bad... I kept mine for years because I was running in salt water. However, having switched over to aluminum and running them on a few other engines, I'm a believer.
01-20-2016 | 01:05 PM
#46
Frank's Marine Service
Joined: Sep 2002
Posts: 11,959
Likes: 142
From: Elkton, MD
Yes, they are. I payed a bit less than that. Actually they were 425 each to my door. They are a favorite in the truck pulling class that mandates iron head per their rules. There are quite a few guys making over 1000hp on motor with these heads, ported of course. Out of the box, they flowed 370cfm at 600 lift, and 388 at .700, .391 at 800. Keep in mind this is an as cast head, 320cc runner, with a 2.25 valve.
Ive talked with quite a few head specialists and engine builders prior to buying them, and read a bunch of posts over on yellowbullet and speedtalk, and couldn't find one negative about them. Once i got them, looked them over, had my head guy give me his opinion, he really liked them. Then once he pulled our darts off the flow bench, and started flowing them, he liked them even more.
Ive talked with quite a few head specialists and engine builders prior to buying them, and read a bunch of posts over on yellowbullet and speedtalk, and couldn't find one negative about them. Once i got them, looked them over, had my head guy give me his opinion, he really liked them. Then once he pulled our darts off the flow bench, and started flowing them, he liked them even more.
01-20-2016 | 01:10 PM
#47
Registered
Joined: Nov 2004
Posts: 14,094
Likes: 3,684
From: On A Dirt Floor
Rumor has it, that EQ may be stopping the iron heads...so, if you are going to use a set, I wouldn't wait too long. Or atleast call EQ to see if this rumor is true or not.
01-20-2016 | 01:20 PM
#48
Registered
Joined: Jan 2006
Posts: 688
Likes: 0
From: wisconsin
You want as much heat to stay in the combustion chamber during the power cycle, which cools as the gases expand and the piston goes down, more heat and pressure at the beginning, more power.
After the power cycle, exhaust, and then compression, you want the combustion chamber cool enough that hot spots don't preingnite the compressing charge. Having the block cooler helps with this. There is a boundary layer at the surface of the metal, whether it is aluminum or iron that keeps the searing hot combustion gases from melting or burning away the metal. Aluminum passes more heat than iron as it is thermally more conductive and therefore is less likely to get those hot spots.
After the power cycle, exhaust, and then compression, you want the combustion chamber cool enough that hot spots don't preingnite the compressing charge. Having the block cooler helps with this. There is a boundary layer at the surface of the metal, whether it is aluminum or iron that keeps the searing hot combustion gases from melting or burning away the metal. Aluminum passes more heat than iron as it is thermally more conductive and therefore is less likely to get those hot spots.
01-20-2016 | 01:30 PM
#49
Thread Starter
Registered
Joined: Jul 2004
Posts: 11,332
Likes: 73
From: chicago
I spoke with Kevin there last week, he didnt mention anything like that. He actually said they are selling alot of them to marine and truck puller guys. At least the bbc heads that is. They have only had the bbc line since 2012, i know they have had the sbc stuff for some time now . Their main office is only a few minutes from my house. Ill have to doible check with him on that though
01-20-2016 | 01:33 PM
#50
Thread Starter
Registered
Joined: Jul 2004
Posts: 11,332
Likes: 73
From: chicago
I ran Iron heads on my blower engines for years and it wasn't terrible. However the boost was low (6-7lbs).
Almost all Mercury's forced induction and high performance engines now have aluminum heads. I think the last time Mercury put an Iron head on a blower engine was the 800SC?
Not saying iron is bad... I kept mine for years because I was running in salt water. However, having switched over to aluminum and running them on a few other engines, I'm a believer.
Almost all Mercury's forced induction and high performance engines now have aluminum heads. I think the last time Mercury put an Iron head on a blower engine was the 800SC?
Not saying iron is bad... I kept mine for years because I was running in salt water. However, having switched over to aluminum and running them on a few other engines, I'm a believer.
Im not suggesting iron is better, im just suggesting that sometimes we cant ignore whats worked in the past.
