Alloy heads

[famous bob]

That's part of the issue. There is nothing wrong with the OE MoPar combustion chamber. In fact, it's better than most of the junk out there being sold today. To get a closed chamber correct is not that easy. Anyone who has ever worked with a BBC closed chamber head knows what garbage that pig is.

The junk chamber in the W5 head is a crime against horsepower. Chrylser should have been ashamed to put that chamber out there. That's why most W7 heads (if not all of them) came without a chamber. That W5 chamber is J U N K junk but Chrysler gave all the whiners and snivelers what they wanted...a closed chamber head.

As I've pointed out in other threads, the material of the head makes ZERO difference regarding compression ratio AND ignition timing.
Detonation resistance is based as much on chamber SHAPE and plug location as much as cam timing is. Maybe a bit more.
A closed chamber isn't always a good chamber, and no amount of marketing can fix that.

Funny , but I`ve been hotrodding for over 50 yrs. , and ur the only one I`ve ever heard claim that. I know my 505 wouldn't run right/good w/ cast iron heads on it /set up the same way it is now, would rattle like hell . ????
Well known gurus all have claimed and stated to run alum heads . Mr. Tom Hoover even said it .------------

 

[j par]

Just because someone says something and they sound convincing, it doesn't mean that it is true.

I know I've already given you an amen on this, but I'll elaborate even more that I've been saying this for years now.. but people continued to like their ears tickled with all the fancy convincing words...

 

[RAMM]

My understanding is that because heat is a major component of detonation and aluminum dissapates heat better than cast iron, this makes them less prone to detonation.
If all things were equal, an engine with aluminum heads would be less effective due to the loss of thermal energy. Cast iron is better at heat retention and keeps the fire in the hole longer whereas aluminum absorbs and dissapates the heat. Perhaps this is why you can bump up the compression with aluminum and retain some heat for the combustion process, putting that heat back in the hole where it belongs and not losing it through absorbtion.

Tinmannz statement above is pretty much the long and short of it. His statement is accurate. Ten years ago I wouldn't have believed that an aluminum head would tolerate more compression than an iron head but it will. Aluminum will suck so much heat energy out of the combustion process it will cause a negative effect on cylinder pressure. Pressure = power. How?

I'm only going to write this once and it is amazing how few truly understand how the force to push against the piston is created. It's heat and the more of it the more pressure. It's not and explosion it is a burn. Air and fuel enter the combustion chamber, the piston squeezes the mixture which helps the heating process, the sparkplug ignites the mixture and the mixture burns which causes the rapid expansion of Nitrogen. It is this rapid expansion of Nitrogen that works against the piston crown. Aluminum can and will reduce the amount of thermal energy available all other things being equal.

Anyone that's ever TIG welded on an aluminum cylinder head would notice that you have to stand on the pedal to get your puddle going but once the head heats up and gets too hot too touch it takes very little amps to produce a nice puddle. This is because aluminum wicks heat energy away like crazy. Same thing in the combustion process. Anyone that argues this is not speaking from experience and lacks critical thinking. J.Rob

 

[RAMM]

Funny , but I`ve been hotrodding for over 50 yrs. , and ur the only one I`ve ever heard claim that. I know my 505 wouldn't run right/good w/ cast iron heads on it /set up the same way it is now, would rattle like hell . ????
Well known gurus all have claimed and stated to run alum heads . Mr. Tom Hoover even said it .------------

You and Tom Hoover would be correct, YR not so much. J.Rob

 

[RAMM]

Nope.

Yup. J.Rob

 

[IQ52]

Tinmannz statement above is pretty much the long and short of it. His statement is accurate. Ten years ago I wouldn't have believed that an aluminum head would tolerate more compression than an iron head but it will. Aluminum will suck so much heat energy out of the combustion process it will cause a negative effect on cylinder pressure. Pressure = power. How?

I'm only going to write this once and it is amazing how few truly understand how the force to push against the piston is created. It's heat and the more of it the more pressure. It's not and explosion it is a burn. Air and fuel enter the combustion chamber, the piston squeezes the mixture which helps the heating process, the sparkplug ignites the mixture and the mixture burns which causes the rapid expansion of Nitrogen. It is this rapid expansion of Nitrogen that works against the piston crown. Aluminum can and will reduce the amount of thermal energy available all other things being equal.

Anyone that's ever TIG welded on an aluminum cylinder head would notice that you have to stand on the pedal to get your puddle going but once the head heats up and gets too hot too touch it takes very little amps to produce a nice puddle. This is because aluminum wicks heat energy away like crazy. Same thing in the combustion process. Anyone that argues this is not speaking from experience and lacks critical thinking. J.Rob

Ouch. First off I hold you in high regard and really appreciate your defense of me on the Moparts forum.

My critical thinking now requires me to disagree.

Having done TIG welding on aluminum and acknowledging the heat required, there seems to me a large difference between TIG welding on aluminum and hot gas expansion in an aluminum combustion chamber. Electrical arcs and expanding hot gasses could have a very different energy exchange rate with aluminum.

I believe the high frequency used in the AC TIG arc breaks down the resistance in the air gap between the tungsten electrode and the aluminum to begin the arc and the transfer of the heat therein.

In a combustion chamber I also believe there may be a cooler air gap boundary that the heat of the gas has to compress and penetrate before getting to the aluminum, and therefor retards the transfer of the heat to the aluminum owing to the speed of the combustion process in the internal combustion engine. This may be similar to the dead air boundary in the port of a cylinder head.

Theory is one thing, scientific (maybe dyno?) tests are another. Though I have done no dyno tests on aluminum vs iron, the only tests I have ever read of have not shown a loss of energy, read horsepower, in switching from iron to aluminum heads. The testers used iron and aluminum heads with the same combustion chamber shapes and similar air flows, and in each case found the aluminum head to produce no loss but slightly more horsepower. They then claimed they didn't believe their own results were accurate. Now there is some critical thinking!

Do you have detonation or horsepower tests that show otherwise? Because I would love to see them!

 

[Tinmannz]

Here's a good read for you. I figure the fellas at Trick Flow, Edelbrock, AFR, World Products and whomever else they quoted for this article probably have the knowledge, backround and expertise to commemt on aluminum vs cast iron cylinder heads.

Hopefully there's enough there for critical minds to think about while having their morning cup of 'joe'.
Or for some, their mid afternoon bottle of 'Iron City Beer'.

We all have our bias's and will always defend what works for us. The link below isn't an attempt to convince you from changing what works for you, but, to inform you what some reputable experts in the industry have found and are willing to share.

That's what I enjoy most about this forum, the different opinions on what works for some and not others. If it weren't for that, we'd all be stuck in the hamster wheel.

Take the time to read the following article and form your own opinion and remain open to others opinions.

Tinmannz out
P.S. Google is your friend

Performance Racing Industry

 

[IQ52]

Here's a good read for you. I figure the fellas at Trick Flow, Edelbrock, AFR, World Products and whomever else they quoted for this article probably have the knowledge, backround and expertise to commemt on aluminum vs cast iron cylinder heads.

Hopefully there's enough there for critical minds to think about while having their morning cup of 'joe'.
Or for some, their mid afternoon bottle of 'Iron City Beer'.

We all have our bias's and will always defend what works for us. The link below isn't an attempt to convince you from changing what works for you, but, to inform you what some reputable experts in the industry have found and are willing to share.

That's what I enjoy most about this forum, the different opinions on what works for some and not others. If it weren't for that, we'd all be stuck in the hamster wheel.

Take the time to read the following article and form your own opinion and remain open to others opinions.

Tinmannz out
P.S. Google is your friend

Performance Racing Industry

Everyone agrees that aluminum transfers heat faster and so we assume it has a measurable effect in an internal combustion engine. Who has tested it in an internal combustion engine and reported the results? All of those "experts" claim something and none of them show any actual tests in an engine. Show me the tests!!!!! Here are mine! Where are yours/theirs?

Iron vs. Alloy Engine Heads - Tech Article - Chevy High Performance Magazine

Comparing Aluminum And Iron Cylinder Heads - Car Craft Magazine

 

[yellow rose]

Funny , but I`ve been hotrodding for over 50 yrs. , and ur the only one I`ve ever heard claim that. I know my 505 wouldn't run right/good w/ cast iron heads on it /set up the same way it is now, would rattle like hell . ????
Well known gurus all have claimed and stated to run alum heads . Mr. Tom Hoover even said it .------------

Then I must be wrong. But I'm not. Why would you build you 505 with iron heads and do it the same as the aluminum heads? That makes no sense.

Unless the are identical copies. Then it won't matter.

 

[yellow rose]

Ouch. First off I hold you in high regard and really appreciate your defense of me on the Moparts forum.

My critical thinking now requires me to disagree.

Having done TIG welding on aluminum and acknowledging the heat required, there seems to me a large difference between TIG welding on aluminum and hot gas expansion in an aluminum combustion chamber. Electrical arcs and expanding hot gasses could have a very different energy exchange rate with aluminum.

I believe the high frequency used in the AC TIG arc breaks down the resistance in the air gap between the tungsten electrode and the aluminum to begin the arc and the transfer of the heat therein.

In a combustion chamber I also believe there may be a cooler air gap boundary that the heat of the gas has to compress and penetrate before getting to the aluminum, and therefor retards the transfer of the heat to the aluminum owing to the speed of the combustion process in the internal combustion engine. This may be similar to the dead air boundary in the port of a cylinder head.

Theory is one thing, scientific (maybe dyno?) tests are another. Though I have done no dyno tests on aluminum vs iron, the only tests I have ever read of have not shown a loss of energy, read horsepower, in switching from iron to aluminum heads. The testers used iron and aluminum heads with the same combustion chamber shapes and similar air flows, and in each case found the aluminum head to produce no loss but slightly more horsepower. They then claimed they didn't believe their own results were accurate. Now there is some critical thinking!

Do you have detonation or horsepower tests that show otherwise? Because I would love to see them!

LOL. Trying to equate welding with an engine is silly. I've been welding on aluminum and most everything else except Titanium and it's not the same thing.

I've been running compression ratios that every swinging guru out there has said was impossible since high school. Before I went in the army I worked on a farm and I bought my fuel from him and farm fuel is junk. That was a legit 10.25:1 engine and it would run on swill.

I'm starting to think that some people are so set in their easy they can't see the forest for the trees.

It has been done, and is being done every day.

The materiel the head is made of makes ZERO difference in what CR you can use.

Just like trying to make people think combustion chamber shape in the number 1 factor in ignition timing requirements.

It isn't. Not by a long shot.

 

[RAMM]

Everyone agrees that aluminum transfers heat faster and so we assume it has a measurable effect in an internal combustion engine. Who has tested it in an internal combustion engine and reported the results? All of those "experts" claim something and none of them show any actual tests in an engine. Show me the tests!!!!! Here are mine! Where are yours/theirs?

Iron vs. Alloy Engine Heads - Tech Article - Chevy High Performance Magazine

Comparing Aluminum And Iron Cylinder Heads - Car Craft Magazine

I do not have anything more scientific than what I've witnessed on the dyno and in the certain customers cars. I know that a rowdy street engine with aluminum heads WILL tolerate more static compression before things like running on, hard starting and pinging start to show up. With iron heads cranking compression of 190-195 psi is on the edge with pumpgas while the same engine with aluminum heads can tolerate 210-215 psi cranking before the same symptoms show up. Can't comment on the power difference on the dyno 'cuz I have never had the opportunity to test the same head but cast in two different materials. Believe what you wish and I was a naysayer too years ago until I saw what I saw. J.Rob

 

[yellow rose]

Here's a good read for you. I figure the fellas at Trick Flow, Edelbrock, AFR, World Products and whomever else they quoted for this article probably have the knowledge, backround and expertise to commemt on aluminum vs cast iron cylinder heads.

Hopefully there's enough there for critical minds to think about while having their morning cup of 'joe'.
Or for some, their mid afternoon bottle of 'Iron City Beer'.

We all have our bias's and will always defend what works for us. The link below isn't an attempt to convince you from changing what works for you, but, to inform you what some reputable experts in the industry have found and are willing to share.

That's what I enjoy most about this forum, the different opinions on what works for some and not others. If it weren't for that, we'd all be stuck in the hamster wheel.

Take the time to read the following article and form your own opinion and remain open to others opinions.

Tinmannz out
P.S. Google is your friend

Performance Racing Industry

I only defend what WORKS. What has worked. What is working. Not some manufacturer and his nonsense.

Want an example? This is a good one. Been some massive arguments by some on this very forum who THOUGHT they knew the right answer because A) it's in ALL the books and magazines (and the web...just read an article online about a month ago telling the same error!) and B) that's what they do. Doesn't make it right either way. So here goes.

If you are using a Holley or Hollye clone carb, and you are setting the power valve timing (opening point) you set it from CRUISE vacuum, not IDLE vacuum like Holley and all the book writers say to do. It's not only wrong, it's stupid and it makes getting the fuel curve from idle to WOT near impossible to get corner.

And yet and still, if you call Holley today, they will tell you to set the PV opening from idle vacuum. That is wrong. Period. End of discussion. Yet Holley and a multitude of others still teach that.

So just because a manufacturer says it don't make it true. Why would any of the above manufacturers want to make the effort to re-educate an entire industry? Why bother? Just like Holley it's easier to maintain the status quo than to admit you have been wrong. For decades. About your own product no less!

It's also a marketing ploy. None of those companies make a cast iron head. So why say it's equal in power output and cast iron can run the same CR?

 

[RAMM]

LOL. Trying to equate welding with an engine is silly. I've been welding on aluminum and most everything else except Titanium and it's not the same thing.


The materiel the head is made of makes ZERO difference in what CR you can use.

Just like trying to make people think combustion chamber shape in the number 1 factor in ignition timing requirements.

It isn't. Not by a long shot.

I wasn't "trying to equate welding with an engine" Your reading comprehension is very poor. I was merely pointing out how much more heat energy a piece of cold aluminum vs pre-heated took to get a nice puddle going --NOWHERE did I say TIG welding aluminum is the same as the combustion process in an ICE. Jesus.

J.Rob

 

[yellow rose]

I do not have anything more scientific than what I've witnessed on the dyno and in the certain customers cars. I know that a rowdy street engine with aluminum heads WILL tolerate more static compression before things like running on, hard starting and pinging start to show up. With iron heads cranking compression of 190-195 psi is on the edge with pumpgas while the same engine with aluminum heads can tolerate 210-215 psi cranking before the same symptoms show up. Can't comment on the power difference on the dyno 'cuz I have never had the opportunity to test the same head but cast in two different materials. Believe what you wish and I was a naysayer too years ago until I saw what I saw. J.Rob

I'm at 195 on iron heads with the cam straight up. I can move it 2, maybe 4 degrees ahead and be over 200 and it STILL won't have an issue IF you built the combo around it, and IF you can tune.

What I'd rather do is pull the heads and put the thin gaskets on and move the CR to 11.25:1 and leave the cam where it is.

 

[RAMM]

I'm at 195 on iron heads with the cam straight up. I can move it 2, maybe 4 degrees ahead and be over 200 and it STILL won't have an issue IF you built the combo around it, and IF you can tune.

What I'd rather do is pull the heads and put the thin gaskets on and move the CR to 11.25:1 and leave the cam where it is.

NOBODY is questioning your MAD enginebuilding skills.

All I'm saying is that I have witnessed aluminum headed engines WILL tolerate more cranking compression before octane related issues start showing up. Don't muddy this up with your MAD tuning skillz. J.Rob

 

[yellow rose]

I wasn't "trying to equate welding with an engine" Your reading comprehension is very poor. I was merely pointing out how much more heat energy a piece of cold aluminum vs pre-heated took to get a nice puddle going --NOWHERE did I say TIG welding aluminum is the same as the combustion process in an ICE. Jesus.

You put it out there like that, as a comparable example. Proof read what you post.

BTW, the head material can only reject heat as fast as the cooling system can reject it. If you can argue that, you'll argue with w stop sign (and you might).

Once the system is up to temp you would need a MASSIVE input of heat across a relatively long period of time to get what you claim. It doesn't happen.

We also know (or should know) that unless something is really wrong, you don't get detonation at WOT.

Most of the time, you get detonation issues and low throttle opening and high load. That's a tuning issue unless you have no clue how to build an engine.

 

[yellow rose]

NOBODY is questioning your MAD enginebuilding skills.

All I'm saying is that I have witnessed aluminum headed engines WILL tolerate more cranking compression before octane related issues start showing up. Don't muddy this up with your MAD tuning skillz. J.Rob

Seems to me you started it, got called out on your bullshit (again) and don't like it much.

What YOU should have said is YOU can't build an engine with the same CR on iron heads as aluminum. YOU can't do it so no one else can either.

My next build will be 12:1 on pump gas. Maybe 12.5:1 but I haven't had time to sort everything out yet. I expect the cranking numbers (which mean almost nothing) to be 200 plus. And it won't detonate.

 

[abodyjoe]

I remember reading a few tips here in the past on how to help or stop this. There was something fellas were dropping into the radiator.

an anode. it is attacked instead of the alumn..
https://www.flex-a-lite.com/accessories/radiator-accessories/radiator-anode.html

 

[RAMM]

Seems to me you started it, got called out on your bullshit (again) and don't like it much. I like debating very much, its good mental exercise.

What YOU should have said is YOU can't build an engine with the same CR on iron heads as aluminum. YOU can't do it so no one else can either. See below

My next build will be 12:1 on pump gas. Maybe 12.5:1 but I haven't had time to sort everything out yet. I expect the cranking numbers (which mean almost nothing) to be 200 plus. And it won't detonate.You're right it won't detonate 'cuz it'll never get built

I have no problem conceding that I do not approach enginebuilding the same way as you.

What I will say is this: I WON'T build an engine with the same CR regardless of the cylinder head material--that would be foolish. J.Rob

 

[Tinmannz]

Tomato-Tomatoe, is it the same fruit? Or some may say its a vegitable. Lets not go down that road.

Time for a chill pill and let our panties unwind.

Cheers!

Go NAVY! Beat ARMY!

 

[yellow rose]

I have no problem conceding that I do not approach enginebuilding the same way as you.

What I will say is this: I WON'T build an engine with the same CR regardless of the cylinder head material--that would be foolish. J.Rob

Only foolish for you.

As I WONT let head material dictate compression ratio.

 

[yellow rose]

Tomato-Tomatoe, is it the same fruit? Or some may say its a vegitable. Lets not go down that road.

Time for a chill pill and let our panties unwind.

Cheers!

My panties ain't wadded. It gets plain stupid to repeat a known error over and over and over.

You can believe what you want. But if you stand by your above stamens you are wrong. If you came to me to build an engine and you were going to make me build off your theory I'd show you the door.

I was over pleasing the customer in 1988.

 

[RAMM]

Everyone agrees that aluminum transfers heat faster and so we assume it has a measurable effect in an internal combustion engine. Who has tested it in an internal combustion engine and reported the results? All of those "experts" claim something and none of them show any actual tests in an engine. Show me the tests!!!!! Here are mine! Where are yours/theirs?

Iron vs. Alloy Engine Heads - Tech Article - Chevy High Performance Magazine

Comparing Aluminum And Iron Cylinder Heads - Car Craft Magazine

Ok so thanks for posting those up again, I read them. In the Chevy HiPerf article the the aluminum heads have a 7 cc larger intake port and CNC combustion chambers which is usually a benefit--in terms of octane tolerance they don't mention anythingn to that end. In the Car Craft article they admit that with the big cam and only 185 psi cranking compression it didn't even exhibit detonation with the iron heads so it sure as heck wouldn't with the aluminum. If they built the engine to run the iron heads into an octane limited condition then maybe they would have been able to detect a difference when switching to the aluminum heads. But they didn't . Magazine dyno articles also never discuss the engines "personality". J.Rob

 

[RAMM]

Only foolish for you.

As I WONT let head material dictate compression ratio.

I don't let it dictate (there's that comprehension thing again) I take it into consideration though. I guess it's just one more parameter I consider than YOU do though.

My panties ain't wadded. It gets plain stupid to repeat a known error over and over and over.

You can believe what you want. But if you stand by your above stamens you are wrong. If you came to me to build an engine and you were going to make me build off your theory I'd show you the door.

I was over pleasing the customer in 1988.

And thats why you're out of business. J.Rob

 

[yellow rose]

I don't let it dictate (there's that comprehension thing again) I take it into consideration though. I guess it's just one more parameter I consider than YOU do though.


And thats why your out of business. J.Rob

Not out of business. I'm retired. I earned it. But I still do some work. I'm just picky about it.

Seems you like making **** up.

And I consider CR and application. I never consider head materiel OR a CNC chamber? How the hell does that affect detonation?