14 replies to this topic

[IronmanG]

Just as a curiosity has anyone tried one of these? Bearing in mind how much it costs to get your cylinder head 'staged' these days and the advantages of aluminium is it a good buy?

https://www.minispar...px|Back to shop

[Spider]

I haven't tried one but for HP, Iron is the ticket.

[imack]

I'd be interested to find out too. I was very close to buying one 2 or 3 years ago, but I think they went out of stock. They would also have needed further machining/modification to get the desired chamber size. I ended up getting an iron one modified.

[DeadSquare]

I had a Speedwell 1100 aluminium head.  I thought that it would cope with the extra heat of supercharging, but the aluminium wasn't man enough between the bores, and it kept blowing head gaskets.

[stuart bowes]

One thing that pops up on the Volvo forum from time to time is with the alloy head, if you overheat there's a serious chance of warping

 

is that likely to be a factor here as well

[IronmanG]

I talked to a well respected A series engine builder who has built hundreds and he said he has never seen 1 fitted so I guess that says a lot

[imack]

One of my concerns was how it would stand up to regular strip down and rebuilds.
Would the rocker post studs pull or the head gasket fire rings eat into the head face. Also didn't know how well it would perform off the shelf compared with an iron head modified by a reputable head grinder. I knew alloy heads are more prone to warping if over heated compared with iron, but it wasn't until recently that I found out, as mentioned by Spider that an iron head of identical spec to an alloy head will ultimately produce more hp.
On the plus side, the alloy head gives a significant weight reduction.

Edited by imack, 14 June 2024 - 12:16 PM.

[Java_Green]

Why will an iron head produce more horse power?

[imack]

I might have got it wrong, but if I remember correctly it is something to do with heat retention within the combustion chamber giving superior burn, aluminium obviously dissipates the heat faster. I first saw in a David Vizard powertec 10 video on YouTube, then Spider mentioned it too.

Edited by imack, 14 June 2024 - 01:53 PM.

[Java_Green]

I might have got it wrong, but if I remember correctly it is something to do with heat retention within the combustion chamber giving superior burn, aluminium obviously dissipates the heat faster. I first saw in a David Vizard powertec 10 video on YouTube, then Spider mentioned it too.

A text I found at internet (Summit racing is the source) which do make sense to me and my knowledge about internal combustions engines. I cannot say that it is right or wrong but it do corresponds to the way OEMs have gone.

 

"Aluminum heads will dissipate heat faster. This allows for higher Compression ratios with less risk of detonation. The cooler head also delivers a cooler air/fuel mixture to the combustion chamber. Cooler air is denser and can make more power"

[Spider]

Why will an iron head produce more horse power?

 

As Imack mention, heat retention. Back to back testing done in the US many years back bore this out. Several test engines in Ford Chev and Mopar were prepared, identical cylinder heads were prepared and fitted in both alloy and iron, only the CR was adjusted between them, the alloy heads needing a high CR, in every case the iron heads made more power. It's only small numbers in difference, but shown to be the definite case across the board.

[timmy850]

I saw an engine masters video on this a few years ago. They did an alloy/iron comparison and used as similar as possible heads from the same company, same compression chamber size, same rubber volume etc. They had 2-3hp more on a few points with the alloy head, but on a 500hp engine this is definitely within testing tolerance

https://www.motortre...der-heads-test/

[Java_Green]

Since the post a couple of days ago, I have read about several tests testing iron vs Aluminium cylinder head and power outputs. Most of them show small differences when it comes to power output and in favor for the Aluminium ones. My assumption is that it has a lot to do with the chamber design, how much the air/fuel mixture is heated in the intake ports (hugh effect on power output) and so forth. The most interesting scenario would have been if somebody would have done the iron vs Aluminium test with what is available and on the A series engine. I will stay with "my belief" and it is up to you to choose yours. 

[Shooter63]

I have a funny feeling that the head is one of those items that will never be in stock again but is still listed, I enquired about a certain type of head gasket which was shown but out of stock,MS hadn't had them for years with non expected.
As for the iron head making more power, it just doesn't add up, if this was the case every race engine would run iron heads from F1 down, or if weight was a problem the heads would run iron skull chambers which they don't.

Shooter

[Spider]

These are last time I looked, thermal engines.