I have been looking for a new head for my project and i saw an advert in a magazine for an alloy cylinder head.
I just wanted a little bit more information on them really.
What are the advantages (if any) of one?
Would i need to uprate any other bits to suit the head?
Would it be suitable for my car which will be a daily runner?
Thanks
Mike
Alloy Heads
Started by
RacingGreen
, Mar 17 2006 08:03 PM
5 replies to this topic
#2
pikey7
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Up Into Fourth
Posted 17 March 2006 - 08:21 PM
I'm not convinced about them (although I will start off by saying none of this is fact, just my thoughts on it).
Basically I see it as a weight saving, but I'm not convinced they'll not give you more problems than they are worth. In my mind the different expansion co-efficients between the steel block and an alloy head would mean that they would not be trouble free. An all alloy engine, fine, but steel & alloy.......?
I would think that to counteract this somewhat you'd need to increase the clamping load (i.e. convert to 11-bolt fixings and ARP bolts). It may also cause issues with the valve clearances changing at different a different/greater rate and maybe causing issues.
Having said all that, as I say, I have no practical experience of this mix!, and also the fact that the KAD 16v head is alloy, and I've not heard of issues with it (although of course the cam is in the head and would negate clearance issues)
Basically I see it as a weight saving, but I'm not convinced they'll not give you more problems than they are worth. In my mind the different expansion co-efficients between the steel block and an alloy head would mean that they would not be trouble free. An all alloy engine, fine, but steel & alloy.......?
I would think that to counteract this somewhat you'd need to increase the clamping load (i.e. convert to 11-bolt fixings and ARP bolts). It may also cause issues with the valve clearances changing at different a different/greater rate and maybe causing issues.
Having said all that, as I say, I have no practical experience of this mix!, and also the fact that the KAD 16v head is alloy, and I've not heard of issues with it (although of course the cam is in the head and would negate clearance issues)
#3
minimole
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One Carb Or Two?
Posted 17 March 2006 - 09:05 PM
there are plenty of car that have alloy heads and steel blocks. Infact i think most cars have an alloy head with steel block . There can be issues with them corriding together. One that springs to mind is the triumph dolimite (spelling)
#4
Dan
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On Sabbatical
Posted 17 March 2006 - 11:20 PM
There's quite a few benefits of an aluminium alloy head. Aly conducts heat better than cast iron, and absorbs heat better too. The result of this is better combustion chamber cooling so you can run higher CRs and generally higher tune than with cast iron. And it won't run on when you turn it off!
The alloy A series heads have been redesigned over the iron version as well in that they have a better water jacket layout for even better cooling. The redesign of the jacket also allows larger valve sizes I think, which is helped by the use of smaller size sparkplugs which the head is designed for. These plugs have also been moved slightly to put the nose in a better place in the chamber.
That's what the makers say anyhow.....
The alloy A series heads have been redesigned over the iron version as well in that they have a better water jacket layout for even better cooling. The redesign of the jacket also allows larger valve sizes I think, which is helped by the use of smaller size sparkplugs which the head is designed for. These plugs have also been moved slightly to put the nose in a better place in the chamber.
That's what the makers say anyhow.....
#5
pdaykin
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Super Mini Mad
Posted 18 March 2006 - 09:03 AM
Not sure that the alloy heads can have larger valves than the steel item as they need inserts in them too.
Isn't it a case of them having larger than standard valves and better flow as standard ?
The only way of knowing is to ask the manufacturers and some of the tuning firms that have worked on them.
But they do seem a lot of money - you could get a really well worked iron head for that money
Isn't it a case of them having larger than standard valves and better flow as standard ?
The only way of knowing is to ask the manufacturers and some of the tuning firms that have worked on them.
But they do seem a lot of money - you could get a really well worked iron head for that money
#6
Bigbudders
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Mini Mad
Posted 18 March 2006 - 01:07 PM
There is an article about the Webcon alloy head in the october 2005 issue of Miniworld. They show the head being modified by MED, they left the exhaust valves standard but put larger inlets in (35.7mm)
The standard alloy head has got larger port sizes but apparently can be vastly improved, although like pdaykin says you could get a well modded head for the money. £615 for the head and £500 to have it modded to road comp spec seems a little steep to me.
The standard alloy head has got larger port sizes but apparently can be vastly improved, although like pdaykin says you could get a well modded head for the money. £615 for the head and £500 to have it modded to road comp spec seems a little steep to me.
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