16 replies to this topic

[sonscar]

Reading about newly cast heads,has anyone made a nice one from clean sheet?Hemi? Four valve?three valve?eight port? Variable valve timing?Just a thought.Steve..

[84 City E]

Reading about newly cast heads,has anyone made a nice one from clean sheet?Hemi? Four valve?three valve?eight port? Variable valve timing?Just a thought.Steve..

 

I have no answer to your question, i simply dont know. But I would ask why? Lots of engineering to make a wholly new design work, or just transplant something else like a K series or similar as has been done lots and is relatively simple compared to say, new pistons etc to suit a hemispherical chamber design. (not saying its not a question worth asking, i just like to play devils advocate)

And remember hemi doesnt necessarily mean power, even 2CV's are a factory hemi 

[stoneface]

This one, no idea how it all finished up.

https://www.theminif...ctual-exercise/

[nicklouse]

Reading about newly cast heads,has anyone made a nice one from clean sheet?Hemi? Four valve?three valve?eight port? Variable valve timing?Just a thought.Steve..

In the old days yes there were loads. Couldwell Moorspeed Alexander and now KAD etc.

[mab01uk]

Some photos I took some years back of the Jack Knight stand at a Mini show showing their 16V head.






 

 

 

Edited by mab01uk, 13 August 2024 - 03:54 PM.

[sonscar]

What killed these developments?Price?Not original?Steve..

[Spider]

What killed these developments?Price?Not original?Steve..

 

Price. Also, keep in mind to add to that is the fitting of these is beyond most people's capabilities, so they'd be forking out even more to have them fitted.

 

As Nick mentioned, KAD still do a bespoke 16 V DOHC Head  https://kentautodeve...ns/twin-cam-16v

 

There's also a few around who are offering the BMW K1100 conversion, in 8 and 16 valve DHOC, but despite these being a kit, there's still a fair bit or welding and machining needed + the K1100 heads are becoming harder to find now.

[mab01uk]

The racing version of the Jack Knight 16V cylinder head for the A-series....

 

 

[mab01uk]

Motospeed 16 valve Twin Cam head

Mini 16 valve Twin Cam head manufactured by MOTOSPEED:-

https://www.ebay.co....tm/235688811621

Edited by mab01uk, 13 August 2024 - 07:53 PM.

[weef]

Early days, and I cannot remember who did the conversion, someone on the forum might, there was a crossflow head configeration using four Amal carburetors.

Probably went out of favour for being too expensive, a pain to balance and set up and maybe not enough power gain for the hassle.

[mab01uk]

Early days, and I cannot remember who did the conversion, someone on the forum might, there was a crossflow head configeration using four Amal carburetors.

Probably went out of favour for being too expensive, a pain to balance and set up and maybe not enough power gain for the hassle.

 

Amal carburettor kit for the Arden 8-Port head. Complete with carbs, manifolds and linkage.

£1,769.15 inc vat

https://www.minispar...port~heads.aspx

 

Arden 8-port Cylinder Head

£2,490.05 inc vat

https://www.minispar...port~heads.aspx

Edited by mab01uk, 13 August 2024 - 09:53 PM.

[timmy850]

I guess there's a few extra questions for you:

Is the head the ultimate limiting factor for making power? I would assume it isn't given the power that the turbo guys are making with 5 port heads

Is there already a head design that makes the maximum power potential of an A-Series?

What would you use the bespoke head for? Racing / road ?

[sonscar]

Just idle thoughts really.If you were tooling up to produce a head that was not eligible for racing where arguably both money and expertise are in better supply then why not make it better.Steve..

[DeadSquare]

Early days, and I cannot remember who did the conversion, someone on the forum might, there was a crossflow head configeration using four Amal carburetors.

Probably went out of favour for being too expensive, a pain to balance and set up and maybe not enough power gain for the hassle.

I had a 7 port aluminium crossflow one once.  It wasn't much good, the valves were too small. I have still got the sliced up Amal carbs somewhere.

 

 

@ Sonscar  asks "What killed them ?",  equally interesting might be "Why were they bought at all ?".

 

The answer is probably ignorance.  People thought that They must be better, and kidded themselves that they were, but it was probably the higher octane fuel in the 1950s that permitted a higher compression, that increased the performance, which they could have got if they'd polished and skimmed their iron head.

Edited by DeadSquare, 14 August 2024 - 07:15 PM.

[Spider]

I think a good starting point with this (and really any other) modification is to come back to basics and have a detailed look at that.

DeadSquare's post here highlights this;-

 

 

Early days, and I cannot remember who did the conversion, someone on the forum might, there was a crossflow head configeration using four Amal carburetors.

Probably went out of favour for being too expensive, a pain to balance and set up and maybe not enough power gain for the hassle.

I had a 7 port aluminium crossflow one once.  It wasn't much good, the valves were too small. I have still got the sliced up Amal carbs somewhere.

 

 

@ Sonscar  asks "What killed them ?",  equally interesting might be "Why were they bought at all ?".

 

The answer is probably ignorance.  People thought that They must be better, and kidded themselves that they were, but it was probably the higher octane fuel in the 1950s that permitted a higher compression, that increased the performance, which they could have got if they'd polished and skimmed their iron head.

 

 

While there is some restriction in the ports and some losses from the siamese inlets, from my own observations and experience, fitting most 7 and 8 port cross flow heads don't give 'telephone numbers' in terms of horsepower improvement over what can be given from a 5 port iron head. Certainly for most street cars, in terms of money and sweat expended for results realised, it's expensive power and by that, I'm referring to that peak number that most seem to focus on. In many cases, there's a loss of usable power in the lower parts of the curve, you know, that part of the curve that most of us use when driving around the streets at legal speeds,,,

 

Also, keep in mind, head for head, Iron makes better power than alloy, it's only small numbers, but measurable.

 

I'd suggest here, doing sensible mods to a cast iron head and adding decent injection. It's be much more drivable and fun.