14 replies to this topic

[alicetheauto]

Are they any good? Were could I get one from (other than SC as I have heard less than good things....)? I REALLY like the idea of saving 20kgs from the front of the car!

[mini_mission]

Try MED, I think they do them.

Whats wrong with the SC one?

[alicetheauto]

Its not the part that I am concerned with, but I googled the company and a few bad reviews came up. I just dont want to risk £900 of my money with a company that has had even one bad review....

[mike.]

If i was going to be spending that much on a head - I'd be getting a 7 port!

[[email protected]]

We also have them available

http://www.minispare...ty=pb&pid=39918
http://www.minispare...ty=pb&pid=38771

[Dan]

I just dont want to risk £900 of my money with a company that has had even one bad review....

Keep it in the bank then, there's no such thing as a company with a clean sheet. You can't please everyone.

[mike.]

Aren't they pretty fragile compared to your normal heads. Doesn't alloy warp easily if the engine over heats for example?

[Dan]

Yes it would be more easily damaged by heat than cast iron. It would also be extremely important to follow the tightening sequence as if you got it wrong there's a greater chance of damaging the head rather than just releasing the gasket. It should give you more leeway for tuning though because the alloy will conduct heat better than iron.

Edited by Dan, 29 January 2009 - 10:14 AM.

[mike.]

Not worth the money imo, especially since the £700-£900 you spend is only for a standard casting. The websites don't mention ny port work or valve sizes.

You could buy a fully worked stage 4/5 MED head (or similar) for the price and still have money left over for a rolling road session after fitting it. This would definatly give you a way better increase in performance than saving a mere 20kg of weight. Also i can imagine if you did want any port work or bigger valves installing, you'd get charged more with it being an alloy head - Being expencive and uncommon already.

[Dan]

The alloy heads aren't cast to the same pattern as any of the iron heads. To my knowledge the port work of these heads as standard is roughly equivalent to many so-called stage three heads. They use smaller spark plugs which have been relocated to a better part of the chamber. They take advantage of the improved cooling to reduce the water jacket size, making all the metal thicker and allowing more reworking in future. There's a much thicker deck so they'll take a much deeper skim than an iron head. There's a lot more scope for bigger valves because of the adjusted spark plug position and thicker metal. All in all a lot of the iron head's shortcomings have been dealt with. The tuning advantage isn't simply down to weight savings (which aren't nearly 20kg incidentally) and design but mainly in the better material. You can run a higher combustion temperature because the head will absorb less heat to start with and conduct what it does aborb away better.

That is if I'm talking about the right head, to my knowledge there are three different alloy A series head castings available.

[mike.]

The alloy heads aren't cast to the same pattern as any of the iron heads. To my knowledge the port work of these heads as standard is roughly equivalent to many so-called stage three heads. They use smaller spark plugs which have been relocated to a better part of the chamber. They take advantage of the improved cooling to reduce the water jacket size, making all the metal thicker and allowing more reworking in future. There's a much thicker deck so they'll take a much deeper skim than an iron head. There's a lot more scope for bigger valves because of the adjusted spark plug position and thicker metal. All in all a lot of the iron head's shortcomings have been dealt with. The tuning advantage isn't simply down to weight savings (which aren't nearly 20kg incidentally) and design but mainly in the better material. You can run a higher combustion temperature because the head will absorb less heat to start with and conduct what it does aborb away better.

That is if I'm talking about the right head, to my knowledge there are three different alloy A series head castings available.

Well in that case - The minispares website is... vague to say the least - 'no data'

[Ethel]

One of the Minspares heads is described as a 940 casting, suggests it's at least similar to an iron head. I'd think they'll have to beef up the casting around the stud holes and there's not masses of spare metal around the pushrod holes either, so improvements in porting can't be massive.

[Dan]

Alloy head at Moss.

Webcon's casting. Visibly a different casting than the Moss version but still using 10mm plugs and other improvements.

Edited by Dan, 29 January 2009 - 02:40 PM.

[Ethel]

Cheers Dan, that's a bit more interesting. Looks like the plugs have been moved towards the Exhaust side of the chambers, I wonder if there's any advantage in similarly tweaking/fitting the plugs in a standard engine?

Wouldn't be hard to make up an eccentric bush for a smaller plug.

[Dan]

I've had a look at the photos I have of the Minispares head in an old accessory catalogue and it looks to be similar to the Webcon head. In fact I have a feeling that the Moss head might yet be the same one with a bit more skimmed off the top, although it doesn't look to have lost any height along the front face. So they might all be the same or they might all be different!

Wouldn't be hard to make up an eccentric bush for a smaller plug.

Might work, I suppose you'd have to thread in and lock a blank and then drill and tap it while in place. Or you could mill the hole out and shrink in a plug with an eccentric bore.

Edited by Dan, 29 January 2009 - 02:58 PM.