66 replies to this topic

[benb12]

I'm only an A-level chemist but I would have said that aluminium corroded more than copper in water. Hence why the copper heater in my 33 year old Mini wasn't corroded at all, and the aluminium mirrors on my dad's 15 year old beemer were completely corroded.

Excerpt snipped from Wiki....sorry for the font being so small, but it is still readable.

I think Aluminum starts corroding easier when in the presence of different metals. I think this is called Electrolysis.

Copper doesn't react with water at all. It reacts with oxygen in the air to form a layer of copper oxide (CuO) which prevents further corrosion, just the same as aluminium. And copper does have superior conductivity to aluminium.

[Trail of Dead]

Well it's been about 15 years since I was in a high school lab but I remember testing corrosion properties of metals in school. Copper definitely corroded faster than the other metals (Nickel & Aluminum) that we tested. This was all in the presence of H2O. Afterwards we gold plated the metals...which was neat. You are correct in that Copper corrodes in the presence of Air, but you have to have water in this reaction as well. Like I said before look at the statue of liberty. I have tons of Pennies that have never been exposed to water (only air) and none of them are corroded.

I think we are losing sight of the what the OP was asking though. He wants to be able to effectively build his own heater. Initially he was going to try MDF which is not the right material for the job. Either steel, aluminum or maybe some type of composite would work well (i.e. Carbon Fiber, some type of aramid fiber...Kevlar comes to mind here). As for the core itself, Personally I am going with Aluminum as they are widely available, lighter, and in many cases cheaper (some are quite pricey though). He can go with copper....it is all a matter of cash, personal choice and what type of result he is looking to achieve.

As for the fans, I am sure you can find a PC fan that would work well. Or, he could find a modern heater from another car and gut it for it's fan. Hack a Day or Instructables always has some awe-inspiring stuff on there. I am only mentioning all of this as it seems we are getting too geeky with all the details. This seems to be no different than when people say 10" wheels handle better and other say 13's handle just as well. Or when people say torque steer in a VTEC/C20XE Mini is unavoidable and others say torque steer is a sign of improperly setup suspension/caster-camber. So, the point of all my posts is to give some insight to the OP, maybe give him some different ideas that may help. I look forward to seeing his end result. I also look forward to building my Aluminum heater for others to see. Austin, Audi and others made Aluminum body shells and we don't hear too much about them rotting away to nothing. Lets get on with the ideas!

(I just took my Mini for a spin and the heater blew luke warm air....ewww)

Edited by Trail of Dead, 25 December 2009 - 05:42 PM.

[sonikk4]

There are different types of Aluminium which is down to the way they are heat treated.

Aircraft spec aluminium is normally T3 which is predominately used in the fuselage skins, T6 is used in areas where higher strength is required ie undercarraige fixings etc.

All of these different specs of Aluminium are also treated with either a chemical corrosion protection system or by a electrolytic process. Then further protection can be added by either covering in paint or using a wax covering or both depending on the area.

Now if any of the above processes are not applied correctly or are damaged say by scratching then corrosion will start and will be rapid especially in damp humid conditions. (I'm an aircraft engineer of 30 years and have seen some extreme corrosion on aircraft due to the above statement)

There are a lot of aluminium radiators on the market especially on the racing circuit due to their lightness. Copper based rads have been used for a very long time and as long as the anti freeze to water ratio is adhered to then there should be no corrosion problems. Its only when this is not followed then corrosion could become an issue, also by external damage say stone impacts. This will also apply to Aluminium rads.

Providing either type of material is looked after correctly then corrosion should not be an issue. Good luck with fabricating your alternative heating system but i would definitely not use MDF as the casing use sheet ali instead.

[Trail of Dead]

OP, I just found some nice complete heating units from Summit Racing. This unit puts out 28,000BTUs and 260CFM! It is also priced in USD so for you Brits this is REALLY cheap at 76 quid! I think I may go this route as it does eliminate all the guess work and saves time and money for other things. The main reason I was planning on junking the stock heater from my Mini was for space reasons. This unit looks promising, I'll research some more!

Edited by Trail of Dead, 25 December 2009 - 09:01 PM.

[dave21478]

..... Aluminum corrodes at a very slow rate. Aluminum does NOT rust or rot......

Have a look at the bottoms of the door skins on landrover defenders. Plenty of them have rotted right through.

[Dan]

The problem with any of the after market kit car heaters or race car heaters, including the unit linked to above is that they have no air controls. You can't set it to a defrost / demist mode because it doesn't have one and doesn't have any outlets or valves that would allow it. To get an aftermarket unit that does all this you have to go to a classic AC specialist like Vintage Air, their units are massive and very expensive but they work exactly as a standard heater does. Because of this most kit cars are fitted with, and you're going to love this, a Mini heater. Get an MPi heater.

[dave21478]

The heater I linked to originally has a range of parts that go with it including an air distribution plenum, various ducts and various vents, (The stuff on the webpage isnt their whole range, contact them for full details) so it can be used for dash, footwell and screen heating.

As i said,yes its a tad expensive, but if he is worried about space, then its 11" long, 5" wide and 8" high - significantly smaller than a mini heater, and even with the plenum and ducts attatched, will still take up less space. I really dont see how it would be possible to build something as compact and as effective without an awfull lot of faffing about.

[mini93]

would there be any use in changing the design of the screen demisters?, the heater to window heater pipe surley isnt going to be very good at delivering air being its got riges running around? of course good thing is thay are flexable

[Trail of Dead]

Dan says "Get an MPi Heater". I can't speak for the OP but in my case I am going to be swapping in a C20XE and all the transmission linkage required. I'm sure the standard heater would clear the linkage to the F20 but I really want more room as I am also going to be running a custom built center console, aftermarket stereo components, a whole mess of Autometer C2 gauges, and quite a few other things. I just want ROOM. I even thought about not running a heater at all so it isn't cluttering up under my dash. I'm a neat freak and want the wiring and such to be routed cleanly and not look cramped or cluttered.

The thing I dislike the most about the mini heater is how it hangs below the bottom dash rail. Why the heck did they do this?! My Dads old 1947 Dodge Power Wagon had a nicer looking heater setup. Also, when you guys talk about "demisters" do you mean "defrost"? Sometimes....even though we both speak English alot can get lost in translation so I want to be sure we are on the same page. To the few people that have cited examples where Aluminum has rot out on BMW's, Land Rovers etc....I did post a link from Wiki that explains HOW that can happen with Aluminum. If it is a Door skin then is the door frame made of Aluminum too or is it steel? (referring to the Land Rover) The article on Aluminum's Characteristics clearly states that it's corrosion resistance GREATLY reduces in the presence of other metals.

Regarding Dan saying it has no air controls (the unit I linked). What do you mean?! It is able to run different attachments that allow it to perform different functions. What kind of controls does my stock Mini heater have? Lets see....there is "Car", "Screen", "Off" and an on/off switch. The heater I linked is 3 speeds and for an additional $25 you can get a fancy kit to add air ducts. It wouldn't be hard to make that heater 150,000,000 times better than an MPi heater. 28,000BTUs! Now don't take what I am saying the wrong way (as it is hard to determine that over the internet), an MPi heater might be fine...I have never seen one. But the heaters in both my 1982 Mini's (1000HL, Mayfair) are craptastic.....there are alot of amazing design cues Sir Alec built into the Mini, the heater isn't one of them IMO.

If my wife & I get stationed in California or Florida after our tour is up here then I will remove the heater. But if we end up in Colorado then I need something I can depend on but at the same time fit nicely up under the dash in a compact type of way.

Edited by Trail of Dead, 26 December 2009 - 07:41 PM.

[Ethel]

A heater wasn't a standard fitment when they launched the Mini but a centre speedo was. Also putting the heater in the middle fitted in with the maximum commonality between LHD & RHD that's parts of the design. The Mini's heater has much in common with the car. It's uncomplicated & very compact - don't forget everything is included, matrix, blower & controls

[Dan]

. I even thought about not running a heater at all so it isn't cluttering up under my dash.

Can you afford a heated front screen? You have to have a method for demisting (yes that's the same as defrosting) the screen, it's the law here.

All these aftermarket heaters have a plenum that you can fit to the front which allow heat to be ducted to specific hose outlets, none of them have controlable valves though as far as I know. You can't select an outlet or a group of outlets, it's all or nothing. There are valve type components and Y selectors that can be fitted to hoses but they don't work very well and getting cable systems to operate them properly is tricky. You say it's easy to make a heater that is far better than the MPi unit, and then say you've never seen one! Given its volume, output, and the fact that all controls, matrix and the fan are built into one unit, it would be hard to make a better unit than the MPi heater. The only real drawback with it is that it doesn't have heated outlets for the dash vents.

[Trail of Dead]

. I even thought about not running a heater at all so it isn't cluttering up under my dash.

Can you afford a heated front screen? You have to have a method for demisting (yes that's the same as defrosting) the screen, it's the law here.

All these aftermarket heaters have a plenum that you can fit to the front which allow heat to be ducted to specific hose outlets, none of them have controlable valves though as far as I know. You can't select an outlet or a group of outlets, it's all or nothing. There are valve type components and Y selectors that can be fitted to hoses but they don't work very well and getting cable systems to operate them properly is tricky. You say it's easy to make a heater that is far better than the MPi unit, and then say you've never seen one! Given its volume, output, and the fact that all controls, matrix and the fan are built into one unit, it would be hard to make a better unit than the MPi heater. The only real drawback with it is that it doesn't have heated outlets for the dash vents.

How much different is the MPi Mini heater from the heater in my '82 Mini? I don't meant to sound like my cheese slid off my cracker.

One thing that is kind of funny is you say it is law that you have a way to defrost your windshield. Why isn't it law to have reverse lights? We bought a 2008 (It is brand new, it just sat in a dealer storage facility in the states) US Spec Ford Ranger pickup and when it finally got over here it had to go through the light conversion (obviously). During the conversion they disconnected our reverse lights in order to facilitate the use of one of those goofy rear fog lights. Now whenever I back up I've almost always got someone honking at me or yelling about how my "reverse light is blown out". But it isn't.

I actually don't plan on driving my Mini in the winter so that solves that problem. But if for some reason I NEEDED to drive it in the winter I would just buy one of those 12v heaters (the little ones) from JC Whitney. Again....problem solved.

The Summit Racing or the Flex-a-Lite Mojave heaters aren't really an "all or nothing" setup. It's no different than the fresh air vents in my Mini. You just manually reach over and close the vents. You could leave the factory vents/duct work in the dash of your Mini and simply route them to the aftermarket heater. Maybe if you want to get fancy you could come up with a butterfly valve from an old carb and hook it up with a hobby servo. There is your solution to close the "demisters"....that is if you want it to be fancy. I suppose you could also just use a cable setup similar to a bicycle brake cable. Fabricating isn't hard....time consuming but not hard.

If you tossed out the factory Austin heater and bought one of the previously mentioned heaters and the vent/duct kit that is half the battle right there. After that you would simply have to hook up the dash vents and a way to close them off and your done. Is there something I am missing? Does anyone have the specs of the factory heater (MPi or otherwise) that shows it out performs a modern heater? I'd like to see the specs of one....

Edited by Trail of Dead, 27 December 2009 - 02:12 AM.

[Dan]

Reverse lights are optional because they aren't a warning lamp, they are only there to be able to see where you are going in reverse. If you choose to reverse into something because you didn't want reverse lamps and so couldn't see it, that's up to you. In theory you can't hit or hurt anyone because you aren't meant to be in reverse at all if there are padestrians or moving traffic nearby. Demisting however means you can see when you are travelling forwards, far more important!

I agree with you completely, you could indeed spend ages fabricating a completely custom duct system but would it get you any improvement over the later heaters? The only specs I've seen for factory heaters describe the difference between standard and cold climate heaters, calling them 2.8 Kw and 4 Kw heaters respectively. The only differences between the units were the blowers. Internal blowers were available in both outputs, the external blower as a 4 Kw unit only. Cold climate heaters were deleted in 1988 when the heater system was upgraded to larger, 5/8" piping. The late plastic cased heaters either single or twin speed were only made to one spec, suggesting that since the introduction of larger hoses and the change to a newer heater design the units are capable of an output of at least 4 Kw. That would be around 13,000 BTU.

[Sleepy Stu]

Ignoring the legalities of all this I presume a heater isnt need to pass an MOT though as mine has gone through the last 2 MOTS fine without one?

[Trail of Dead]

About my reverse lights...I don't want to imply I back up without looking. It's like when you go to McD's a drive off with a drink on your roof or leave a gas station with your gas door still open. People just try to get my attention as they think they are doing me a favor by telling my reverse light is blown out, as I said it is not. In Pennsylvania a reverse light is required in order to pass state inspection. A Heater is not, one of those little 12v heaters would suffice to defrost your windshield.