40 replies to this topic

[William Hunt]

After the disaster at Le Mans in 1955 Mercedes was accused of having used illegal fuel because the car of Levegh was burning much more intensely than it should have been.
Mercedes proved the accusations to be wrong and said that the car burned so heavily because it has magnesium bodywork which was lighter.

But magnesium was also a lot more dangerous because it was more difficult to cease the fire if the car caught fire, pooring water on magnesium would in fact make it burn harder and the temperatures of magnesium on fire was also significantly higher.

Then in 1968 Honda came with an experimental car that had magnesium material (I think the engine was even made out of magnesium), John Surtees refused to drive it because he claimed the car was not suited for a race track, dangerous and a driving laboratory.

Honda insisted that the car would drive so they could sell more cars in France because of the publicity so Honda France entered it and they chose a French driver, Jo Schlesser who was already 40 but a leading F. Junior & F.2 driver was the natural choice.

 

We all know what happened at Rouen that year so.

Because of the magnesium the fire was so intense that marshalls, even in their fireproof suits, didn't manage to pull Jo from the burning inferno and they couldn't contain the fire, in fact the fire became more intense when they tried to fight it.

Then two years at later a horrible accident happened at Zandvoort, the victim beiing Piers Courage in the Frank Williams entered de Tomaso.

Again an intense fire that they didn't manage to cease and that actually got worse, the driver perishing inside although he probably had died instantly of the impact of a tyre against his head, that was discovered later.

Now I have two questions:

 

- which other F1 cars (or Le Mans entered cars) had magnesium material?

- why did they keep on using magnesium (I assume because it's lighter) when accidents had already occured with it and especially since it was so hard to control it on fire.
Clearly a magnesium car was more dangerous to the driver, even in an era where they didn't seem to care much about safety (especially the track owners) I still find it baffling that magnesium was not forbidden after the Honda inferno in Rouen.

Edited by William Hunt, 12 July 2017 - 18:34.

[Doug Nye]

Sheet magnesium was banned, I believe (without checking just now), but magnesium alloys in cast form remain extremely useful and are still widely-used. Magnesium in this form is actually quite difficult to ignite but once it gets going - burning at over 3,000 degrees - it remains extremely difficult to extinguish.  

 

Jo Schlesser's fatal accident at Rouen in 1968 shook Dan Gurney so badly that - in addition to insufficient sponsorship funding - what became a major factor in his abandoning Formula 1in 1969 was the fact that the next-generation F1 Eagle under construction had a magnesium-alloy monocoque.  Of course the great attraction of such magnesium material was its light weight -  specific gravity of 1.8(ish) compared to aluminium's 2.8 (ish). But after witnessing the Schlesser Honda fire Dan concluded that driving a mag-hulled car was simply not worth the risk. 

 

The Mercedes 300SLR conflagration at Le Mans began as atomised fuel from burst tanks ignited, quickly igniting torn and tangled elektron sheet in what remained of the body panelling. That burned fiercely enough to ignite in turn mag-based engine and transmission-case castings. I believe some water was used on the fire in its early stages which simply exacerbated the problem, since water reacts with magnesium to produce hydrogen gas...and as the Hindenburg and R101 disasters had demonstrated the presence of hydrogen is rather bad news in any fire.

 

DCN 

[Talisman]

 

Then in 1968 Honda came with an experimental car that had magnesium material (I think the engine was even made out of magnesium), John Surtees refused to drive it because he claimed the car was not suited for a race track, dangerous and a driving laboratory.

Honda insisted that the car would drive so they could sell more cars in France because of the publicity so Honda France entered it and they chose a French driver, Jo Schlesser who was already 40 but a leading F. Junior & F.2 driver was the natural choice.

 

 

There are several errors here.

 

Firstly the engine was not made of magnesium.  The engine was air cooled and therefore heavy but otherwise conventional, the chassis had to be lightened to compensate hence magnesium was used.

 

The car was not entered to raise publicity in France for Honda cars, I am not even sure they were even sold in the French market.  

 

The air cooled car was entered due to internal Honda politics.  Mr Honda was convinced simpler air cooled cars were the future.  His engineers including the F1 team were convinced water cooling which resulted in more stable temperature control were worth the increased complexity for better performance and emissions controls.  Mr Honda assembled a skunkworks team that designed and developed the air cooled car and wanted it entered against the conventional entry.  Surtees of course famously refused and Schlesser stepped in with fatal consequences.

 

The crash had two main consequences, Honda pulled out of F1 to start mass producing cars and Mr Honda himself withdrew from being involved in engineering decisions, he was reported to have been heartbroken because of Schlesser's death.  Honda did indeed stick with water cooled cars and the Civic was the end result.

 

Magnesium does burn as you described, however it also has a high ignition temperature and is therefore difficult to set alight.  It is still used for vehicles including armoured cars and light tanks where reducing weight is an issue.  The rationale is that if the magnesium chassis or body reaches ignition temperature then the vehicle is destroyed anyway.

[funformula]

The Le Mans winning Porsche 917 from 1971 was built from magnesium.
Porsche informed the drivers Gijs van Lennep and Helmut Marko about the fact only after the race suggesting that they may not have taken the risk of racing that very car if they had known.

[Lee Nicolle]

There are several errors here.

 

Firstly the engine was not made of magnesium.  The engine was air cooled and therefore heavy but otherwise conventional, the chassis had to be lightened to compensate hence magnesium was used.

 

The car was not entered to raise publicity in France for Honda cars, I am not even sure they were even sold in the French market.  

 

The air cooled car was entered due to internal Honda politics.  Mr Honda was convinced simpler air cooled cars were the future.  His engineers including the F1 team were convinced water cooling which resulted in more stable temperature control were worth the increased complexity for better performance and emissions controls.  Mr Honda assembled a skunkworks team that designed and developed the air cooled car and wanted it entered against the conventional entry.  Surtees of course famously refused and Schlesser stepped in with fatal consequences.

 

The crash had two main consequences, Honda pulled out of F1 to start mass producing cars and Mr Honda himself withdrew from being involved in engineering decisions, he was reported to have been heartbroken because of Schlesser's death.  Honda did indeed stick with water cooled cars and the Civic was the end result.

 

Magnesium does burn as you described, however it also has a high ignition temperature and is therefore difficult to set alight.  It is still used for vehicles including armoured cars and light tanks where reducing weight is an issue.  The rationale is that if the magnesium chassis or body reaches ignition temperature then the vehicle is destroyed anyway.

Magnesium ribbon as most school kids will attest can be lit with a match. Old VW crankcases when chucked on a bonfire really burn well.White and incadescent.  So in reality highly flammable. And they are like many 'mag' wheels a high magnesium alloy not pure magnesium.

And those materials as many will know have a real problem with moisture which breaks down the magnesium and become very brittle. All modern alloy wheels are aluminium, a bit heavier but a lot more durable. And later VW cases were as well. they just buckle in a fire.

As an aside, Friends and I in the distant past used to go play with beach buggies and bikes at a country beach area, one weekend we discovered a dumped VW in a sandhill puddle. By the following weekend half the engine and gearbox cases had corroded away and you could see the internal components protected with the oil. The water was primarily rain water though I am sure there was a salt content. After that we did make a point of cleaning our 'equipment' promptly and thoroughly. The buggies ofcourse were VW based.

Edited by Lee Nicolle, 12 July 2017 - 23:01.

[Victor_RO]

As late as '92, the unraced 3.5 liter Mercedes C292 had a magnesium engine block. They had the car on display for the first time in 25 years at Goodwood this year, and I had a brief discussion with one of the people taking care of the car on display and she mentioned this, while also saying that because of this fact, the blocks tarnished quickly and they cannot restore the car to working condition with original engine blocks precisely because they are made from magnesium.

 

They had done some interesting metallurgical trickery with the block for oil circulation, until the engine block warmed up to operating temps it would leak oil everywhere but basically seal itself when the temperature rose.

[Henri Greuter]

I have read that somewhere in 1977 Cosworth built a few magnesium alloy DFV's but that these were very sensitive for drastic differences between temperatures and had to be stored in air conditioned storage rooms.

 

 

The Granatelli brothers once built a Novi V8 indycar engine out of as much magnesium alloy based parts at possible but that was no success for unstated reasons. I suppose that magnesium alloys and methanol based fuels would have been very happy together when making op a cylinder/combustion chammber ant fuel....

 

 

Henri

[Roger Clark]

I have read that somewhere in 1977 Cosworth built a few magnesium alloy DFV's but that these were very sensitive for drastic differences between temperatures and had to be stored in air conditioned storage rooms.


The Granatelli brothers once built a Novi V8 indycar engine out of as much magnesium alloy based parts at possible but that was no success for unstated reasons. I suppose that magnesium alloys and methanol based fuels would have been very happy together when making op a cylinder/combustion chammber ant fuel....


Henri

Cosworth built a magnesium DFV in 1969 for their own car.

[Henri Greuter]

The 1964 built Shrike chassis, built by Halibrand engineering for the "Indy 500" of that year also used a magnesium based alloy for the monocoque.

 

Ironically, one of these cars ended up in the gruesome 2nd lap disaster of that year's race, in the middle of the fire that was part of this tragedy. Curiously, the fire damage to that car was pretty mild, given the inferno it had been in.

 

 

Henri

[f1steveuk]

Yes Cosworth built a, as in one, magnesium engine for the 4wd car.

 

I also recall reading that BRM (about the time of the 133 and 153 I think)  had hand beaten magnesium bodywork, or at the very least nose sections. I cannot recall where I read this, and am more than happy to be corrected!

Edited by f1steveuk, 14 July 2017 - 10:16.

[Sisyphus]

I wonder if Surtees not wanting to drive the RA302 was necessarily because of the magnesium tub.  The 302 was radically different from the RA301 in dimensions and layout.  The tub had a beam over the engine behind the driver which the air cooled engine was suspended from (I can't recall another modern F1 car with that design).  So, many different design features with apparently little testing which is likely enough justification for Surtees not wanting to drive it.

 

The engine might have been heavy (an argument for using mag in the chassis) but that isn't necessarily a feature of an air cooled engine--in fact, it is typically just the opposite.  You need extra material to enclose water jackets and the water in the block itself adds weight as does the necessary water pump, etc.

 

A problem with substituting mag for aluminum is that the elastic modulus divided by the density of all common metals is nearly the same.  So, mag is lighter than aluminum but to carry the same load without having extra deflection (which is often a design criteria) means you have to use exactly that much more of it.  For some unloaded panels, then, yes, the lower density is a net advantage for mag.  Not clear that it is so for the loaded parts of a chassis or in an engine because of the loss of stiffness.  The stiffness and strength of mag tends to fall off at a lower temp than aluminum as well.

 

With respect to the fire risk, certainly mag is difficult to extinguish once it gets started and requires different materials and techniques.  That drivers in the 60's raced laying between 16 gauge aluminum pannier tanks full of gasoline--which not infrequently leaked onto their pre-Nomex uniforms--seems a bigger issue.  

[Roger Clark]

The 312B Ferrari (1970) also had the engine suspended from a beam.

[Henri Greuter]

As late as '92, the unraced 3.5 liter Mercedes C292 had a magnesium engine block. They had the car on display for the first time in 25 years at Goodwood this year, and I had a brief discussion with one of the people taking care of the car on display and she mentioned this, while also saying that because of this fact, the blocks tarnished quickly and they cannot restore the car to working condition with original engine blocks precisely because they are made from magnesium.

 

They had done some interesting metallurgical trickery with the block for oil circulation, until the engine block warmed up to operating temps it would leak oil everywhere but basically seal itself when the temperature rose.

 

 

leaking everywhere...  reminds me about the SR71 `blackbird`. That one also kept weating when still on the ground when prepared for flight.

 

Henri

[ddmichael]

 

 

 

The car was not entered to raise publicity in France for Honda cars, I am not even sure they were even sold in the French market.  

 

 

Honda had entered the French market by 1968 and were being quite heavily promoted - I think Beltoise road tested an S800 for Champion magazine.

 

I wonder if Surtees not wanting to drive the RA302 was necessarily because of the magnesium tub.  The 302 was radically different from the RA301 in dimensions and layout.  The tub had a beam over the engine behind the driver which the air cooled engine was suspended from (I can't recall another modern F1 car with that design).  So, many different design features with apparently little testing which is likely enough justification for Surtees not wanting to drive it.

 

 

Surtees drove the RA302 in practice at Monza, so it certainly wasn't the magnesium that put him off - I just don't think he considered the car to be sufficiently well-developed for the challenges of Rouen.

 

DM

Edited by ddmichael, 14 July 2017 - 12:18.

[Doug Nye]

John told me he was totally opposed to Honda Racing running the air-cooled car at Rouen. He considered it under-developed and a distraction from his own V12 mount. However, the air-cooled V8 was a pet project of Mr Honda's and the decision had been made on high. The tragic outcome was extremely difficult for the Japanese to handle, and for Mr Honda himself it was a considerable blow.  Perceived loss of face in such a public arena was considered shameful in Japan at that time - and still is, though not - I understand - to quite to the same degree.  Perhaps, considering the current McLaren-Honda saga in Formula 1, this is no bad thing...  Or, conversely, has it been a contributing factor in that the current generation of engineers and managers just do not care enough?

 

DCN

[kayemod]

... drivers in the 60's raced laying between 16 gauge aluminum pannier tanks full of gasoline--which not infrequently leaked onto their pre-Nomex uniforms--seems a bigger issue.  

 

I don't want to take anything away from the rest of your post, but your "16 gauge aluminium tanks" is a little out. It's actually referred to as 16SWG, Standard Wire Gauge, which is a little over 1.5mm, and with the the grades of aluminium used in monocoques in the days before composite materials, that would be much too heavy, 18SWG which is roughly half the thickness, or even lighter would be the norm. My only involvement with monocoques back then was making and fitting fibreglass bodywork around them, but they were much lighter than 16SWG. A tank made from that thickness, you could almost jump up and down on without causing much damage, and the car would weigh a ton. It would of course help a lot with crash protection though, cars were generally flimsy back then by later standards, and you're quite right about the leaking fuel dangers.

[Tim Murray]

[pedantic mode]

16 gauge - 64 thou - 1.626 mm
18 gauge - 48 thou - 1.219 mm
20 gauge - 36 thou - 0.914 mm
22 gauge - 28 thou - 0.711 mm

I used these conversions in my work for many years, and still know them by heart fourteen years after I retired.

[/pedantic mode]

[Lee Nicolle]

My experience is with fuel tanks on tintops. Most  alloy tanks I have anything to do with have been at least 50 thou thick and I have seen several split open. The worst when I ran out of brakes and backed the car into a tyre wall. The car [effectivly external skin] crumpled up to the back window. The tank mounted on the back 'chassis rail' which were 1.5" lightweight sq tube. The tank squashed to about a third of its size and 40 litres of avgas onto the ground. probably luckily the engine [ Chev] bounced back on the mounts and broke the distributor cap turning the engine off. 

In recent times having seen similar accidents with plastic tanks which still bend but do not tear that is what I use and recomend now. The only down side is that they for some reason only half full of foam. Why? 

And it seems noone sells the foam any more. In those days I sourced it from K&A.

On that as well, another alloy tank was filled with aircraft foam which just turned to sludge. Very dubious stuff! Ended up as scrap.

The alloy tank was replaced with another [now 20 years ago] The filler neck and the foam was all that was salvaged.

Bag tanks also have problems when they are full as the bag can split in a big shunt, I have seen that several times with Sprintcars which either get hit or end for end on first lap crashes when the tanks are full. And yes they do have 'head space'

The old GpC Tourers were probably lucky with the big 'drop tanks' hanging down in the back of the car.. Later they went to bag tanks.

A friends speedway sedan split the tank after a moderate shunt in the back, the fuel tank bar saved the tank from any actual damage but it moved the rear rails and the tank mounted [as per rules] too solidly split. That one we dropped the tank out and 5 min Araldite was used to patch the crack.. Great stuff for this type of repair.  Should be in every racers tool box.

[SJ Lambert]

Australian racing car manufacturers such as Elfins were using magnesium to cast wheels and uprights from the early sixties in their Formuls Juniors (wheels) and Monos (uprights & wheels all round) - their monocoque tubs were aluminium sheeted affairs - as I understand it they only ever used magnesium in castings done by the Commonwealth Aircraft Corporation in Melbourne and that continued into the seventies on their ANF1 & F5000 cars. They did cast engine to gearbox adaptors and oil filter heads and machine some reasonably small components in magnesium too - suspension bits, engine bits, steering rack parts could all be turned out of mag from time to time.

They had a magnesium machining (swarf) fire or two along the way, but I don't think any of their cars fell foul of a racing incident fire that involved a magnesium engulfment - an aluminium clad Mono (ANF1.5) was barrel rolled in period without splitting the tub!

The boss used to specify his mag wheels to be machined thin to save weight - we have been able to cast new magnesium wheels in recent years - I have as much material as possible left in them ( the bosses thin rims split sooner than thicker ones).

Edited by SJ Lambert, 15 July 2017 - 01:57.

[Lee Nicolle]

Australian racing car manufacturers such as Elfins were using magnesium to cast wheels and uprights from the early sixties in their Formuls Juniors (wheels) and Monos (uprights & wheels all round) - their monocoque tubs were aluminium sheeted affairs - as I understand it they only ever used magnesium in castings done by the Commonwealth Aircraft Corporation in Melbourne and that continued into the seventies on their ANF1 & F5000 cars. They did cast engine to gearbox adaptors and oil filter heads and machine some reasonably small components in magnesium too - suspension bits, engine bits, steering rack parts could all be turned out of mag from time to time.

They had a magnesium machining (swarf) fire or two along the way, but I don't think any of their cars fell foul of a racing incident fire that involved a magnesium engulfment - an aluminium clad Mono (ANF1.5) was barrel rolled in period without splitting the tub!

The boss used to specify his mag wheels to be machined thin to save weight - we have been able to cast new magnesium wheels in recent years - I have as much material as possible left in them ( the bosses thin rims split sooner than thicker ones).

They had a swarf fire at Elfin, luckily extinguished quickly. Been told that by a few people.

With all those old hi mag uprights and wheels are good museum pieces, at very least X ray them.

[SJ Lambert]

We penetrant test and inspect for and treat against corrosion

[SJ Lambert]

Lighting a box of swarf with a newspaper wick and then hosing it with water produces incandescent results!

[Ray Bell]

On the subject of the DFV variant with magnesium block...

These were built for Tyrrell, IIRC, at a time when they were the only ones not yet racing with turbos and weight was a factor in trying to match the cars with compressed inlet charges.

What I recall of the information promulgated at the time is that there was a special warm-up procedure different to the engines with aluminium blocks.

[Henri Greuter]

On the subject of the DFV variant with magnesium block...

These were built for Tyrrell, IIRC, at a time when they were the only ones not yet racing with turbos and weight was a factor in trying to match the cars with compressed inlet charges.

What I recall of the information promulgated at the time is that there was a special warm-up procedure different to the engines with aluminium blocks.

 

As if that cheatcontraption needed a magnesium DFV to reduce its weight. ..... It was illegal underweight with a regular DFV already......

 

 

Meanwhile,  I've felt myself pressed enough to find out where it was stated that Cosworth was working on magnesium DFV's in '77 already.

Well, if it was true or not, the original quote I remembered to have read is printed in the book: "The complete history of Grand Prix Motor racing" by Adriano Cimarosti, sponsored by a cigarette company that had a blue `ship of the desert` on yellow background. The English version was edited by David McKinney and released in 1990.

 

For they who own the book too, and want to put me to the test:

The quote about the magnesium Cosworths can be found on page 309, in the middle one of the three columns text on the page. There was talk of tests which were no success because of the high coefficient of expansion.

 

Henri

[Charlieman]

Meanwhile,  I've felt myself pressed enough to find out where it was stated that Cosworth was working on magnesium DFV's in '77 already.

UK motorsport press reported in spring 1977 that a small number of development engines had been seeded to selected teams -- McLaren, Tyrrell, Lotus, Wolf?. They were all teams who had DFVs maintained by Cosworth and by independents. The blurb about the development DFVs was vague. Cosworth were testing in public and it is likely that teams tested different elements at different times. It would be nice to know what was learned.

[arttidesco]

IIANM the article Charlieman refers to may have been 1978 when Motor Sport spoke with Mike Costin who alluded to development DFV's fitted with bigger valves and ports and still even later examples fitted with revised crankshafts with 60 psi oil
pressure instead of the usual 100 psi in persuit of increased reliability.

[chr1s]

I'm pretty sure that Ferrari used  magnesium cylinder blocks for their Flat twelve engines. I read quite recently (can't remember where) that somone who ownes a 312T had the car restored and in the process it had one of the last aluminium cylinder blocks fitted to replace the original magnesium one. The Transverse gearbox cases were definitely mad from magnesium.

[SJ Lambert]

Hewland utilised magnesium for their gearbox casings from early days - I think Brabham (and presumably others) fitted HD5 boxes which utilised mag VW casings to their 1500cc F1 cars.

I presume that Hewland embraced magnesium for many of their development gearboxes once they started doing their own casings

[GMACKIE]

James, please forgive me if this is wrong, as it purely from 'memory'.

 

The early Hewland cases were made by VW, and were magnesium alloy. The later cases were aluminium alloy. Was this to increase strength? Or maybe to eliminate the 'reliance' on VW to provide cases? Or both?

[SJ Lambert]

No worries Greg, without looking anything up, I think you are right - the HD 4 & 5 boxes were "upside down" VW castings in mag alloy, later on (maybe Mk 8?) Hewland did their own VW style box casing - I've not worked on any of the later ones, but those that I've seen look at a casual inspection as though they are aluminium. I presume Hewland did their own to optimise their strength/ability to absorb torque, more so than having to rely on VW, but that's just a guess.

Edited by SJ Lambert, 16 July 2017 - 10:01.

[Lee Nicolle]

James, please forgive me if this is wrong, as it purely from 'memory'.

 

The early Hewland cases were made by VW, and were magnesium alloy. The later cases were aluminium alloy. Was this to increase strength? Or maybe to eliminate the 'reliance' on VW to provide cases? Or both?

VW boxes at least until the late 60s were magnesium alloy, as were the crankcases. To pick  up a 40 horse case and a 1600 is a fair difference in weight but the later cases were a good deal stronger. 

And no I have not worked on them, but know a few VW experts. Offroaders unsurprisingly found all the weakness's.

In the 70s when a lot of speedway midgets were VW powered they were fragile. The aftermarket supplied better cases that would take the very large power they were making. Autocraft seemed to be the best though they had different bore and strokes. Though the cases had limited life, many were welded. The well off blokes bought a new one every year and had no trouble. Some offroaders used those engines as well though very different state of tune.

Ofcourse there was no gearboxes there, I know there is 'improved' cases that came from Brazil. They resolved many small engined offroad boxes for a period. I doubt any offroaders use a VW box these days apart from maybe 1200.

The later VW Kombi cases seem to live in road racing, far less bumps and far lighter wheels and tyres help there a lot.

I guess James Elfin is still an earlier type Hewland/VW thing. Be gentle.

My understanding [may well be wrong] that when Hewland copied the VW casting they reinforced the weak parts of the case. The gears are seemingly strong enough but not the case.

Though VW may well have cast them to order. I have seen F2 Golf heads that are very different from a road Golf head,, with the same VW part number!

[SJ Lambert]

Frank Hallam commissioned Kevin Drage through Clisby Industries to make light weight magnesium-aluminium alloy cylinder heads for the Repco Brabham 3 litre and Tasman engines in 1967 - the 3 litre engines may have debuted at Monaco. I'm not sure whether timing chests and cam covers were in straight mag or not.

Edited by SJ Lambert, 17 July 2017 - 01:15.

[Sisyphus]

From John Blunsden's "The Power to Win" on Cosworth's V-8 engines, he notes that development engines in 1977 using magnesium castings (but not specifying which components):  "...were to be allocated on a loan basis to Lotus, McLaren, and Tyrrell teams..." and later Wolf was also part of the arrangement.

 

The same reference notes the 1983 narrow angle valve DFY used ...front covers for the block and cylinder heads and the cam covers as well as the intake manifolds and the water pump." from magnesium.

[Henri Greuter]

From John Blunsden's "The Power to Win" on Cosworth's V-8 engines, he notes that development engines in 1977 using magnesium castings (but not specifying which components):  "...were to be allocated on a loan basis to Lotus, McLaren, and Tyrrell teams..." and later Wolf was also part of the arrangement.

 

The same reference notes the 1983 narrow angle valve DFY used ...front covers for the block and cylinder heads and the cam covers as well as the intake manifolds and the water pump." from magnesium.

 

 

As for the 1977 part of the post, could those engines be among the ones about it is told that because of Lotus using them, that may have cost them the world title for Andretti because of too many retirements? (Other than of course the case when Chapman was too focussed on letting Mario race with as less weight as possible and thus sent him ont a race with too less fuel)

 

 

Henri

[SJ Lambert]

There's a magnesium wheel casting that's just been partially machined

 

[stephenS800]

I have optional Sport Kit cast magnesium wheels on my Honda S800 but recently damaged one very slightly, took a small piece from the lip on the inside edge, still holds air. They were made in Italy (ALBA) for Honda. I am guessing that welding such a reactive metal, never mind cast, might be impossible. Any suggestions? Thanks PS, the reduced weight c.f. stock steel rims does make a huge difference in how the suspension reacts to bumps.

[Ray Bell]

A good workshop, probably with racing connections, should be able to fix that.

[Lee Nicolle]

A very experienced welding shop. Though I know most will not touch wheels at all as they do not need the liability problems. From what I am told welding that type of alloy is quite dangerous. This by someone who would not touch it. 'Normal' alloy wheels maybe

And as I said above those old hi mag alloys only have a short life. That is NOT over 40 years

[David Birchall]

Porsche 911 crankcases-of which a few have raced-were magnesium from the sixties through to the later seventies-I don't have my pedants cap on right now but I am sure somebody does...

[pete3664]

Aren't almost all Hewland gearboxes, FT, LG, DG, cast in magnesium? I know if you don't keep them wet with WD40 or the like they tend to corrode.

 

[fyrth]

I find silicone spray even better - much the same on period uprights. As far as wheels are concerned I have no confidence in original mags and use modern split rims, keeping the pretty originals for high days and holidays!.