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Ian Metcalf
Milton Keynes, UK
(36 posts)

08/15/2009 12:57PM

Main British Car:
1955 MG Magnette 427ci Chevy

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1955 MG ZA Magnette 427ci Part 2
Posted by: 427ZA
Date: September 15, 2009 10:17AM

...continued (click here for part 1).

Moving on from the front suspension it was time to continue with the fabrication and move on to the roll cage. This was going to have to be strong and had to meet rules and regulations for Bonneville and for drag racing in the UK so a lot of lengths of 1 5/8" cds2 was purchased.....just as the price of steel went through the roof.
Before we could start assembling the cage there were a couple of things that needed doing. First problem was not actually owning a mandrel bender to make the tight bends so a quick trip to Robinson Race Cars and they kindly made the four tight bends that I would be needing, the rest I could do with my hydraulic pipe bender.
The second issue was the glue and hairy stuff left stuck to the inside of the roof of the car. I don't know if you've ever tried removing glue that's more than fifty years old but it is incredible stuff. We tried everything and no chemicals we could get our hands on would even soften it let alone remove it. There was only one solution......brake cleaner. I liberally dosed the inside of the roof with brake cleaner and then pointed a lit blow lamp at it...DO NOT TRY THIS AT HOME!!.....This is the result and, yes, I was stupid enough to point a camera at it whilst my friend ran out of the workshop.

The fumes and smoke took a couple of hours to clear so it seemed a good idea to take a lunch break at this point.
When we returned it took two of us 10 minutes to clean the inside, job done.

Now we could get on with the roll cage.

The main hoop was trial fitted. After tweaking some extra bends in it at shoulder hight to follow the profile of the car it was tacked to it's mounting plate. To get the postion correct we tacked a bar across the car and then cable tied the hoop to it.

Next was the two bars that run directly backwards to the rear chassis rails. A piece of advice if you are making your own it with two of you. One person can do the mods to the bars and the other can be inside the car doing the trial fitting, it's so much easier than climbing in and out.

The two rear bars tacked into place...

Now, becaust the rear axle is narrowed and the chassis rails are quite close together this meant that the bars met the main hoop at the top a good 6" inboard of the corners which isn't strong enough so I needed to make a rear cross as well.
Once fabricated I tacked it into place..

Then I took the cross shape out in one piece and welded it out of the car.
Once back in it looked like this...

Rear cross mounting points welded in...

At this point I realised that the boot (trunk) lid hinges were getting in the way and quite frankly looked ugly. As I'd done away with the huge spring mechanism that holds it open I could cut away half of it and drill/rivnut some extra mountings further in.


The hinges could then be trimmed to match.


Next I needed to fit the wiper motor before I could continue with the front half of the cage. Being a cruel sort of person I don't see why the passenger should enjoy seeing where they're going in the rain so I'm only fitting a single wiper mechanism on the drivers side. Then again I don't want to be out in the rain in this beast if I can help it.

Carefully mark the roof and drill a hole for the spindle, then mark up inside of the car and make a mounting bracket for the motor assembley.

Fit the motor and the wiper arm..

Next up was the interior trim panels. The hardest part of this project has been making and fitting stuff in the correct order! At this stage all I need was templates so I got hold of some art card and proceeded with the origami.
This is the B pillar and the section that runs along the tops of the doors. Using the template I was able to mark, drill and rivnut the interior of the car ready to accept the alloy panelling. The card has all of the rivnut holes marked so it will be easy to transfer it to the alloy.

Finally I could get back to the roll cage. The next parts were the bars that run above the windows from the back to the front of the car. Normally this would continue straight down to the chassis rails at the front of the car but my bulkhead already had seamless tubing uprights in place so I needed a really strong way to connect to it. With some very careful machining I made some plugs that were a very tight fit in the tube (hammer tight!). I machined them with a 5mm shoulder in the centre that stood up for exactly half the thickness of the wall of the tubing, this would give me a good channel to fill with weld. I also drilled the tubes to plug weld the inserts into place just to make sure.

The front to rear bars could then be tacked to the rear hoop.
It looks odd in this picture because I dropped the whole assembly through the chassis to get some tacks on the top.

Finally for the roof I made a diagonal bar and some gussets for the opposite corners and a header bar to go above the windscreen. Once they were all tacked into place I dropped the cage back down through the chassis and seam welded the lot!

It was then all put back into place, the front bars dropped onto their spigot and the rear bars onto their mounting pads and the whole lot was welded into place for the last time.
Moving on it was time for some door bars. At the moment I have made only two of the three door bars for each side, I'll make the others once I don't have to climb in and out so much.
Two bars were bent, one to follow the profile of the sill and the other profiled to miss the drivers/passengers elbows. I the cut a front mounting plate out of 1/4" (6mm) steel and tacked it all together in the car. I then took it out, seam welded it and refitted fitted it for the last time.

I still have some bars to fit to the cage but I need the new seats before I can make them so that I get the harness mounting points in the right places.

Moving away from the cage for now it was time to fit the 12 gallon fuel cell.
First I made myself a kit of parts to fit it with..

The long bar mounts at the rear of the boot area, the other parts are a rear bracket that allows room for the fuel line take-offs as they are in an anti-surge sump.
Welded the brackets first...

Then fitted them to the chassis...

Once the rear bar was in place I drilled a rivnutted the mountings for the tank straps and then bolted it all in place. The straps look a little loose in the pictures as they don't have their rubber mounting straps under them.

(note: hyperlink to part one added by Moderator)

Next update:-

At this point I finally worked out what I was going to do with the window frames. I want to fit plastic side and rear windows to save weight so I will not be needing window winder mechanisms and, to be honest, I really didn't want to have to design a mechanism for the extra long doors.
To start off I broke out the art card again and once more I practised my origami skills...I should be a black belt in origami by the time the car is finished.

The card in place...

The card was removed in one really long piece and laid out on the sheet steel to transfer the shape. Once it was carefully cut out I roughly bent it to the profile of the window frame and started to tack it into place. At this point you really need a helping hand and a lot of patience....

The corners involve a lot of dressing and stretching to form the compound curves but eventually you end up with...

With the welds all cleaned up...

I now have a nice smooth area that I can fit some alloy angle to and then the windows can be bolted into place on the angle.
Once the back windows were complete I could move on to the fronts, these took a full day to do each one. The method was exactly the same as the rear.

Now we could move on to a really exciting part, stripping the paint!
First job was to remove everything that I could unbolt so that the paint stripper didn't get into it and then mask the lower body up as I was initially just going to start on the roof.
The old paint was scuffed up and then Nitromors paint stripper was liberally brushed on. Warning!! Always do this in a well ventilated area as the fumes can be a little 'overwhelming'.
As it began to work we started to get some interesting effects.......I think I was bored with waiting!...

A relief map of the Himalayas??

Once the stripper had done it's stuff the paint was scraped off. Another Warning!! Wear breathing masks when doing this as 50+year old paint has some very dangerous chemicals in it.

The roof was thouroughly degreased and panel wiped to get rid of any residue and then given a light dusting of single pack primer to keep the rust at bay...

Then I moved on to the rest of the bodywork...

The last picture gave me an idea for a paint scheme. I quite fancied just polishing the bare metal as much as possible and having rivets airbrushed along all of the seams just like a WW2 aircraft. This idea was knocked on the head by the rules and regulations for Bonneville. You are not allowed to have silver/white or any similar colours as the safety teams can't see the car against the glare of the white salt. As they put it "how will we know which way up you are?"
So...back out with the single pack primer again.

Now I could see how the door handles sit in the panels. A couple of hours of beating and fettling saw them sitting smooth ready to have the edges sealed with fibreglass.

For a change of job I thought I'd do a bit of fabricating again, a change is as good as a rest and all that tosh....
I've never worked with aluminium before so this was going to be a learning exercise. I though I'd make a parachute mounting plate.
First I used the old mounting plate from the original yellow beasty..

I then made yet more cardboard templates, transfered them to sheet alloy, cut it out and folded it. In reality it took four attempts to work out how to bend it without marking the alloy. I stuck gaffer tape to the area's that would be clamped so that they wouldn't be marked and then held the piece in a vice between a couple of pieces of hardwood.
The end results...

I found some old alloy bracketry that was going spare, drilled them and fitted rivnuts..

Once the side plates were bolted to the front plate and the brackets were fitted we have this....

Once I'd drilled some holes in the appropriate places on the boot lid it just bolts into place ready for the parachute pack to bolt to...

Thats all for now.....

Next update added 30/09/2009

There's not much more to add to the thread mainly because the next few months in the build timeline was spent filling & sanding, filling & get the picture. :)

To start the process I spent a couple of days gently massaging the body roughly in to shape with various hammers. The aim was to end up with the thinnest of skims of filler possible compared to the 1"+ that it originally had.

First I wanted to seal the welds on the doors and quarter panels to give them more strength plus I needed to seal the door handles.
This I did with fibreglass paste and then filed into shape.

Some areas only required a very light skim of filler. This was the fuel filler flap....

Fast forward a few weeks and it was time to put the suspension, engine and gearbox back in. This was mainly because I'm much happier with spanners and welders than I am with body preperation and I needed a break.

Three weeks, two sets of sore fingers later and the doors are complete...

Whilst this was going on a friend of mine turned up with a donation to the cause for a price that was impossible to refuse.
Now we have added...

Ok, back to mechanicals again. :)
The steering had been an issue, initially how and then followed by where. To resolve the how I took a rough measurement between the steering knuckles with the wheels pointing roughly in the same direction and then spent an afternoon going through an old manual of steering racks from a local parts supplier. I wasn't worried using the latest manual as nearly all modern cars have power steering and I'm going for the more manly muscle powered version.
Once I had a list of potential racks I talked the supplier into allowing me to spend a dusty afternoon in their warehouse checking each possible steering rack. The happy victim that was the nearest to my requirements was the rack from an MG MIdget which made me very happy as we have to keep it in the family if possible!.
The first trial fit required the rack to be narrowed....yes, a Midget rack was too wide! Luckily one of the reasons I'd gone with this model is that the track rod arms are very long so I was able to trim 40mm off of each end and cut the threads further along the rods which effectively narrowed the rack by a total of 80mm...just right!

To mount it to the car I dug through my pile of spare steel stock until I found some 3mm thick angle which looked about right.
First job, notch the ends...

A little bending of both ends and some more notching gives me...

The notches fit nicely between the chassis rails and the bent up ends gives me a lot more welding area.
After a lot of very careful measuring it was finally welded to the chassis...

Ebay was the source for some refurbished rack mounts and some funky track rod ends from a well known UK race car parts supplier.
As an aside, ebay has been very useful in this entire project. I set up a paypal account specifically for the project and as I've gone along I've sold a lot of parts that I wouldn't be needing from the original yellow car and also from the donor car. The money went into the new paypal account and was used for buying parts for the car. Complete recycling system and no having to touch other money to buy parts. :)
Back to the plot...
I drilled the angle for the mounting brackets and then it was a case of simply bolting it all together..

PS...the filler on the chassis rails is purely because I'm a fussy bugger and want the rails to be really smooth once they're painted!

Motor plate and engine mounts...
Because eventually this car will be producing some monster horsepower I really need it to be securely mounted to the chassis in a way that meant it stayed put.
The front motor plate is exactly what it says, it's an alloy plate that bolts to the front of the engine and then, in turn, bolts to the chassis.
With a little fettling the plate was bolted to the engine...

A bit more needed as the ends were in the way of the chassis rails. Once that was done it was back to the origami and a template was made for the chassis tabs..

This was transfered to some 1/4" plate that was then simply welded to the chassis...

Some bolt holes drilled, job done!

Engine mounts.. As strong and well thought out as I'm sure they are the original Chevy mountings are no good for this application...

Yet more careful measuring, more origami, more 1/4" plate and we have another flat pack kit...

Which, when welded together, looks like.....

That'll hold the engine in then....

With this next part we have finally caught up with ourselves and this is where the project stands today, October 2009.
I have been very fortunate in that a friend of mine donated the use of a part of his workshop to the cause so I've been carefully clogging up the back of his shop for the two years that the build has taken so far. A little longer than anticipated but I did have heart failure in the middle of it all and that slowed me down for a while. Unfortunately for me his business has grown and he now needs the space back but I am very grateful for the free use that he gave me, it made all the difference.
To move the car to it's new, much smaller but equally free, home I wanted to push on with the body prep.
Once the bodyshell was near to the standard I wanted it was time for a splash of primer. A new product on the market for the UK (everything is going waterbased here) is a primer that can be sprayed, rollered or brushed on!
It works really well and saves a fortune in time and product with masking if you choose to go with the rollering and brushing route as there's no tedious masking required.

Finally, this is how the beastie looks today, October 2009...

On it's way to it's new home...

There will be a small delay in further progress as the garage that it's going in next is getting an extension to give us room to get all of our equipment in. The garage belongs to my long suffering team mate Steve who has kindly kicked his VW outside into the cold to allow us to finish the race car in the warm.

There'll be more updates soon

Edited 5 time(s). Last edit at 10/02/2009 12:55AM by 427ZA.

Curtis Jacobson
Portland Oregon
(4578 posts)

10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: 1955 MG ZA Magnette 427ci Part 2
Posted by: Moderator
Date: September 22, 2011 01:19PM


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