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Wire Wheels. Nice to look at, not so good for going and stopping. 1970 MG Midget wire wheel to steel wheel conversion.

Posted in Cars, MG Midget by Tom Harvey on January 10, 2010

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It was time. After an engine rebuild provided a little more power and a lot more torque, the car is now even more of a pleasure to drive. The increased torque means there’s far lees need to continually downshift when you are faced by a hill, however, a little more torque and power has it price.

About a year ago a certain clicking sound became apparent when accelerating from a dead stop or braking – this was not good news. The wire wheel splines were worn. So i was left with 4 options:

  1. Ignore the problem
  2. Have the wire wheels rebuild
  3. Buy new wire wheels and hubs
  4. Convert to steel wheels (or minilites)

The problem with ignoring a problem like this  is one day you might put your foot on the brake and the splined hub will be so worn that it will turn within the splined centre of the wheel and you won’t stop like you were planning.

Rebuilding wire wheels also has its’ problems. To my knowledge when wire wheels are rebuild the spokes are replaced and re-tensioned, however, the worn splined centres cannot be replaced as no new ones are available. This means you end up with a lovely rebuilt wheel which still has a worn centre (rumour has it that it’s pretty damn expensive too).

New wire wheels are expensive, whether chromed or painted (~$2000-2500 AUD). By replacing wire wheels with wire wheels means that at some point down the road you’re going to have the same problem – clicking worn wheels that were not designed for the power.

So converting to steel wheels (or minilites) seemed like the best solution. A cheap way to covert from wire wheels to steel wheels is to have the wire wheel hubs machined and drilled and simply use 1/2 inch wheel spacers either side. The wheel spacers are required as the differential housing is an inch wider on steel wheeled cars (I think 42 vs 41 inches). There is however, a problem with this approach. In NSW it is illegal to fit wheel spacers, unless they came standard with the original car. This is not something that a policeman is going to pickup on the side of the road, however, it is something that an insurance accessor  might pickup at some stage in the future (like after a prang and before or during a claim). So what do you need to do to do it properly?

Major Parts Required:

  • Front
    • 2 x bolt-on style hubs
    • 8 x wheel studs
    • 2 x brake rotors
    • 8 x bolts, hubs to brake rotors
  • Rear
    • 1 x rear steel wheel axle housing
    • 2 x half-shafts
    • 8 x wheel studs
    • 2 x wheel bearing kits
    • 1 x diff and axle flange gasket set
    • 2 x O-rings
    • 4 x Urethane axle to spring pads
  • And of course
    • 5 x wheels with caps and chrome nuts (minator)

I sourced all these parts from Colin Dodds at Sprite Parts, and I’m sure he’d be more than happy to help you out if you’re considering doing a similar thing.

Here are a few pictures of the whole process:

New front hub assembly. You might also notice that I’ve added up-rated springs and had to replace my worn wishbones. (Neat little trick – there’s no need to use wire to support the calliper while it is removed from the upright, simply leave a bolt in a it fits nicely into the triangular hole in the chassis)

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MG Midget jacked up minus rear differential assembly.

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Newly painted steel wheel axel housing – Almost ready to go in.IMG_0104

This was no quick task. Converting the back and front took me nearly 4 full days under the guidance of Colin. A time consuming part of the whole process was having to remove and replace my worn wishbones (for everyone’s reference they wear because they are a metal on metal surface and should be greased via their grease nipple about every month – most like mine hadn’’t be greased in about 2 decades). The 4 bolts that attach the wishbones to the chassis will come out in 3 minutes of 3 hours, and getting them back in is a similar affair – I was unlucky enough to have  2 of the 4 bolts not want to play ball.

These changes have really improved the handling of the car. Previously it was soft, a bit sloppy and made clicking sounds. It also caused a very unnerving wobble at around 50mph.  Now the handling is much more direct and precise and there is no wabble (a wheel alignment certainly helped as it was about 4 degrees out). Although these changes have  moved away from the car’s original condition, it has resulted in a car which is much safer and roadable, and as I like to drive it as much as possible and not just on weekends I couldn’t be happier.

Another big thanks to the very generous Colin Dodds from Sprite Parts, without him this wouldn’t have been possible.

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1275cc MG Midget Engine Rebuild Part 2

Posted in Cars, MG Midget by Tom Harvey on April 5, 2009

Rebuild has begun. More pictures and descriptions coming soon.

 

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The History Behind Our 1970 1275cc MG Midget

Posted in Cars, MG Midget by Tom Harvey on February 19, 2009

1965 Jaguar S-type

The story of our MG Midget actually starts with a 1965 S-Type Jaguar. This car was most certainly responsible for a few shades of gray on my fathers head and was looking like it might have induced a committal. It is easy to see how we were both tricked into falling in love. A jaguar S-Type is a car with truly gorgeous lines, this one had recently been finished in a light metallic rose red and renewed leather interior throughout. It also had an immaculate timber trim with a walnut dash and the quint essential picnic table. The problem was it was a jaguar, so when it went wrong it went extremely wrong.

There were a few problems with the car:

  • It was for ever dropping oil
  • It had a non standard 4.2 litre XJ6 engine in it (the standard engine being a 3.8 litre) which had flow on effects
    • It slightly interfered with the dip stick feed to the automatic gear box, which caused us to crack two separate pans in about 2 years
    • It caused overheating problems
    • The overheating problems affected the brake booster which had been added, meaning that as the engine heated up the brake would be applied more and more – making the problem even worse
  • Jaguars are difficult cars to work on, there is very little space and servicing didn’t appear to be in mind when designing the cars. For example to replace the hand brake pads (which were definitely designed for gentlemen, being the size of a matchbox), which were on a separate rear disc my father and I had to drop the whole rear subframe out of the car. This is not an easy task when all you have is two engine stands and hydraulic jack. The things must have weighed about 200+ Kgs. To add insult to injury the model a year later added an inspection panel which would have made it an hour long job not a 10+ hour job.

The car was unbelievably good fun to drive when it was all going smoothly, but unfortunately there was always this guy Murphy looking over your shoulder to make sure it went wrong at the most inconvenient of times. A few memorable times include on the Harbour Bridge and 8 hours before my year 12 formal.

So time for a slightly more practical classic, something that was a little smaller (not difficult), easy to work on, had readily available parts and was good fun to drive. The search began for an MG Midget or Austin Healey Sprite.

We looked at 2 other cars before we settled on ours, The first a 1098cc Austin Healey Sprite. This car turned out to be quite the rust bucket, and the guy was "dreaming" (asking $9 G). The second was a really nice bright yellow 1275cc MG Midget which had been heavily modified. It had a Weber carburetor, a hot cam, high compression pistons, head work, brake boost kit, telescopic suspension conversion, etc. It was definitely in better condition than the previous car, however we weren’t sure that we wanted such a molested car (or if we did we wanted to do the work ourselves). It was also significantly more expensive which was the nail in the coffin, the guy wanted $12 G for it.

After browsing through Carpoint again we noticed that we somewhat overlooked the cheapest MG Midget advertised. It was located out towards Camden and the guy was asking $8,500 G. The reason we’d overlooked it was that it was a very original "Golden Harvest" colour (baby poo browm/yellow). Anyway we decided to look beyond the colour and check it out.

The car turned out to owned by a collector of mini’s who’d picked it up off a lady in a job lot when buying a few mini’s. Initially we were a bit concerned when we were told that it was unregistered. But we couldn’t believe it when the cars history as it was explained. The reason that it was unregistered was that it had been in storage (a dry garage) for the past 16 years since it had been acquired. The car had an original ~60,000 miles on the (that’s less than an average of 2000 miles a year). We asked the owner it he’d done any work the the car while he had owner it:

"Yeah I reconditioned the engine and resprayed the body it in the original colour, and its’ just sat there"

We took it for an extensive test drive around the car park (as it was unregistered) and told the guy we’d have a think about it and get back to him shortly. A few days later we said that we’d be happy to take it of his hands for $8,000 as long as a blue slip was provided. The deal was done! And we’ve loved the car ever since.

The Diagnosis Doctor – 1275cc MG Midget Engine Rebuild

Posted in Cars, MG Midget by Tom Harvey on January 15, 2009

The reason that there was more smoke blowing from the exhaust than observed at a Bob Marley concert has become clear:

  1. The bore was extremely glazed, almost to a mirror finish
  2. The piston ring gaps were more than double the recommended size (~26 thousands as apposed to 12-14 thousands)
  3. The piston rings had been annealed. This is the tempering process metals under go when exposed to repeated heating and cooling. This was made obvious by the degree to which the piston rings could be stretch up and down when they were removed. The piston rings are made from cast iron so they should be brittle, snapping after very little deforming – these did not.

All these problems would have contributed to the excessive consumption of oil, which was so bad we were thinking of buying shares in The Penrite Oil Company.

So what’s the solution?

  1. We had the bore honed. The reason to have the bore honed and not re-bored was simple – cost. There was nothing wrong with the pistons (AE 21253 + .40″) so we wanted to avoid having to replace them. To re-bored and buy a new set of pistons was going to be ~ $500.
  2. Buy a new set of AE 21253 Piston rings. Not the cheapest set of rings by any means at ~$185, but still cheaper than the re-bore and new pistons.

While we’re at it and the engines out of the car we also decided to do the following:

Fit a new RE-13 camshaft. This is a fast road cam produced by an Australian firm called Russell Engineering. It is a good cam for around town as it’s power is very useable even at low revs. We got the cam on exchange for a very reasonable ~$150, it was noticeably lumpier than the standard, visibly having a lot more duration. To get the most out of the cam we also chose to replace the cam followers with light weight cam followers ( ~$105).

We had the crankshaft, flywheel and clutch pressure plate dynamically balanced. This seemed to be an absolute bargain at ~$100, especially when we got them back and realised how much material had be shaved off – BMC/Leyland were definitely knocking out their components at a price!

All this was made very easy by Colin Dodds from Sprite Parts who was extremely helpful, a wealth of knowledge and more than happy to work to a fairly restrictive budget. A big thanks to Colin!

With a relatively small amount of money and a little time we should end up with an engine than is more reliable, has a little more power and hopefully consumes a little less oil (sorry Penrite).

Let the rebuild begin…

Taking the engine out of our 1970 1275cc MG Midget

Posted in Cars, MG Midget by Tom Harvey on January 2, 2009

It was becoming embarrassing to drive the car, when taking off from traffic lights the car/s behind would disappear in a cloud of blue smoke. After much procrastinating it was time for a quick engine rebuild.

Firstly off with the head to measure the capacity using a burette. Bearing in mind that the head was only cleaned up 18 months ago, there was a huge amount of carbon build up, an indication of how much smoke the car was burning.

MG Midget 1275cc Head With Carbon Deposits

MG Midget 1275cc Engine With Head Removed

MG Midget 1275cc Engine Head Removed Carbon Deposits on Pistons

Using a burette purchased off ebay for $25 AUD, some kerosene and a perspex disc we measured the head capacity – a consistent 21cc (standard). It appears the head is unmolested and hasn’t been skimmed. The nifty little magnetic stand was a worthwhile purchase (bought at a machine shop called Hare & Forbes ) it kept the burette perfectly steady and could be easily and quickly adjusted.

MG Midget 1275cc Measuring Cylinder Head Capacity

Using the same method we measured the capacity of the bore – 10cc. This is slightly less than standard, and explained by the AE 21253 pistons that were fitted.

 MG Midget 1275cc Measuring Block Capacity

The a-series is a pretty small engine, and could probably be lifted out by two people – but a borrowed engine winch made life very easy.

MG Midget 1275cc Engine Crane

MG Midget 1275cc Engine Removed

Just as a matter of interest and to try out our new dial gauge and stand – a quick check with a timing disc show the camshaft to be within 1 degree of the recommendations in the workshop manual.

MG Midget 1275cc Measuring Cam Timing

MG Midget 1275cc Engine Removing Con Rods From Crank

Pistons came out without any dramas. Appear to be in very good condition. Revealed extremely glazed bores and piston rings with an excessively large gap of 0.0026′.

MG Midget 1275cc Engine Removing Pistons From Block