General Heated handbrake and other musings

[smart51]

Today was a sunny day, so it was time for a road trip. I just followed my nose through the villages or Worcestershire where the little 500 seems to be at home. For the first time, I had the heater on. It heated up the handbrake nicely, and there was a trace of warmth out of the windscreen vents, but it took a good half hour before I noticed any warmth in the cabin. Anyway, 45 miles later and I find myself at Clee Hill in Shropshire, a nice vantage point over the valley below. The hills, though, are not the friend of the 500. I sat here, taking in the view, and thinking how well the car is running and how I'd trust it on a longer journey.

A few minutes after heading home, there was a pop and lots of exhaust noise. The rest of the journey sounded like the inside of a Harley. Looking in the back, this is what I found. I guess I'll need a new one.

 

[Toshi 975]

I would think that the exhaust was under a lot of stress for that to happen. Always best to tighten the bolts into the head last to get the best alignment.

 

[smart51]

I would think that the exhaust was under a lot of stress for that to happen. Always best to tighten the bolts into the head last to get the best alignment.

looking at the tears in the can, it looks like the silencer clamps were done up last and pulled the can down, putting constant tension on the heat affected zone round the weld. The exhaust was looking pretty tired anyway, so I'm not upset.

 

[Goldnrust]

Lovely roads out that way in west Worcestershire and beyond, some of my favourite to take the car out on.

That exhaust must have been cracked for some time, I wonder if the crack vibrating making noise, or the mismatched back pressure in the system, might have been part of the midrange issues you were chasing?

On the heater, I’d invest a bit of time sealing up any gaps or leaks in the ducting system that you can find. I have just done so on my car, and it’s made a good difference to how much air is coming out of the dash vents. It made a pretty big difference.

 

[smart51]

Now that it has cooled I've done a bit of forensic engineering on the failed exhaust. The joint with the can failed first. About half of the surface of the break is old rust like in this photo. The remainder is split between patches that are partly rusted and partly shiny with small areas that are completely shiny. This break has been happening over some time. The time before last when I took the car out, it started making a new noise. A ringing like tapping a piece of steel. I suspect that this is the cause of that noise.

The header tube has been formed out of two pieces. A 90° bend and a short straight piece up to the joint with the elbow. The short straight is butt welded to the elbow at an angle so that the whole curve is less than 90°. A better method would have been to bend a tube to slightly less than 90° and make it all out of one piece of tube. Perhaps they were buying in pre-formed components rather than making their own. In any case, you can see that the weld between the two pieces has failed. There is shiny metal but also rust all around this break, which suggests it happened at once, rather than over time.

Looking closer, you can see that about only 1/3 of the circumference is welded with penetration through the metal. The remainder is weld above the metal. The bottom third looks like the weld isn't even attached to the tube. This is where the worst corrosion is. I suspect that condensation has gone between the pipes into the void between the tube and the weld, rusting it from the inside out. Once the joint with the can failed, the tube was unsupported at the far end and free to vibrate, which sped up the failure of this second joint. The second failure was caused in part by a less than optimal design and in part by inadequate welding. Neither shortened the fully working life of the part as it failed at the can first.

The design of the silencer is interesting. The header pipes are closed at the end furthest from the engine. There is a mini 'pre-silencer' towards the end of each header, with 12 holes punched through the header tube into the void between a larger tube. There are then holes punched into the header tube that let gasses through into the main can. Looking into the can, the two tail pipes also have holes punched into them, to let the gasses exit the can into the tail pipes. There appear to be no other baffles.

 

[smart51]

On the heater, I’d invest a bit of time sealing up any gaps or leaks in the ducting system that you can find. I have just done so on my car, and it’s made a good difference to how much air is coming out of the dash vents. It made a pretty big difference.

In replacing the exhaust, I had to take off the hose. It's seen better days and was only fitted over the pipes. It's no wonder the hot air is being lost.

 

[smart51]

One new exhaust fitted. What a pain in the proverbial that was. It took a fair amount of persuasion to get it to line up. The joy of aftermarket parts I guess. The bodywork is touching the pipe in this picture. A bit of bending later and there is (probably) enough clearance.

 

[smart51]

What a transformation! I've just been out for a short ride and wow! The car is so much quieter, more refined sounding and with much less vibration. I guess a crack in the silencer and a wobbly header pipe would do that for you. The short trip today was just to heat everything up to running temperature. When it has cooled down, I'll check all the fastenings for tightness and go for a longer run.

 

[smart51]

I did a longer shake down run on the new exhaust today. There was a sound like a parcel sliding about in the boot when turning left. Closer inspection showed some rubbing on the exhaust. It seems that the new one is bigger than the old, even though they look quite similar. I've bent the tinwork out of the way a bit more.

The car is generally running well, though it does feel a bit down on power. I only hit 58 at my usual speed trap. Previously it would do 64, and in theory, a 595cc engine should give you 67. Something's not right somewhere, but it doesn't seem to be causing a worrying problem.

 

[smart51]

Top speed is up to 62 MPH after a adjusting the throttle cable slightly and resetting the ignition timing. Its still a bit on the low side but it's otherwise running really well.

 

[smart51]

I am 1.7 miles from home, where my jack and wheel brace are. I guess I'll be walking.

 

[smart51]

Looking at the spare, it is different to the other 4 wheels. It has a standard 125 R13 where the others have 145/70 R12s. Are they aftermarket rims or Fiat?

 

[fiat500]

I am 1.7 miles from home, where my jack and wheel brace are. I guess I'll be walking.

View attachment 433262

Bugger!

 

[fiat500]

Looking at the spare, it is different to the other 4 wheels. It has a standard 125 R13 where the others have 145/70 R12s. Are they aftermarket rims or Fiat?

View attachment 433265

That's a bit confusing...the spare (on the right?) is a 125R12. The spare actually an original 500R by the look of it, and the regular wheels don't look at all standard. The 125 will have been used as a spare because the wider ones won't tit in the well.

 

[smart51]

That's a bit confusing...the spare (on the right?) is a 125R12. The spare actually an original 500R by the look of it, and the regular wheels don't look at all standard. The 125 will have been used as a spare because the wider ones won't tit in the well.

The one on the right is the spare. They have the same overall diameter within a millimetre or so, but one is obviously wider. Neither will fit between the headlight and battery without a bit of persuasion but each will go in. A new tyre will arrive on Monday.

 

[The Panda Nut]

Is the one on the right a wheel from a 126?

 

[Toshi 975]

Is the one on the right a wheel from a 126?

That pattern were made in 3 1/2J x 12 for the 500R and 4J x 12 for the 1st series 126

 

[smart51]

Today is oil change day. A nice drive through the country to warm it up, then drain the oil. It came out exceptionally clean, which is nice. While I was at it, I removed the sump. Partly to replace the gasket to see if it will stop the small oil leak. Partly just to look inside to see how it looks. Also good. I was hoping to jet wash the sump at the petrol station but it is out of order. A bit of soapy water will have to do.

 

[grubscrew]

The wheel on the left is a Borrani…..very nice too, better looking than the 500r.

 

[Bigvtwin996]

yes left is a Borani.... they are usually found to be wider, than normal often 5-6" the narrower the rarer....
you won't find a correct set of hub caps for them at a realistic price, I think there is a set for sale for over £4000...
Borani actually made wire wheels for 500s and still do....

they are also known as CMR if you get them lightly noasted there should be a CMR branding on the inside