New to me manual 400GT 24649

Congrats! Pics.


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Congratulations Jay!

I'm sure the little niggles will show up all by themselves, as with my car #43733
I'll also be having a look at my airco, but I think it might just be a case of renewing the gas, as it's already been converted to R134a.

Cheers

• Esben

 

Propane is an alternate to R134a. It is compatible with both R12 and R134a oil. You use about half the weight.
Ken

 

Correct; Duracool and other R12 alternative are just purified shale gas. Bigger molecules than R12 or R134 so less leaks and cools better.

I personally prefer R416a which is R134 with ~3% of propane. The propane allows to convey the old petroleum oil that was used with R12, which makes these oils compatible with R134. (R134 normally requires PAO or ester oils).

R134 and R416 do not cool as well as R12, which in turn does not cool as well as propane. This being said, R134 and R416 are supported in any AC shop whereas in my area they won't touch a system filled with propane.

 

Thanks, Raemin for filling in the details.

 

You cannot blame them, as there would be a significant liability given that propane is flammable. Complicating things further are the generic leak AC leak detection tools which use an open flame and a low pressure "port"/hose...which tends to do "interesting" things when exposed to flammable gases.

Cheers,

Sam

 

Raemin

emin
I checked some data. Propane is a much SMALLER molecule than R12 or R134a:
- Propane MW = 44
- R12 MW = 121
- R134a MW = 101
Propane's big advantage is its high Latent Heat (heat of Vaporization:
- Propane Hv = 183 BTU/lb
- R12 Hv = 78
- R134a Hv = 93

 

I've heard that argument that 'Oh my God, propane is flammable.' You have 15+ gallons of gasoline being pumped to the engine pay at high pressures for new FI systems. When I move to Belgium in the 1970's, about one third of the cars in Belgium and Holland were equipped for LPG with tanks the size of a large SCUBA tank in the trunk and LPG injection into the carburetor.
The propane charge to the AC is less than 2 lbs, closer to 1 lb, about half of a R12 charge. AC systems are designed to be leak-free for many years. AC techs do a high vacuum leak test before charging any refrigerant. Most AC leak detectors are ultrasonic not flames, but a little flame will be a good detection system! The reluctance to work on a propane AC system is more legality, warranty, etc.

 

Duracool is actualy propane and isobutane.

It does leak less, but as you said this may not be due to the gas itself: propane grabs the oil, I would assume that this is the mix of gas and oil that seals the potential leaks in the hoses?

My car had r416 (so with 3% of hydrocarbon), and after 4 years, there was still plenty of pressure in the system, so the added hydrocarbon did its job.

 

Good day Ken,

This is no question that there are other items more volatile than propane based AC refrigerant. However, AC refrigerant has a higher probability of leaking into the auto's cabin... because the AC lines are actually inside the cabin. Secondly, most systems are designed to be leak free... unless a leaky gas line, coolant, ac line etc is a design "feature" ... needless to say, the AC and other items do leak over time and if there is a failure in the system. As I mentioned in my comment... there would be a liability (intended as being both business and personal safety) working on a Propane based system.. especially if the shop did not know in advance that the system was propane filled.... so, yes, legally there could very well be caveats, but also the potential for unintended consequences (flame, etc) if using a propane based system. As an individual, you can do as you see fit, but as a business or a professional there are potential liability consequences.

Cheers,

Sam

 

Hi!

I didn't do the work myself on the 400, but I did the conversion on my Bentley together with a colleague of mine.
It's not rocket science

Cheers

Esben

 

The new becker is nice. Retrosound looks flimsy.

This being said, I do have 2 period correct Philips for my car. Quite happy with these, and you can use a bluetooth tape.

A full din radio can fit in the tray.

 

Freons are very TOXIC. I would prefer a small propane leak in the cabin with windows closed than a propane leak.
Ken

 

I'm no safety police and am guilty of removing airbags from cars and ABS systems. I'd feel a little nervous about propane. It's a pressurized system with a condenser right behind the bumper. Liquified propane gas is explosive and completely different from a fuel pump pumping gasoline into a fire. Putting propane in your AC is similar to driving your car with a propane tank strapped to the front bumper.

 

Good day Ken,

Either gas is not the best for living creatures. That said, I have not heard of any auto occupants that have had any form or Freon toxicity that required medical attention. They could have, but it could have been minor and unnoticeable ...or maybe the cars were drafty enough that enough air was moving about to dilute the gas leak? Carbon Monoxide, CO, poisoning is far more common (leaky exhaust, etc)... but then again CO tends to bind itself to the blood which prevents O2 transfer... and CO poisoning "builds" up over time and takes a reasonable amount of time to unbind. But I digress. I tend to keep to existing standards to maximize my options and so if AC shops will not assist/service a propane filled system, then this is enough for me to not go this route. However, everyone needs to make their own assessment as to how best to proceed.

Cheers,

Sam

 

24649 is still in its original colours (Argento Metallizzato Italver with Sabbia VM 3234 Connolly hide). It was orginally supplied through the Milan dealership, Crepaldi. Completed 31 May 1978.

 

Unlike Freon, duracool does also contain mercapan (the gas the smells horrendous)' so if it leaks you know it.

Best bang for the buck are hydrocarbon gases. If you ac shop does service it, that's the way to go. For a universal alternative, R416 is better than R134 die to the better lubrication. This being said, Aspera piston compressor can make it do with so-so lubrication (Sanden rotary compressors are much more sensitives). So you can even try straight r134...

 

Hi Jay, It's all original. Grigio Argento Metallizzato and Argento Metallizzatto are just different terms used at the time by the Ferrari factory for silver. When 24649 was produced it was common that the paint sticker had different terminology too. All originally silver 400s produced around the time as yours have the same paint sticker and code stating Grigio Chiaro Metallizzato, eg 24481 and 24551.