Colourtune

[Matchless]

What about reading the plug?

not with modern fuel,

 

[Matchless]

Stromberg 175 on a Volvo B20

just lift the piston a tad, engine speed should rise a bit then fall if the mixture is correct, I use a 12v CO machine..........

 

[Paulc20au]

You should not use the vacuum line to the distributor to attach your vacuum gauge, it is normally a timed port that will not be at manifold pressure at idle. (Absolute Pressure)

 

[Mr Fro]

I had a colourtune back in the olden days - I think they're alright for ball parking the mixture but nothing else.

@Burdekin - if you have a wide band O2 sensor could you not make up an extension piece for the exhaust?

 

[Sean]

And reving an engine with no load on it tells you very little

Cheap standalone AFR guage the way to go.

 

[Morris]

I have one (I was given it), next to useless in my opinion.

 

[Burdekin]

I had a colourtune back in the olden days - I think they're alright for ball parking the mixture but nothing else.

@Burdekin - if you have a wide band O2 sensor could you not make up an extension piece for the exhaust?

I bought a boss for the wideband last night so will weld it on. Will need to dig out the kit, not sure where it is as haven't used it for a while.

 

[Alan Reynolds]

A trip down memory lane with the Colortune. I used one on my motorbikes. Anyone remember the Wal Philips fuel injector carb? Worth selling if you have a pair in the shed as they're asking £500 a pair.

 

[8ob]

A trip down memory lane with the Colortune. I used one on my motorbikes. Anyone remember the Wal Philips fuel injector carb? Worth selling if you have a pair in the shed as they're asking £500 a pair.

They were a contraption,most of the guys I know that fitted them spent a few days jumping up and down on the kickstart and then took them off. Carbs were once described to me as an organised fuel leak, not far off the truth

Bob

 

[droopsnoot]

I've got a few Colourtunes* that I sometimes try to use on the Vauxhalls, but I don't usually find that they tell me a lot, either because I'm not reading them properly, or the carbs are worn. Interesting about modern fuel, though, it might be that too.

How would I connect a vacuum gauge to use that instead? Would it be a case of putting an outlet into each inlet manifold tube somewhere? I picked up one of those Gunson gauges for a couple of quid last year and haven't thought of anything to use it for yet.

* I've got a few for more than one reason. First of all, the plugs on the Vauxhall slant-four engine are between the exhaust manifold pipes, and if the Colourtune extension pipe slips off it'll melt against the manifold, so I like to have spares. I pick them up at car boot sales for a pound or two when people are tidying out their sheds, I believe Halfords still sell them and they're quite expensive. The other reason I collected a few is that the Firenza has Dellortos on it, which have an individual idle adjustment jet on each carb. To set them all up with a single Colourtune would mean fitting it to cylinder 1, running the car up to warm, setting it, then letting it cool down sufficiently to get the plug out, then move it into the next cylinder, warm it up, adjust it, cool it down, and so on. My idea was to put four in at the same time and adjust all cylinders together. Also I'd maybe get four cheap USB cameras instead of trying to line up the mirrors, and run them to an old laptop display. I've never got around to this, and if modern fuel means that the burning colour isn't as relevant, I probably won't bother now.

 

[Blobber]

I think we all had a coloutune back in the day, seem to remember it working but how accurate it was no idea!

Ive also found the modern fuel seems to burn hotter?

 

[CompoSimmonite]

I've got a Gunson's Gastester. Works far better than colourtune for setting up for best performance and economy. Doubt it's any good for non carb engines though

 

[Burdekin]

I've got a Gunson's Gastester. Works far better than colourtune for setting up for best performance and economy. Doubt it's any good for non carb engines though

Ordered one, does it come with instructions?

 

[Ross365]

I wonder how the Gastester works? Many years ago, the American Hawke company brought out a low-cost tester and what it actually did was to measure the hydrogen gas in the exhaust (which is easier to do) and then display the result as carbon monoxide on an analogue meter. The amount of CO and the amount of H2 are directly related in exhaust which hasn't been through a catalyst. However, the Gastester says it works on any vehicle, which would imply it reads CO directly. Possibly one of the tin oxide gas sensors? I think the profession grade ones work on infra red gas analysis, but that is more expensive to do.

 

[bricol]

I bought a Gunsons gas tester off a mate 20 yrs ago . . . after it told me the surround air was a perfect stoichmetric mix, but my engine wasn't, but couldn't give the same results more than once, its been stored somewhere safe ever since . . . in-fact, I'm not too sure where now I come to think of it . . .

 

[Cobbler]

I’ve got a borrowed one (20 years) in the shed & it works well on the odd occasion I’ve used it.

 

[droopsnoot]

I've got a couple of those Gunsons Gastesters as well, one with an analogue meter and another with a digital one, and I can't say I've had much success with them, with a series of random readings as I recall it, or perhaps the inability to have it settle down prior to going in the car. @Burdekin, I'm sure the Gunsons web site has some instructions in downloadable format.

I've got this one, which I picked up on a car boot sale a few years ago. When I was putting my project back on the road, I borrowed one of these from a mate and it did seem to produce a reading that matched the MOT station a few days later, so I jumped at getting my own. I've never matched the results, but to be honest I haven't tried it much since the cars became MOT exempt. I should do, just to get an indication of whether it's running properly.

 

[Rannsachair]

Hi, The trouble with them nowadays is that modern fuels burn differently and flame colour is not so noticeable or as clear cut. So they're not suitable now.

Colin

I assumed it was my eyesight that was getting worse

 

[premmington]

If you were closer - the OP. You could come use our TEN four gas analyser.

 

[CompoSimmonite]

Ordered one, does it come with instructions?

yes - they come with instructions