13 replies to this topic

[84sprite]

Hi all 

just a hopeful request really, I have just finished a rebuild on my engine and gearbox and tuned the engine as best I can, and wondered if anyone on here had a colour tune kit I could borrow for a couple of days in the North West (Warrington, Widnes, Liverpool area) 

Because this is a complete full car rebuild it’s not in a condition I can take it for a run to warm up and load the engine - it’s still just 1/2 a shell and an engine - and not safe or legal to take on the main road.

I would only need to borrow for a couple of days so I don’t coke the engine up or burn something out while running the engine - I know it’s running rich currently because the plugs are black - so just need a way of leaning it down enough to not damage anything.

 

thanks in advance of any Good Samaritan that can help me out 

[sonscar]

I do not think the plug colour is a reliable indicator of mixture she idling and not under load.I would avoid running the motor until you are going to drive it.Steve..

[Chris1275gt]

I've found, as a novice, the colour tune plug is a excellent aid in initial setting of the mixture to the extent on my basic 1275 engine it's all I've used. The plugs are a good colour, exhaust colour fine and it comfortably passed the emission test on 2 mot tests and drives excellently. It's also recommended in the Brooklans book Su carburettor tuning tips and you can always rolling road it and fine tune it when it's all up together and ready to go.
I'm in Berkshire but if you can't borrow a local one pm me and I'll post it you and you can send it back when you've finished with it.

[84sprite]

I've found, as a novice, the colour tune plug is a excellent aid in initial setting of the mixture to the extent on my basic 1275 engine it's all I've used. The plugs are a good colour, exhaust colour fine and it comfortably passed the emission test on 2 mot tests and drives excellently. It's also recommended in the Brooklans book Su carburettor tuning tips and you can always rolling road it and fine tune it when it's all up together and ready to go.
I'm in Berkshire but if you can't borrow a local one pm me and I'll post it you and you can send it back when you've finished with it.

Thanks Chris ... your a gent

[Ethel]

I'd agree with not running before you can do so properly, if it's avoidable.

[richmondclassicsnorthwales]

I got rid of my Colour Tune, they are ok to get a ball park idea, but not as good as they could be as there is no lead in petrol any more.

 

The ethanol just doesn't help in setting the mixture correctly

 

Most may disagree, but sometimes, the old fashioned methods are best.

 

The Gunsons air and fuel meter which used the meter and tube up the exhaust I found was a really good machine.

 

Depends on your MOT man too - and how well you get on with them

 

If my motor ever ran slightly high, he would weaken the mixture and get it bang on with the Sun air- fuel ratio machine.

[Edington]

That's probably why my colour tune didn't work very well as I have an-leaded head. I'd almost forgot that I bought a Gunson's air in fuel meter new a few years ago, I'll have to dig it out if I can remember where I put it!

[sonscar]

Colourtune was made to tune a completely standard mechanically fit motor using the fuel of the time.At best it gave idle mixture and assumed all the rest.With wear and possible modifications is this now true?.I have one and do not use it having a gastester instead.Amusing toy from the past which may have some niche used.Just my 2p.Steve..

[84sprite]

Colourtune was made to tune a completely standard mechanically fit motor using the fuel of the time.At best it gave idle mixture and assumed all the rest.With wear and possible modifications is this now true?.I have one and do not use it having a gastester instead.Amusing toy from the past which may have some niche used.Just my 2p.Steve..

Thanks Sonscar

there are no mods on the engine just standard replacement parts 

[Richard_]

I had an idea recently. (I don't have many.)
You can buy an endoscope these days for around £20. This is essentially a tiny camera on the end of a long lead which connects to a phone. It would theoretically enable observation of colortune while test driving the car. ( This may not be legal on the highway so I'm not encouraging this. Might be ok on a test track.)
Has anyone tried this ?

Edited by Richard_, 14 May 2021 - 07:03 AM.

[3VILC]

I seem to remember in the booklet that came with the one I had years ago, its not to be used under load. I imagine the flat glass isn't intended to be strong enough to survive use in an engine running under load. Sure you must just bust the thing, but I'd hate for the broken glass or electrode to fall into the cylinder.
Cool idea tho and who knows it might work.
I've wondered about how well a cheap air/fuel gauge with an o2 sensor in the manifold would work.

[3VILC]

I seem to remember in the booklet that came with the one I had years ago, its not to be used under load. I imagine the flat glass isn't intended to be strong enough to survive use in an engine running under load. Sure you must just bust the thing, but I'd hate for the broken glass or electrode to fall into the cylinder.
Cool idea tho and who knows it might work.
I've wondered about how well a cheap air/fuel gauge with an o2 sensor in the manifold would work.

[Edington]

While were on the subject I have a Gunson gas meter, is there an ideal %CO reading for setting up the fuel/air mixture? I note the book suggests it needs to be no greater than 4.5 but is this just because of MOT limits?

[cal844]

While were on the subject I have a Gunson gas meter, is there an ideal %CO reading for setting up the fuel/air mixture? I note the book suggests it needs to be no greater than 4.5 but is this just because of MOT limits?

Mot limits and fuel consumption