clear glass spark plug
 

Was watching "Restoration Garage" on Velocity and there was an English chap on there working on a Jag XKE tuning the SU carbs and he had a clear glass spark plug that he used to "FINE" tune the air and fuel mixture on the carbs by watching the cylinder ignition flame in the cylinder. Anyone have one, seen one or know where you can buy one???

Re: clear glass spark plug
 

Google colortune

Re: clear glass spark plug
 

I sold a kit that was exactly what you describe. I'd never used it so can't tell you with any authority as to how well it may have worked.
I trust you realize that you can't believe all of what you see on TV.

Re: clear glass spark plug
 

I have one. It is a Colortune and what it does is allow you to see into the combustion chamber. If the combustion flame is orange then the mixture is too rich. If it is a light blue it is too lean. If it is a pretty medium blue then it is close to the right mixture.
Run it through the RPM range and you can see where the carb needs to be adjusted, whether it needs adjustment in the low, medium or high speed range.

One caution, these units are not made for continuous running. They will not last. Just use it for test purposes when the engine is already warmed up, then take it out.
You only need one unit in one cylinder. You can move it around to other cylinders if you are looking for differing problems.

I have had mine since motorcycle racing in the mid-60's and still use it.
And NO, I will not give it to you! :)

Re: clear glass spark plug
 

Have one and used it to set mixture . It works in that you can see the color of flame change from rich to lean.
With the introduction of AFR gauges they pretty much became a novelty but in the right situation, still useful.

Re: clear glass spark plug
 

Here is a link to the Colortune. There is a video also. When I bought mine a long time ago it was a whole lot cheaper!
http://www.gunson.co.uk/tech-torque/...ustion-chamber

Re: clear glass spark plug
 

WOW! They are proud of them, aren't they?

Re: clear glass spark plug
 

An O2 sensor ratio meter is what most high end shops use now days. Reading the plugs is another way that only costs the labor to pull one & put it back in. The clear spark plug will only be practical in an unloaded situation unless a dyno is used.

Re: clear glass spark plug
 

The British car guys sweat by Colortune. I have one but never got the handle on using it correctly.

~ Carl

Re: clear glass spark plug
 

Re: clear glass spark plug
 

I've seen them and wondered about them.
The vacuum gauge seems a cheaper and I suspect just as good an alternative .
I can understand the Brit guys liking them. My Father used to say he had never worked on an British car that was easy to tune-He believed that the Brits struggled to get the carburation right on their engines (and I own a 1967 Sunbeam Alpine- Twin Stromberg 150CDs-ugh !! )

Re: clear glass spark plug
 

Why knock it if you never used it? I used it in the minutes just before a race to final tune for the most power in those particular heat & humidity conditions. without risking the mixture being too lean resulting in a blown piston. Too lean = too hot = piston melt in the blink of an eye. Sometime the piston disintegrates, sometimes it just makes a clean hole right under the sparkplug.

Re: clear glass spark plug
 

I have had one for many years and used it on vintage English motorcycles to get the carb jetting correct. It worked well on the 1928 Brough Superior SS 100 V Twin. Regards, Kevin.

Re: clear glass spark plug
 

I use one in combo with a vacuum gauge , just lets you know things are right ..
Of course its never going to be like a wide band...

Re: clear glass spark plug
 

Kevin you have a Brough? You are my idle if you do!!!
Cheers
Tony

Re: clear glass spark plug
 

Wow The Rolls Royce of Motorbikes . I'm envious . Saw one in Southwards car museum over here and spend about 30 minutes admiring it .Wasn't Lawrence of Arabia killed riding one ?


I can see that the colour tune would be very useful if you were changing jets.
Most of my tuning is just changing the mixture at idle in the 34 . Might be quite useful tuning my 1910 Hupmobile however - Karl

Re: clear glass spark plug
 

Its what I thought to...

Re: clear glass spark plug
 

Lawrence of Arabia had one of those bikes and it took his life. Remember seeing an English TV show years ago "Lovejoy", about a "dodgy"antique dealer. He got an SS100 BS, bent the handlebars and tried to pass it off a T E Lawrences "death machine" in order to get a bit of extra coin,it was hilarious ..nice bike too.

Getting back on subject I've seen the Colour Tune advertised here in NZ on Trade Me and have often wondered how they work and if it was worth getting one so this is an informative thread for me. I think they also have a kit for balancing twin carb setups which is particularly useful for "pesky" SU types. Thanks to the poster.

Jay Leno Brough Superior https://www.youtube.com/watch?v=VdhgDvc2AWo

GB

Re: clear glass spark plug
 

There were more dang tuning tools, top-end 'injectors', funny 'superchargers', custom super-mileage carburetors, ignition gizmos, . . . the whole post WWII period made just about everybody an inventor of some sort! I just love reading some of the old magazines - every claim known to man was made.

Anyway, in these times, use a wide-band O2 sensor with a gauge or even better - data collector and you'll really know what your fuel-mixture is like (under any load condition). I set one up on my 32 - with a special 6 - 12 volt converter so I could run it. I only use it to tune, then it comes back out of the car. In addition to wideband O2, I also have EGTs. Can't beat modern stuff for tuning . . .

Note: Given today's fuel mixtures, it is MUCH harder to read plugs than 40 years ago.

Re: clear glass spark plug
 

I used them on the British cars I have had. Between it and the flow meter helpful in getting both SU's set up right.