Coupes and Colortune

Stevehose

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Since DeQuincey asked about the Colortune in my carb project (a device which temporarilly replaces the spark plug and allows viewing the combustion mixture in the cylinder through a sightglass), I'll start a separate thread on it with his questions and a few things that are coupe-specific to help prevent pulling your hair out using it:

really interested in the colortune expereience, so if you dont mind i have some questions:

. for the two zeniths setting do i have to check the colortune in each one of the six cyl, or i can do it in one out of three, that is for example, cyl 2, and cyl 5 ?
i mean, as you can only stablish the settings for the carbs, and each carb feeds three cyls,...

YES ONE PLUG WILL SUFFICE BUT SINCE THE MANIFOLDS ARE SLIGHTLY DIFFERENT LENGTHS IT WILL BE A COMPRIMISE, 2 AND 5 ARE THE SHORTEST LENGTHS FOR FUEL TO TRAVEL, 61PORSCHE OR OTHERS COULD TELL YOU BETTER THAN I WHICH CYLINDER TO TEST FOR BEST AVERAGE.

. i do not understand the principle, but i think that i have to remove the sparkplug and fit the colortune instead, ok, but do i have to aply the same torque to the colourtune than the one that is applied to the plug ?

YES REMOVE THE SPARK PLUG AND REPLACE WITH THE COLORTUNE BUT IT IS ONLY SLIGHTLY HAND TIGHTENED


there is a 12 and 14mm version of the colour tune, for our case it will be the 14 right ?

YES 14MM

. does the colortune become very hot when you use it ? can you remove it immediately to move on the next cyl ? any special care ?

IT DOES NOT BECOME ANY MORE HOT THAN SURRONDING METAL, YOU ONLY KEEP IT IN THERE A FEW MINUTES TO MAKE THE ADJUSTMENT, IT IS NOT DESIGNED TO STAY IN LONG OR REV HIGH FOR VERY LONG, IT IS A FRAGILE PIECE, SEE MY TIPS BELOW TO KEEP YOUR SANITY WHILE USING.
YOU CAN DO EACH CYLINDER AFTER THE OTHER WITHOUT WAITING AND ONCE YOU GET USED TO IT, ALL 6 CYLINDERS IN ABOUT 45 MINUTES OR LESS IF YOU DON'T LOSE THE DAMNED COPPER WASHER (SEE BELOW).

. do you have to previously set the timing ? which action comes first colourtune or timing ?

I ALWAYS SET TIMING BEFORE MIXTURE BUT I AM NOT AN EXPERT ON THIS


. is the colourtune to be used at iddle ? at 1700rpm (as is stated for the carbs) ? other rpms ?

IT CAN BE USED ALL THROUGH THE REV RANGE TO CHECK RICH/LEAN BURN AS RPM'S CHANGE, BUT THE MIXTURE SCREW WILL ONLY CHANGE THE IDLE CIRCUIT (IDLE TO 2000 RPM'S OR SO), A JET WILL CHANGE THE HIGHER RPM'S MIXTURE. USUALLY JUST USED AT IDLE FOR ADJUSTMENTS.


. is there any relationchip between colourtune tune and CO correct setting ? i mean, i assume that when the combustion is perfect a certain value of CO is reached, can this value be zero, i do not remember my old school days

I DON'T KNOW THE EXACT CORRELATION BUT LEANER BURNING LOWERS CO LEVEL, OUR CARS SEEM TO LIKE THINGS SLIGHTLY TOWARD THE RICH SIDE


Here is the coupe-specific setup I came up with to keep from going crazy using this device, the Colortune is a useful piece of equipment but is fragile and a few mods will make it easier and quicker to use on our cars (yes that's my wife's placemat and yes that's leftover grime from the triple weber project, I will be buying her replacements very soon):

IMG-20120617-00502.jpg


To the left is the Colortune plug and wire, this is 2 pieces that I have taped together, if you don't you'll have to try and feed the plug in then screw the wire onto it when in the cylinder hole - NFW in our cars so I wrapped them together with electrical tape.

The next piece is the small black plastic hex thingy that fits over the Colortune plug to tighten it, again it is impossible to fit this over it in the cylinder so I used an old OEM spark plug tool. These are perfect for the job because they are hollow and allow the wire from the Colortune to come up through the middle. I removed the piece of metal inside that was used to grab the plug so it is completely hollow. I put some tape on the black plastic piece and stuck in to the spark plug tool so it wouldn't come out. This is used for hand-tightening the Colortune.

Next is the black plastic sight tube - this is what you slide over the Colortune once you have it threaded and the wrench removed, it has a mirror attached (which sucks but works ok) so you can see the burn from above. It comes in 2 pieces and must be taped together for our use to prevent it coming back apart when removing it.

Next is my trusty magnetic telescoping nut/bolt/washer retriever (this thing is priceless when working on the engine). It is used to remove the annoying little copper washer that goes on the Colortune plug, the washer is not magnetic but by inserting the tool into the area and fishing several times in the vicinity of the plug hole, the washer, which falls off the plug into the hole (bot not into the engine cylinder), will come back out. This is the most annoying part of the procedure and why they didn't devise a better system of keeping the washer on I don't know. Others have said a little grease will hold the washer to the plug but it didn't work for me so I had to fish it out after each cylinder check.

The process is to warm the engine, remove the plug, insert the Colortune with the wire attached, turning it to start it threading. With the black plastic hex thing in the OEM plug tool, insert them over and down the wire onto the plug and just tighten it snug, not too much. Remove the tool and then slide the black tube/mirror over the wire and plug then attach the regular plug wire to the Colortune wire. Fire up the car and adjust mixture to desired blue color. Crappy pics but you can see the difference:

too rich (orange):
Rich-burn.jpg


Just right (barely see the blue ring):
Good-burn.jpg


Once adjusted, remove the black tube, insert the OEM tool and remove the Colortune, if the copper washer doesn't come out with it then fish it out with something like the magnet rod that I use. Repeat for each cylinder if you have tripe webers or for each intake manifold for stock carbs.

More reading:
http://forums.pelicanparts.com/porsche-911-technical-forum/604309-colortune-carb-tuning.html


The Colortune is frustrating at first, but if you can manage the tool's fragility with the above tweaks it is pretty useful.
 
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deQuincey

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thank you so much, you have answered all my questions, and included useful tips on the use
regards

yes you are right about the different manifold lenghts, i assume that the short one in the middle will be the one to tune a little richer so the two laterals would be in the right mixture

only my guess, so some comments will be appreciated
 

Stevehose

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Update

Did another colortune this evening (warning: having a couple adult beverages whilst doing so could possibly make you do something stupid like not know why the device won't go into #6 cylinder until you realize the spark plug is still in), anyway, I did so without the annoying disappearing copper washer and it seemed to work fine so not having to use it will save you a lot of heartache and misery.

Wideband gauge on the way to spec out the rest of the rpm range.
 

deQuincey

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good
i bought my colortune set last week
looking forward to use it asap
 
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