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Coil exposure/cooling shielding
- TeK9iNe
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- What did you do!?!
Has anyone used some sort of heat shield or something of the like, to protect thier coils from the scorching heat of engine exposure?
I think it would greatly increase the life span of the coils, especially with the design of always having voltage with the key on.
What do you think? Any design ideas?
Just throwin it out here...
Motorcycle Shop Owner/Operator
79 Kawie Z1000 LTD
81 Kawie Z1000 CSR
83 Honda VT750C A
85 Kawie GPZ900 A2
86 Zukie GS1150 EG
93 Yamie XV1100 E
Lucky to have rolled many old bikes through my doors
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- MFolks
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If the high tension leads are not molded into the coil and a place was suitable for re-location, new longer sparklug wire could work, but then I'd be concerned about the spark shoting to ground.Might even give a "tingle" or two when the sparkplug fired if it was close to a body part.
Kinda like the lesser of two evil's.
1982 GPZ1100 B2
General Dynamics/Convair 1983-1993
GLCM BGM-109 Tomahawk, AGM-129A Advanced Cruise Missile (ACM)
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- PLUMMEN
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Still recovering,some days are better than others.
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- bountyhunter
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IMHO, the heat abuse of the coil is more self inflicted than externally applied by engine heat. You can have like 30W of power dissipation in a coil and it self heats very badly. A standard kawi coil is 4 Ohm. Key on (not running) puts 12.6V on that 4 ohms which burns 40 WATTS which is a ton for an item half the size of your fist! Some harleys will actually cook a coil just by leaving the key on.Thinking, as I answered another post...
Has anyone used some sort of heat shield or something of the like, to protect thier coils from the scorching heat of engine exposure?
I think it would greatly increase the life span of the coils, especially with the design of always having voltage with the key on.
What do you think? Any design ideas?
Just throwin it out here...
I don't know if heatsinks are justified by increased life span. I suspect if they were, coils would have heat sinks.....
1979 KZ-750 Twin
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- loudhvx
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Ask anyone who has left the ignition on without the bike running and found a melted coil.
1981 KZ550 D1 gpz.
Kz550 valve train warning.
Other links.
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- TeK9iNe
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Maybe not a heat shield, but a small air deflector panel...
or not... Heatsinks, I guess if your leaving the key on for long periods without the engine running, which IS NOT the intended use of coils.
Since they do last fairly long without any sort of cooling mod, then peraps it really isnt necessary.
I do know that after a decent ride, that in about 10mins from sitting, the coils are scorching hot to the touch from the heat soak cycle of the engine. Not melting hot, but not touchable.
How hot is too hot for coils then?
Are the current temps they are being exposed to after stopping, acceptable?
:huh:
Motorcycle Shop Owner/Operator
79 Kawie Z1000 LTD
81 Kawie Z1000 CSR
83 Honda VT750C A
85 Kawie GPZ900 A2
86 Zukie GS1150 EG
93 Yamie XV1100 E
Lucky to have rolled many old bikes through my doors
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- otakar
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As BOUNTYHUNTER said there are some major Wats on these bikes. Those of us that run lower resistance coils like 3-Ohm or 2.4-Ohm Nology or 2.2 -Ohm "J" series coils have it even worse. Figure 66W on the Nology and 72W on a "J" series Ignition. If you are worried about heat, than a small blower would be better than shielding. Figure that a 4-Ohm coil puts out 640 BTU and a 2.2-Ohm coil puts out a whopping 1150 BTU of heat. It is not the heat absorbed you have to watch out for but the heat dissipated, you have to worry about. Cool the coil, don't box it in. Some guys actually mount them on the front frame uprights.
74 Z1-A stock
76 KZ-900 Totaly stock vice MAC pipe
77 KZ-1000A stock
78 Z1-R 100%MINT 500 original Mi.
78 Z1-R Yoshi 1103 kit stage 1 cams Yoshi pipe. Etc
79 KZ-1300 (1400)
80 KZ-1300
81 Scratch built GPz1150R
82 KZ1000
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- bountyhunter
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The best thing about CDI (capacitive discharge ignition) is there is no DC path to the coil primary, a capacitor couples a pulse. With key on, the coil power dissipation is basically zero.Great brainstorming guys...
Maybe not a heat shield, but a small air deflector panel...
or not... Heatsinks, I guess if your leaving the key on for long periods without the engine running, which IS NOT the intended use of coils.
In the older stock Kawi electronic ignitions, they are not CDI they are "transistor" style using a FET or bipolar transistor switch on the coil primary at the negative end of the coil to ground. I don't know if "key on" leaves the transistor on or off which determines if current flows in the coil.
1979 KZ-750 Twin
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- bountyhunter
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1979 KZ-750 Twin
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- MFolks
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Small fans are available that are brushless and are used in some electronic enclosures.
Some websites for electronic suppliers:
1. www.digikey.com
2. www.alliedelec.com
3. www.mouser.com
1982 GPZ1100 B2
General Dynamics/Convair 1983-1993
GLCM BGM-109 Tomahawk, AGM-129A Advanced Cruise Missile (ACM)
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- bountyhunter
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I would say no to both. Fans are very low reliability components in electronic systems. They would need to be shock mounted on rubber dampers. But, even if the fan fails, you are no worse off than stock setup. On the upside, you don't need a thermostat since the coil self heats, so it is impossible for it to get "too cold", no matter how cold the air is.I suppose a small fan(s) could be rigged for cooling air, but would they resist the vibration a bike produces and be water resistant?
1979 KZ-750 Twin
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- loudhvx
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The Dyna S cooks the coils at almost 100% duty cycle when the bike is running, and powers the coils anytime the ignition is on.
Factory points have approx. 50% duty cycle. Each coil has about a 50-50 chance of being on when the key is on and the motor is not turning.
1981 KZ550 D1 gpz.
Kz550 valve train warning.
Other links.
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