Question about Ignition Module Mounting
01-30-2011, 01:53 PM
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Question about Ignition Module Mounting
Just got my stripped and modified harness back from Marc Heibeck and I'm putting the top end back together for the last time. There was a white grease type substance between the plenum and the ignition module which I cleared off during the painting process. Is that just dielectric grease? Thanks!
01-30-2011, 07:22 PM
#6
Drifting
My Factory Service Manual for my 90' page 6E3-C4-9 states and I quote
"Dielectric grease to back of ignition module (figure C4-10)"
Figure C4-10 caption reads "Dielectric Grease Application"
So I don't think dielectric grease will do any harm....
H
"Dielectric grease to back of ignition module (figure C4-10)"
Figure C4-10 caption reads "Dielectric Grease Application"
So I don't think dielectric grease will do any harm....
H
01-31-2011, 10:34 PM
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Not dielectric grease
Hans,
The manual may refer to it as dielectric grease, but Dominic and bdw are right. The ignition module should have heat sink compound applied liberally to the back side before installation. Dielectric grease is an electrical insulator, whereas heat sink compound conducts heat away from the coil drivers in the ignition module. Using the wrong compound will cause the coil drivers to fail in short order. With the rarity and cost of ignition modules, I wouldn't take any chances.
Jep
The manual may refer to it as dielectric grease, but Dominic and bdw are right. The ignition module should have heat sink compound applied liberally to the back side before installation. Dielectric grease is an electrical insulator, whereas heat sink compound conducts heat away from the coil drivers in the ignition module. Using the wrong compound will cause the coil drivers to fail in short order. With the rarity and cost of ignition modules, I wouldn't take any chances.
Jep
Last edited by VetteVet86; 01-31-2011 at 10:36 PM. Reason: added detail
02-01-2011, 12:34 AM
#8
Le Mans Master
Hans,
The manual may refer to it as dielectric grease, but Dominic and bdw are right. The ignition module should have heat sink compound applied liberally to the back side before installation. Dielectric grease is an electrical insulator, whereas heat sink compound conducts heat away from the coil drivers in the ignition module. Using the wrong compound will cause the coil drivers to fail in short order. With the rarity and cost of ignition modules, I wouldn't take any chances.
Jep
The manual may refer to it as dielectric grease, but Dominic and bdw are right. The ignition module should have heat sink compound applied liberally to the back side before installation. Dielectric grease is an electrical insulator, whereas heat sink compound conducts heat away from the coil drivers in the ignition module. Using the wrong compound will cause the coil drivers to fail in short order. With the rarity and cost of ignition modules, I wouldn't take any chances.
Jep
Apology accepted.
02-01-2011, 04:30 PM
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Wakefield 120
Just got my stripped and modified harness back from Marc Heibeck and I'm putting the top end back together for the last time. There was a white grease type substance between the plenum and the ignition module which I cleared off during the painting process. Is that just dielectric grease? Thanks!
http://www.newark.com/wakefield-solu...2oz/dp/00Z1245
02-01-2011, 04:44 PM
#10
Le Mans Master
Follow his link to the product that you need. Mark Haibeck recommended this to me and I used it, works!
http://www.newark.com/wakefield-solu...2oz/dp/00Z1245
http://www.newark.com/wakefield-solu...2oz/dp/00Z1245
http://www.buzzillions.com/reviews/r...ase-6g-reviews
02-01-2011, 04:50 PM
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Wakefield 120
That should last you several lifetimes. The RS stuff is here, just a small tube lasts a long time.
http://www.buzzillions.com/reviews/r...ase-6g-reviews
http://www.buzzillions.com/reviews/r...ase-6g-reviews
Hope to see photos of your project soon!
02-02-2011, 11:22 AM
#13
Drifting
It appears there's room for everyone in this debate. In order to get a proper answer I went to the source, Mark Haibeck, on this question. I e-mailed him and got the following answer. I hope he doesn't mind me posting his reply word for word.
"Hi Hans,
The factory used high efficiency zinc oxide thermal compound. The color is white.
When GM sold the service ignition modules they supplied a clear silicone grease.
The module dissipates up to 120 watts so thermal transfer efficiency is important. I believe that the specialized white heat sink compound is the better material. I recommend using it. It's available from places that sell supplies to electronic repair shops. A serious computer store should have it.
If you want to order it on-line go to:
http://search.digikey.com/scripts/Dk...54&k=wakefield
The two ounce jar pn 345-1007-ND is enough to install about three modules.
So it seems that GM was not smoking dope when they wrote the Service Manual as they did.
Is the the "white" stuff better... probably.
Will the clear dielectric grease fry your module... no.
Dom, I'll accept your appology now, it's just faster that way...
H
"Hi Hans,
The factory used high efficiency zinc oxide thermal compound. The color is white.
When GM sold the service ignition modules they supplied a clear silicone grease.
The module dissipates up to 120 watts so thermal transfer efficiency is important. I believe that the specialized white heat sink compound is the better material. I recommend using it. It's available from places that sell supplies to electronic repair shops. A serious computer store should have it.
If you want to order it on-line go to:
http://search.digikey.com/scripts/Dk...54&k=wakefield
The two ounce jar pn 345-1007-ND is enough to install about three modules.
So it seems that GM was not smoking dope when they wrote the Service Manual as they did.
Is the the "white" stuff better... probably.
Will the clear dielectric grease fry your module... no.
Dom, I'll accept your appology now, it's just faster that way...
H
Last edited by ccmano; 02-02-2011 at 01:05 PM.
02-02-2011, 11:29 AM
#14
Le Mans Master
It appears there's room for everyone in this debate. In order to get a proper answer I went to the source, Mark Haibeck, on this question. I e-mailed him and got the following answer. I hope he doesn't mind me posting his reply word for word.
"Hi Hans,
The factory used high efficiency zinc oxide thermal compound. The color is white.
When GM sold the service ignition modules they supplied a clear silicone grease.
The module dissipates up to 120 watts so thermal transfer efficiency is important. I believe that the specialized white heat sink compound is the better material. I recommend using it. It's available from places that sell supplies to electronic repair shops. A serious computer store should have it.
If you want to order it on-line go to:
http://search.digikey.com/scripts/Dk...54&k=wakefield
The two ounce jar pn 345-1007-ND is enough to install about three modules.
So it seems that GM was not smoking dope when they wrote the Service Manual as they did.
Is the the "white" stuff better... probably.
Will the clear dielectric grease fry your modual... no.
Dom, I'll accept your appology now, it's just faster that way...
H
"Hi Hans,
The factory used high efficiency zinc oxide thermal compound. The color is white.
When GM sold the service ignition modules they supplied a clear silicone grease.
The module dissipates up to 120 watts so thermal transfer efficiency is important. I believe that the specialized white heat sink compound is the better material. I recommend using it. It's available from places that sell supplies to electronic repair shops. A serious computer store should have it.
If you want to order it on-line go to:
http://search.digikey.com/scripts/Dk...54&k=wakefield
The two ounce jar pn 345-1007-ND is enough to install about three modules.
So it seems that GM was not smoking dope when they wrote the Service Manual as they did.
Is the the "white" stuff better... probably.
Will the clear dielectric grease fry your modual... no.
Dom, I'll accept your appology now, it's just faster that way...
H
02-03-2011, 09:03 AM
#16
Drifting
No apologies needed Jep... I was just giving my buddy Dom a hard time, as he was with me. One of the nice things about the ZR-1 community is that you can have discussions like this without getting into a flame war.
Regards,
Hans
Regards,
Hans
02-03-2011, 09:17 AM
#17
Tech Contributor
02-03-2011, 09:43 PM
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Flamethrower
Last edited by VetteVet86; 02-03-2011 at 09:45 PM. Reason: Correct emoticons
02-04-2011, 05:58 AM
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Zinc oxide sink application
About heat sink application: If some is good, then more is better? NOT!
In a previous life I used to repair a variety of electronics, including power supplies and other high heat components that needed to be "sunk" to avoid premature thermal breakdown. So, take it (or leave it) from an old electronics repair dude: A microscopic view of the two machined heat sink surfaces looks like two moonscapes. Pressing them together sans other material results in random "point" contacts across the surfaces, i.e., much less actual contact than you might imagine! And, that is where the heat sink compound comes in; it bridges the gaps between metal to metal contact points and conducts heat better than surface to surface radiation alone.
But, zinc oxide does not conduct heat better than metal to metal contact and too much will actually insulate instead of enhance heat transfer. This is why it is very important to be careful to avoid getting any grit in the sticky compound and proceeding to clamp the parts together. the grit will open the distance between the metal surfaces, and heat will not be transferred efficiently. The same happens if too much goop is used. After all, we're trying to enhance heat transfer; we're not making "Smores", in other words.
I recommend a wide blade putty knife to spread and then remove all but a thin, film on one surface. If you can just begin to see the cloudy metal surface under a skin of the oxide, work the oxide until the metal just disappears under the layer...and that is about right.
FWIW,
P.
In a previous life I used to repair a variety of electronics, including power supplies and other high heat components that needed to be "sunk" to avoid premature thermal breakdown. So, take it (or leave it) from an old electronics repair dude: A microscopic view of the two machined heat sink surfaces looks like two moonscapes. Pressing them together sans other material results in random "point" contacts across the surfaces, i.e., much less actual contact than you might imagine! And, that is where the heat sink compound comes in; it bridges the gaps between metal to metal contact points and conducts heat better than surface to surface radiation alone.
But, zinc oxide does not conduct heat better than metal to metal contact and too much will actually insulate instead of enhance heat transfer. This is why it is very important to be careful to avoid getting any grit in the sticky compound and proceeding to clamp the parts together. the grit will open the distance between the metal surfaces, and heat will not be transferred efficiently. The same happens if too much goop is used. After all, we're trying to enhance heat transfer; we're not making "Smores", in other words.
I recommend a wide blade putty knife to spread and then remove all but a thin, film on one surface. If you can just begin to see the cloudy metal surface under a skin of the oxide, work the oxide until the metal just disappears under the layer...and that is about right.
FWIW,
P.