Heat sink grease

C

casexxhemi

Registered User
To me heat sink grease is white and comes from Ford. When you get a new module they sell you dialectric grease. I don't think it works as well as heat sink / white.
 
When I got a new replacement from ford, mine included heat sink grease(white stuff). Did the shop that sold you the module, tell you to use the dialectic grease, or did the module come with the dialectic grease? Either way, you should just get some heat sink for the dis.
-Kris
 
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heat sink grease

New module from O'rielly came with dialectric grease (clear) & I don't like using it. I think i'd better go to ford tomorrow & get some. Do you have a better source?
 
The new DIS module came with dielectric? I should think they'd include heatsink grease.. as that is an absolute necessity. See if it describes it somewhere, and if it is heatsink, you should be fine using the included contents. If nothing else I would think an instruction sheet for proper grease application would be included, it may give a description as well.

Others may also have first hand experience..
 
You can get heatsink grease from any RadioShack or any other electronics store. Most computer stores that build custom systems should have it also, just bring the module and ask them for a small amount of grease ( a teaspoon is plenty).

If Ford charges more than two bucks for it, they are ripping you off.

Aaron
 
RadioShack #276-1372 is a little smaller and 1/2 the money.
But any elcectrics store will have it for about a buck, its used between the CPU chip and the heatsink fan and either is a lot better the dielectric grease which should be used on spark plug boots. Good luck
 
I am going to take my jackshaft bracket off. And mill some slots in
the top of the AC/jackshaft bracket under the DIS to act and look
like a heatsink.I was going to mill the slots about .050 to.060 width.
Don't know if it will work but I am going to give it a go.The slot will at least
let the air travel through and under the DIS.

RANDY
 
Randy

You don't want to reduce the contact patch between the module and the support.

The best thing to do would be to add a heatsink to the module that is thermally insulated from the engine. An old CPU heatsink/fan would actually work quite well if you put a 5 volt regulator ($.79) to power the fan from 12 volts.

Aaron
 
pastera, Why ,I would think that the bracket being sloted would be of help
with air flow under the DIS.A contact patch will still be there for grounding.
My common sence says it will help,But I no that common sence does not apply
always..What is your veiw on this ?

I had plans to do the slots in about one hour.

randy
 
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Randy, the key to heat transfer is surface area.

On the module side you want the surface to be nice and smooth so the two metal surfaces make maximum contact and the heat transfer compound fills in the gaps.

To transfer the heat away from the bracket, you need maximum contact with the air, which means lots of surface area. Sandblasting a rough finish and painting with a flat black paint (best would be a heat transfer paint). This is why you see all of the fins on heatsinks, for max heat transfer. The problem with the 'new' CPU heat sinks is most are polished. We polish chambers and exhaust ports to reduce heat transfer through two mechanisms, first is reduced surface area and more important is laminar air flow.

Aaron

If you want to discuss this live, email me at pasterisaj@npt.nuwc.navy.mil with a number and I'll call you an my cell.
 
Aaron, So you are saying that the heat that is bad for the DIS .Comes from the DIS.
Not the heat from the bracket that the DIS is mounted to.?

RANDY
 
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my experience...

on my 91 SC, i got 2 heat sinks (from my work) drilled holes (went to Radio Shack to get heak sink compound and they didnt have any, i did buy it from them in the past and had some at home i forgot about so i used that), went to home depot and bought 1 inch holow stand offs and mounted it to my front passanger fender compartment and extended my wiring harness and soldered all the wires and used black tubing and black tape and tapes it up...works great, looks stock, i know its alot better than before.. this was my second attempt.. Alex LaChance

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...

First attempt, but heat sink got hot, and someone mentioned on here to get 1" stand offs, so i did that and relocated it all at the same time..i like it now (pic up top in previous post..)
 
What SuperCoupeSC91 did is what I am refering to. Those two TO-3 heat sinks will definately move some heat.

The DIS module generates a very large amount of heat. The unit, being automotive, should be rated to operate at case temperatures up to 125 degrees Celcius. Now if the engine is raising the temperature of the bracket to 100C before the DIS module add heat into it, things over heat fast.

So, if you insulate the DIS heatsink from the engine, then the only temp you are worried about is the under hood temp, about 75C. Now lets assume the DIS module generates 50 watts of heat. Heat sinks are rated by the temperature rise per watt of heat for a given air flow, so for the 75C case the heat sink has to be half as efficient as the 100C case to keep the module temperature under 125C. At 50 watts and a 75C ambient you need a heatsink rated at 1DegC/Watt in still air (unless you add a fan). You would really want a much larger heat sink than that to cover for dirt and grime fouling.

I would use two CPU heatsinks with fans to cool the module, that way it gets cooled even when the radiator fan is not running.

Aaron
 
Aaron, Thanks for you insight .I was looking at this all wrong.I didn't machine
my bracket after reading your post.So you saved me some time.I am going
to remove the AC/Jackshaft bracket any way,in a couple weeks.And replace
it with a center mount jackshaft aluminum plulley,were the water pump was
located.I will move my DIS over to the fenderwell then.

Thank all Randy
 
Randy,

You can get those TO-3 heatsinks for about $4.00 each at digikey or visit the local computer junk store and pick up some CPU heatsinks. Prep the mating surfaces as if you were going to weld them before putting the heatsink grease on.

If you go with the two heat sinks, tack weld them together so you get even clamp pressure across the entire surface.

Aaron
 
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