dis overheating

nascar john

Registered User
gentlemen, i have a question on dis overheating. what do you think about small phenolic washers on each screw to seperate the dis from the ac compressor to allow air flow. it seems this would keep the dis cooler. i live in dallas and the heat is hot-it is 95 degrees today-----in october
thanks
john
rjpim@hotmail.com
 
Unfortunately air flow is limited in that region. You would need a fan to try to help but even then... it would have to have a cool air source.

Putting heat sink compound (not dielectric grease) helps alot and aluminum absorbs heat quickly. The contact bewteen the dis and bracket will transfer heat quickly, you just hope the bracket is cooler than the DIS itself. If its not, I would be more concerned of why the DIS is so hot itself.
 
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thanks for the prompt reply-i think i will leave well enough alone and use good heat sink. thought it might be a help to others who experience 50 or 60 100 degree plus days a year
 
Doesn't the DIS ground through the base and the bolts? Putting spacers might short it out.

Not 100% sure on that, but I've heard it before.
 
I replaced my dis with an autozone part, and before I mounted it I rubbed it on a piece of sand paper. This showed a lot of low spots. so I sanded it flat and scotch brighted the mounting surface of the mounting bracket. I used a "thin"coat of Artic silver heatsink compound--and no more dis problems
 
Actually, the cause of a DIS overheating is not related to high temps coming from the bracket into the DIS, but from the heat generated internally by the module not being properly dissipated through the bottom surface area. I am still using the original DIS that came on the car (15 yrs ago). I clean the old compound off both surfaces about once a year and apply new.
Putting spacers between the DIS and bracket would probably cause the DIS to build up heat internally (and eventually fail).
 
I replaced my dis with an autozone part, and before I mounted it I rubbed it on a piece of sand paper. This showed a lot of low spots. so I sanded it flat and scotch brighted the mounting surface of the mounting bracket. I used a "thin"coat of Artic silver heatsink compound--and no more dis problems

I second the arctic silver never had a problem since
 
Actually, the cause of a DIS overheating is not related to high temps coming from the bracket into the DIS, but from the heat generated internally by the module not being properly dissipated through the bottom surface area. I am still using the original DIS that came on the car (15 yrs ago). I clean the old compound off both surfaces about once a year and apply new.
Putting spacers between the DIS and bracket would probably cause the DIS to build up heat internally (and eventually fail).

This is correct.

Although the bracket gets hot, the DIS gets hotter (in theory-I haven't actually measured), so the bracket is the DIS's heat sink...not the other way around.;) If the bracket was hotter, why would you put heat sink between the two - to warm up the DIS and keep the bracket cool? Also, the DIS definetly gets grounded through at least one of the little 5.5mm bolts (depending on what brand of DIS you have)

I'm thinking that the best thing to to is relocate it or at least clean and reapply heat-sink often. I got a heat sink off eBay that wil fit a DIS perfectly. I think I'm going to mount it to the side of the "air filter / hot engine divider" when I make one. That should keep it cool and not heat up the intake air too much.:D Look around on here, I know there's some pictures of relocation ideas on the boards.
 
Who said anything about needing the bracket hotter than the DIS? I just mentioned that you HOPE the bracket is cooler than the DIS, otherwise heat transfer is going to go the wrong way.
 
I didn't say that it needed to be hotter than the DIS... It just seemed like nascar John was assuming that the bracket was making the DIS hot, since he thought it might help to get the DIS off the bracket. Maybe I read between the lines a little too much.

Not that this must be true, but if the bracket was expected to be warmer than the DIS, they (Ford Engineers) probably would have put it elsewhere.
 
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Ford moved the dis in 94. Basically bolting the dis directly to the head was a crappy idea in the first place, and should be treated as such.


Heres how I fixed this problem:

put some fiberglass cloth between the bracket and a 1 1/2" tall heatsink from a sturdy house amp, and clamped the dis down on it with heatsink lube and some longer screws. It made a noticable temp difference on mine and it only took 20 minutes.
 
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