Problem mounting 80mm fan adapter to heatsink

[Ohaya]

Hi,

I'm trying to replace the heatsink fan on my Alpha heatsink with an 80mm fan
and an adapter. The problem is that the original screws from the Alpha are
too long because they are longer by the thickness of the original 40mm fan
(I hope that that's clear ).

I'm sure that others here have run across this problem before, and was
wondering what you all did? I'd prefer not to cut the original screws.

Jim

 

[sooky grumper]

Hi,

I'm trying to replace the heatsink fan on my Alpha heatsink with an 80mm fan
and an adapter. The problem is that the original screws from the Alpha are
too long because they are longer by the thickness of the original 40mm fan
(I hope that that's clear ).

I'm sure that others here have run across this problem before, and was
wondering what you all did? I'd prefer not to cut the original screws.

Jim

didn't your adapter come with a pack of differently sized screws?

 

[Overlord]

I have an old alpha somewhere. Don't recall anything about the screws...
I do speak hardwarestore-ese tho.
Go buy some new ones the length you want. Or buy an extra set of the old
ones and a single nut. Put the nut on the screw, snip off the screw to length,
screw the nut off to clean up the threads.

Hi,

I'm trying to replace the heatsink fan on my Alpha heatsink with an 80mm fan
and an adapter. The problem is that the original screws from the Alpha are
too long because they are longer by the thickness of the original 40mm fan
(I hope that that's clear ).

I'm sure that others here have run across this problem before, and was
wondering what you all did? I'd prefer not to cut the original screws.

Jim

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[Ohaya]

didn't your adapter come with a pack of differently sized screws?

Hi,

No, no screws came with it...

FYI, after my post, I was able to jury-rig something, at least temporarily,
by cutting some tubes and using them as kind of thick washers . I'm kind
of surprise tho, after I mounted the 80mm fan, temp on the CPU shot WAY up
and very quickly. Tried the 80mm fan both ways, blowing into the heatsink
and sucking from the heatsink. Same result both ways.

The adapter was tight to the top of the Alpha heatsink, and the 80mm fan was
tight to the adapter, so I'm kind of puzzled.

Temporarily back to the original 40mm fan ...

 

[sooky grumper]

Hi,

No, no screws came with it...

FYI, after my post, I was able to jury-rig something, at least temporarily,
by cutting some tubes and using them as kind of thick washers . I'm kind
of surprise tho, after I mounted the 80mm fan, temp on the CPU shot WAY up
and very quickly. Tried the 80mm fan both ways, blowing into the heatsink
and sucking from the heatsink. Same result both ways.

The adapter was tight to the top of the Alpha heatsink, and the 80mm fan was
tight to the adapter, so I'm kind of puzzled.

Temporarily back to the original 40mm fan ...

If you disrupted the thermal transfer material beneath the heatsink then
this could account for that. Best to remove the heat sink, clean it and
the chip, attach the fan to the heatsink, apply thermal compound to the
chip, and then attach the HSF (with the new 80mm fan).

 

[Ohaya]

If you disrupted the thermal transfer material beneath the heatsink then
this could account for that. Best to remove the heat sink, clean it and
the chip, attach the fan to the heatsink, apply thermal compound to the
chip, and then attach the HSF (with the new 80mm fan).

Hi,

I thought about that theory, but the problem with it is that when I put the
original 40mm fan back on again, temperatures go back to the way they were
before.

So, I'm still wondering: is this "normal" when using an adapter and larger
fan. I'm assuming it's not, but I thought that I'd ask....

 

[Patrick]

If you disrupted the thermal transfer material beneath the heatsink then
this could account for that. Best to remove the heat sink, clean it and
the chip, attach the fan to the heatsink, apply thermal compound to the
chip, and then attach the HSF (with the new 80mm fan).

1. the fan needs to blow into the heatsink for positive displacement of
hot air on the fins... this is very important in all the thermal flow
tests on Anand's Hardware, and Tom's Motherboard webpages.

2. you don't mention fan speeds!!! If the 40mm fan is a 5000rpm vs. an
80mm fan at 2000 rpm, the speed can be a large part of the temperature
difference!

3. I agree, that the thermal compound is a necessity, and, if you have
any thermal tape that came installed on either the cpu, or on the
heatsink, it is only good for one use, and if disturbed, should be
entirely removed, and a good thermal paste applied!

 

[Ohaya]

1. the fan needs to blow into the heatsink for positive displacement of
hot air on the fins... this is very important in all the thermal flow
tests on Anand's Hardware, and Tom's Motherboard webpages.

2. you don't mention fan speeds!!! If the 40mm fan is a 5000rpm vs. an
80mm fan at 2000 rpm, the speed can be a large part of the temperature
difference!

3. I agree, that the thermal compound is a necessity, and, if you have
any thermal tape that came installed on either the cpu, or on the
heatsink, it is only good for one use, and if disturbed, should be
entirely removed, and a good thermal paste applied!

Patrick,

Re. 1: Per my post, I tried with the fan mounted both blowing and sucking.

Re. 2: Sorry, I forgot to include that info. Both the 40mm and 80mm fans
are Vantec Stealths. I think the 40mm shows about 2800 rpm, and the 80mm
was showing about 2000 rpm.

Re. 3: No thermal tape, we used AS2 or AS3 (can't remember).

 

[sooky grumper]

Patrick,

Re. 1: Per my post, I tried with the fan mounted both blowing and sucking.

Re. 2: Sorry, I forgot to include that info. Both the 40mm and 80mm fans
are Vantec Stealths. I think the 40mm shows about 2800 rpm, and the 80mm
was showing about 2000 rpm.

Re. 3: No thermal tape, we used AS2 or AS3 (can't remember).

The extended washers you made, did you put them between the adapter and
the heat sink or is the adapter in contact with the heat sink and the
washers are within the volume of the adapter?

 

[Ohaya]

The extended washers you made, did you put them between the adapter and
the heat sink or is the adapter in contact with the heat sink and the
washers are within the volume of the adapter?

Hi,

This is kind of hard to explain with just words, but the short answer is
that "yes, the adapter is in contact with the heatsink", i.e., the 40mm end
of the adapter was flush with the top of the heatsink.

If you recall, the problem was that, basically, when using the adapter, the
original screws for the 40mm fan were too long (by the thickness of the 40mm
fan). I took some tubing, and cut 4 pieces, each with length approx. equal
the thickness of the 40mm fan. I then slipped the original screws into the
tubing, and then into the holes in the adapter, and then into the top of the
heatsink:

===
| <=== original screw
| |
| | <=== short piece of tubing
| |
|
|
|
===== <== bottom of adapter (4 holes)
\\\\\\\\\\\ <== top of heatsink

Jim

 

[sooky grumper]

Hi,

This is kind of hard to explain with just words, but the short answer is
that "yes, the adapter is in contact with the heatsink", i.e., the 40mm end
of the adapter was flush with the top of the heatsink.

If you recall, the problem was that, basically, when using the adapter, the
original screws for the 40mm fan were too long (by the thickness of the 40mm
fan). I took some tubing, and cut 4 pieces, each with length approx. equal
the thickness of the 40mm fan. I then slipped the original screws into the
tubing, and then into the holes in the adapter, and then into the top of the
heatsink:

===
| <=== original screw
| |
| | <=== short piece of tubing
| |
|
|
|
===== <== bottom of adapter (4 holes)
\\\\\\\\\\\ <== top of heatsink

Jim

Thanks Jim. I figured you'd done that, but I just wanted to confirm.
I've replaced the fans on a couple of Athlons (XP 1700+ and XP 1800+)
with 80mm->60mm adapters and Vantec Stealth 80mm fans and they run just
as cool as with the noisy 60mm fans. I even replaced the case fan in
these systems with the stealth 80mm. This caused system temp and CPU
temp to increase by 2 degrees C (on average).

 

[Ohaya]

Thanks Jim. I figured you'd done that, but I just wanted to confirm.
I've replaced the fans on a couple of Athlons (XP 1700+ and XP 1800+)
with 80mm->60mm adapters and Vantec Stealth 80mm fans and they run just
as cool as with the noisy 60mm fans. I even replaced the case fan in
these systems with the stealth 80mm. This caused system temp and CPU
temp to increase by 2 degrees C (on average).

Hmm. That's (that the larger fan + adapter) what I was expecting, but it
definitely wasn't what I got. With the Stealth fan+adapter, the temperature
was REALLY flying. I was almost afraid that I wouldn't be able to shut it
down fast enough (a bit of an exaggeration, but it was rising really fast).

Any guesses why my setup wasn't cooling as well? Like I said, I checked,
and the adapter was flush. I wonder if I need to seal the gap somehow,
maybe with some tape or something?

Jim