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Delete Fan Hub And Install Thermos (water Pump Pulley, Need Brace?)

The Mafia

By The Mafia,
in Engines & Forced Induction

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The Mafia Grand Master

The Mafia

Posted
Posted

Hi Everyone

BNR34

I am removing my stock fan hub and fan, and installing a thermo fan.

Just curious, it's probably not a good idea to just put the nuts back on the pulley. I was thinking of making a round plate with 4 holes as a brace.

Either that or 4 decent sized washers to increase the torqued surface area of the nuts.

Any suggestions?

Thanks!

The Mafia Grand Master

The Mafia

Posted
  • Author
Posted (edited)

I had cooling issues. PWR radiator and my factory shroud. I even tried the stock radiator and still no luck. (Checked water pump, it was fine)

For some reason the car wouldn't stay cool at idle any more. As soon as I was 60kmph or more, it was fine and would drop the temps to 70 degrees on the highway. (I have a Nismo low temp thermostat).

I installed a brand new fan hub - no good.

Then I installed a Craig Davies fan hub (which is just locked all the time and a pain in the ass) and it worked. Everything stayed cool and the car idles cool now. But it was as loud as hell and dragging all the way to 8,000rpm. I didn't like the idea of a fan loading up that hard all the time.

So I got a bracket laser cut and fit a SPAL 3000cfm fan to the car.

Solid state relay, PWM, etc. Now I can set a full duty cycle via the ECU, and have it start up gently.

Edited by The Mafia
Shoota_77 Veteran

Shoota_77

Posted
Posted

can i ask why? generally a big step backwards

Hi Trent, I'm genuinely interested to know why you say that? Everyone has their own theory on it (most based on "cause I read it on..... forum") but you've obviously got the experience to back it up! I'm about to change over mine to thermos but before I do would love to hear why not before I do it!

Cheers.

GTSBoy Grand Master

GTSBoy

Posted
Posted

It's simply because there is no electric fan that can beat the air pumping rate of a good engine driven fan at idle speed. The invention of the viscous clutch hub allows that same fan to not be too parasitic on the engine at higher engine/vehicle speeds. Best of both worlds without having to run electric fans, which require a larger alternator, heavy(ish) motors at the front of the car, big fat wiring, fuses, etc etc.

There is a solid reason that vehicle manufacturers stuck with engine drive clutch fans for many years in RWD applications. FWD applications seldom had any choice but to go electric, which is probably the only reason that any level of development work was put into them.

  • Like 1
KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

I had cooling issues. PWR radiator and my factory shroud. I even tried the stock radiator and still no luck. (Checked water pump, it was fine)

For some reason the car wouldn't stay cool at idle any more. As soon as I was 60kmph or more, it was fine and would drop the temps to 70 degrees on the highway. (I have a Nismo low temp thermostat).

I installed a brand new fan hub - no good.

Then I installed a Craig Davies fan hub (which is just locked all the time and a pain in the ass) and it worked. Everything stayed cool and the car idles cool now. But it was as loud as hell and dragging all the way to 8,000rpm. I didn't like the idea of a fan loading up that hard all the time.

So I got a bracket laser cut and fit a SPAL 3000cfm fan to the car.

Solid state relay, PWM, etc. Now I can set a full duty cycle via the ECU, and have it start up gently.

Just trying to nail down your problem. What do you mean by staying cool at idle? Why do you want it to be cool? If it overheats in traffic you have a problem but running or idling at normal operating temps is not a problem. A Nismo thermostat will not guarantee that you will idle at 70 deg. It just opens your thermostat earlier.

The Mafia Grand Master

The Mafia

Posted
  • Author
Posted

Just trying to nail down your problem. What do you mean by staying cool at idle? Why do you want it to be cool? If it overheats in traffic you have a problem but running or idling at normal operating temps is not a problem. A Nismo thermostat will not guarantee that you will idle at 70 deg. It just opens your thermostat earlier.

I have no idea why, but if my oil temp was up around 90 degrees, when my car was idling it would just idle into oblivious. seen it get to 112 degrees once when I wasn't looking.

As soon a sI put the craig davies fan on with more airflow, it stayed at 86 degrees.

KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

I have no idea why, but if my oil temp was up around 90 degrees, when my car was idling it would just idle into oblivious. seen it get to 112 degrees once when I wasn't looking.

As soon a sI put the craig davies fan on with more airflow, it stayed at 86 degrees.

That's certainly getting warm. Is it possible you have a slight leak across the headgasket?

The Mafia Grand Master

The Mafia

Posted
  • Author
Posted

That's certainly getting warm. Is it possible you have a slight leak across the headgasket?

I thought that too, but exhaust gas test was negative, and it isn't using any water at all.

Also, it makes over 400awkw without any issues whatsoever.

Just needed more air hey. The factory fan wasn't blowing much at idle at all

GTSBoy Grand Master

GTSBoy

Posted
Posted

Just needed more air hey. The factory fan wasn't blowing much at idle at all

Can't be true. Doesn't matter if the engine is a huge power monster. At idle it should be making a small fraction of the heat required to make it boil against the cooling power of the stock fan. For it to all go wrong, SOMETHING must be wrong. Only one of two options. 1) Way more heat being produced than it should be. 2) Some big dent in the cooling power.

1) is quite unlikely. Can you come up with any ideas how an idling engine can make a bunch of heat?

2) happens all the time. Just have to find out why. All the usual suspects, including poorly bled cooling system, worn out pump vanes, blockage in a an important coolant passage or external hose, stupid amounts of other stuff installed in front of the radiator, etc etc.

I don't think it matters that your solution to the problem seems to have been the solution. It may just be a bandaid to the problem if it hasn't actually identified and dealt with the problem.

The Mafia Grand Master

The Mafia

Posted
  • Author
Posted

Can't be true. Doesn't matter if the engine is a huge power monster. At idle it should be making a small fraction of the heat required to make it boil against the cooling power of the stock fan. For it to all go wrong, SOMETHING must be wrong. Only one of two options. 1) Way more heat being produced than it should be. 2) Some big dent in the cooling power.

1) is quite unlikely. Can you come up with any ideas how an idling engine can make a bunch of heat?

2) happens all the time. Just have to find out why. All the usual suspects, including poorly bled cooling system, worn out pump vanes, blockage in a an important coolant passage or external hose, stupid amounts of other stuff installed in front of the radiator, etc etc.

I don't think it matters that your solution to the problem seems to have been the solution. It may just be a bandaid to the problem if it hasn't actually identified and dealt with the problem.

I will be investigating it more, but I do have a larger PWR intercooler installed.

I also put a lot of foam around the rad to seal it properly because it was sealed very poorly beforehand too.

I inspected the waterpump with an inspection camera, and it looked okay to me. Here are some pics. If you can see anything wrong please let me know!

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niZmO_Man Grand Master

niZmO_Man

Posted
Posted

Story time, my stocker R31 (RB30E, clutch fan with straight blades) used to get hot sitting in traffic in summer, had to keep the revs around 3,000rpm to keep it from flaming up (would hear the fan moving a lot of air).

Issue was a tiny crack in the factory plastic end tanks + lazy clutch fan hub (hence the revving while standing, changed fan to an R32 one, much quieter). Haven't had an issue since.

OP mentioned he put a locked hub and temps were fine. I'd question this "brand new" hub.

GTSBoy Grand Master

GTSBoy

Posted
Posted

OP mentioned he put a locked hub and temps were fine. I'd question this "brand new" hub.

Most of the aftermarket viscous hubs for RBs suck balls. I went through several trying to find one that worked after my original one seized. The Davies Craig ones were pretty much the worst. Made the car sound like a Patrol climbing a steep hill, all the time. Was much tighter/poorly calibrated for temperature than it should have been. The other generic brnad replacements were barely any different.

A 2nd hand OEM Nissan one was perfect from the get go. If I had to do it again I'd drop the cash on a new OEM one, and cross my fingers and hope they're not sourcing the same crap ones as the generic replacements!

The Mafia Grand Master

The Mafia

Posted
  • Author
Posted

What was the temp climbing rate? On a 30deg day with only the ac fan on mine will go from 90 to 110 in about 10 minutes at a stand still. I'd say you might have a problem

Mine wouldn't climb that fast, but it would climb and the highest I have let it go was 110. What was your problem?

  • Like 1
Trex Grand Master

Trex

Posted
Posted

Mine wouldn't climb that fast, but it would climb and the highest I have let it go was 110. What was your problem?

That's with no fan, no hub, no thermos etc. only the little ac fan was going. Was a test to see how fast it heated with no fans.

Mine doesn't have a problem since going to thermos, a new rad and thermostat.

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