Fan shroud

[shadowj38]

What’s everyone’s preference for a fan shroud with a 4 blade GM fan?

[MasterSbilt_Racer]

Home made...

[Jking24]

Theirs a ton of stuff out their but with so many different radiators and engine position differences. The best way is just to make something like masters said. Your gonna wind up cutting up whatever you buy anyway so...

[shadowj38]

What about the outerwear radiator protector? Any chance it can restrict air flow just enough to raise the temp a bit? I ran 225ish Friday night when it was about 75 degrees out. Just trying to get it to cool a little better before the air temp gets hotter in a few weeks.

[MasterSbilt_Racer]

What about the outerwear radiator protector? Any chance it can restrict air flow just enough to raise the temp a bit? I ran 225ish Friday night when it was about 75 degrees out. Just trying to get it to cool a little better before the air temp gets hotter in a few weeks.

I haven't noticed a temp rise.

[Mopar DLM]

Keyser carbon 4 blade fan 3/4" from radiator with no shroud. Up to about 80 degree days we run 1 row of tape to get it to stay around 200. All aluminium on dry sump with wire shaker screen and honeycomb on the front of radiator for protection.

[shadowj38]

I’m currently running a homemade shroud. Running without it was going to be the next this I try. I’m wondering if I don’t have it built to where it could potentially be causing turbulence and hurting me more than it’s helping.

[billetbirdcage]

Grab the fan and see how easy you can turn the fan without the motor turning, if so inspect pulleys if V groove the pulley is probably worn out and belt is running on bottom of groove and not the sides.

it should be extremely hard to get the fan to slip, I mean if you're pulling super hard and you get a little slippage your probably fine but if it moves with anything but a super hard pull with your hand you need to inspect to find issue.

Running that hot in mild temps shows a problem and it's not likely the shroud (unless this was some wide open throttle track and had a ton of dust to plug radiator)

[billetbirdcage]

I should note that most un-anodized V pulleys will wear out in about half a season as they are too soft, I could get maybe half a season out of a lower pulley before it was worn enough the belt no longer runs on the sides of the V. Anodized pulleys are typically hard anodized and have much better wear resistance and will last a long time.

If it's a serpentine system, the small diameter pulleys stink, there isn't enough belt contact for it to not slip on the water pump. Those ones that are under 3" or so diameter are worthless (IMO) and need to rap around the pulley at least 180 degrees worth to get any actual belt contact (IE need an idler if going to PS pump)

[shadowj38]

Belts pulleys and fan were all new at the beginning of the year. Less than 100 laps for far. Radiator was spotless and beginning of year. And even after inspecting after this last race, it was still pretty clean. I did clean it out and didn’t get much out of it.

[TheJet-09]

Are you cleaning it by running water through the fins, backwards? Just curious...about every four weeks or so, I remove mine from the car, hold it about a foot above the ground (face down) and drop it (onto concrete). I read that somewhere (Griffin maybe) as how to actually clean the debris out. I'm continually amazed at how much comes out (it usually takes about 5-6 drops total).

I also switched to the Gorsuch fan this year, and am quite impressed (although I haven't run in real hot temps yet). But many swear by them old GM fans...

[shadowj38]

On a weekly bases I run water through it from front to back with a garden hose when I wash the car. Then every 4 or 5 races I will pull it and mist hot water through it from a steam Jenny until it’s clean. I was also curious about the new 6 blade gorsuch fan but am a little afraid of plastic fans.

[shadowj38]

I run water from back to front i meant.

[riddle28]

id go up a couple jet sizes, it sounds like you have a good cooling setup as it is and with mild temps id be surprised to see it much above 200

[over4T]

Don't be afraid of the Gorsuch fan for being "plastic." It's a really nice piece made of a composite material and not anywhere near the old skinny cheapo fans. In a piece I wrote in the tech section a year or so back the Gorsuch was by far the best of any of several fans we tested.

Billetbirdcage also has a good point about worn out pullies that is usually overlooked. I think belt slippage is something many guys never consider.

Jet's mention of the old drop-the-radiator-on-concrete does get a lot of crap out but I still cringe when thinking about a light thin aluminum piece hitting the concrete and can't bring myself to do it. Used to do it regularly 30-40 years ago when they were brass/copper and a lot stouter.

The old half in-half out and as reasonably close to the radiator as you can get the fan still is best location in the shroud.

The hot part of the season is just beginning and I'm sure a lot of guys will be fighting the temps very soon. Hottest night we've had so far was high 90s and we ran 180 all night. Hope our luck holds.

[shadowj38]

Over4t did you run 180 with the gorsuch fan?

[billetbirdcage]

I just started using the ran fan and ran it on a crate a month ago with 2 blades since it was cool outside and ran cooler then an old GM 4 blade (now this fan is old and getting pretty worn and flattened out blades though) and ran on a 450" all aluminum engine last week and warmed engine to 200 and made laps and dropped and maintained at 140 degrees (with a 19" 3 blade). Several of my guys run the race fan and turn RPM of 9300 for qualifying and ran a 100 laps at 8800, so I wouldn't be scared of the good plastic/composite fans now that they been sorted out.

Side note: I also use the radiator drop, about 8 to 10" over concrete until you see no more debris come out. If that breaks/damages a radiator, then I don't want to use it brand. I still wash them but it's a fast way to remove the dirt in a hurry but I still do every time before cleaning them

[over4T]

Shadow, Yep 180 with the Gorsuch.

[shadowj38]

After inspecting my plugs, I think I’m going to try giving the car a little bit more fuel. I did end up replacing my shroud since mine has seen better days. I went with a dominator shroud part #DOM-545. It worked out perfectly in my rocket with an FSR radiator. No cutting or fitting necessary. Just drilled a few holes to bolt it in. We will see what happens as long as the rain holds off. Thanks for the replies everyone!

[Lizardracing]

Just food for thought, Oil temps can effect water temps. Oil, also a coolant, picks up quite a bit of heat that also gets dispersed through the cooling system. When oil temps get too high, that adds a significant load to the radiator. I don't want to say that your biggest issues, it's just something to think about when chasing heating problems and the cooling system has been checked well.
I've also seen the water pump impellers slip on the shafts at operating temps and tighten up again when cool as well as corroded away.

[shadowj38]

My oil temp is always around 230/235.

[TheJet-09]

And don't overlook the gauge itself. I had a problem where mine slowly kept creeping up the longer I ran, but the idiot light never came on. I finally got a new gauge and it took care of that.

[shadowj38]

I replaced the gauge at the beginning of the year.

[grt74]

Home made...

thats what we do

[JustAddDirt]

take out radiator and set it in a kiddie pool full of water for a day or two. You will be surprised of the dirt debris laying in the bottom of the pool.

[over4T]

...or try your unfriendly neighbor's hot tub, preferably when he's not home. Half an hour usually does the job.

[JustAddDirt]

...or try your unfriendly neighbor's hot tub, preferably when he's not home. Half an hour usually does the job.

excellent idea !!!!!!

[over4T]

Missed the opportunity to do some serious hot weather testing over the weekend with our class off all over our area. Had temps all weekend in the 107-110 range and wouldn't have gone if we could. Got Stockton next Saturday and, right now, they're forecasting 103 so we'll get ready and see if my old bod is up for that.
Northern CA's summers are brutal and might as well reopen the old Death Valley Speedway. It was 125 there.. that's Fahrenheit.