Spacer on clutch fan / fan to shroud depth

[bdrainy]

Hi all,

So I just replaced the leaking radiator with broken mounting brackets in my 87 GW. I used a Champion CC441 (3 row aluminum). It's not listed as fitting my 87 GW (listed as 72-79 Cherokees and J trucks) but every where else lists the radiators as the same for the Cherokees, J trucks, and GW. So I bought it and it fits perfectly and cools great. And the $229 price tag wasn't bad at all.

As I was swapping it out I noticed that the fan blades are not in the shroud at all...maybe just a hair. I did a bunch of searching on here and saw that someone added what looks to be ABS plastic to the stock shroud to fully enclose the fan blade with great results.

My question is...would it be detrimental to the water pump to add a 1" spacer behind the fan clutch to accomplish the same thing? Not sure if that would put more load on the water pump bearings and cause it to fail (sooner than normal).

One way or another I want to get my fan to sit further in the shroud and just trying to determine the best and cleanest way to do it. Be that with a spacer, extending the shroud with am ABS plastic strip, or eventually down the road build a custom shroud for it.

I should note that I am not having cooling problems. In Sacramento summers of 95+ degrees I run right at the 210 mark while cruising and it starts to creep up if I sit in one place for too long. Highest it has gotten was 220 (middle of the gauge) when I sat idling for about 20 mins on a high 90's degree day. Logic tells me I should leave well enough alone...but I can't stop myself from constantly trying to improve things.

Thanks - Brian

[letank]

the fan barely sticks inside the shroud... I did the abs cover up many years ago for experimentation (the old wrangler had a wrap around shroud)... but I removed the lower piece and the cooling went down a 1/16" or a needle width... and later removed the wrap around.

Why... looking at other cars with fancier designs... german stuff... the mechanical fan barely sticks inside the shroud... and with the AC on in 108F... the gauge does not move, of course, this gauge is doing a reading average.

[bdrainy]

So it really only ended up helping marginally? Not enough to keep on...

[letank]

So it really only ended up helping marginally? Not enough to keep on...

the short: it did not help at all.

the long version: I never had overheating issues even idling on SIerra trails ... only when the fan clutch let go going to the Death Valley ride in August. What annoyed me, even after changing the gauge voltage regulator is that the gauge was almost dead center, while the 74 barely ran in the first quarter of the green range. The infra red thermometer read in the 195-200F range at the thermostat housing, oil pan at 215F.

Probably 8 years ago, I was trying to better the system, our design is over 50 years of age... when looking at others cars in the junkyard ... so I installed a mercedes 380 or 560SL fan, lightweight aluminum, saves about 1lbs of rotating mass... and has 9 blades instead of 7, with a fancy blade curve. Gauge was still in the middle...



so I decided to wrap the shroud on the top, then did the side, then added the bottom with no changes....

3 or 4 years ago or so, I had to replace the CVR again... and it failed after very few miles... so I use the home made CVR and the temp was slightly lower... so I decided to remove the home made shroud... and the temp is now in the lower 1/4 of the green range, like the 74... I have not pull out the infra red thermometer or may be I did... too many Jeeps, too many mode of transportation needing my attention!

as it stands


as it was in 2006, as a OEM set up


Another note: the 74 fan sits a little more inside the shroud than the 85, different trans and TC, which was one of the reason I started the project

and the 74 OEM set up

[bdrainy]

Thanks for all the info!! The pics are fairly small so just want to make sure... The pic that says "As it stands" is your 85 with the Mercedes fan and stock jeep shroud? That appears to have the fan to shroud depth I am looking for.

And the pic that says "as it was in 2006, OEM setup" is close to how mine sits now. I would say my fan is slightly further in the shroud than that.

I appreciate you taking the time! Thanks - Brian

[letank]

Thanks for all the info!! The pics are fairly small so just want to make sure... The pic that says "As it stands" is your 85 with the Mercedes fan and stock jeep shroud? That appears to have the fan to shroud depth I am looking for.

And the pic that says "as it was in 2006, OEM setup" is close to how mine sits now. I would say my fan is slightly further in the shroud than that.

I appreciate you taking the time! Thanks - Brian

Yes to all... you're welcome. if you are eager to click on the links below... you can spend some time looking at the larger picts