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Project Unicorn - a light duty trail rig

Its all those cheap parts you keep using... But seriously, in this case it was the $80 Spectra radiator.

It was $43 open box, and it worked just fine for like 3 years. ;)

Wasn't a problem until I tried to wheel at 12,000 feet elevation in 100 heat with the AC on.
 
I didn't realize that you stopped using the Mishimoto that long ago. Are you going to try the cold case at 12,000 ft in 100 heat with the AC on?
 
I didn't realize that you stopped using the Mishimoto that long ago. Are you going to try the cold case at 12,000 ft in 100 heat with the AC on?

To be honest I hope to never somewhere that hot again (it was 110 in camp) but yes i'm going back for a rematch.
 
12000 ft and 110° and the xj would be the last thing on my mind... I start over heating around 90 🤣

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12000 ft and 110° and the xj would be the last thing on my mind... I start over heating around 90 🤣

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I mean, they weren't at the same time. It was 110 at camp at about 6000 feet, upper 80's at 12k.

Still, my cooling system wasn't up for it. Working on that, when i get some more free time.
 
It was $43 open box, and it worked just fine for like 3 years. ;)

Wasn't a problem until I tried to wheel at 12,000 feet elevation in 100 heat with the AC on.

So is the spectra radiator a good buy? I might hit wheeling at 10k ft here in CO, but nothing good happens at 110*! Fish don't bite, jeep don't like, hell I can't even stand those temps unless I'm deep sea fishing or something super fun.
I'd like a good middle of the pack upgrade over stock radiator, not quite ready to pull the trigger on the cool case setup you got goin. Mishimoto is still highly respected in the subi world... price wise they are higher end tho.

Do you recommend Spectra? Other?

Interested in the zj clutch fan... us ZJ guys were quick to ditch our clutch fans tho. Efans out of ford Taurus were all the rage in my zj days. Did the swap and was happy with it. Kind of curious how the V8 318 in the zj can be fine with the efan only, but this 4.0 needs the clutch fan as well as efan.... and still runs hot lol
 
i know the 4.0 runs hotter if the timing chain stretched if everything else is good. my 97 XJ runs at just under 210 here in lower Alabama while riding a trail in 4 lo down hill at up hill at around 20 degree incline with AC on full blast. I'm running 2 inch lift 30x 9.5 all terrain tires with 242 T case and 3.55 gears. The trail was mostly dirt and unshaded with 108+ heat index Saturday middle of the day. Everything cooling under hood is factory replacement new radiator, water pump , t-stat, ac fan with no mods and it did very well. Just my 3 cents... And this is the XJ that I converted from 2wd just over a month ago.
 
So I yanked the Spectra out and tossed it. For what it was, it was a workhorse but it just didn't get it done.

20210806_151026-me.jpg


Not sure what i was trying to show when I took this photo but here it is?

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Pulled the cold case out to prep it.

20210806_151146-me.jpg


@Anak warned me about this o-ring

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Solved that by removing the o-ring and resealing with some JB Quik.

20210806_152828-me.jpg
 
Started looking at the ZJ fan and fan clutch vs the XJ stuff.

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the ZJ fan is quite a bit bigger!

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Buuuut it's not going to fit within the XJ shroud.

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Overall it is 1.5" bigger OD and sticks forward just a hair closer to the radiator.

Dallas and I are going to revisit later if we can build a new custom shroud that lets people run this fan.
 
Then I bolted up the ZJ fan clutch to the XJ fan and installed it, and dropped the radiator in for a test fit.

During that process I managed to break my fan shroud, and ended up having to go pickup a spare from @CharlesDB so I could keep working. With that distraction I forgot to take any more photos.

I redrilled the holes on the rubber upper isolators for the radiator to move the top forward ~.750 the same as the bottom. ZJ fan clutch with the ZJ fan fit great leaving me about 7/8" to the radiator from the fan clutch. Installed a new MotoRad high flow thermostat with 1/8 holes drilled at 6 and 12 to burp air, new GMB high volume water pump, new Mopar thermostat housing ground a bit for higher flow, and filled the system with water wetter, cheap autozone coolant and distilled water.

For the time being the trans cooler is still routed through my little one in front of the radiator and the radiator itself, until I can get the Derale 13740 mounted up and plumbed. Still working on where that's going to go.
 
Oh I know. I even keep a spare new fan shroud in the garage.

I didn't post up that i broke my shroud, and broke my spare, and amazon was 3 days to deliver but I was being impatient. ;)

2 new shrouds are out for delivery now.
 
Dallas and I are going to revisit later if we can build a new custom shroud that lets people run this fan.

I think a better shroud for the stock fan would be a significant improvement. The stock shroud creates almost no suction tunnel to the radiator. Extending the shroud back 1.5 inches back where possible should make the fan pull more air through the radiator. Also, its helpful to seal off short circuit paths, in particular, between the radiator and top crossmember.

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I think a better shroud for the stock fan would be a significant improvement. The stock shroud creates almost no suction tunnel to the radiator. Extending the shroud back 1.5 inches back where possible should make the fan pull more air through the radiator. Also, its helpful to seal off short circuit paths, in particular, between the radiator and top crossmember.

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Stock to engine moves too much to build a shroud like that, but i suppose with the SFR motor mounts it would stay in place well enough.

But i wouldn't go through all that work to keep a stock fan.
 
Stock to engine moves too much to build a shroud like that, but i suppose with the SFR motor mounts it would stay in place well enough.



But i wouldn't go through all that work to keep a stock fan.
How much radial engine movement- 1/2 inch at the fan at most?

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Cal, I just talked to Russ and he thought you were trying out a new AFE cold air intake?
 
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