Hood Spacers?

[ArmyGuy45]

Anyone here every heard or tried anything like this?

http://i.ebayimg.com/t/Jeep-Cherokee-XJ-Hood-Spacer-riser-Vent-Kit-prevent-overheating-Rock-Crawler-/00/s/NDUwWDMzNQ==/z/TDEAAOxy1klRdg4g/$T2eC16d,!)0E9s37HlEpBRdg4e8RNw~~60_12.JPG

http://i.ebayimg.com/t/Jeep-Cherokee-XJ-Hood-Spacer-riser-Vent-Kit-prevent-overheating-Rock-Crawler-/00/s/MTA2NlgxNjAw/z/MREAAMXQkl9RdhnC/$T2eC16VHJFoE9nh6oV+uBRdhnB4ttQ~~60_12.JPG

http://www.ebay.com/itm/Jeep-Cherokee-XJ-Hood-Spacer-riser-Vent-Kit-prevent-overheating-Rock-Crawler-/221254956350?pt=Motors_Car_Truck_Parts_Accessories&hash=item3383d2b53e&vxp=mtr

[90ARMYxj]

I have them on my 1990 Xj they are pretty cool but you have to remove the rear weather seal and part of the hood liner it helps lower the under hood temps by almost 50 degrees on a hot day

[4.3LXJ]

Yes, we have heard of them. We have a thread here somewhere in the Tech section on it. However, we need to make a disclaimer concerning spacing the rear of the hood. If this is just for trail use, I suppose it is OK. But by spacing the hood up in the rear, if there is a hit to the front of the hood it can shear loose and come through the windshield. If it is left where it is supposed to be, it will buckle in the middle as intended. I can speak with some authority on this as a former firefighter/paramedic. It is really more effective to put vents in the front part of the hood.

[ArmyGuy45]

Yes, we have heard of them. We have a thread here somewhere in the Tech section on it. However, we need to make a disclaimer concerning spacing the rear of the hood. If this is just for trail use, I suppose it is OK. But by spacing the hood up in the rear, if there is a hit to the front of the hood it can shear loose and come through the windshield. If it is left where it is supposed to be, it will buckle in the middle as intended. I can speak with some authority on this as a former firefighter/paramedic. It is really more effective to put vents in the front part of the hood.


Why the front and not the rear of the hood where its highest?

[4.3LXJ]

Because when the air breaks over the front of the vehicle, it creates an area of vacuum there and with a vent there, it will help draw air through the radiator. At the rear of the hood is actually an area of high pressure. So at speed, air will be forced into the engine compartment there and have the opposite effect of what you want. When idling, it would work though

[ArmyGuy45]

Because when the air breaks over the front of the vehicle, it creates an area of vacuum there and with a vent there, it will help draw air through the radiator. At the rear of the hood is actually an area of high pressure. So at speed, air will be forced into the engine compartment there and have the opposite effect of what you want. When idling, it would work though

Well, looks like I can remove these spacers from my list of things to buy and look into vents.

[4.3LXJ]

Not as cheap, but the results are better. Check into Gen Rite. They have some nice vents

[ArmyGuy45]

Not as cheap, but the results are better. Check into Gen Rite. They have some nice vents

I know that in the back you would want the vents to point so that the air flow from front into the engine bay but would you want the front vents to be reversed?

[bigjim350]

But by spacing the hood up in the rear, if there is a hit to the front of the hood it can shear loose and come through the windshield. If it is left where it is supposed to be, it will buckle in the middle as intended. I can speak with some authority on this as a former firefighter/paramedic.

You would have to be one of the most un-lucky person in the world for something like that to actually happen.

[Mudderoy]

Yes, we have heard of them. We have a thread here somewhere in the Tech section on it. However, we need to make a disclaimer concerning spacing the rear of the hood. If this is just for trail use, I suppose it is OK. But by spacing the hood up in the rear, if there is a hit to the front of the hood it can shear loose and come through the windshield. If it is left where it is supposed to be, it will buckle in the middle as intended. I can speak with some authority on this as a former firefighter/paramedic. It is really more effective to put vents in the front part of the hood.

Thanks for putting this up as people do need to know about this possibility.

[4.3LXJ]

I know that in the back you would want the vents to point so that the air flow from front into the engine bay but would you want the front vents to be reversed?

These are home made, but they need to be pointed like this. As the air flows across the louvres, it creates additional vacuum to draw more air out of the radiator and engine area.

http://i649.photobucket.com/albums/uu215/warriorsuspension/IMG_1105.jpg

[EekGirl96]

I was going to run vents on my XJ to help cool her down but I ended up putting the fan on a switch so that I can control when it came on and that helped alot, never got above the 210 mark

(I think I still have the vents laying around my house somewhere...)

[Cheromaniac]

Because when the air breaks over the front of the vehicle, it creates an area of vacuum there and with a vent there, it will help draw air through the radiator. At the rear of the hood is actually an area of high pressure. So at speed, air will be forced into the engine compartment there and have the opposite effect of what you want. When idling, it would work though

Here's a couple of examples of factory-fitted hood vents (note the location and the direction that they face):

http://image.motortrend.com/f/12209778+w750/112_0901_20z+2010_ford_shelby_GT500+hood.jpg
http://encarsglobe.com/data_images/gallery/02/mitsubishi-lancer-evo/mitsubishi-lancer-evo-04.jpg

[ArmyGuy45]

These are home made, but they need to be pointed like this. As the air flows across the louvres, it creates additional vacuum to draw more air out of the radiator and engine area.

http://i649.photobucket.com/albums/uu215/warriorsuspension/IMG_1105.jpg

Do the fans on your hood push or pull out of the engine bay?

[4.3LXJ]

Right now they pull, but I am going to change that to push in. More efficient cooling that way on the trail

[ArmyGuy45]

Right now they pull, but I am going to change that to push in. More efficient cooling that way on the trail

Do you have to do all of this since you did an engine swap and there is little room?

[4.3LXJ]

I did not have to with the tranny cooler, but I wanted more efficient cooling. One thing that happens with a V shaped motor in an XJ is there is little or no air flow through there. Got it real hot right away with a hood on. So I started looking at every alternative I could to reduce the chance of it ever getting hot again and having to replace head gaskets. The venting, super strong fans and separate oil coolers is what I did. Glad I did. Great trail rig now and it handles hard core stuff just as well without heat problems. I rock crawl with the air running :D