Instead of hood vents....
04-21-2010 | 12:11 PM
#61
Senior Member
Joined: Apr 2009
Posts: 922
Likes: 2
From: Grand Haven, Michigan
Year: 1998, 1999
Model: Cherokee
Engine: 4.0
The XJ hoods are made to buckel on impact. I doubt running shims would effect the hood from performing as designed. It's going to buckel long before it breaks the bolts...
04-21-2010 | 04:49 PM
#62
Senior Member
Joined: Apr 2010
Posts: 649
Likes: 4
From: Houston, Tx
Year: 1999
Model: Cherokee
Engine: 4.0L
still would rather just put a switch on the fan, like the lines of my hood to match with the rest of the jeep
(and less mud in the engine, cause I always end up with mud on the hood)
04-23-2010 | 09:53 PM
#63
Senior Member
Joined: Apr 2009
Posts: 954
Likes: 2
From: New Waverly, Tx
Year: 1997
Model: Cherokee
Engine: Used engine just put in less than 79kmiles onit jeepersCreepers 60mm TB, '99-'01 intake, BorlaHeader
A quick calculation of a 3/8" grade 8 bolt. According to rockcrawler.com and a few other sites the average shear strength is roughly 10000 lbs. Now, using F=ma where 1g equals approximately the acceleration to 22mph in 1 second.
The mass of a Jeep (conservative according to wikipedia) is 3057 lbs or 1387kg.
Acceleration (or deceleration in the event of an accident) is 32.2 ft/s^2 or 9.81m/s^2
Assuming the Jeep stopped from 22mph in 1 second
F= 1387*9.81 = 13,606 N or 3058 pound force
So according to this it would take an accident equivalent of stopping from
66 mph in 1 sec to come close to shearing a 3/8" grade 8 bolt.
Given that most of my driving is highway 66mph is not that unlikely. Even if the bolt didn't break I still don't think I would risk it. Only if it was for trail only where the speeds never reach 10mph. Now as for the hood buckling before the hood...probably...but again I wouldn't risk it.... jmo though
The mass of a Jeep (conservative according to wikipedia) is 3057 lbs or 1387kg.
Acceleration (or deceleration in the event of an accident) is 32.2 ft/s^2 or 9.81m/s^2
Assuming the Jeep stopped from 22mph in 1 second
F= 1387*9.81 = 13,606 N or 3058 pound force
So according to this it would take an accident equivalent of stopping from
66 mph in 1 sec to come close to shearing a 3/8" grade 8 bolt.
Given that most of my driving is highway 66mph is not that unlikely. Even if the bolt didn't break I still don't think I would risk it. Only if it was for trail only where the speeds never reach 10mph. Now as for the hood buckling before the hood...probably...but again I wouldn't risk it.... jmo though
Thats what I am thinking, and if I did come to a complete stop at 66+mph in 1 second I would hope the hood would come through the windshield and finish me off cuz I am pretty sure I'd be a vegetable if it didnt.
04-23-2010 | 10:12 PM
#64
CF Veteran
Joined: Aug 2008
Posts: 6,588
Likes: 494
From: Chico, CA
Year: 1986
Model: Cherokee
Engine: 4.3L with headers and full 3" exhaust system
Here we go again with the hood spacers and "It won't happen to me". The truth of the matter is that with the back of the hood raised up like that it will not fold up like it is supposed to. It doesn't matter whether or not you have grade 8 or 12 or even Caterpillar bolts which are quite beyond that. They are going into grade 2 nuts tack welded on to sheet metal and will tear out. As for that bad of a wreck, anybody ever hit a deer. They come up over the hood and will force it back through the windshield and it will take your head off. This is truly a BAD mod, even if it is cheap and works.
04-23-2010 | 11:10 PM
#65
Former Sponsor
Joined: Mar 2010
Posts: 61
Likes: 0
From: Rockwall, TX
Year: 2001
Model: Cherokee
Engine: 4.0
spacers
If your just going into the "cowl" area it may not effect much just make sure to seal off any double wall seams with proper automotive seam sealer(its fire proof). however it may not do the same job as vents. Another option is to use some hood spacers. I cut holes in my hood and regret it now. Living in the great lakes area, the summers are not all too hot. So I saw no real differance in temps. Wish I would have used spacers first.
However do not leave them as if you wreck it does add another element of danger...safe wheeling is fun wheeling even on the interstate. If you see a change in temp that you like the hood vents will increase it..so take off the spacers and cut the holes.
Last edited by Colinjohns; 04-23-2010 at 11:15 PM.
04-29-2010 | 11:32 AM
#66
Junior Member
Joined: Sep 2009
Posts: 94
Likes: 0
From: michigan
Year: 2000
Model: Cherokee
Engine: 4.slow
I used some home heating vents from the home depot and i thought they looked pretty good. The only problem i had was when i was in PA and the rain eventually got into my sensors on top of the intake. so, if i did it again i would use some 4" by 12" vents and place them outside of the hood ridges. that way they will dissipate heat and any water that gets in will avoid the wiring. However i also moved my computer, so you may want to avoid that though as well. Hood spacers work, but vents look super sick. get some, cut up your hood, use some self tapping screws and space them evenly, itll look bad as hell. I still dont regret cutting up my hood, but i regret replacing it when i had all of the sensor/water issues. My new hood is likely to get the chop treatment soon. If i can get pics posted then there will be some.
04-30-2010 | 07:52 PM
#68
Senior Member
Joined: Dec 2009
Posts: 538
Likes: 3
From: zeeland mi
Year: 1997
Model: Cherokee
Engine: 4.0
https://www.cherokeeforum.com/f51/ho...ion-how-41967/ just read this much better than spaceing the hood
05-01-2010 | 12:36 AM
#69
CF Veteran
Joined: Sep 2009
Posts: 4,145
Likes: 0
XJs have Metal hoods. Unless its aftermarket. Either way the best way I know of to cut fiberglass is either a dremel with a cut-off wheel or the rotary cutting blade things.
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