Yes. The goal is to measure the radius of the tire with the weight of the Jeep on it. Then double that number.
05 Flame Red TJ Build
- Thread starter JMT
- Start date
I think the "best" way to get an accurate rolling radius of the tire is to make a chalk mark on it and the floor, then roll forward until the mark is in the same spot, one revolution ahead of where you were. Mark the new spot on the floor, then measure the distance between the two marks on the floor. That will be your tires rolling circumference. Since pi*Diameter = Circumference, if you Divide the Circumference by Pi, you'll have the diameter. Use that number...
I can tell you that the last time I took this measurement using Grimmjeeper, I came up with a diameter of 31.6" to match the gps speed and engine rpm I recorded with my phone connected to the computer. This matched the ~15.8" hub height I was reading with a tape measure.
This is the same idea as the chalk method, except that instead of a few full rolls of the tire you are getting hundreds of rolls that greatly reduce the errors.
This is the same idea as the chalk method, except that instead of a few full rolls of the tire you are getting hundreds of rolls that greatly reduce the errors.
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My rig has an S in the 8th VIN position and is an 05 TJ. I could not find out if the engine manufacture date was between Oct 25, 2004 and Feb 1, 2006, but people have had OPDA issues outside of those parameters, so I replaced it this AM. Takes about 1hour. The hardest part is turning the engine to get the holes to line up and getting the bracket back on that holds the OPDA in place. Thanks to @Chris again for the write up and video. No codes flashed up. Oil pressure looks normal. The old one looks fine. Worm gear not worn. Can anyone see anything wrong with it?
OPDA looks fine to me!
Did you notice any where on the gear inside the block that the OPDA is driven by?
Did you notice any where on the gear inside the block that the OPDA is driven by?
I didn’t even
. I should have shined a flashlight 
down in there. You live and learn. I could pull it off, but that stupid bracket is hard to get back on.
I’m a little bit proud to say my rig has parts of other forum members rigs on it. @bobthetj03 driveshaft, @ac_ speedo, @JamesAndTheSahara quick disconnects. I consider it a Mosaic. Maybe that’s the name it should be given. It’s the only name that seems natural.
You should get hood stickers made where the "rubicon" goes to say "mosaic" That would be cool.
One man’s trash is another man’s treasure!
You got the CA’s if I recall. Who got the Rokmen Skid? There was the JCR bumper! Tons of good stuff went out. But he’s mid-arm now and we’re short arm.
So clearly @Chris has the advantage.
I didn’t even
I wouldn't worry about it. Usually if the gear on the camshaft is damaged, the drive gear on the end of the OPDA would be damaged as well.
Geez, the last couple of days have been hell. I went to change the oil and rotate my tires. While I was under there I discover that I'm only recovering 4.5 quarts of oil. WTH? Then while I'm rotating the tires I notice my clearances have changed after the Dana 44 axle swap. Now my shocks are interfering with the spring perch. They're dented. Driver's side worse than passenger. Suck. I also notice my front diff is weeping, due to my breaking the seal and putting on the hard hat. So I start looking for the OEM bolts for the diff cover, because due to the thickness of the HardHat, they send you some longer bolts, but they require a hex key to tighten down and I thought maybe they just didn't get enough torque to seal the diff. After an hour of looking and cleaning up all sorts of crap, I find them. I go to trade them out and the last one I strip! Suck #2. As I was cleaning I found a small gasket. It went to the OPDA I put in last week. Now I'm like, Hmmmm...that's why I'm leaking oil. Suck #3. Sure enough, open the engine bay and that's why. So, I pull the OPDA 1" above the opening, slip the gasket on and put it back just like I find it. An hour later I go to start the Jeep, NOT. At this point I'm thinking I should just not touch the thing for the sake of not finding anything else wrong. I can’t sleep so I wake up and start researching at 4:30am. OPDA most important, who the hell cares if you can't go anywhere. By 6:45am I'm ready to fix this thing, armed with some knowledge thanks to @mots and @Chris and some other people on the OPDA threads. LOL. There are many. I need to rotate the OPDA housing, just get it around 4 o'clock, that's what the FSM says. So, I literally adjust it about 100 times trying to find a sweet spot. I got it to start sometimes, but never smooth starts and I'm throwing codes, p0016, p0344, and even p0522. WTH? That's it. Back to the drawing board. So I end up going back to the FSM, finding the way to set the Top Dead Center, because by now I've lost it. Aligning the tab by your harmonic vibration pulley with the notch on the pulley itself. Then I take out the OPDA, align the two holes, reinstall by slightly altering the cam shaft and it drops in, I crank the Jeep and it roars like a KING. GEEZE (I know I misspelled that, but I don't care). Then to the diff, try to fix that bolt by rethreading it. That seemed to sort of work. I got a bolt in and torqued the others down good. We'll see if it holds. Otherwise I'll have to drain the fluid and re-seal with RTV or a gasket. I'm thinking a gasket next time. Then I tried to turn my shocks upside down so I don't have to do lower shock relocation brackets. This will take some time to figure out because I have to remove the bar pin and the bushing and put them on opposite ends. At least I'm up and running. Man that was a lot of SUCK. I almost put the Jeep up for sale during this fiasco. Some lucky bastard would have gotten a kick ass rig.
I am putting airbags in my GMC and a new bathroom vent/fan in my camper, then I am ready. Now my pressure is hoping nothing breaks between now and then.
Yoo hoo.... next time the jeep throws u a curve ball and u get mad at it, I mean really mad... u have my contact info.lol
@JMT tho all that was frustrating, scary n all, you worked thru it just fine.
There's plenty of jeep heads on here to help out. We all go thru some jeep panic, some more than others. It was just your turn.
It's all part of bein a jeep head.
Now u have more experience under ur jeep belt.
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