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Rebuilt 225 in the jeep and now looking for jetting at higher altitude for Colorado

Discussion in 'Early CJ5 and CJ6 Tech' started by mntbuggy, Jul 9, 2015.

  1. Jul 9, 2015
    mntbuggy

    mntbuggy Member

    Andale , Ks
    Joined:
    Nov 21, 2007
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    We are planning a trip to Rocky Mountain National park in Colorado in August and I was curious what some of you are running for Jetting? This is my first trip to the mountains so I will be playing on the simple trails around Estes Park. Looks like the elevations will typically be around 7-10,000 ft . I am currently in flat land KS around 1500 ft. From what I can read you should drop the jets 1 size for every 2,000 ft. I am currently running a 390 holley (new one , so much for the smoking deal I got :cry:) with the following Mains 51 , Power valve 6.5 ( my vac is aprox 14 -15 lbs), Center squirter 28 ( changed form 25 to get rid of stumble at cruise speed). Still need to do a little tweaking but it is close. I am going to put the off road vent tube, spring loaded needle and seats, and the whistle tube for the vent to get to front of bowl. The motor has a 252 comp cam, offy 360 intake, HEI dist. I have 31" tires and 3:73 gears.
    By doing the calculation I should use drop the mains about 3 to 4 sizes to a 47 or 48????

    Thanks in advance!!!

    Here are a couple pics of the motor.

    [​IMG]


    [​IMG]



    [​IMG]
     
    mntbuggy, Jul 9, 2015
    #1
  2. Jul 10, 2015
    colojeepguy

    colojeepguy Colorado Springs

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    Re: Rebuilt 225 in the jeep and now looking for jetting at higher altitude for Color

    Your jetting sounds about right...but what is just as important is timing.
    You'll want to bump your initial timing up about 6-8 degrees from the factory spec.
     
    colojeepguy, Jul 10, 2015
    #2
  3. Jul 10, 2015
    uncamonkey

    uncamonkey Member

    Greeley CO
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    Re: Rebuilt 225 in the jeep and now looking for jetting at higher altitude for Color

    You ask a lot of questions here and I know nothing about that carb. Both of my Jeeps are adjusted for my 4960 elevation, or is that 4860, who cares? both are 2GC or a 2G rochester.
    Lately Iv'e noticed more issues with the float level being too high on a trail. At 11,000 feet I do have to shift the 3B out of OD at the tunnel.
    I wouldn't be all that concerned about about it but you could bring along a set of smaller jets if you would be happier about it. As Doug said, the old rule of thumb was to advance the timing one degree of each 1000 ft of elevation. Never done that and a V6 will run fine. By the way. nice looking Jeep.



















    .
     
    uncamonkey, Jul 10, 2015
    #3
  4. Jul 10, 2015
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
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    Re: Rebuilt 225 in the jeep and now looking for jetting at higher altitude for Color

    Doug - do you mean 6-8*BTDC or 11-13*BTDC (given factory spec of 5*BTDC)?

    Sorry - can't help with carb, but yea if it was easy for day trips, I would switch jets for high mountain runs even with DDing in Denver. Agree with Uncamonkey about the float setting on the 2G - seems as mine is a bit too high on trail and gets that sort of surging/flooding on steep climbs.
     
    FinoCJ, Jul 10, 2015
    #4
  5. Jul 10, 2015
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
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    Re: Rebuilt 225 in the jeep and now looking for jetting at higher altitude for Color

    Timing and float are the ones I change on a trail as I would go up. I'll have to see what I was running in my 390s when I get home (in GA right now) but 49 sticks in my head for mains so you sound close.

    I run 8* to 12* with the HEI on my rigs.
     
    Warloch, Jul 10, 2015
    #5
  6. Jul 10, 2015
    colojeepguy

    colojeepguy Colorado Springs

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    Re: Rebuilt 225 in the jeep and now looking for jetting at higher altitude for Color

    6-8 degrees above the factory spec.
    Honestly, for my 6000 foot elevation, plus the fact that some of the trails I do can be double that, I advance the timing as much as possible without pinging. I think I'm up around 14 or 15 degrees initial if memory serves...
     
    colojeepguy, Jul 10, 2015
    #6
  7. Jul 10, 2015
    mntbuggy

    mntbuggy Member

    Andale , Ks
    Joined:
    Nov 21, 2007
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    Re: Rebuilt 225 in the jeep and now looking for jetting at higher altitude for Color

    Thanks for all the advice. I had never heard of the timing before. I had been around 8 and I went ahead and bumped it up to 10 for now and will see how it does. I will take the light with me !!! just got done doing a brake job on it. Figured it was about 12 yrs ago I did it, no more miles than I put on it the shoes were fine but the master cyl was pitted and had to be replaced, the wheel cylinders cleaned up with new cups. I did Silicone fluid this time so shouldn't have the pitting in the future. Went ahead and packed the front wheel bearings while I had it apart. Thanks to the forum I learned about 'Corn Head Grease" and filled the front knuckles with it maybe it will not mark its spot as bad. I also added new shoulder harness for the front seats and new lap belts for the kids seat. This trip is getting more expensive!!! Oh well it will be good for many more years!

    Thanks again
    Mike
     
    mntbuggy, Jul 10, 2015
    #7
  8. Jul 10, 2015
    uncamonkey

    uncamonkey Member

    Greeley CO
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    Re: Rebuilt 225 in the jeep and now looking for jetting at higher altitude for Color

    As said, I know nothing about that carb but neither of my Jeeps complain at any altitude and isn't that why you have a V6? The old L head did take a bit of tweaking to get it to run right at altitude. I wouldn't be as worried about it as you are. The 3B has done many trips to Moab, the 11,000 foot passes didn't seem to bother it much other than I noticed some lack in power. I get that in my turbo charged diesel too, so not too surprising.
     
    uncamonkey, Jul 10, 2015
    #8
  9. Jul 11, 2015
    lafester

    lafester Sponsor

    loveland, co
    Joined:
    Sep 24, 2002
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    Re: Rebuilt 225 in the jeep and now looking for jetting at higher altitude for Color

    Check out pole hill rd and storm mtn. Pretty much all there is around there but fun none the less.
     
    lafester, Jul 11, 2015
    #9
  10. Jul 11, 2015
    mntbuggy

    mntbuggy Member

    Andale , Ks
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    Re: Rebuilt 225 in the jeep and now looking for jetting at higher altitude for Color

    Just have heard so may horror stories over the years about coming from an low elevation 1500 ft to the mountains of 4-10,000 that the carbs run super fat or not at all. I just am playing it on the safe side. When I bought the jeep 25 yrs ago never gave the V6 much thought it was just a play toy for cruising around. Guess it still is. This is my first trip with the jeep to the mountains on vacation with the family and the last thing I want is to have the jeep not run at the higher altitudes
     
    mntbuggy, Jul 11, 2015
    #10
  11. Jul 11, 2015
    mntbuggy

    mntbuggy Member

    Andale , Ks
    Joined:
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    Re: Rebuilt 225 in the jeep and now looking for jetting at higher altitude for Color

    lafester Thanks for the suggestions. A friend sent me to http://www.traildamage.com/. It is a good ref for the trails and what to expect. Pole hill rd had been recommended. Had not heard about storm mtn
     
    Last edited: Jul 11, 2015
    mntbuggy, Jul 11, 2015
    #11
  12. Jul 11, 2015
    colojeepguy

    colojeepguy Colorado Springs

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    Re: Rebuilt 225 in the jeep and now looking for jetting at higher altitude for Color

    Also check out http://bushducks.com/tripreps/passopen.htm for current trail conditions.
     
    colojeepguy, Jul 11, 2015
    #12
  13. Jul 11, 2015
    mntbuggy

    mntbuggy Member

    Andale , Ks
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    mntbuggy, Jul 11, 2015
    #13
  14. Jul 11, 2015
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
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    Re: Rebuilt 225 in the jeep and now looking for jetting at higher altitude for Color

    There are a lot of trails in that area. Be aware that some of the trail damage reports are from before the massive floods almost 2 years ago so the conditions may have changed and some trails were closed and still waiting repair.

    Another place to get info is front range 4x4. Its a local wheeling group that is very friendly. I run my ecj5 with them a lot (same username as here). Can browse trip reports for info or even join for a run.
     
    FinoCJ, Jul 11, 2015
    #14
  15. Jul 12, 2015
    mntbuggy

    mntbuggy Member

    Andale , Ks
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    Re: Rebuilt 225 in the jeep and now looking for jetting at higher altitude for Color

    Added it to my favorites thanks!!
     
    mntbuggy, Jul 12, 2015
    #15
  16. Jul 13, 2015
    army grunt

    army grunt Member

    Georga USA
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    Re: Rebuilt 225 in the jeep and now looking for jetting at higher altitude for Color

    Great looking CJ, Good luck on ride.
     
    army grunt, Jul 13, 2015
    #16
  17. Jul 13, 2015
    mntbuggy

    mntbuggy Member

    Andale , Ks
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    Re: Rebuilt 225 in the jeep and now looking for jetting at higher altitude for Color

    Thanks
     
    mntbuggy, Jul 13, 2015
    #17
  18. Jul 13, 2015
    bcurtman

    bcurtman Member

    Rosebud, MO
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    Re: Rebuilt 225 in the jeep and now looking for jetting at higher altitude for Color

    That is one sharp jeep! Try to keep the damage down!
     
    bcurtman, Jul 13, 2015
    #18
  19. Jul 18, 2015
    lafester

    lafester Sponsor

    loveland, co
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    Re: Rebuilt 225 in the jeep and now looking for jetting at higher altitude for Color

    I'll be on the lookout for a bright orange jeep with Kansas plates.
     
    lafester, Jul 18, 2015
    #19
  20. Jul 19, 2015
    mntbuggy

    mntbuggy Member

    Andale , Ks
    Joined:
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    Re: Rebuilt 225 in the jeep and now looking for jetting at higher altitude for Color

    That's the one good thing about a bright orange jeep its easy to find !!!!

    No silly stuff this is my first time in the mountains with the jeep so I will be on the easy trails
     
    mntbuggy, Jul 19, 2015
    #20
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