Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: IrishCJ6 on April 23, 2011, 10:48:18 AM

Title: CJ Speedo
Post by: IrishCJ6 on April 23, 2011, 10:48:18 AM

I think my speedo that came with the Jeep is knackered, the dial needle sits at 20 MPH mark instead of zero at rest? Is my assumption right? Any ideas where I would find a replacement, mine is the old style without the fuel gauge and temp gauge.

Also how is the speedo calibrated for different gearing/wheel sizes

Title: Re: CJ Speedo
Post by: Nosebolt on April 23, 2011, 11:07:11 AM

as with most of the original gauges, the speedo is an optimistic estimate of what your actually doing. there are places that will recalibrate but we have a calc on the site (http://www.birtydastards.com/frm/index.php?action=ezportal;sa=page;p=8) where you can enter -

Original Tire Diameter:    New Tire Diameter:    Speedometer Reading (M.P.H.):  and it will tell you the Corrected Speed(M.P.H.):

so for example if you have 33s and speedo is correct at 30MPH the fitting 35s will mean when you are showing 30 you are travelling at 31.818 MPH

the easy answer is then to put a mark on the speedo at 30, 50 etc

Title: Re: CJ Speedo
Post by: IrishCJ6 on April 23, 2011, 11:10:06 AM

Thats all good but I have no idea what the original wheel sze is, spose I could always use the GPS to find ot as well, wasn't sure if there was different drive gears to alter the reading

Title: Re: CJ Speedo
Post by: ferretjuggler on April 23, 2011, 11:21:19 AM

There must be different drive gears available.

These Jeeps came with a choice of axle ratios didn't they :017:

Title: Re: CJ Speedo
Post by: Nosebolt on April 23, 2011, 11:22:56 AM

original fit was a 670-15 cross ply, this had a dia of 726mm or 28.58"

going by that on 35s when std speedo reads 30 you are doing 36.7, bear in mind all of this is subject to the rest of the gearing being standard

Title: Re: CJ Speedo
Post by: Nosebolt on April 23, 2011, 11:44:42 AM

hopefully I will be corrected or confirmed but from a quick read it seems there are 2 std CJ speedo gearings identified by the face, 0-85 & 0-90, both also available in KPH, but can only find replacements with fuel and temp, now heres the bit I'm not to sure about, there may have been some early 6's that had 3B speedos fitted, a pic and some dimensions would help if available

Title: Re: CJ Speedo
Post by: IrishCJ6 on April 23, 2011, 11:59:19 AM

Here is the photo of the speedo, don't have a measurement though

(https://birtydastards.com/frm/proxy.php?request=http%3A%2F%2Fi274.photobucket.com%2Falbums%2Fjj254%2Fandrewspalding%2Fspeedo.jpg&hash=13fbe1655da65eb7a151466008ded80f5da23a5a)

So do you think its busted?

Title: Re: CJ Speedo
Post by: Bulldog67 on April 23, 2011, 12:22:45 PM

http://store.philaboat.com/philboat/details.php?ITEM=8178120&ProdClass=Antennas,+Radios+and+Electronics (http://store.philaboat.com/philboat/details.php?ITEM=8178120&ProdClass=Antennas,+Radios+and+Electronics)

Title: Re: CJ Speedo
Post by: ferretjuggler on April 23, 2011, 12:56:33 PM

Mr Phillips, wash down your keypad down with soap and water at once!

Most of us CJ owners are happily lurking in a sort of  pre-microchip stone age type existence thankyou.

Not a digit in sight :greggmo:

Title: Re: CJ Speedo
Post by: Bulldog67 on April 23, 2011, 03:32:55 PM

I am the future  :hysterical:

Title: Re: CJ Speedo
Post by: Mike Pavelin on April 23, 2011, 07:57:26 PM

Replace the drive gear to calibrate the speedo. Here are the part numbers......                                                                                          J321 2724 1 24 Teeth - White
J321 2725 1 25 Teeth - Blue
J321 2726 1 26 Teeth - Red
J321 2727 1 27 Teeth - White
J321 2728 1 28 Teeth - Blue
J321 2729 1 29 Teeth - Black
J321 2730 1 30 Teeth - Yellow
J321 2731 1 31 Teeth - Green
J321 2732 1 32 Teeth - Black
J321 2733 1 33 Teeth - Yellow
J321 2734 1 34 Teeth - Green
J321 2735 1 35 Teeth - Orange
J321 2736 1 36 Teeth - Red
J321 2738 1 38 Teeth - Blue
J323 0221 1 39 Teeth - Green
J323 0222 1 40 Teeth - Orange
5300 1488 1 41 Teeth - Red
5300 1489 1 42 Teeth - White
J323 8143 1 43 Teeth - Blue
J323 8144 1 44 Teeth - Black

Title: Re: CJ Speedo
Post by: Bubba on April 23, 2011, 08:02:27 PM

i dont thunk they will work  as i they aree for post amc jeeps

Title: Re: CJ Speedo
Post by: Bulldog67 on April 23, 2011, 09:38:32 PM

Quote from: Mike Pavelin on April 23, 2011, 07:57:26 PM

Replace the drive gear to calibrate the speedo. Here are the part numbers......                                                                                          J321 2724 1 24 Teeth - White
J321 2725 1 25 Teeth - Blue
J321 2726 1 26 Teeth - Red
J321 2727 1 27 Teeth - White
J321 2728 1 28 Teeth - Blue
J321 2729 1 29 Teeth - Black
J321 2730 1 30 Teeth - Yellow
J321 2731 1 31 Teeth - Green
J321 2732 1 32 Teeth - Black
J321 2733 1 33 Teeth - Yellow
J321 2734 1 34 Teeth - Green
J321 2735 1 35 Teeth - Orange
J321 2736 1 36 Teeth - Red
J321 2738 1 38 Teeth - Blue
J323 0221 1 39 Teeth - Green
J323 0222 1 40 Teeth - Orange
5300 1488 1 41 Teeth - Red
5300 1489 1 42 Teeth - White
J323 8143 1 43 Teeth - Blue
J323 8144 1 44 Teeth - Black

gordon bennett  :icon_eek:

my vote says live with it  :003:

Title: Re: CJ Speedo
Post by: Mike Pavelin on April 23, 2011, 10:15:05 PM

Quote from: V8 Bubba on April 23, 2011, 08:02:27 PM

i dont thunk they will work  as i they aree for post amc jeeps

They're from the '81-'86 parts list

Title: Re: CJ Speedo
Post by: Bubba on April 23, 2011, 11:35:32 PM

well cool mike i had no idea i take back my first statement

Title: Re: CJ Speedo
Post by: dieselj20 on April 24, 2011, 10:37:24 AM

late type gears only fit 81 on . Early gears go from 1941 to late 1980

Title: Re: CJ Speedo
Post by: IrishCJ6 on April 26, 2011, 08:36:26 PM

Ok so I decided to open the speedo up and look at why the needle is not sitting at zero, unfortunatley it looks like I was not the first to open it up as the speedo does infact have the 2 small water temp/fuel gauges installed however the previous owner had blanked these off using black card as they were not used with the revised motor/trans setup. So I'm looking for a replacement speedo if someone has one

Title: Re: CJ Speedo
Post by: Bubba on April 26, 2011, 09:41:50 PM

hmmm is that so

Title: Re: CJ Speedo
Post by: IrishCJ6 on April 26, 2011, 09:44:16 PM

Does that mean you may have one Bubba