Home » Public Forums » GMCnet » Speedometer differences
| Speedometer differences [message #350507] |
Thu, 05 December 2019 21:04  |
Shawn Bennear
Messages: 43
Registered: February 2007
Location: Edinburg, PA
Karma: -1
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My speedometer in my 77 PB is acting up. I have a spare, but the one in the coach is a 85 mph one, and my spare one is the 120 one. Is there something I need to change other than the speedometer, or is it just simply changing the speedo?
Shawn
http://www.gmcmotorhomeworld.com
1977 Palm Beach, 403 V8 w headers.
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| Re: Speedometer differences [message #350509 is a reply to message #350507] |
Thu, 05 December 2019 21:39  |
C Boyd
Messages: 2629
Registered: April 2006
Karma: 18
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Senior Member |
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Wow, 3 23'ers.. I believe the speedo gears are the same and you should be able to swap heads as in your 2nd coach.
Shawn Bennear wrote on Thu, 05 December 2019 22:04My speedometer in my 77 PB is acting up. I have a spare, but the one in the coach is a 85 mph one, and my spare one is the 120 one. Is there something I need to change other than the speedometer, or is it just simply changing the speedo?
Shawn
C. Boyd
76 Crestmont
East Tennessee
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| Re: Speedometer differences [message #350520 is a reply to message #350507] |
Fri, 06 December 2019 08:52 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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Shawn,
I have a careful caution for you.
If your speedometer is acting strangely, it is often the cable. Particularly with headers, the cable gets too close to the exhaust heat.
So, before you do much else (and you might as well anyway), disconnect both ends of the lower cable and confirm that it spins freely in the housing. If it does not, lube it NOW.
Just so you know, if the cable jams up, it can take out the governor gear and then you are stuck in first gear until you remove the left header to get at the gear and change it out for the spare that you should carry.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: Speedometer differences [message #350521 is a reply to message #350507] |
Fri, 06 December 2019 09:04 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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"acting up"?
Bounce tracking with vehicle speed is cables
Swing with road bumps or maneuvers is loss of damping in speedo itself.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] Speedometer differences [message #350523 is a reply to message #350522] |
Fri, 06 December 2019 09:54 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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Sounds like a 40+ year old instrument that is in need of being cleaned,
lubricated, and adjusted by someone with delicate hands, good vision, and
knowledge of instrument repair and maintenance.
It also needs its cable(s) carefully removed from their sheaths,
lubricated, and routed well away from header heat. If you freeze up a
cable, it almost always strips out the nylon governor gear. If that
happens, you will be driving home in low gear. If you do have headers, most
often the drivers side will have to be removed to accomplish this. This
many times results in broken manifold bolts, stripped threads, etc. Grease
is cheap and easy to use. Your choice.
Jim Hupy
Salem, Oregon (presently at the GMC CASCADERS Christmas rally at LaConnor,
Washington.)
On Fri, Dec 6, 2019, 7:32 AM Shawn Bennear via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Its really kind of odd... it bounces at lower speeds, then seems to float
> around at higher speeds (50+)
>
> --
> http://www.gmcmotorhomeworld.com
>
> 1977 Palm Beach, 403 V8 w headers.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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| Re: [GMCnet] Speedometer differences [message #350525 is a reply to message #350523] |
Fri, 06 December 2019 10:27 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Best to do the lube thing and tie the cable away from the exaust.
Keep eye on the cruse control as well as they do present a problem.
On Fri, Dec 6, 2019 at 7:51 AM James Hupy via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Sounds like a 40+ year old instrument that is in need of being cleaned,
> lubricated, and adjusted by someone with delicate hands, good vision, and
> knowledge of instrument repair and maintenance.
> It also needs its cable(s) carefully removed from their sheaths,
> lubricated, and routed well away from header heat. If you freeze up a
> cable, it almost always strips out the nylon governor gear. If that
> happens, you will be driving home in low gear. If you do have headers, most
> often the drivers side will have to be removed to accomplish this. This
> many times results in broken manifold bolts, stripped threads, etc. Grease
> is cheap and easy to use. Your choice.
> Jim Hupy
> Salem, Oregon (presently at the GMC CASCADERS Christmas rally at LaConnor,
> Washington.)
>
> On Fri, Dec 6, 2019, 7:32 AM Shawn Bennear via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> Its really kind of odd... it bounces at lower speeds, then seems to float
>> around at higher speeds (50+)
>>
>> --
>> http://www.gmcmotorhomeworld.com
>>
>> 1977 Palm Beach, 403 V8 w headers.
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmcrvparts.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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