Speedo Bounce
Thread Starter
Burning Brakes
Joined: Aug 2001
Posts: 1,060
Likes: 33
From: Eagleville PA
Speedo Bounce
Since I got my Vette back from having my engine replaced, and trans rebuilt they speedo needle bounces. As first it seemed to only be at high speeds, now it seems to do it all the time.
What could be the source of the problem? The cable, the speedo head, ??
Also, is it conicidence that this starting happening since I got it back, or could the work have f'ed something up?
:confused:
Thanks!
What could be the source of the problem? The cable, the speedo head, ??
Also, is it conicidence that this starting happening since I got it back, or could the work have f'ed something up?
:confused:
Thanks!
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Re: Speedo Bounce (adamw1979)
Since I got my Vette back from having my engine replaced, and trans rebuilt they speedo needle bounces. As first it seemed to only be at high speeds, now it seems to do it all the time.
What could be the source of the problem? The cable, the speedo head, ??
Also, is it conicidence that this starting happening since I got it back, or could the work have f'ed something up?
:confused:
Thanks!
What could be the source of the problem? The cable, the speedo head, ??
Also, is it conicidence that this starting happening since I got it back, or could the work have f'ed something up?
:confused:
Thanks!
:cheers:
Olivier
Safety Car
Joined: Feb 2002
Posts: 4,286
Likes: 4
From: Guam
Re: Speedo Bounce (adamw1979)
Speedo bounce is usually caused by a dry cable. I suggest pulling the cable out and lubing it. I normally pull the whole cable out and clean it first. Look for any frayed areas while it is out. If you find any bad spots, it is best to replace it.l like to use a very light grease. My choice is a munitions grease which I think contains some anti seize particles in it.
:cheers:
:cheers:
Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
Re: Speedo Bounce (adamw1979)
When I bought mine it seemed to be fine then it started to bounce and final just quit. Found out the speedo cable was laying against the exhaust pipe. Most have heated it up and made it sticky then just melted it.
Thread Starter
Burning Brakes
Joined: Aug 2001
Posts: 1,060
Likes: 33
From: Eagleville PA
Re: Speedo Bounce (Sharky Guam)
.... I suggest pulling the cable out and lubing it......
Melting Slicks
Joined: Apr 2000
Posts: 3,286
Likes: 8
From: San Jose California
Re: Speedo Bounce (adamw1979)
All of the above are good suggestions. Yet mine bounced for a different reason. The cable inside was being compressed between the tach head and the distributor gear. I am using the MSD tach drive dist. I ground off about 1/8" from the square tipped cable end and the tach needle is now perfect.
To test, try using a variable electric hand drill on the dist end of the cable. You need to use the reverse direction. Gently pull and push on the cable as it spins within the cable sheath. If you can see a difference when you gently pull back, revving the drill up and down, this may be your problem too. BTW, my Stanley 1/4" variable speed drill will only spin the tach to about 3500-4000 rpm.
Chuck
Chuck
To test, try using a variable electric hand drill on the dist end of the cable. You need to use the reverse direction. Gently pull and push on the cable as it spins within the cable sheath. If you can see a difference when you gently pull back, revving the drill up and down, this may be your problem too. BTW, my Stanley 1/4" variable speed drill will only spin the tach to about 3500-4000 rpm.
Chuck
Chuck
Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
Re: Speedo Bounce (Chuck Harmon)
Chuck
That's for tach not speedo right? His problem is speedo but still my apply. I had no problems with my Pro-Billet set up, must have been inner your cable length.
[Modified by Fevre, 12:26 PM 8/14/2002]
That's for tach not speedo right? His problem is speedo but still my apply. I had no problems with my Pro-Billet set up, must have been inner your cable length.
[Modified by Fevre, 12:26 PM 8/14/2002]
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Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
Re: Speedo Bounce (Chuck Harmon)
But grinding 1/8th inch of the tach cable won't do for much for him. :p:
Just wanted to clarify that his problem was with the speedo and you described a fix for a tach problem. If the problem just appeared and none of his componants changed then the cable length will be a non-issue. Again I was just trying to clarify that you knew his problem was with the speedo system not tach system and following your fix to the 't' would do nothing to fix his tach problem. No flame intended, at least not the first post. :)
Just wanted to clarify that his problem was with the speedo and you described a fix for a tach problem. If the problem just appeared and none of his componants changed then the cable length will be a non-issue. Again I was just trying to clarify that you knew his problem was with the speedo system not tach system and following your fix to the 't' would do nothing to fix his tach problem. No flame intended, at least not the first post. :)
Le Mans Master
Joined: Aug 2000
Posts: 9,341
Likes: 0
From: Las Vegas Nevada
Re: Speedo Bounce (Fevre)
My speedo has bounced badly below 15MPH and a little bit above 15MPH since I bought the car... I've replaced both the upper and lower Speedometer cables and rebuild the Cruise control transducer and still haven't fixed the problem. As soon as Zip gets some more 140MPH speedometers in stock I'll be buying one of them and if that one bounces well, I don't know what I'll try next... lol
Melting Slicks
Joined: Apr 2000
Posts: 3,286
Likes: 8
From: San Jose California
Re: Speedo Bounce (Fevre)
Fevre,
No flame taken. But the same cable design and head assembly is used for both. The sheath can change in its effective length through age, as parts take a different bend, etc. which can create the compression of the cable in the speedometer just like it did with my tach. It is so easy to use a hand drill to check. I wouldn't suggest nipping even 1/100" without first verifying that this would cure the problem.
I had heard all of the normal responses listed above, but they didn't work for me. My problem ended up costing no money to repair and was very easily cured. Pulling a speedo when the normal cures don't work is a royal PITA, and is not cheap. What a shame to go through all that only to have it still bounce.
Chuck
P.S. You didn't burn me as badly as I might have burned you for advising the repair of one thing when it was in fact something else. Kind of like suggesting repairing the front tire when the back tire is flat. But I swear the front tire was closer and therefore easier to repair!
:conehead
No flame taken. But the same cable design and head assembly is used for both. The sheath can change in its effective length through age, as parts take a different bend, etc. which can create the compression of the cable in the speedometer just like it did with my tach. It is so easy to use a hand drill to check. I wouldn't suggest nipping even 1/100" without first verifying that this would cure the problem.
I had heard all of the normal responses listed above, but they didn't work for me. My problem ended up costing no money to repair and was very easily cured. Pulling a speedo when the normal cures don't work is a royal PITA, and is not cheap. What a shame to go through all that only to have it still bounce.
Chuck
P.S. You didn't burn me as badly as I might have burned you for advising the repair of one thing when it was in fact something else. Kind of like suggesting repairing the front tire when the back tire is flat. But I swear the front tire was closer and therefore easier to repair!
:conehead
Race Director
Joined: Mar 2001
Posts: 12,577
Likes: 0
From: I live in my Hubby's little world
Re: Speedo Bounce (adamw1979)
Adam..been having that problem with the tach...happened every mornin when it is ''cold'' but as things warm up..then it works again prorperly....sometimes the speedo makes some really strange noises!!!
Sounds like another ''project'' to add to all the others!
Sounds like another ''project'' to add to all the others!
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Re: Speedo Bounce (LakotasRose)
when either one startws bouncing, like Chuck Harmon says....the heads are the same thing, mechanically....now the point is...IF it's not the cable...just replace it with new one, trimme and fit and lubed right...and it's still bouncy...it's the head...every time...
NOW to fix the heads, might as well do both of them while your' in there....
pull that damm dash assy...heve fun....6 pak will dooooooo......
now with a jewlers screwdriver set take the head end apart...pull the needle off directly, it's a press fit, may be tight as hell after 30 years, but it's still a press fit...take off the dial...now we are down to the casting..housing//take it apart far as you can and last step is the aluminum piece fitting over the mechanism and two screws into the zinc....
take that off, and you find a pin bearing in there...it needs a bit of oil....
that's it...oil the rest of it, and put it all back together carefully....
GENE
NOW to fix the heads, might as well do both of them while your' in there....
pull that damm dash assy...heve fun....6 pak will dooooooo......
now with a jewlers screwdriver set take the head end apart...pull the needle off directly, it's a press fit, may be tight as hell after 30 years, but it's still a press fit...take off the dial...now we are down to the casting..housing//take it apart far as you can and last step is the aluminum piece fitting over the mechanism and two screws into the zinc....
take that off, and you find a pin bearing in there...it needs a bit of oil....
that's it...oil the rest of it, and put it all back together carefully....
GENE
Race Director
Joined: Mar 2001
Posts: 12,577
Likes: 0
From: I live in my Hubby's little world
Re: Speedo Bounce (mrvette)
Thanks mrvette..
sounds like a ''project'' for Hubby the next weekend I have to work!! :lol: I HATE electrical/dash stuff!! get too frustrated to fast and tend to ummm.......well get frustrated!!!!! :lol:
sounds like a ''project'' for Hubby the next weekend I have to work!! :lol: I HATE electrical/dash stuff!! get too frustrated to fast and tend to ummm.......well get frustrated!!!!! :lol:
Race Director
Joined: Aug 2000
Posts: 10,854
Likes: 3
From: HONOLULU HAWAII
Re: Speedo Bounce (adamw1979)
I had this problem.......I replaced the speedo gear....however I think the problem was caused when the mechanic put other trans in he never poped the speedo gear in all the way, and securely bolted the clamp on.....After I replaced the gear....I made sure it was in all the way, and secured solid with the holding clamp.....checked the needle during a run.....smooooth....Also make sure you snug the cable cap into the trans port. :seeya Cappy
[Modified by 8T1-7T9 BIONIC VETTE, 8:55 PM 8/14/2002]
[Modified by 8T1-7T9 BIONIC VETTE, 8:55 PM 8/14/2002]
Le Mans Master
Joined: Apr 2002
Posts: 7,281
Likes: 5
From: Boston
Re: Speedo Bounce (8T1-7T9 BIONIC VETTE)
Why don't you go ahead and get a new one.
Here's a good place:
REDLINE GAUGE and CLOCK REPAIR (no web site)
1-800-375-2310, attn: JOHN
This company will send you a complete 140mph Speedo with installation directions. One major advantage is they will send you a new one within a week, and wait for you to install it, (within 10 days, no core charge) to send yours, NO DOWN TIME!!!!
ALL THIS FOR: $57.00
For $57 it's not worth the headache. :cheers:
Paul
Here's a good place:
REDLINE GAUGE and CLOCK REPAIR (no web site)
1-800-375-2310, attn: JOHN
This company will send you a complete 140mph Speedo with installation directions. One major advantage is they will send you a new one within a week, and wait for you to install it, (within 10 days, no core charge) to send yours, NO DOWN TIME!!!!
ALL THIS FOR: $57.00
For $57 it's not worth the headache. :cheers:
Paul
Intermediate
Joined: Aug 2002
Posts: 27
Likes: 0
Re: Speedo Bounce (adamw1979)
My speedo used to bounce a little at first then it progresively got worse. Just recently it stopped working, so I called a local Bob's speedo and they told my they could fix it. They said it was the magnito. Good Luck
Race Director
Joined: Nov 2000
Posts: 11,872
Likes: 12
From: Waterloo ontario Canada
Re: Speedo Bounce (adamw1979)
Mine started bouncing a slow speeds so I decided to lubricate it. I reached under the dash and found the back of the speedometer cable where is goes onto the speedometer. You push the clip towards the speedometer and pull the cable off the back at the same time. This is tricky but it does work. Then you pull the cable out from under the dash to where you can see the end. Then you can grab the end of the speedo cable and pull it out. Clean it then reinstall lubing it as you feed it back in. I lubed all the way to the end but this could lead to oil wicking up into the speedometer itself. I think they recommend stopping say a foot before the speedometer to protect it.
Worked for me. My speedometer is rock steady.
Norval
Worked for me. My speedometer is rock steady.
Norval
Racer
Joined: Dec 2000
Posts: 289
Likes: 0
From: Wisconsin Rapids, WI USA
Re: Speedo Bounce (adamw1979)
Do you have cruise control? Mine bounced too, then it just quit. The transducer for the cruise was bad. It is a poor design by GM, the cable is always under a side load and takes the bushings out. Try to lube it first. It is obviosly binding/dragging somewhere. Perhaps someone at the tranny shop thought they were being nice and cleaned it off for you.
