My 71 Duster work in progress

Dr.Jass said:
The factory lubricant in the needle-shaft bearings gets sticky with age. That's the most-likely problem; it happens to tachometers as well. As far as I know you don't really have access to the one nearest the face without removing the face itself. I would probably try something like Lock-Ease, aiming the straw in there as close as you can. Then work the needle back and forth via the drum (so you don't upset the needle's at-rest position and hence, accuracy). Rinse, repeat.

Yeah, you'll have little choice but to disassemble the cluster to do it. While you're in there, try the same trick for the fly-magnet bearings. A squeaking speedometer will drive you nuts.

Auto Instruments charges something like $250 to disassemble and re-lubricate the needle and fly-magnet shafts.
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Nah if it takes all that it will be just fine like it is.
 
I don't know if that's all it takes, but I'd sho' 'nuff try it prior to dropping that kind of money on a squeak. 😁

Lock-Ease is messy shit. You were warned.
 
I'm guessing just shoving the straw off a can of WD-40 in the cable hole and giving it a blast is a bad idea. :D

If the speedo doesn't start sticking at random places I ought to be able to use it as is. Maybe running it for a while will free it up. Maybe?

I checked the OP switch too, of course there's nothing wrong with it. The light connects to a trace from the PCB so tracing the wires is going to be difficult at best. It looks like if I take the seat out again I should be able to get the bulb holder in and out so I can check that, and maybe get a better view of the wiring I moved to see if anything is disconnected.

I did find a fair deal on a Holley 3310 that I'm going to eventually use to replace that 850 DP. If anybody needs the DP, let me know.
 
The needle isn't likely to free up much in use--it neither moves that much nor that quickly. Blasting Lock-Ease (or similar) down the cable is a good idea, just make sure the straw is well-seated in the can. WD wouldn't be nearly as effective as something with graphite in it, either on the speedometer head itself nor the cable. When speedo-cable lube was a thing, it was always "graphited". I haven't seen it in years.

I would suggest removing the cluster entirely to have a good look-see at the PCB and pins. Make sure you've got good continuity between everything, and check the terminals in the "gatling gun" plug to make sure they'll connect securely. While it's apart, replace every f__kin' bulb in the cluster. A box of bulbs is literally less than $5 at my store, and then you know they're all new. I did not change them all in mine and had a bitch of a time replacing them with everything installed and the bench seat in my way.

For added peace of mind, I'd suggest getting AllStar part #ALL99059 (street price around $20) to replace your OE oil switch. The factory switch is rated for 4PSI, which is simply too late. The AllStar part turns the light on at 20PSI, which gives you time to kill the engine before everything's junk. I have a 1/8"NPT street tee installed in my W2 engine; one side feeds a VDO gauge and the other is for the AllStar switch. At idle, the light is just flickering and the gauge is right at 20PSI.

That 3310 is much-better suited to your combination unless you discover a radical roller cam and a 4,000+ stall speed. I'm going to assume it's a 3310-x since "non-dash" (OE Chevy) 3310s tend to be rather expensive. The lower the "dash" number (i.e. 3310-1) the better. The OE Chevy 3310 has a fantastic air-bleed/"emulsion port" calibration for real-world driving, including fuel economy. For some reason, Holley changed all that for the aftermarket ("dash") versions. The newer the carb, the worse it is. It's probably not a big deal to you considering the intended usage, but if you end up loving to drive the thing (it could happen!) and want to improve it, the OE calibration is tough to beat.

I'm all set for silly carbs, having no less than five double-pumpers already, the smallest (two) being 750CFM and the largest being the 830 on the W2 engine. I also have a 1355 triple-pumper, a.k.a. the Direct Connection mechanical-secondary Six Pack setup. That's for the 440 with no intended home at the moment.
 
lliquid lock graphite is similar to the old speedo cable lube, or as similar as ive ever seen, and if you can find the lock de-icer with graphite in it ..it "might" unstick the speedo without dissasembly but dont count on it....honestly pulling the unit and cleaning inside and outside the lenses alone does an amazing thing to the dash, replacing all the bulbs and everything else doc mentiond is all wise investment of time, so much so its one of the first things i do even on my alfas.....if your adventurious washing the guage faces with rubbing alch will useualy bring them back to showroom ....but be warned a heavy sun bleached cluster may rub some white off the numbers...but ive only had that happen on bike units

and the gattling gun of pins is what i copper nail from the back side to assure they NEVER fail again
 
Removing the cluster isn't on my imaginary list of things to do, so it's unlikely. I'll just figure out if 10 MPH is zero, or if it's really 10, and move on. I may find a can of that lock lube and give it a squirt, so long as it's not going to blow out and get graphite all over the gauge faces.

The carb is a a 3310-2. I always run those on the street and tune them based on the Dave Emanuel carb book. The 850 should be fairly easy to sell, priced right, or use as trade bait. Once I get the 6-pack installed on my road runner, I'll have two double-pumpers that I don't need. I need to start selling some of this stuff.

I don't know if the carb has anything to do with the way the motor runs or not, but I do know that's way too big of a carb for what is just a warmed over probably low compression 400.

I had a 67 Dart GT with a 273 that came with a 750 DP and a 509 cam. That taught me that there is such a thing as too much.
 
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69.5CUDA said:
yup, or they just shread the cable..if it shreaded the cable allready then a new cable will likely do something like that.....what was wrong with your cable anyway?
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The clip end was broken off and the ferrule was held on with electrical tape. There was nothing obvious wrong with the inner cable.

I looked in the my mopar chassis manual for specific instructions on taking the cluster out, and of course those pages are missing. It goes from 8-61 to 8-64. Once again, I get what I paid for (y) The ralley dash is in the book and it talks about reaching up under the dash and unhooking things and I don't remember seeing that as a possibility when I was last under there. At least it's a bucket not a bench seat that I have to take out again.
 
good news, the a body ralley cluster is the OE 67-9 fish unit...so its not really "special" in my book LOL

that said, it should be the row of screws across the top going up tward the dash pad, loosen the column (tho i have pulled them without dropping the column its just "tight"), additionaly there should be a hand full of screw thru the face of the unit, if yours has the cig lighter option it must be removed

after that its all about preferance, but with the dash tilted and pulled out you can access the 3 clips that hold the heater control cables, as well as the alt wires and various other plugs , i prefer to remove the gatling plug and angled 3 pin connector(it sits oposite the tach hole) as well as pulling the speedo cable prior to tilting, after that you can pull the 2 ALT wires as well as the flasher and headlight and wiper plugs with it tilted

if you want i can dig out my 69 plymouth service manual and see about scanning the pages...if someone doesnt beat me to it

if your dash is tachless like most...there are a few that can be "tweaked" to fit in the OE hole without molesting the dash in any way shape or form ...some can even pass for stock at a glance
 
He doesn't have a Rallye dash. His is the standard square-speedometer cluster, which doesn't require messing with heater controls, etc. Just drop the column a little bit and take out five or six screws (all on the cluster bezel), and it's loose. I was able to pull mine forward enough to reach behind and release the speedometer cable without having to get under the dash. After that and the nuts holding the ammeter wires, the cluster moves freely enough to get the rest unplugged easily enough.
 
Yeah it's already out. I loosened up the steering column and tilted the cluster out on the left side and unplugged things left to rightL headlight, ammeter, big round plug and .speedo cable, and wiper switch. It came right out like I thought it would.

I would've went nuts trying to unplug the two switches and the big round plug from under the dash, there's a lot of stuff in the way. But I didn't have to.

It's a 73 cluster, not that it matters. I stuck a piece of old speedo cable in it and turning it one way it will go to zero and stop but as soon as I turn loose it pops back up. I spun it the other way and it worked as expected other than not returning to zero. It seems like the magnet has turned just enough to raise the needle up but I don't know what's really wrong. I didn't have any graphite handy to try lubing it some.

There's continuity between all the pins and traces so no problem there and I still don't know why the OP light doesn't work. The bulb looks OK but I'm going to replace all those while it's out. Yeah I know I could easily test it. There were some tiny pieces of hard plastic inside the cluster, that kind of looked like pieces broken off the bulb holders.

As for the speedo I will probably clean it as good as I can with graphite per recommendos and try to reposition the needle if it's still needed.
 
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You can check it for accuracy with a 1,000RPM drill. 1000RPM on the input = 60MPH. I have a 30+-year-old Makita 9.6V drill on which high speed is 1,000RPM. It's about the only thing for which it gets used anymore. 😄
 
Dr.Jass said:
You can check it for accuracy with a 1,000RPM drill. 1000RPM on the input = 60MPH. I have a 30+-year-old Makita 9.6V drill on which high speed is 1,000RPM. It's about the only thing for which it gets used anymore. 😄
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is that linear? Seems like it should be.

I've got an 18v dewalt and it has 0-450 and 0-1500 according to the interwebs. If it's linear 450 would be 27 and 1500 would be 90
 
I couldn't hold it, look at it, and work the drill all at once but it seems to be close if not right on. There's probably some difference in the posted vs actual drill RPM too. I think it's good to go once I sort out the oil light.
 
The speedometer was mounted with some sort of rubber washer, that is now disintegrated. Is that necessary or can I just use a flat washer? I get the feeling it is, either to prevent ground or to shock mount it..
 
The speedometer RPM:MPH should be linear, since it's a linear multplication from tire to cable gear (i.e. no variables or exponential changes). Speedometers have some inherent inaccuracy unless they're certified (police) units so yeah, 1,500 should be 90-ish. However, because it's a multiplication, any error present is a percentage. Drives me insane when someone says their speedometer is "five off". At what speed? Five off at 25MPH means you've got a 13MPH error at 65MPH. If your needle is five off at 35MPH and has the same error at 70MPH, the needle has moved on its shaft.

My guess is something's wrong with the spring in yours since spinning it backward took it back down to zero. Still, it may well be accurate above the level where it sticks. It's the kind of thing that would drive me batty, but it's not like one comes across "SPEED LIMIT 9MPH" signs out in the world either. I'd be able to live with it while I looked for another speedometer, but I couldn't let it stay that way for any period of time.

I believe the rubber mount serves both purposes, electrical and vibratory. The cable itself is grounded to the cluster while the housing is grounded to the transmission case. Any significant voltage potential could theoretically cause the cable and housing to arc to each other. Mind you, you'd need some rather significant grounding issues elsewhere, but I seem to recall at least one instance decades ago where a speedometer failure was blamed on a cable essentially welding itself together (believable here in salt country). It only takes a few amps.

You could use a simple hardware-store grommet to replace the degraded bushing; the original is T-shaped when viewed in cross-section. There's supposed to be a metal ferrule in the grommet with a washer face (i.e., also T-shaped in cross) that the screw fits into, to secure the speedometer better. It may just be a captive washer on the screw on an A-body, but on later/other cars I know it can fall out and be lost. I'll get a picture of one later; the camera's in the garage at the moment.
 
The tiny dished washer just fell out when the rubber crumbled. I think I have both of them. At least I know I have one and hope I have the other one. I might have something left on a 70 b-body cluster, but the rubber's probably crumbling on that too if it's still there.

This is what they look like, used on e-bay:
s-l1600.jpg
 
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