spyder tac.

[Iceland Spyder]

Hi folks and happy new year. My RPM indicator in 64 Spyder starts up fine, then slows down to 1000 RPM during cruse at 50 or 60 MPH? is there a reason for that? any repair for that? and my gas indicator is reading over full when full and empty at 1/4, all new in tank and good ground by the tank. Thanks, Stefan.

[b74eqcm]

Bad ground at dash?

[Iceland Spyder]

Thanks, but I have not found any ground connection on any drawings like on the late model. I have the assembly manual for 64 but no sign of ground connection except the screws that hold the instrument panel?

[bbodie52]

Both the tachometer and fuel gauge require a good 12 VDC power source and a good ground to function properly. This is also true of the cylinder head temperature gauge. The speedometer and manifold vacuum/pressure gauges are both mechanical and do not require power to operate properly.

Since at least two of these powered gauges appear to be acting up, the only thing they have in common is a 12 VDC power source that is switched on by the ignition switch, and chassis ground provided by the metal contact between the instrument panel and the dash board. A poor wiring connection from the power source or a high-resistance ground that has loosened or corroded over time could result in a voltage drop that is causing a malfunction. You could try substituting a temporary ground wire between the chassis ground and the instrument housing, to see if that solves the problem. A new temporary power feed wire between the fuse block and the instrument power connections could test the power supply side.

[Iceland Spyder]

Thanks Brad, I will try that, The cyl hed temp works OK, rises normally and is about 380 to 400 during cruse. New ground wire from bat to chassis to engine, and strong starting. Thanks. Stefan.

[66vairguy]

Brad made good points. The gauge cluster ground is often an issue since it relies on simple contact via screws to the dashboard metal that can become corroded. Keep in mind the instrument bezel is metal and the instruments are held in by screws - more possible contact issues.

Please state what kind of engine ignition system you are using to see if that is an issue, but most ignition systems are compatible with the tachometer.

Having said that -- since the tachometer seems to work at startup, then slowly settles to a low 1,000RPM during driving that could indicate a problem with the meter. The tachometers used a very good meter and electrical components - but it has been about half a century. The capacitors are the first suspect items as they are ALL well beyond design age. Next the electrical components, transistors, resistors, etc. need to be evaluated. THIS IS A PRECISION INSTRUMENT AND SHOULD ONLY BE REPAIRED BY A QUALIFIED TECHNICIAN.

Considering your location - you might consider buying a good rebuilt tachometer from a reputable supplier like Clark's - assuming you don't find an issue with power or ground in your car.

[Iceland Spyder]

The ignition is stock, I had removed the panel once and most plugs wear wrongly hocked up, the tin strip on back of gas gauge was melted. I fixed that and new sending unit vas installed, rectified connections of instruments. Gas gauge has red over full ever since and fluctuates when less then full. all lights work and dim. I will start with the ground and see if that is the problem, hope fully. Thanks vairguy.

[66vairguy]

I suspect that "tin strip" on the back of the fuel gauge was a wirewound resistor. On the 1964 cars (and earlier) this resistor is part of the gauge circuit and is mounted on the back of the gauge because it gets very warm. When removing the instrument cluster the resistor tends to get bumped and damaged. The resistor was attached with a with a physical bond (not sure if it was a rivet or spot welded). The simple fix is to replace the fuel gauge.

Another possible problem is the the fuel sender ground. The sender frame needs a GOOD ground and originally a short wire was run from the sender at the tank to the body. Years of driving tends to cause corrosion of the wire adding resistance to the circuit (gauge reads high).

[bbodie52]

The pictures below may help with visualizing the rear connections on the Spyder instrument panel...

Left-click each image with your mouse to enlarge the picture for better viewing...

[Iceland Spyder]

Thanks Brad, I will have to pull the panel and might have to get a fuel gauge and tac, we´l have to see. Thanks for your help. Stefan.

[Iceland Spyder]

found the needle

Hi all, a litle update on my tack and fuel gauge problem. I bought a full instrument panel for 64 on ebay and the handling was not at its best. The needle in RPM gauge han fallen of and was inside the gauge, the cylinder temp gauge was ruined. But the good news is I managed to glue the needle in the RPM gauge and it works perfect. Ichanged the fuel gauge and installed a new sending unit and tested the sending unit function prior installing into tank, all worked OK. After install in tank it goes only to half reading 1/2 at full tank, scratsing my hed over this?.

[Iceland Spyder]

Some pictures fro corvair garage in Iceland.

[66vairguy]

Glad you are making progress.

Your description suggests your old tachometer had an electrical problem. Keep it, or sell as is. The electronics can be repaired. The meters usually cannot be repaired and are obsolete. The Spyder tachometers with there narrower sweep usually don't suffer a meter failure. The LM Corsa tachometers are much more prone to meter failures.

[Iceland Spyder]

THANKS 66 vairguy, I never throw any corvair stuf. My gas gauge is stil a pussle to me? it registered correct when I tested it prior installing it to the tank? Tank is full so I have to do some dryving before I tackle that problem. Thanks.

[66vairguy]

I'm not that familiar with the early cars, but I believe they used the same gas tank as the later cars.

There has been an issue with some of the senders having the float installed reverse so the long end points in the wrong direction hitting the tank sides (happened to me). Also a bent arm can limit the float travel - not saying this is your problem.

A simple electrical test is to remove the wire at the sending unit from the gauge - left unconnected the fuel gauge should go to FULL or more (ignition key on of course). Connect the wire to a good ground and the fuel gauge should go to EMPTY or lower. If this does not happen you have an electrical problem with the gauge - poor contacts - bad instrument frame ground (common).

[Iceland Spyder]

Thanks, I have to look in to that with the float thing. It tested good with the float outside the tank. Have to do some dryving to lover the fuel. Thanks. Happy Corvairing.