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TR4/4A Updating my TR4 Gauges

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J

jimitro

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Hi,
I'm a new member in Upstate NY with a '62 TR4.
I would like to update my old Lucas gauges to more accurate, modern ones. Will the 2 1/16" gauges work?
Any suggestions on preferred brands?
Will the fuel gauge work with the original sending unit?
Thanks for all your suggestions.
 
What? update our beloved dark, inaccurate guages? but why?
hehehe
But seriously, yes. The holes in both the steel and wood dash are 2 1/16" so they should work good.(just went out and checked on an extra dash in the garage)
Whatcha doin with the old ones?
Welcome to the forum from a fellow "upstater" /ubbthreads/images/graemlins/thumbsup.gif
 
Any modern gauges you get will have to be matched with an appropriate sender. They generally work on a variable resistance, and will probably not match what's in the TR. They also might work backwards. Some gauges rise with falling resistance, others rise with increasing resistance. Getting a matching sender for the temp gauge should be no problem, as it will probably come with it. At worst, you might need an adaptor fitting. The original oil pressure gauge is a direct pipe in. They can still be had, or you could convert to electric. An ammeter is an ammeter, no problem there. The real problem is the fuel gauge. You need to know the range of the sending unit from full to empty, and get a gauge that will match that. I'll dig around, I think I have a good sending unit that I can measure.
 
I replaced the gauges in my TR6 with Autometer gauges, so perhaps my experience will be helpful for a TR4.

Speedo: The cable fitting on the back of the mechanical speedo doesn't match the Triumph cable, so you will need an adapter if you use the mechanical speedo. There is a company that specializes in adapters to match gear ratios, so they should be able to make one for you (I still don't have mine connected yet). You could also use an electric speedo, but you probably would still need an adapter to mate with the transmission output.

Tacho: No problem there, it just hooks right up. You'll need to set the switches on the back of the tach to match your cylinder count, ie, 4, 6, or 8.

Temp: I removed the stock temp sender and drilled the guts out. I then tapped the hole in the sender to match the Autometer sender and screwed it in. No problems at all with that.

Fuel: Using the stock sender worked fine, but it was very non-linear. At a half-full reading, I only have about 3-4 gallons left. I modified the stock sending unit mounting to make it fit the Autometer sender, but I haven't installed it yet (I had a spare from my junk bin). That matched the sender to the gauge, but there is still a non-linearity, as the tank itself is non-linear. Te tank tapers in the bottom half, so one inch of gas is less gallons at the bottom than it is at the top. I'll be curious to see how that works out, but it should be better than using the stock sender. E-mail me if you want details.

Oil pressure: No problem here - the Autometer electric sender screwed right in the hole where the old mechanical sender went. If you want a mechanical gauge, the fitting for it would, I imagine, screw right in also.

Ammeter: As stated above, an ameter is an ammeter, so no problem here. If you have any idea that you may want to upgrade to a larger alternator, you may want to consider a 60-0-60 amp meter instead, but if that's the case, I recommend getting a voltmeter instead. There are a lot of reason for using a voltmeter instead of an ammeter, but I don't agree with any of them. If you have no plans for upgrading your electrical system, I say stick with the ammeter. The real reason for getting away from ammeter by the auto makers was one of simple practicality. As the surrent needs went up, the wire size needed to handle it also went up. When the ammeter wires were small, it was pretty easy to connect them to the small lugs on the gauge, but if your current needs require an 8 gauge wire, for example, it get mighty hard to work with that size on a small gauge.
 
Ooops! One thing I forgot to mention: the five inch aftermarket speedos and tachs are too small to fit in the stock openings, so you'll need to make a pair of adapter rings to reduce the hole openings. I've done this now for two TR6s, and it's really pretty easy to do if you have a drill press. E-mail me for details if you're interested. The 2 1/16 inch gauges drop right in.
 
[ QUOTE ]
...I would like to update my old Lucas gauges to more accurate, modern ones...

[/ QUOTE ]

If you like a modern look that's one thing, but if the main concern is accuracy the original gauges can usually be made quite accurate. Speedo, Tach and fuel are the ones that usually get out of whack but are also the simplest to adjust. Temp gauge inaccuracies seem most likely to be the sending unit. I have always found the oil pressure gauges to be pretty accurate and since it is the presence of oil pressure and the changes in oil pressure that are most meaningful I'm not sure extreme precision is needed there anyway.

Well, (as the above post suggests) you can at least trade those original gauges for some of the $$$ to replace them.
 
Thanks for your assistance on my gauge questions.
I'm going to keep the original gauges in case I revert back
to originality.
 
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