TR2/3/3A TR3 Temperature Gauge

[TR3driver]

Could someone post a photo of what the radiator end of the tube looks like?

The original temperature gauge doesn't connect to the radiator at all, only to the thermostat housing on the engine. Here's a photo of what the end inside the housing looks like.

 

[Brooklands]

Tom,
The tube was not around the heater under the dash and not attached anywhere in the engine compartment. It flopped around in there, and I must have moved it near the steering column when I put the tach cable back in place. Since nothing held it away, it may have dropped down on a bump or something. I am a slow learner, but I will get if figured out down the line. If I get a chance I will photo and post yet tonight, before heading to San Antonio to see our son at Randolph AFB. We have a 6:15 am flight out tomorrow, so if not, I will post upon our return before next weekend. (We are meeting the "very serious" girlfriend this weekend)

 

[Brooklands]

Here's a photo of what the end inside the housing looks like.

Now I know what I am looking for. This makes more sense, but I could not find any appropriate photos in the various books I have started to accumulate. Thanks.

 

[NutmegCT]

Dave - have a *great* trip. And remember - the "serious girl friend" is probably as nervous as a long-tailed cat in a room full of rocking chairs.

As they say down in ol' San Antone ...

Tom

 

[Brooklands]

Thanks Tom,

We will have a great time, and we are eager to meet "Kelli" as she seems to be a great gal.

I got the nut off okay, but I still have the rest of the sensor bulb stuck in there, although it spins around in place.

I will try working on it next week. Meanwhile, this is the full view of this side of the engine that you requested, but the capillary tube is already out. I won't get the gauge shipped out this week, but now the car is laid up for at least two more weeks after I remove the bulb. I hope it comes out okay after a few days vacation.

 

[martx-5]

Well, the intake and carbs certainly aren't stock! /bcforum/images/%%GRAEMLIN_URL%%/smile.gif

 

[TR3driver]

Likely what's spinning is not the bulb itself, but rather the little steel collar that provides some reinforcement of the capillary tube where it enters the bulb.

Most likely, you're going to have to remove the housing from the engine, so you can push on the bulb from the inside. The good news is that the bulb is already ruined, so no need to worry if you mangle it further getting it out.

I doubt they really need the bulb anyway, you could just show them the photo I posted. But you'll need the hole open to install the new gauge anyway, so might as well get it out now.

BTW, if all else fails, new housings are available (as well as good used ones).

 

[Brooklands]

Well, the intake and carbs certainly aren't stock! /bcforum/images/%%GRAEMLIN_URL%%/smile.gif

Nope, the block is not the original either, but eventually I plan to go to SUs with the proper look anyway.

I did not know enough to realize the engine had been swapped when I first made the purchase.

 

[Brooklands]

Likely what's spinning is not the bulb itself, but rather the little steel collar that provides some reinforcement of the capillary tube where it enters the bulb.

I discovered that about 30 minutes ago, and have now shot some penetrating oil on the bulb to try and loosen it from this end.

Maybe it will be loose by the time we get home next week.

 

[Geo Hahn]

Well, the intake and carbs certainly aren't stock! /bcforum/images/%%GRAEMLIN_URL%%/smile.gif

Of course they are... for a late TR4 engine (which is what this appears to be).

In addition to penetrating oil (you didn;t say what kind, I like PBlaster, WD40 is more or less useless here) you might also apply heat. For that spot I used a heat gun to good effect when I had a stuck cap tube. It was the threaded portion of mine that was stuck but I think heat would help in any case.

You'll find it is a matter of a couple minutes work to get that tstat housing off so you can get at it from the inside (as Randall suggests) -- I'm guessing that will be what does it.

 

[Brooklands]

Well, the intake and carbs certainly aren't stock! /bcforum/images/%%GRAEMLIN_URL%%/smile.gif

Of course they are... for a late TR4 engine (which is what this appears to be).

Exactly what a PO had installed. For now I am staying with that until other things are all sorted and dependable (or as dependable as a 45 year old LBC with Lucas electrics should be). Hopefully I can get this done in about a week.

 

[Geo Hahn]

It appears Dave may have a TR4 thermostat housing (note the square corner... not rounded):

Sooo... are threads on the electric sending unit (that would have been on this engine) the same as on the fitting for the capillary tube? Are the openings into the coolant area the same? Just wondering if this might be why the bulb got stuck in his housing.

 

[TR3driver]

AFAIK the sender/bulb holes are identical between the two versions of housing. Although the mold obviously changed, it appears that the later housing even had the same part number as the earlier one, 203781.

At any rate, he got the nut out, and the bulb isn't threaded. However, it's easy to get dissimilar metal corrosion going on between the brass of the bulb & the alloy of the housing, if the coolant isn't kept changed on a regular basis. And judging by that layer of rust on the (non-original) iron T-stat cover, I'd guess this engine hasn't been particularly well cared for at some time in it's past.

 

[PeterK]

The bypass outlet passage on later TR4s has been reduced internally also, compared to the TR3.

 

[Brooklands]

Well,
I got the sensor out today once I found my small vise grip in my slot car tool kit. It was able to grab the sensor and pull it out. I will package this stuff to ship to Nisonger Monday morning.
This is the sensor that was on my car:

Is this the one that should have been there for the late TR4 engine, or is this the one that should have been on a TR3B? For now I plan to stay with this engine, but may someday consider getting a 3B block to make the car more 'authentic'. I am not sure if I should ask Nisonger for this sensor or another one would be better. Suggestions would be appreciated if this is a question.
Who carries the clips that I should use for mounting the capillary tube in the engine compartment? I could not find them in my moss or TRF paper catalogs.
Finally, while this is out and the car not running, I want to figure out why nothing happens when I turn the heater switch. Is there a motor I should be hearing? I assume that the circular box under the dash is a blower, but I don't know if the motor is shot, if it is wired improperly, or if the switch is bad. Before I start tearing things apart, is there something that I should check out first?
Thanks to all for your help so far.

 

[Bugeye58]

Start with simple voltage checks. To the switch, through the switch, and at the motor. If you have power to the motor, disassemble and find out why the motor doesn't run. If no power, check back along the line and find out where you lose it.
Jeff

 

[BOXoROCKS]

before you tear the heater apart, if you have power to the motor,blast some solvent oil of some sort into the motor area by the fan bushings and spin the fan blade with a small screwdriver.Then turn on the power and spin some more. Its a good chance the motor will free up and run.

 

[TR3driver]

Is this the one that should have been there for the late TR4 engine, or is this the one that should have been on a TR3B?

That's the bulb for a TR2-3B mechanical temp gauge. The TR4 sender looks quite a bit different, including the brass flats being part of the sender rather than a separate steel nut.
<div class="ubbcode-block"><div class="ubbcode-header">Quote:] I am not sure if I should ask Nisonger for this sensor or another one would be better.[/QUOTE]It's not really an option, since the TR4 electrical gauge is completely different in both construction and operation. If you want to convert to a TR4 gauge, that's fine (early ones look very similar to the TR3 gauge), but you'll have to source the gauge, sender and voltage stabilizer. It's not practical to convert the mechanical gauge to electrical. The later electrical gauges are generally regarded as more robust (mostly because they don't have the fragile capillary tube) but I prefer a mechanical gauge.
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Who carries the clips that I should use for mounting the capillary tube in the engine compartment?[/QUOTE]Ordinary plastic tie wraps work quite well (although obviously non-original in appearance). The Moss P/N for the reproduction metal wraps is 760-055, TRF is 38303.<div class="ubbcode-block"><div class="ubbcode-header">Quote:]
Finally, while this is out and the car not running, I want to figure out why nothing happens when I turn the heater switch. Is there a motor I should be hearing?[/QUOTE]Yup. It's kind of feeble, but you should be able to hear it. As others have said, check for power to the motor before you start pulling things apart. Note that very few sources give the correct connections for the heater motor; the wire from the control does NOT go to the wiper switch as mentioned in the shop manual/Bentley on later cars with self-parking wipers. Near as I can tell, the factory would have connected it to the 'green' terminal on the fuel gauge.

 

[Brooklands]

I am not sure if I should ask Nisonger for this sensor or another one would be better.

It's not really an option, since the TR4 electrical gauge is completely different in both construction and operation.

I knew that, but brain fade is always painful...
Thanks for all the advice. I will become an able mechanic someday, although never will I be as daring as Tinster or NutmegCT...