Ade-TR4 Posted June 9, 2008 Report Share Posted June 9, 2008 (edited) Hi All, Still scratching my head about this one: Why does the later TR4 temp gauge have 70 deg as normal? Mine runs at 85 deg (measured with infra-red non-contact thingy at the thermostat) and thus reads slightly to the right of the normal window on the gauge. Bill's "bible" states that operating temp is 86 degrees, so why the flip does the gauge have normal as 70 deg? Should there be a resistor/ shunt in the loom to shift the needle? Or maybe I should just paint a white line on the gauge where 70 deg is so that I can concentrate on the road from now on! The whole cooling system appears fine, the rad will allow a fast running hose-pipe flow to run through it without backing up in the slightest, there's a new proper 80 deg thermostat in the housing, and the the Kenlow ticks in and out when stationary: On for about 3-4 mins on a really warm day, then off for about 5 mins. arrrggh! Cheers Adey Edited June 9, 2008 by Ade-TR4 Quote Link to post Share on other sites
Rhodri Posted June 9, 2008 Report Share Posted June 9, 2008 Is the car, or gauge, of ex hot country origin, when the thermostat would have been a 74* model ? Quote Link to post Share on other sites
Ade-TR4 Posted June 9, 2008 Author Report Share Posted June 9, 2008 It's an Ex-Californian car. However, all late TR4s had the 70 deg temp gauge. ? Ade Quote Link to post Share on other sites
TR 2100 Posted June 9, 2008 Report Share Posted June 9, 2008 Still scratching my head about this one: Why does the later TR4 temp gauge have 70 deg as normal? I don't have any real information on this one, but considering the documented reasons for such factory anomalies as changing from SUs to Strombergs then back to SUs, my suspicion would be the reason would be nothing to do with the operating temperature!! AlanR Quote Link to post Share on other sites
Ade-TR4 Posted June 9, 2008 Author Report Share Posted June 9, 2008 Can any owners of TR4s report similar issues with their gauges? If it's a gauge issue then Triumph must have been plagued by owners worrying about their engine temps! Thanks for the replies so far Ade Quote Link to post Share on other sites
Ade-TR4 Posted June 9, 2008 Author Report Share Posted June 9, 2008 (edited) FIXED IT!!!!!!! Checked the resistance of the original thermocouple/ thermistor against a brand new one Old = 66 ohm at 80 deg New = 95 Ohm at 80 deg (GTR104 pn) Looks like the old one was either knackered or incorrect type. Just had to take it out for a drive (obviously). The temp never budged above the "normal" region either side of 70. Kenlowe kicks in as normal and keeps the temp from going out of the normal region !!! Adey Edited June 9, 2008 by Ade-TR4 Quote Link to post Share on other sites
davidgsmith Posted June 9, 2008 Report Share Posted June 9, 2008 I have a '63 TR4 and mine too has 70 as the midpoint. the temp is always reading on or just above the right-hand mark if that makes sense!!! Quote Link to post Share on other sites
MikeF Posted June 9, 2008 Report Share Posted June 9, 2008 FWIW: My domed glass 4 runs at 185 in old money, equivalent to 85 in Celsius (Centigrade as was). Mike Quote Link to post Share on other sites
Ade-TR4 Posted June 10, 2008 Author Report Share Posted June 10, 2008 My point exactly! Why have an engine running at 185 DegF which is 86 deg C, but have a gauge indicating "Normal" as 70 deg C? I suspect that there was a mistake in production as 70 deg C is 158 deg F, not 185 deg F. Coincidence? Anyway, The new thermistor has mysteriously cured the "problem" by basically increasing the resistance and landing the needle smack bang on 70 deg C on my gauge! Cheers Adey Quote Link to post Share on other sites
Smokey Posted June 11, 2008 Report Share Posted June 11, 2008 Here's my guess: they designed it to read 70 when the actual temperature was 85 so that the customers wouldn't get concerned about overheating. The factory notice about fitting tropical fans for customers who complained about overheating came out in July 1963 - the first summer for the TR4. My January 1962 TR4 has a domed glass temp gauge that reads 185 F under normal circumstances - and a tropical six-bladed fan. Quote Link to post Share on other sites
Ade-TR4 Posted June 11, 2008 Author Report Share Posted June 11, 2008 That would explain the higher temp-sender resistance for the late TR4/TR4a Quote Link to post Share on other sites
TR 2100 Posted June 11, 2008 Report Share Posted June 11, 2008 (edited) The factory notice about fitting tropical fans for customers who complained about overheating came out in July 1963 - the first summer for the TR4. My January 1962 TR4 has a domed glass temp gauge that reads 185 F under normal circumstances - and a tropical six-bladed fan. I think this must be the notice you mean, but I don't think it's relating to overheating in the context of this thread. I can understand the factory putting 70ºC to avoid drivers worrying about the temperature getting too close to boiling, as I'm sure most people wouldn't realise that the boiling point of water under pressure is higher that if NOT under pressure, but if that were the reason, then I would expect it to be factory policy throughout the range, not just for TRs. Is there any evidence of that? I'm no expert, but isn't 85ºC more like a normal operating temperature than 70ºC? Two interesting little asides in the notice - Reference to TR-4, not TR4 or TR 4 (this isn't fully consistent throughout the bulletins) "A number of water pumps has . . . ." - grammar looks wrong but in fact absolutely correct. Perhaps wrote the manuals had a degree in English rather than mechanical engineering!! AlanR Edited June 11, 2008 by TR 2100 Quote Link to post Share on other sites
Ade-TR4 Posted June 11, 2008 Author Report Share Posted June 11, 2008 "I'm no expert, but isn't 85ºC more like a normal operating temperature than 70ºC?" My point exactly! Which is why I think the 70c was a production mistake (158F not 185F) and the higher resistance temp-sender was the remedy! My engine runs at 86C, with the new sender the gauge shows 70C dead. With the earlier Smiths sender, it shows 86C on the gauge and "looks" like it's running hot. Ade Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.