QuestionQUESTION: I have a 1976 Spitfire 1500. I replaced the stock temperature guage with an Autometer Z series 2 1/16 guage. I also added an Autometer Z series 2 1/16 oil pressure guage as well.The guages fit and look fantastic, however the problem is with the sending units. The thread size in the thermostat housing is, I believe, 5/8-18 UNF where as the sending unit's thread size is 5/8 NPT. Is there an adapter to convert the threads. I have gone to a dozen auto and hardware stores and they don't have a clue. I called Victoria British where I ordered it from and they were of no help. They said they had less than 1% problems associated with it. I called Auto Meter and there solution was a hose adapter, but due to size restrictions I would be forced to put it on the lower radiator hose?? That would then only measure the water temperature after the thermostat opens I believe. There has to be an easier way?? I haven't even begun to tackle the thread issue with the oil pressure sending unit. Auto Meter couldn't even help me with the Oil Pressure issue. Any ideas??
ANSWER: Matt,
One idea for the thermostat housing would be to drill/retap the housing to take a larger size fitting (3/4"??) that would then be internally tapped for the 5/8"-18. I am surprised that Autometer doesn't offer a sender unit with the correct thread.
As to the oil pressure fitting I want to say that the block is tapped 1/8" NPT. Most of the autoparts stores and even some of the home improvement stores have brass 1/8" NPT fittings so it's possible to figure something out. Again, it might be easier to find an oversized fitting and tap it to match.
Cheers,
Jim
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QUESTION: I plan on rebuilding the engine this fall. If I use the hose adapter that Auto Meter sells and I install it on the lower radiator hose, will the sender only measure the water temperature after the thermostat opens. If so is that okay since you would be watching for higher temperatures anway. I will retap the thermostat housing when I rebuild the engine. I just want to monitor the engine's temperature until then and the adapter seems like it would be a simple solution until then.
ANSWER: If you put the sensor in the lower radiator hose all you'll be measuring is the coolant temp AFTER it's been cooled off in the radiator.
Cheers,
Jim
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QUESTION: Good point. If I put it in the upper hose then it will measure the temp. as soon as it leaves the thermostat housing. That would seem to provide a more accurate reading. Would that work?? The hose that links the housing and the radiator is ribbed. Is that stock or aftermarket. Should it be smooth? I would have to temporarily replace it with a smooth one so I will be able to splice in the adapter.
AnswerMatt,
Using the upper radiator hose for a measuring point sounds like the best compromise you can figure out for now. Keep in mind that the gauge won't move until after the thermostat opens.
And yes, the proper upper hose should be smooth.
Cheers,
Jim
