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Temp. Probe for 1275 with Bugeye Radiator?

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paulsherman

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I have a 1275 in my Bugeye with the original Bugeye Radiator. I am wondering if it is best to install the temperature probe in the 1275 head or in the radiator?

Thank you
 
Best? Beats me... but I have the probe in the radiator (with my 1275). I suppose a case could be made that it would be better in the head because that (and the block) are what you are trying to cool... and the radiator temperature wouldn't always reflect engine temp (though surely most of the time).
 
I would put it in the head. After all, that's the temperature you're interested in.
 
Be aware, the temp probe that fits nicely in a Downflow Radiator, needs an adapter to fit into a 1275, IT will fit but the Temp bulb is too long and when you screw it down the bulb gets crushed and yiou are now out $150 for a new gauge. There is an adapter and sealing ring listed for the 1500 engine in the MOSS Catalog but someone else will need to weigh in on whether or not a 361-065 Adapter Temp Gauge and 324-805 O Ring are what is needed to put a BE Temp/Oil Gauge into a 1275 Block. The outlet on the radiator is best left for a 10" electric fan temp switch.
 
Back to the top. IS the adapter I mentioned in this thread the one needed to install a Radiator Temp probe in a 1275 Block.

There is an adapter and sealing ring listed for the 1500 engine in the MOSS Catalog but someone else will need to weigh in on whether or not a 361-065 Adapter Temp Gauge and 324-805 O Ring are what is needed to put a BE Temp/Oil Gauge into a 1275 Block. The outlet on the radiator is best left for a 10" electric fan temp switch.
 
JIm, I know that they are the part's needed to fit the electric temp probe but I've never personally fitted the bulb. I would guess that they are what you need. I'm running the electric sender in that hole just to seal it off and the bulb in the radiator. I'm curious as to where you can get a temp sending unit for an electric fan that will fit in the BE radiator?
 
Thatā€™s a good question, the down flow radiators for Bugeyes use Ā½ BSP. I research this and concluded that if you want options then donā€™t go down that path, not many to choose from. I had my radiator design to accommodate a 17mm bung to have many options if I choose. Right now itā€™s set up to operate at 70c & 75c.
 
I am not familiar with the Bugeye radiator temperature sending unit (be it mechanical or electric). Is it really 1/2 BSPT? That's an awful large thread. The thread in the head will be 5/8-18 with a conical seat to seal the sending unit. It's easy to confuse that thread with 3/8 Pipe.

The Moss part (361-065) mentioned by Jim is discussed in their tech article linked below. They say it is for the dual gauge on cars up to 1977. That would definitely be for gauges with the 5/8-18 male threaded nut, not 1/2" pipe. If you measure your BE's sending unit thread and it is male, 5/8-18, you need the Moss adapter and matching sealing washer to fit the sending unit to the 1275 head.
https://www.mossmotors.com/graphics/products/PDF/361-761.pdf
 
Griffin radiator is 10 minā€™s from my front door. I wanted my radiator custom built here in the USA but had a horrible experience with Griffin. I knew of Ron Davis radiators built quality so I called with some questions, they said that they would get back to me with a quote and answers. The following day late Ron Davis called with their quote and answers, one was the standard bung size 5/8ā€ 18.


However, I already knew the answer, because the day before I was chatting with a friend who was running a Serck Motorsport radiator in his Bugeye. I told him about my experience with Griffin, his answer was go to the mother land and get something that will fit perfect. Early the following morning I was on the phone to the UK speaking with Roy at Serck Motorsport https://www.serckservicesmotorsport.co.uk/p0/austin-healey/187508.htm who is the sales and production manger.

The same questions were poise to Roy and a very quick response ā€œOhā€ thatā€™s easy itā€™s Ā½ā€ BSP. I knew right then who was going to build my radiator; they gave me an exact quote with precise answers. What was so impressive was everyone here in the USA wanted payment up front, Roy said they only take payment after customer was satisfied.


The Whitworth 55Ā° angle remains commonly used today worldwide in form of the 15 British standard pipe threads , which are commonly used in water supply, cooling, pneumatics, and hydraulic systems.

P1030546.jpgP1040149.jpg
 
Wow... stunning photos!
 
Thanks for the information. I will remember that for next time.

With a 1/2" pipe thread for the BE radiator sensor, it will be difficult to adapt it to a later A-series cylinder head and the Moss part will be too small.
 
Doug, Iā€™m not absolutely sure what size thread the adaptor that threads in cylinder head below thermostat housing is? My thoughts are that a 5/8ā€ 18 is very close to the Ā½ ā€œ BSP? Being the head temperature is most critical, I decided to use that location to take the temperature of engine. I Teflon taped the threads of the OE Bugeye probe and threaded it into the adaptor, no leaks so far and everything appears Ok, we will see how this plays out?
 
Thanks for the answers. Looks like adapter and sealing washer will allow me to move probe from radiator the head. Thanks all for the answers and help. And saving from a $150 mistake.
 
I think I mentioned in a previous post that 3/8" pipe is close to 5/8-18 in size (with the pipe being slightly larger OD). The modern designation for European pipe threads are G (formerly BSPP) for straight threads and R (formerly BSPT) for tapered threads. The numbers below are nominal pipe sizes.
3/8: NPT nominal OD = 0.675", G (BSPP) & R (BSPT) = .656
1/2: NPT nominal OD = 0.840", G (BSPP) & R (BSPT) = .824

The adapter sold by Moss is threaded 5/8-18 male on the nose end and 5/8-18 female on the tail end. Its purpose is to move the expansion bulb of mechanical temperature gauges "out" so it doesn't bottom against the inside of the head casting. With the BE being 1/2" pipe as you said, it won't thread into the smaller Moss adapter.
 
So are you saying my BE is going to need a full compliment of gauges from Speedhut other than gas gauge. I may just leave probe in the radiator then.
 
Sooo...Bluemax. Disregarding thread size where is a good source for the thermostatic switch that will turn the fan off and on? I looked about a bit when I was putting my Datsun swap together and couldn't determine if they were to be used in series with the fan motor or through a relay or what the current requirements would be. I ended up with the over the counter generic parts store kit that is supposed to have a probe through the radiator fins. I ended up using a hose clamp to clamp it to my top tube that I made up out of conduit and it works fine. Don't completely trust it though and would prefer something that actually went into the water passage. Actually would prefer something that monitors the temp for that fan at the bottom hose. That is where I have seen Nissan do it on their newer vehicles. I'm monitoring it on the top of the system and if one was to lose coolant I don't think the fan would run.

Kurt.
 
Kurt, if you are going to disregarding thread size on a threaded thermo fan switch. I would look at the 77 VW Dasher or 76-77 Rabbit. You have four temperature options to choose from. 17mm 1.5



823 959 481E: 65-60c
823 959 481: 75-70c
823 959 481D: 82-77c
823 959 481F: 92-87c
 
Great! Thanks Bluemax, but now should they be wired through a relay or is in series OK. Wondering if anyone would know what the typical water temp is returning to an engine after it has been cooled by the radiator? Seems the 65 to 60C would put coolant temp's around 140 F which may be cool enough for the return.

Kurt.
 
I would wire it through a relay to ease the strain on the electrical system, I did. But also I installed a manual override switch too!!
 
Kurt,

nomad said:
Great! Thanks Bluemax, but now should they be wired through a relay or is in series OK. Wondering if anyone would know what the typical water temp is returning to an engine after it has been cooled by the radiator? Seems the 65 to 60C would put coolant temp's around 140 F which may be cool enough for the return.
Click to expand...

You might be interested in these: Untitled.jpg

They come in a set of three on eBay for $16 (click here). I put one on the head right next to the thermostat housing, and two on my radiator - one at the top near the inlet and another at the bottom near the outlet. No more guessing about how well the radiator is working or whether the head temperature is different than the radiator temperature!

Dan
 
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