S1 Otter Switch

[eddiecross]

Hi,
My 1967 US Import S1.25 currently has the Otter Switch disconnected and a small plastic Kenlowe type fan connected direct from the coil. Original fan motor is missing along with the fan shroud. I don't know why the guy did not use the original green motor feed wire- I need to locate it. I have located the short loom and connectors for the otter switch.

1st question. If the original Otter switch is ok or I buy a new one (£30 SNG), are they reliable? Reason is that I saw a modern standard switch on ebay with a neat brass adaptor plate but its £55 and you then need to fit a relay as the S1 is direct connection from motor to switch.

2nd Q: Any advantage in using a relay for the original type Otter switch- will it last longer?

I managed to find a fan shroud at the spares day so will add that back as well.

Many thanks
Eddie Cross

[cactusman]

For what its worth I bought a replacement otter switch. Long and short of it... Utter crap. I dismantled it and used the case to house an electronic temp sensor that I now use to operate the relay on mine. Adjustable and far more precise than the repro otter that had to almost boil to come on and then did not shut off until the temp was below 70 deg C...hopeless. Not sure how original otter switches were made...presumably a bimetallic switch of some sort but the repro one I got contained a cheap bimetallic switch element that I could buy from e.g radiospares for a few quid. I have seen the kit on eBay. That may be better from a temperature accuracy point of view but they say it must have a relay.

[Gfhug]

Get one of these, they work:
http://www.coolcatcorp.com/Merchant5/me ... ry_Code=CS

Geoff

[eddiecross]

Many thanks for the advice. Glad I didn't waste any time on a pattern replacement.

I will probably go for the modern unit. I have an engineer friend who could turn me up the brass housing.
Alternatively, I just dug out an unused Kenlowe fan thermostat with the bulb and adjustment knob.

Thanks again
Cheers
Eddie

[288gto]

Many thanks for the advice........................ I have an engineer friend who could turn me up the brass housing.


Thanks again
Cheers
Eddie

Failing that Eddie I bought an M14 solder in brass boss from Car Builder Solutions and cut a circle of brass to silver solder it into.

Total cost less than £5. I can now fit any modern M14 threaded switch of which there is a large selection of temperature ranges.




By the way have you fitted that exhaust yet?


Simon

[alfazagato]

Sorry to appear to be dim but the sender you show is threaded so why solder it into the housing and does the aluminium plate fit with the boss inside the rad so that it is in touch with the water?

[Moeregaard]

The CoolCat solution is superb one. Their replacement fan uses the factory mount, integrates nicely with the radiator shroud, and they do make an adaptor to allow the use of a modern thermal switch. I installed this on my last FHC and everything stayed cool in southern California traffic.

[cactusman]

I think there is a chap selling what looks like the coolkat kit on a well known auction site for about £60....I stress looks like.

I have had bits (series 1 fan kit for example) from coolkat direct from the states....excellent service and top notch product....just takes a few days to get here and you might have to pay the vat.....

[288gto]

Sorry to appear to be dim but the sender you show is threaded so why solder it into the housing and does the aluminium plate fit with the boss inside the rad so that it is in touch with the water?

Hi, not dim at all, ask away.

The adaptor on the right is the part I made by soldering a brass M14 boss onto a circle cut from brass with holes that line up with the original fixings on the radiator.

While not a copy of the Cool Cat adapter I would say it was certainly "inspired by it".

The threaded switch on the left then screws into it and can be removed independently.

There is as mentioned above someone on a well known auction site selling these for considerably more than it cost to make mine.

My solution might not be to everyone's liking but was intended to show what could be done if, like me, you find it satisfying and slightly therapeutic making stuff like this.

The bezel part will go into the rad to hopefully give better contact with the water.

Simon

[JagWaugh]

While not a copy of the Cool Cat adapter I would say it was certainly "inspired by it".

I've got one of the Cool Cat adaptors for the hisser on my S. I just haven't got around to finding a switch that is closed at low temp and opens as the engine gets closer to operating temp.

[288gto]

I'm not sure what thread Cool Cat use but mine is M14. Below is just a small selection of switches available.

ON at 87 and OFF at 82
ON at 97 and OFF at 85
ON at 100 and OFF at 95

All in degrees Celsius.

If you go up to an M22 thread there are even more available including a two stage one that offers:

Stage 1
ON at 88 OFF at 83

Stage 2
ON at 97 OFF at 92

This would allow independent switching of twin fans on a Series 2 or 3 for instance.


The likes of Demon Tweeks and Merlin Motorsports have more.

Simon

[JagWaugh]

I'm not sure what thread Cool Cat use but mine is M14. Below is just a small selection of switches available.

ON at 87 and OFF at 82
ON at 97 and OFF at 85
ON at 100 and OFF at 95

All in degrees Celsius.

The likes of Demon Tweeks and Merlin Motorsports have more.

Simon

It's for the starting carb. I'd need something like off above 60 C and on anything below.

[288gto]

Closest I can find is by using a change over relay.

OFF at 107 ON at 97

I know that's way off the temps you require but
makes me wonder if a change over or latching relay might work on a lower temp switch to give you the required on and off parameters?
Just thinking out loud really.

Simon

[MSM]

Simon

You said

''If you go up to an M22 thread there are even more available including a two stage one that offers:

Stage 1
ON at 88 OFF at 83

Stage 2
ON at 97 OFF at 92

This would allow independent switching of twin fans on a Series 2 or 3 for instance.''


I can't speak for Series 3 fans but unless you have a seperator plate between the two fans, operating just one of them will draw air through the other fan in preference to the radiator.

I presume that this is what you intended - operate one fan and then if needed the other one comes on as well. Only works as intended if you divide the two air flows. Hope that is helpful.

[eddiecross]

Hi Simon,
S/S Exhaust is now joined by other new shiny bits such as wheels and all waiting to be fitted....am just grabbing an hour here and there to get the minor jobs done.

[288gto]

Eddie,

That's great!

Mike,

Sorry, I was just showing what MIGHT be possible. Yes if you wanted the fans to work independently on both a Series 2 and 3 some sort of divider / separator would be advisable.
My comments were intended to show that by fitting a threaded adapter the choice and availability of fan switch becomes much greater.

Simon