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Scavenge belt failure & low OP warning light

Smithy77

By Smithy77
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Smithy77

Smithy77

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Hi all and merry Christmas etc etc. The time has come to turn attention to the Caterham for some winter jobs, one of the first for me will be fitting a warning light for both low oil pressure and also belt failure using some sort of microswitch.

I've done some searching of the archives but most contain broken links.

The low oil pressure warning is the easy bit; I will simply fit the Longacre kit with adjustable pressure switch here. Simply fit the T-piece between existing union on the filter housing and capillary tube for the OP gauge, then add the adjustable switch on the T and wire to the warning light on the dash. Simples.

The bit that is less clear from my research is the belt failure warning set up, and as far as I can see, kits for such a warning system do not exist like with the low OP kit.

1. Does anyone have access to a how to guide/thread or shopping list for best method of doing this?

2. In terms of wiring, I'm guessing I can fit a microswitch on the pump belt wired in parallel with the low pressure switch and utilise the same warning light for both warning systems?

3. Will the red light that comes with the Longacre kit be bright enough on sunny days, or can anyone recommend a brighter alternative?

Thanks

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Jonathan Kay

Jonathan Kay

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1. Does anyone have access to a how to guide/thread or shopping list for best method of doing this?

2. In terms of wiring, I'm guessing I can fit a microswitch on the pump belt wired in parallel with the low pressure switch and utilise the same warning light for both warning systems?

3. Will the red light that comes with the Longacre kit be bright enough on sunny days, or can anyone recommend a brighter alternative?

Haven't seen one of those belt warning systems: are they used in racing? Aircraft? Industry? 

I can imagine either having the actuator for the switch acting directly on the belt with a low friction thing or having an idler wheel on the belt and the actuator on the spring-loaded support arm. (Or an optical solution... )

What are you going to do with the existing warning light?

Tht Longacre kit has a 194 lamp socket, which should give you a big choice of incandescent and LED lamps.

Jonathan

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simon_h

simon_h

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If I remember correctly someone did something with the fan belt warning system from an air cooled 911 once. I think they have a small wheel with a switch attached that runs on the belt. It's something you would need to work something out to use rather than a kit but it's designed for a similar problem. 

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Smithy77

Smithy77

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Thanks for the replies.

Haven't seen one of those belt warning systems: are they used in racing? Aircraft? Industry? 

I can imagine either having the actuator for the switch acting directly on the belt with a low friction thing or having an idler wheel on the belt and the actuator on the spring-loaded support arm. (Or an optical solution... )

 

If I remember correctly someone did something with the fan belt warning system from an air cooled 911 once. I think they have a small wheel with a switch attached that runs on the belt. It's something you would need to work something out to use rather than a kit but it's designed for a similar problem. 

In answer to Jonathan/Simon, from reading the archives I kind of accepted that the belt warning system is not particularly common, nor is a proprietary kit available (I'm guessing), but I understand people have done it on their K-series Caterhams; it was the links to these solutions that were always broken in my searches. Example. 

So really I'm trying to reach out to anyone who has successfully done it and who can share their wisdom.

What are you going to do with the existing warning light?

Tht Longacre kit has a 194 lamp socket, which should give you a big choice of incandescent and LED lamps.

Existing warning light? I don't currently have one! Although my plan is to use the warning lamp in the Lonacre kit for both warning systems. Just wire the pressure switch and belt microswitch in parallel with each other, so if EITHER switch is activated, the light will come on. 

So I can just upgrade the bulb within the Longacre lamp, if I understand you correctly? Simple enough.

You could speak to SBD, IIRC they had a belt monitoring solution

Thanks! Will give them a call

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Smithy77

Smithy77

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Tazio, I've just bought the Longacre kit which comes with a 15-50 psi OP warning switch. I would also like to add a belt warning switch wired up to the same warning lamp as a "belt and braces" measure, if it proves to be relatively simple. 

I have the Titan/Caterham DS set up with a single scavenge pump and OEM pressure pump, so if the scavenge pump/belt lets go I will have a few seconds in which oil pressure will remain good as the oil in the bell tank is used up. If I just had the low OP warning light alone, I would lose this extra "safety buffer" before the OP drops to zero. Could be the difference between a £3K bill or not.

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Tazio

Tazio

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I have a very expensive VX engine with Pace Dry Sump set up, I have a warning light that comes on at 30 psi, so in the event of a belt failure when the pressure falls to 30 it comes on, and I switch off! lol. 

Each to their own, but I would rather not have any sensor on the belt which has the potential of failing and compromising the belt's integrity...

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Paul Deslandes

Paul Deslandes

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My heart sank when I read the headline Pete, but I recovered when I realised that you were only looking at precautionary measures.

What you do after getting the belt failure warning depends on the pressure/scavenge pump system.  If they're combined into one unit, e.g. Pace, then even if you're lightening quick in switching off and dumping the clutch you'd be a brave man to start your engine again without a strip down and inspection.  More than one 7 owner with the Pace/SBD style system on a Vx 2 litre has regretted continuing when a rod has appeared through the side of the block a couple of weeks after just changing the belt.

However, if it's a system with the pressure and scavenge pumps separated, with the pressure run directly off the crank and belt driven scavenge, you're more likely to get away with it as the pressure pump will be fed by a full oil tank for a while after the scavenge has stopped and the alarm has gone off.

I don't see why the roller switch wouldn't work but you still have to have something to get your attention through the red mist.  I have a very large bright multi LED from RS that comes on at 30psi but I doubt I would react to it fast enough to avoid potentially catastrophic low oil pressure damage as I have the combined Pace pump.

Happy New Year to all

Paul

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Smithy77

Smithy77

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Hi Paul!

Yes sorry, this is purely precautionary. Having learnt the hard way about the "quirks" of DS maintenance, shortly after getting my current car, I'm determined never to have to deal with another impromptu rebuild. EVER!

So fitting a low OP warning light is a no brainer, but because I do indeed have a Titan scavenge pump and OEM pressure pump driven off the crank, I think that it makes a lot of sense to try and fit a belt failure warning in conjunction with a low OP warning.

I have already ordered the Longacre kit I linked to in my original post. I'll test the included lamp for brightness when I get it, but I'd be keen on replacing it with the brightest LED lamp possible. Maybe something like this?

For sure there must be a way to detect belt failure with a light beam.

Not sure I'm keen on any kind of "optical" sensor/switch. Due to the location, keeping it clean could be an issue. Think a mechanical microswitch is the better way to go

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Paul Deslandes

Paul Deslandes

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Pete

I use one of these.  It almost hurts your eyes when fully on.  Being an LED it needs a series resistor or constant current limiter.

Although probably not strictly necessary, changing the pump belt annually is also a wise precaution for the sake of a few quid.

I looked at an optical belt warner but I suspect a mechanical switch would be a lot simpler.

Paul

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Smithy77

Smithy77

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Paul,

That LED lamp is MASSIVE! Perhaps a little too industrial to mount on the dash of my road/track car. I was going to suggest these with tongue in cheek, but it would seem yours isn't too far away! *rofl*

Maybe something like this could be a good compromise between brightness and elegance. Presumably this will also need some sort of resistor too? (forgive my lack of electrical knowledge)

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Paul Deslandes

Paul Deslandes

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It's not that big Pete!  It's the same element as is/was available from Demon Tweeks as a rain light.  It needs to be big and intrusive if you're going to see it, especially on the track through the red mist.  I really don't think that you'd notice the smaller ones and an audible alarm is unlikely to be heard.

I suppose if it flashed your peripheral vision might catch it but mine is straight in front of me and even then I'm not certain I'd react immediately.

Paul

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