Clavis gauge

What one of them, and what do it do?

I've heard you can get good results using a laptop, a microphone and some music software that does spectrum analysis. Might be worth a try...

Cheers,

Colin.

Measures (in my case) cambelt tension. Ford specify the cambelt tension as

98Hz and you need a £600 meter to measure it. Along with all the other special tools they come up with to make life difficult so people have to pay their overbloated prices for a totally shit service.

OK rant over now.

Oh yeah! That's a good idea. (starts looking for his copy of CoolEdit 2k)

Thanks.

What Ford?

Use the twist test coupled with ear 1.01. If it don't twist through=20 more than 90 degrees and doesn't hum then its OK.

--=20 Conor

Opinions personal, facts suspect.

Heh! That's one reason why for anything remotely modern, I'll only ever go to a main dealer for a cambelt change. On my Fiesta 1.8TDI van, the Haynes manual said to use a Clavis gauge, and there was no equivalent way of doing things (like twisting it a quarter or half turn). It sounded a bit too much effort, especially as one engine mount needed to be disconnected in order to gain access - meaning even with the engine mount removed it'd still have been a real pig of a job. Can't remember exactly what Ford quoted for a cambelt change, but it was around £150-200, which I'd be happy to pay given the PITA nature of the job.

It's also another reason that when I thought the head gasket had gone (turned out to be a cracked oil cooler that had caused it) I took it to them - a straightforward head gasket job was around the £500 mark, but the cambelt would have to be removed and refitted, so obviously replaced as a matter of course, so effectively the job would have only cost me £300 as it was due a cambelt change anyway.

In the end they quoted me silly money (around £2k) to fix it, recommending new big thick pipes to the rad (surely they're the easiest thing in the world to flush out, probably what they'd have done anyway, and blacked them up a bit!) - the four pipes were around £200 alone, bloody ridiculous.

So I put it on ebay and got a very decent price for it, considering the head was in the boot and the cooling system was clogged with brown gunk.

When it was on ebay, someone emailed me (actually lived in the same town) offering to buy it if the sale fell through he'd have it off me. Turned out he had the same model Fiesta van and the oil cooler cracked between the ports (like mine) at 40k and Ford fixed it under warranty, so they knew the oil cooler to be a problem, but still told me it was likely to be the head gasket and charged me half of the head gasket job (sort of fair as they did do half of the job). Had they any sense of ethics they'd have told me the oil cooler was the likely fault and checked that out first.

In hindsight, all that would have needed doing to get it running would have been a replacing the oil cooler (£120) and chucking washing powder in the coolant, and draining and refilling the coolant several times, and it would have been fine, and I would probably have done another 50,000 miles in the thing.

Peter

-- "The truth is working in television is not very glamorous at all. I just go home on my own at night and sit alone and eat crisps."

I would normally but this apparantly is not recommended for these belts and can lead to early failure. Sounds like a crock IMO but it's an interference diesel and clouting all 8 valves is not something I relish! Hence I'd prefer to get the correct tooling if possible.

The Focus doesn't look too bad. The RH mount needs to come off but I've already done a dry run and access is easy, as it getting all the bolts and covers off. The garage want £420 which translates to £390 labour for a three hour job which quite frankly is just taking the p*ss. Considering I can do it myself I don't mind shelling out the cost of a swap on tooling as I plan on keeping the vehicle for many many years.

Yes that sounds like the Ford stealerships I've dealt with before.

Are there any local specialists? Citroen wanted £350 to do my cambelt. The chappy in the street next to them did the cam and fanbelts for £113.30. Which was nice.

-- Malc

Right. Do you know how it works? I'm interested to know how frequency comes into it.

Any tensioned belt is like a guitar string. The frequency is related to belt length, mass and tension, since the only one that varies is tension it's easy to use the frequency to check the tension is correct.

The sensor is an ultrasonic head that watches the speed of vibration and gives you a digital readout of the vibrating frequency. Higher frequency = tighter belt and vice versa

The message from Chris Street contains these words:

Set of pitch-pipes should do you.

Or find a bit of freeware that'll let your sound card to 98Hz, record it, and play it back on the car CD player and adjust till they're in tune.

98 hz is quite low and not going to be easy to tune to by ear...

'Tension' is a load, e.g. kilograms, Newtons, pounds. Hertz (Hz) is a frequency. I can't quite see how these are connected, unless it's the 'piano wire' connection. That is, 'twang' the belt in some standard way and measure the resonant frequency. A computer microphone, soundcard, and spectrum analyser software might then do the job, for little additional cost.

It's not even going to be very loud either I suspect. It's twice bottom G though which handily enough is the lowest note I can sing....:-)

Ah. I'd be interested just how they actually pick up the sound. A cambelt will be a pretty poor sound generator - no sounding board.

98Hz would be easily picked up by near any microphone, and that sort of frequency accurately measured by a decent DVM like some Flukes. Assuming you could get a clear sound from it not drowned by other engine noises, which is what bothers me.

The message from "Tim S Kemp" contains these words:

Depends on how musical you are. It's only a couple of octaves below middle C.

The message from "Dave Plowman (News)" contains these words:

One assumes the engine ain't running at the time.