I am desperately seeking this tool pictured below.



It's number is 1895879000. I will pay for postage both ways and for the use of the tool.

Tony

have seen them on ebay in the past have you looked?

http://cgi.ebay.co.uk/Laser-3630-Ca...tZUK_Hand_Tools_Equipment?hash=item3a58d486d4

Hmm, that seems to be only the locking tools. I need the gauge shown in picture two. Have you seen the gauges online?

Several come up if you search eBay for "TDC tool" but you also need to buy the dial gauge. Be sure to get the correct thread to match your spark plugs.

I made one years ago for my old Croma Turbo from an old spark plug, some metal tube and a dial gauge.

Davren said:

Several come up if you search eBay for "TDC tool" but you also need to buy the dial gauge. Be sure to get the correct thread to match your spark plugs.

I made one years ago for my old Croma Turbo from an old spark plug, some metal tube and a dial gauge.

Click to expand...

Amazing! Can you tell me, is it worth buying a third party tool like this? Will it be as accurate? Also, where do I get a gauge from and how do I know it's threaded for my plugs?

Whoever sells the mounting tube, probably also sells the dial gauge. If not, search eBay for "Dial Gauge". The dial gauge doesn't need to be very accurate for your application, so the cheapest one you can find will do.

I don't know the thread size for Barchetta plugs, but probably 14mm.

Thanks, you're a hero.

If you can get a hold of a dial gauge, you can break the ceramic centre out of an old spark plug then drill and tap a small hole through the side of the plug above the spanner flats. Screw a small bolt through the tapped hole and it will grip the dial guage. Check out Axminster Tools for a cheap gauge. The advantage of using a proper extension is that it will guarantee the probe will touch the piston. I was going to suggest that you use a screw driver and "feel' for TDC like we use to on British Bikes but I know Adam will have a fit, so I wont. Have you seen the Alfa kit on Ebay?

Steve

I really need to make sure that this is done by the book, so I'll need to get the proper gear :-( Got a link for that Alfa kit?

Ebay 120554785488. Looks the correct part for the job.

There are different types of dial gauge.. for measuring TDC you will need a "plunger" type dial gauge, which measures up and down, as opposed to a "lever" type dial gauge, which measures offset (or side to side).

TBH, I'd doubt if you really need a dial gauge to measure TDC - the whole point of the exercise is to make sure that the cam belt isn't a tooth out and that's going to be several degrees either side of TDC once the cams are locked.

Actually, that's given me an idea to make a go/no go tool that would do the job.. :idea: but best not to wait for that, FDL.

Cheers,

Plug

I need to check but I'm fairly sure the dial guage is not really required.

I'm pretty sure the 'B' has on the gearbox bell housing an inspection/timing hole window where you can just as accurately set TDC. This allows TDC to be set at flywheel diameter as opposed to crank pulley wheel diameter and is thus far more accurate.

Typically 5 degrees is about 25mm / 1 inch at flywheel diameters. This means that one can set TDC easily to within about 0.2 to 0.5 degrees.

The problem with TDC guages is they they measure depth at the top/bottom of the crank throw and this is the most innacurate position to measure. The most accurate position to measure is at a crank angle of 90 degrees. Here any crank movement produces the maximum height/depth change.

This is how the older Fiat twin cam engines are set up. TDC is measured at 90 degrees and a perfect 90 degree positioning tool is used to set the acutual TDC position.

The cam lobe locks will be required.

Hmm, very interesting. All the documentation for the Barchetta tells you to use a TDC though. Surely if there was a more accurate method - that would be the suggested method? I'm not sure though, I'm no mechanic.

Although, from what I've heard, the B needs to be set precisely or problems will occur. To be honest, I don't believe that it's a timing issue - I just need to rule it out.

Hmm, very interesting. All the documentation for the Barchetta tells you to use a TDC though. Surely if there was a more accurate method - that would be the suggested method? I'm not sure though, I'm no mechanic.

Although, from what I've heard, the B needs to be set precisely or problems will occur. To be honest, I don't believe that it's a timing issue - I just need to rule it out.

Have just checked our '05' 'B'

It does have the timing inspection hole on the top of the bell housing. It is marked 0, 5 and 10 degrees. The hole is covered by an oblong rubber blanking plug that will lift out.
When remove you will find three notches on the top enge of the hole that correspond to the 0 - 5 -10 timing positions.

To gain good visibility for accurate positioning you will need to remove the battery.

If you go down the depth guage route the I also suggest you verify by using the bell housing timing window as well. I think you will find that at TDC there is very little depth guage change making locating TDC a bit fiddly. I would also like to hear your view on ease of locating TDC by the two methods.

Hope this helps.

Thatnks very much s130. Will have a look!

To help explain some maths and values behind TDC timing.

The crank follows a pure Sine Wave motion. So like a Sine Wave the peaks and troughs (at 90 & 270 degrees) are shallow curves/inclines but at 0, 180 & 360 degrees are the steepest gradients.

Now when an engine is at TDC it is at the top of the crank throw and on the shallowest, even zero curve rate.

TDC on a car = 0 degrees which is actually equivalent to 90 degrees on a sine wave.

The Barchetta crank throw is 82.7mm.

Now as we all now x = Sin theta where theta = angle in degrees.

Sin 0 = 0 (this is 90 degrees off TDC)
Sin 45 = 0.71
Sin 90 = 1.0 (this is TDC)

So at TDC a 1 degree change equates to:
82.7 * (Sin 90 - Sin 89) = 0.01259 mm change

So at TDC a 0.5 degree change equates to:
82.7 * (Sin 90 - Sin 89.5) = 0.0031489mm change

At a 90 degree crank angle a 1 degree change equates to:
82.7 * (Sin 179 - Sin 180) = 1.443 mm

At a 90 degree crank angle a 0.5 degree change equates to:
82.7 * (Sin 179.5 - Sin 180) = 0.722mm

These last two measurments show a near linear relationship compared to the first TDC figures.


So at TDC 1 degree = 0.01259 mm
and at 90degrees, 1 degree = 1.443 mm

This is why it is far more accurate to set TDC at 90 degrees and measure back 90 degrees. This of course does require a suitable and accurate means of measuring a 90 degree offset. Fixed tooling can do this as can rotation guages.

Hope this adds a little extra info to the TDC timing issues.

Nick

Having read that I think my brain is about to explode, but at least it made sense. Well, the first and last words did.

I will be changing my cambelt soon on the Bravo 1.8, I have never done it before on this egnine and finding TDC is the part im worried about.

Looking throught the manual's I immediatly thought it would be very hard to find TDC through a guage because of piston dwell.

My 1.4 was very easy because you had a bracket that went into a notch on the Crank sprocket at TDC.


Aligning by the flywheel sounds far better to me especialy with the increased accuracy the flywheel diameter will give you. Thanks for the informative post's s130.

On every Fiat I've had, excluding first car a Fiat 600D (not sure about my Croma 05 as it is a GM box) there has been the inspection / timing hole on the top of the bell housing. When changing cam belts over the years I've always used the flywheel timing marks.

Now with the more modern cars with variable inlet cam timing, like the 'B' and Coupe I've not done a cam belt change yet. I no longer have the Coupe, just a 'B', Strada Abarth and Croma.

The 'B' will be due for a cam belt so I'll get the fun? of doing this belt change. Due to the low mileage of the car (27K) I'm considering not changing the water pump UNLESS there is obvious wear, play or noise. As I know the current timing is OK then I'll also skip the camshaft cover removal and lobe locking UNLESS the cam civer gasket is leaking any oil.

As every budding car DIYer know the best laid plans of vapourise when you get started on the job and for this reason you should be prepared to start the job again with plan B.