Smiths Speedo And Signal Pick Up Setting

[Guest greengrass]

Can anybody help me in how to set the speedo on my zero. I have the instructions that came with the gauge but it reads a little confussing . Just to clarify I have smiths flights gauges, gbs main loom and gbs gauge loom. The sender is lined up on the prop shaft and will pick up on four bolt heads. The instructions talk about diff ratios as well mine is a 3.62 my tyres are 195/50/15

 

Any help on the best way to set this up or the best way to do this ie what numbers to put in and how to do it much appreciated . Cheers

[Snapperpaul]

Instructions are on the Caerbont web site

The calculation requires

pick up points. 4 bolts

Diff ratio

Wheel rolling circumference or diameter or radius

On a piece of paper write what you know and perhaps we can help with the rest

[Guest greengrass]

Hi thanks the reply . The diff ratio is 3.62

The circumfere of wheel is 183 cm

The pick up points is 4

I'm I right in thinking I have got to work out how many 183cm their are in a mile ?

 

Cheers

[knights_templar]

that sounds a lot of mental stress for new year eve

Edited December 31, 2012 by knights_templar

[fry61]

that sounds a lot of mental stress for new year eve

 

To help the dark knight see the light --- 879.4 wheel revolutions per mile.

[cb750]

You need to input the calibration number on the speedo. On the fitting sheet that I have it says:

 

Calculating The Calibration Number

 

You need to know the number of times your wheels revolve per mile (or kilometre). Stand the vehicle on a flat surface and mark the tyre at the closest point to the ground, mark the ground at the same point. Move the vehicle forward by one complete wheel revolution and measure the distance travelled.

 

 

 

Wheel revs per mile = 63360 divided by the distance travelled in inches.

 

 

 

Wheel revs per km. = 1000 divided by the distance travelled in metres.

 

 

 

To Calculate the Calibration Number (pulses per mile/km)

 

- For magnetic sensors, magnets or bolt heads moving past the sensor (eg. prop shaft mounting).

 

 

 

• Calibration number = (wheel revs per mile/km) x (diff ratio) x (number of magnets or bolts).

 

The instructions for inputting the Calibration Number are on the CA website as Snapperpaul says. If you ring them and speak to their technical guy he is very helpful.

 

Whoops!! 2 more replies have been added before I posted this - hope I haven't repeated what they have said!

[fry61]

Another valid point,hopefully---- I found it impossble to get a steady sender reading from the bolt heads; because some locked off at bolt head "point" being the nearest to sender & some were "flat" to sender. Took a file to the offending "points" & all was well once the sender/bolt gap was adjusted to fag paper clearance.

[Guest greengrass]

Ok chaps thanks for all the advice and a happy new year. Here is what I have done

(160934cm per miles ,divide by 183 cm tyre circumference ) X. 3.62 diff ratio. X. 4 bolt heads

=. 12734. Just got to get in programed in now.

 

Cheers

[johnhetherington]

Can someone explain to me how to work out the diff ratio

Thanks

John

 

http://www.johnskitcar.com

[Guest greengrass]

Hi John . I have a chart somewhere with a cross refencece to the ford diff from the modal of car. When I get home I will see I'd I can find it, mine is out a sierra xr4i if that helps with bolt on shafts . If you don't know we're diff came from it may be a bit harder. Their should be a tag bolted to one of the back plate housing bolts. This some how can tell you the ratio. Not sure it's the actual ratio or a code. Hope this helps

[johnhetherington]

Yes I do know where the diff came from so the chart will be very helpful thanks, will check the tag in the morning.

I thought maybe if I turned the propshat and counted how many times the wheel went round it is worked out from there.

[Bob Tucker]

Jack up one wheel.

Mark a point on the wheel & a point on the propshaft.

Turn the wheel excatly twice & count the propshaft turns.

Most common diff ratios are 3.62 & 3.92.

No need to be precise, it will be just over 3 & 1/2 or nearly 4

[johnhetherington]

That's brilliant Bob, will give it a go tomorrow.

Cheers

[Guest greengrass]

 

XR4i (1982-1984.5)

Non LSD

7' rear

smaller Sierra stubshafts

drum brakes

3.62:1 ratio

 

Merkur XR4Ti

Non LSD

7.5' rear

smaller Sierra stubshafts

drum brakes

3.64:1 ratio

 

All XR4x4 V6-powered vehicles

LSD

7' rear

smaller Sierra stubshafts

disc brakes

3.62:1 ratio

 

Late model XR4x4 w/ 2.0 engine

LSD

7' rear

smaller Sierra stubshafts

disc brakes

3.92:1 ratio

 

All Sierra Cosworth RWD

LSD

7.5' rear

LARGE Granada stubshafts

disc brakes

3.64:1 ratio

 

All Sierra 4WD Cosworth & Escort Cosworth

LSD

7' rear

smaller Sierra stubshafts

disc brakes

3:62:1 ratio

 

Scorpio 24v (Cosworth)

LSD

7.5' rear

smaller Sierra stubshafts

disc brakes

3.64:1 ratio

 

Any RWD Sierra with any 2.0 engine (non-Cosworth)

Non LSD

7' rear

smaller Sierra stubshafts

drum brakes (disc optional on last Sierras)

3:92:1 ratio