Isuzu marine control tacho glass

[andybarrett1]

Hi

 

Thank you for reading...Am looking for a replacement Tacho glass as in photo.

 

Mine has a huge crack letting in water.

 

Any pointers welcome 

 

Andy

 

 

[BEngo]

Your local glass (double glazing) merchant should be able to cut and toughen a suitable size disc in 4mm glass.  It might have to go away for toughening.  

 

Laminated is probably also available, but will be thicker.

 

The hard part is usually dismantling the old instrument.

 

N

[Tracy D'arth]

4" in diameter is too small to put through a toughening furnace, it will drop through the rollers.  Polycarbonate and cut a disc by hand.

[BEngo]

According to the chaps who made and fitted my windows you don't need a furnace to toughen glass these days.  A lot of it is done chemically.  Don't  have any more details though.

 

N

[Tracy D'arth]

4 hours ago, BEngo said:

According to the chaps who made and fitted my windows you don't need a furnace to toughen glass these days.  A lot of it is done chemically.  Don't  have any more details though.

 

N

That is interesting,

I have problems getting small porthole glasses, laminated is too thick and a devil to cut circles in.

[BEngo]

A bit of googling reveals that you soak the glass in potassium salt, commonly potassium nitrate, at 300-400 °C. There is an then an  ion exchange reaction with the sodium in the glass so it ends up with a Potassium rich, tough skin.

 

N

[Tracy D'arth]

6 hours ago, BEngo said:

A bit of googling reveals that you soak the glass in potassium salt, commonly potassium nitrate, at 300-400 °C. There is an then an  ion exchange reaction with the sodium in the glass so it ends up with a Potassium rich, tough skin.

 

N

Thank you for that, its been a school day again.

[Jen-in-Wellies]

Replacing the "glass" on that type of instrument will not be simple. It is not a flat sheet, but a transparent plastic dome that is part of the gauge and projects through the metal panel. I believe the gauges are from VDO, but don't know what series. You may have success filling the crack with something to glue, or seal it. Any surface roughness afterwards can be polished out with Brasso, which will also remove any surface scratches. I have worked on this type of Isuzu panel before.

Jen

 

Edited September 10, 2021 by Jen-in-Wellies

[TheBiscuits]

Or just buy a new VDO tacho - the LCD has gone wonky too on that photo - and replace the whole unit in the panel.

[Telstar]

I replaced mine with 2mm clear polycarbonate, carefully cut with a jigsaw.

Finished job is perfect.

Cost a couple of quid off ebay for an A5 sheet.

Enough to do several.

If it needs to be dished to clear the needle, or you want something that is easy to fit, I think you'll need a new tacho.

As "TheBuscuits" said, the hour meter LCD is toshed anyway.

[Jen-in-Wellies]

On 10/09/2021 at 22:54, TheBiscuits said:

Or just buy a new VDO tacho - the LCD has gone wonky too on that photo - and replace the whole unit in the panel.

If replacing, the techo either needs to be identical, or the hole in the panel may need altering. The hole for the tacho in these Isuzu panels is 83mm diameter. These particular VDO instruments are unlike other instruments from VDO, or anyone else. These instruments are fixed by flanged washers on studs welded to the back of the panel. The studs may need removing to allow the more typical lock ring on a replacement to be used. Isuzu may be the best chance of finding an identical replacement.

 

I designed a new panel to replace the rather tatty Isuzu panel for some friends boat. Had it made by a local panel making company, so I got to learn about the oddities of these instruments.

Edited September 13, 2021 by Jen-in-Wellies

[Guest]

On a related matter, does anyone have one of these hours counters that still works after a few years?

 

Ours in our Isuzu panel failed at about 6 years of the boats age.

[cuthound]

3 hours ago, The Happy Nomad said:

On a related matter, does anyone have one of these hours counters that still works after a few years?

 

Ours in our Isuzu panel failed at about 6 years of the boats age.

 

Mine is 14 years old and still going strong.

 

The trick is to keep them warm and dry. They last longer on trads than cruisers.

 

The display usually fails when it gets damp but the hours counter itself keeps counting. 

 

Putting the tacho in an airing cupboard often dries out the damp and brings the display back to life.

Edited September 13, 2021 by cuthound
Trads not reads- bluddy autowrong

[Jen-in-Wellies]

6 minutes ago, cuthound said:

 

Mine is 14 years old and still going strong.

 

The trick is to keep them warm and dry. They last longer on reads than cruisers.

 

The display usually fails when it gets damp but the hours counter itself keeps counting. 

 

Putting the tacho in an airing cupboard often dries out the damp and brings the display back to life.

 

Same here. 14 years, still going, but inside a boat that is lived in, so warm and dry almost all the time.

[Guest]

Ours was a semi trad, but we had a pram hood but that doesnt mean it never got wet, as if we cruised in the rain the vision through the front was very poor so invariably it was down.