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-   Marlin Sportster, Cabrio, Berlinetta and Roadster builds (https://madabout-kitcars.com/forum/forumdisplay.php?f=13)
-   -   Mikes BMW Marlin Cabrio (https://madabout-kitcars.com/forum/showthread.php?t=1559)

Mike 5th March 2012 15:31

Quote:

Originally Posted by jeremy (Post 27641)
That is a work of art!congrats.

Sue doesn't think so - at least not on the kitchen table! - whereas I just want to keep looking at it!

GreatOldOne 5th March 2012 15:49

Huh. Women, eh? ;)

Nice job Mike.

Chris Cussen 5th March 2012 17:41

Gulp!
Wow! that looks superb. Makes mine look really crude. I went for functional!

Patrick 5th March 2012 17:51

Looks fantastic, incredibly detailed finish.

cabrioman 5th March 2012 19:30

Very impressive Mike, I think the effort to add the centre vents is really worth it.

John

peterux 5th March 2012 20:11

I'm a bit late in seeing this so......... ditto all the above comments :smile:
Very nice finish, well done :thumb:

Mike 18th March 2012 17:31

Oh dear...............................
 
Bit of a mixed weekend....................

I have started to fit the electrics in to my car, which most of you will know, I am not looking forward to.Front light loom fitting and connection all went ok.

Next job was to wire in the electric fan. I had included a spare union/socket in my radiator to allow me to fit a standard Sierra radiator fan sensor switch. As a temporary measure I had fitted an old sensor just to bung the hole up. When I came to remove it , it would not budge -so a bit more brute force was applied.........and you've guessed it - the nut has split away from the thin walled tank, and I now have a puddle on my garage floor.

It has just taken me three hours to remove all the electrics to the light bar (thatI had spent all morning fitting), then the light bar itself, along with the nose cone, and finally extract the radiator. Plus another hour to clean the brass tank around the socket nut, ready for it to be re-solder tomorrow.

Harumph - not a happy bunny!!!

On the brighter side my friendly welder has welded together all my bits for the Berlinetta and Roadster light bars which I have made for some of the other MOC members.

If anyone needs any stainless parts - let me know, and I will see what I can arrange? - all at non commercial rates!
Mike

peterux 18th March 2012 21:27

I think we've all had moments like that during our builds, but you'll forget them once your finished!
I'm sure you'll have it all back together in no time at all......

Mike 31st March 2012 09:11

Steaming!!!!!!!!!!!!!!!!!
 
I'm not happy!


The Smiths Classic Water Temp gauge I chose is not compatible with the BMW VDO sender in the cylinder head. Caerbont (the manufacturer of Smiths gauges) advised I would have to use one of their senders for it to register correctly. I bought one, and after spending several hours adapting it to fit into my cylinder head, I decided to test its callibration.

According to Caerbont, water now boils at 135 degrees C!

http://farm8.staticflickr.com/7223/6...20056810_n.jpg

............and it is consistently out across the scale.
True 90 reads 125deg C
true 80 reads 110
true 70 reads 85
true 60 reads 75

below that it is not worth using the gauge (......or at any temp based on above!!!)


Do any of you auto electrician bods have any suggestions?

peterux 31st March 2012 11:38

Quote:

Originally Posted by Mike (Post 28734)
I'm not happy!


The Smiths Classic Water Temp gauge I chose is not compatible with the BMW VDO sender in the cylinder head. Caerbont (the manufacturer of Smiths gauges) advised I would have to use one of their senders for it to register correctly. I bought one, and after spending several hours adapting it to fit into my cylinder head, I decided to test its callibration.

According to Caerbont, water now boils at 135 degrees C!

http://farm8.staticflickr.com/7223/6...20056810_n.jpg

............and it is consistently out across the scale.
True 90 reads 125deg C
true 80 reads 110
true 70 reads 85
true 60 reads 75

below that it is not worth using the gauge (......or at any temp based on above!!!)


Do any of you auto electrician bods have any suggestions?

Hi Mike,
I'm not very familiar with these gauges but a quick Google seems to suggest they need a voltage stabiliser to provide a 10 volt supply.

http://www.merlinmotorsport.co.uk/p1...duct_info.html

Maybe your stabiliser is faulty?

Mike 31st March 2012 13:00

Quote:

Originally Posted by peterux (Post 28746)
Hi Mike,
I'm not very familiar with these gauges but a quick Google seems to suggest they need a voltage stabiliser to provide a 10 volt supply.

http://www.merlinmotorsport.co.uk/p1...duct_info.html

Maybe your stabiliser is faulty?

Hi Peter

Thanks for that.

Although I was aware it needed a voltage stabiliser, I did not appreciate it needed to be 10 volts. That will explain the over reading when I tested it direct from the battery.
Trouble was, when tested through the stabiliser I could not get any reading.

I've now checked the stabiliser and it does not work, so I'll order a solid state one from RS instead of the mickey mouse one Smiths supply which even has to be physically mounted vertically otherwise it does not work in its normal state!

Would one of these from RS be a better voltage regulator?
http://uk.rs-online.com/web/p/linear-regulator/2393067/

peterux 31st March 2012 15:47

Quote:

Originally Posted by Mike (Post 28751)
Hi Peter

Thanks for that.

Although I was aware it needed a voltage stabiliser, I did not appreciate it needed to be 10 volts. That will explain the over reading when I tested it direct from the battery.
Trouble was, when tested through the stabiliser I could not get any reading.

I've now checked the stabiliser and it does not work, so I'll order a solid state one from RS instead of the mickey mouse one Smiths supply which even has to be physically mounted vertically otherwise it does not work in its normal state!

Would one of these from RS be a better voltage regulator?
http://uk.rs-online.com/web/p/linear-regulator/2393067/

Hi Mike,
it was just a hunch. I hope it works better with the 10 volt supply.
Certainly an interesting voltage stabiliser that relies on gravity.:eek:
I think a solid state one that can supply all your instruments that need 10 volts is a nice idea, but it might be cheaper and quicker to get a new Smith's one. If you buy that RS component you will need to solder it on a piece of 'vero' board and add two bypass capacitors. Then mount it in a small box with some connectors to make it robust for a car environment.
Not impossible but I would just order a Smith's one from Merlin Motor sport.

Mike 31st March 2012 16:02

Quote:

Originally Posted by peterux (Post 28760)
Hi Mike,
it was just a hunch. I hope it works better with the 10 volt supply.
Certainly an interesting voltage stabiliser that relies on gravity.:eek:
I think a solid state one that can supply all your instruments that need 10 volts is a nice idea, but it might be cheaper and quicker to get a new Smith's one. If you buy that RS component you will need to solder it on a piece of 'vero' board and add two bypass capacitors. Then mount it in a small box with some connectors to make it robust for a car environment.
Not impossible but I would just order a Smith's one from Merlin Motor sport.

I was planning to connect it direct - why does it need two bypass capacitors?

There is an interesting article from the MG forum:

http://www.britishv8.org/Articles/MG...Stabilizer.htm

Chris Cussen 31st March 2012 16:04

A quick look at your numbers shows an interesting ratio
Actual Reading ratio
90 125 1.39
80 110 1.38
70 85 1.21
60 75 1.25



Its not linear but up beyond 80+ it seems fairly consistent.

The temp gauge works onmeasuring the current flowing through the sensor, so to have it over-read there is too much current. You could reduce it by putting a resistor in-line with the wire to the sensor. What you will need to know is the resistance of the sensor at, say 90 to do the calculation.

If you use a multimeter to measure the resistance (R) then the in-line resistor would need to be 0.38*R

peterux 31st March 2012 16:26

Quote:

Originally Posted by Mike (Post 28761)
I was planning to connect it direct - why does it need two bypass capacitors?

There is an interesting article from the MG forum:

http://www.britishv8.org/Articles/MG...Stabilizer.htm

That's pretty neat solution!
My comment about bypass capacitors was based on the application note with the component you picked.
Note number 3 in the application notes.

Mike 31st March 2012 16:52

Does anyone know the current taken by a Water temp sender/gauge and a fuel sender/gauge?

Looking on RS Components site there are a number of 10v chips, with varying current capabilities.

Is the one I've identified below likely to be suitable?

Jeepers Peter - you read the detail! Given my application, will this chip work in the set up described in the British V8 forum without the capacitors ?

It seems such a simple fix it it will work reliably?

peterux 31st March 2012 21:03

Quote:

Originally Posted by Mike (Post 28769)
Does anyone know the current taken by a Water temp sender/gauge and a fuel sender/gauge?

Looking on RS Components site there are a number of 10v chips, with varying current capabilities.

Is the one I've identified below likely to be suitable?

Jeepers Peter - you read the detail! Given my application, will this chip work in the set up described in the British V8 forum without the capacitors ?

It seems such a simple fix it it will work reliably?

Without more knowledge of these gauges it's pretty much impossible to answer these questions although reliability will probably depend more on how well you build it!
Did the gauges come with any kind of datasheets?

MartinClan 1st April 2012 20:27

Just my 5 penneth.....

You will certainly need a voltage stabiliser if the instrument is designed to work that way. The theoretical 12v that comes from your car's electrical system is not actually 12v anyway, and also not particularly stable.

Using an electronic regulator may or may not work well - although a linear one is better than something fancier (digital). Car electrical systems are full of noise which plays havoc with anything electronic.

Personally I would try to stick with stuff specifically designed for the job. I would use the smiths regulator - even if you have to fix it the right way up!

Robin

Mike 1st April 2012 21:06

Hi Rob

I have wasted most of the wekend playing about with electrical things I do not understand! - although I have learned a great deal - "receivers - base - emitters"!
I bought a 10v LDO chip from maplins for 99p - well I bought three.
After messing around we got 9.88v out of it. Then I blew it up - quite literally the whole thing blew it self apart! We then got 10.4 vaults when aa 22k ohm resistor was included
At this point I decide to pull the Smiths regulator apart, and to my surprise it is solid state, with a chip, and its own non oscillating resistors.....................

................so, tomorrow, I shall do exactly as you suggest and buy another Smiths solid state regulator, which will cost £15 including p+p!

Out of interest, why would it need to be physically installed vertically - or is this just a sop to the old days when it would have been a bi-metallic strip?


Quote:

Originally Posted by MartinClan (Post 28847)
Just my 5 penneth.....

You will certainly need a voltage stabiliser if the instrument is designed to work that way. The theoretical 12v that comes from your car's electrical system is not actually 12v anyway, and also not particularly stable.

Using an electronic regulator may or may not work well - although a linear one is better than something fancier (digital). Car electrical systems are full of noise which plays havoc with anything electronic.

Personally I would try to stick with stuff specifically designed for the job. I would use the smiths regulator - even if you have to fix it the right way up!

Robin


MartinClan 2nd April 2012 07:28

Quote:

Originally Posted by Mike (Post 28849)
Out of interest, why would it need to be physically installed vertically - or is this just a sop to the old days when it would have been a bi-metallic strip?

I think you hit the nail on the head there. Just a hang over to when it was an electro-mechanical device. In general, anything electronic is not sensitive to orientation - unless it is designed to be so.

Cheers

Robin

PS - Even us electronic engineers blow stuff up occaisionally. You get used to the smell of burning chips...


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