"Dave Plowman (News)" wrote in message
...
In article ,
David Billington wrote:
That was my fear that they were sort of built in. I'm
thinking of
fabricating brackets that attach to the exhaust manifold
fixings.


Dave,

I think the main thing is you have a good solid fixing to the
block
without flexure as they're basically an acoustic pickup, you
wouldn't
want possible relative movement giving false indications
(noise).

Indeed - I assume they're just some form of contact mic. I was
thinking of
supporting it by a bracket, but actually using epoxy to stick
it to the
block. But open to better suggestions. ;-)

For a solid fixing, I would suggest drilling and tapping the
block. No doubt they would break into the water jacket, but a
pair of brass inserts screwed in with sealant, maybe using
'Loctite Retainer' so they wouldn't easily unscrew if the sensor
bolt became tight, would not cause any problems as far as water
leaks were concerned, and I can't think of a better way to get a
really solid fixing.

With a central blind hole tapped to suit the knock sensor, you'd
have a fixing as solid as any OE fitted one. I certainly wouldn't
advise you glue them. I don't think they would stay glued for
long.

I could make the inserts for you if you decided on that method.
All I would need to know is the water jacket thickness, (easily
checked after drilling) and the sensor bolt diameter.

If you're interested, I assume you still have my email address.
Mike.

*If you're doing nothing, how do you know when you've finished?*

Dave Plowman (News) wrote:
In article ,
David Billington wrote:

You might also look at the ones used by
Megasquirt, IIRC they would also do and last time I looked a year or so
ago were stocked by RS.


Thanks for the heads up - despite using electronics suppliers I never
thought to try them.
Got exactly what I wanted from Farnell - at about 15 quid rather than the
75 or so for 'car' ones. Only difference is it has Molex connectors rather
than an automotive one.


That's good. I used to have an account with Farnell but as their printed
catalogues dried up, and they pushed more to the website I stopped
buying from them and switched to RS. I didn't have a RS catalogue but I
found RSs website vastly superior to Farnells and it still is by the
look of it. I found using Farnells website a waste of time when it might
take an hour to get an order together that would take 10 minutes with
the printed catalogue.

In article ,
Mike G wrote:
Indeed - I assume they're just some form of contact mic. I was
thinking of
supporting it by a bracket, but actually using epoxy to stick
it to the
block. But open to better suggestions. ;-)

For a solid fixing, I would suggest drilling and tapping the
block. No doubt they would break into the water jacket, but a
pair of brass inserts screwed in with sealant, maybe using
'Loctite Retainer' so they wouldn't easily unscrew if the sensor
bolt became tight, would not cause any problems as far as water
leaks were concerned, and I can't think of a better way to get a
really solid fixing.

Hmm. It would certainly make for a good fixing, but I'm not sure the
sensors - being a type of microphone - are a) waterproof, b) would cope
with the pressure of the coolant and c) wouldn't get confused by the sound
of the coolant rushing past the diaphragm. The circuit does include a high
pass filter to remove unwanted noises from those to be sensed but My
feeling is it wouldn't filter that out.
Of course it's only guessing on my part.

With a central blind hole tapped to suit the knock sensor, you'd
have a fixing as solid as any OE fitted one. I certainly wouldn't
advise you glue them. I don't think they would stay glued for
long.

My thoughts were to support if firmly with a bracket bolted to the
exhaust manifold fixings as well as gluing to the block. Although some
subsequent research on Google shows contact may not be necessary.

I could make the inserts for you if you decided on that method.
All I would need to know is the water jacket thickness, (easily
checked after drilling) and the sensor bolt diameter.

That's very kind, Mike.

If you're interested, I assume you still have my email address.

I do indeed.

--
*Learn from your parents' mistakes - use birth control

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
David Billington wrote:
Thanks for the heads up - despite using electronics suppliers I never
thought to try them. Got exactly what I wanted from Farnell - at about
15 quid rather than the 75 or so for 'car' ones. Only difference is it
has Molex connectors rather than an automotive one.


That's good. I used to have an account with Farnell but as their printed
catalogues dried up, and they pushed more to the website I stopped
buying from them and switched to RS. I didn't have a RS catalogue but I
found RSs website vastly superior to Farnells and it still is by the
look of it.

I'm not sure there's much between them once you suss them out. They are
both slow if you have a slow connection or computer.

I found using Farnells website a waste of time when it might
take an hour to get an order together that would take 10 minutes with
the printed catalogue.

I tend to use Farnell/CPC cost wise. And Rapid. RS tend to be a last
resort. ;-)

--
*Someday, we'll look back on this, laugh nervously and change the subject

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote in message
...
In article ,
Mike G wrote:
Indeed - I assume they're just some form of contact mic. I
was
thinking of
supporting it by a bracket, but actually using epoxy to
stick
it to the
block. But open to better suggestions. ;-)

For a solid fixing, I would suggest drilling and tapping the
block. No doubt they would break into the water jacket, but a
pair of brass inserts screwed in with sealant, maybe using
'Loctite Retainer' so they wouldn't easily unscrew if the
sensor
bolt became tight, would not cause any problems as far as
water
leaks were concerned, and I can't think of a better way to get
a
really solid fixing.

Hmm. It would certainly make for a good fixing, but I'm not
sure the
sensors - being a type of microphone - are a) waterproof, b)
would cope
with the pressure of the coolant and c) wouldn't get confused
by the sound
of the coolant rushing past the diaphragm. The circuit does
include a high
pass filter to remove unwanted noises from those to be sensed
but My
feeling is it wouldn't filter that out.
Of course it's only guessing on my part.

You missed the part about the sensor fixing being blind.
Imagine a solid plug screwed into the block. Say 12mm long. The
plug is then drilled 10mm deep and tapped to suit the sensor, so
the sensor never contacts the water.
Im thinking of the sensors that are mounted on a flat surface,
and retained by a bolt that passes through them. The ones like a
thick washer, for want of a better description.
Mike.

"Mike G" wrote in message
...

"Dave Plowman (News)" wrote in message
...
In article ,
Mike G wrote:
Indeed - I assume they're just some form of contact mic. I
was
thinking of
supporting it by a bracket, but actually using epoxy to
stick
it to the
block. But open to better suggestions. ;-)

For a solid fixing, I would suggest drilling and tapping the
block. No doubt they would break into the water jacket, but a
pair of brass inserts screwed in with sealant, maybe using
'Loctite Retainer' so they wouldn't easily unscrew if the
sensor
bolt became tight, would not cause any problems as far as
water
leaks were concerned, and I can't think of a better way to
get a
really solid fixing.

Hmm. It would certainly make for a good fixing, but I'm not
sure the
sensors - being a type of microphone - are a) waterproof, b)
would cope
with the pressure of the coolant and c) wouldn't get confused
by the sound
of the coolant rushing past the diaphragm. The circuit does
include a high
pass filter to remove unwanted noises from those to be sensed
but My
feeling is it wouldn't filter that out.
Of course it's only guessing on my part.

You missed the part about the sensor fixing being blind.
Imagine a solid plug screwed into the block. Say 12mm long. The
plug is then drilled 10mm deep and tapped to suit the sensor,
so the sensor never contacts the water.
Im thinking of the sensors that are mounted on a flat surface,
and retained by a bolt that passes through them. The ones like
a thick washer, for want of a better description.
Mike.

I should have added that the same principle could be used for the
type that screw into the block, but for that type I'd need to
know the thread spec of the sensor, which could be an odd thread.
Mike.

Dave Plowman (News) wrote:
In article ,
David Billington wrote:

Thanks for the heads up - despite using electronics suppliers I never
thought to try them. Got exactly what I wanted from Farnell - at about
15 quid rather than the 75 or so for 'car' ones. Only difference is it
has Molex connectors rather than an automotive one.



That's good. I used to have an account with Farnell but as their printed
catalogues dried up, and they pushed more to the website I stopped
buying from them and switched to RS. I didn't have a RS catalogue but I
found RSs website vastly superior to Farnells and it still is by the
look of it.


I'm not sure there's much between them once you suss them out. They are
both slow if you have a slow connection or computer.


It was mainly that the printed catalogue had the data in it with the
component so I could make a decision quickly, I found the Farnell site
presentation poor and the data had to be downloaded if present. RS at
least had quite a bit of data on the webpages detailing many of the
components so was far quicker to get an order together.

I found using Farnells website a waste of time when it might
take an hour to get an order together that would take 10 minutes with
the printed catalogue.


I tend to use Farnell/CPC cost wise. And Rapid. RS tend to be a last
resort. ;-)


Must look at CPC as I haven't in awhile. Got a nice shiny new Maplins in
Bath now so for odds and ends I can pop in there and pick them up.

Dave Plowman (News) wrote:
In article ,
Mike G wrote:

Indeed - I assume they're just some form of contact mic. I was
thinking of
supporting it by a bracket, but actually using epoxy to stick
it to the
block. But open to better suggestions. ;-)



For a solid fixing, I would suggest drilling and tapping the
block. No doubt they would break into the water jacket, but a
pair of brass inserts screwed in with sealant, maybe using
'Loctite Retainer' so they wouldn't easily unscrew if the sensor
bolt became tight, would not cause any problems as far as water
leaks were concerned, and I can't think of a better way to get a
really solid fixing.


Hmm. It would certainly make for a good fixing, but I'm not sure the
sensors - being a type of microphone - are a) waterproof, b) would cope
with the pressure of the coolant and c) wouldn't get confused by the sound
of the coolant rushing past the diaphragm. The circuit does include a high
pass filter to remove unwanted noises from those to be sensed but My
feeling is it wouldn't filter that out.
Of course it's only guessing on my part.

Bosch ones are shown here
http://www.bosch.com.au/content/lang...sors_knock.pdf
and shouldn't have any problem with bits getting wet from the look of it
if you tapped right through into the water jacket.



With a central blind hole tapped to suit the knock sensor, you'd
have a fixing as solid as any OE fitted one. I certainly wouldn't
advise you glue them. I don't think they would stay glued for
long.


My thoughts were to support if firmly with a bracket bolted to the
exhaust manifold fixings as well as gluing to the block. Although some
subsequent research on Google shows contact may not be necessary.


I could make the inserts for you if you decided on that method.
All I would need to know is the water jacket thickness, (easily
checked after drilling) and the sensor bolt diameter.


That's very kind, Mike.


If you're interested, I assume you still have my email address.


I do indeed.

"David Billington" wrote in
message ...
Dave Plowman (News) wrote:
In article ,
Mike G wrote:

Indeed - I assume they're just some form of contact mic. I
was thinking of
supporting it by a bracket, but actually using epoxy to
stick it to the
block. But open to better suggestions. ;-)



For a solid fixing, I would suggest drilling and tapping the
block. No doubt they would break into the water jacket, but a
pair of brass inserts screwed in with sealant, maybe using
'Loctite Retainer' so they wouldn't easily unscrew if the
sensor bolt became tight, would not cause any problems as far
as water leaks were concerned, and I can't think of a better
way to get a really solid fixing.


Hmm. It would certainly make for a good fixing, but I'm not
sure the
sensors - being a type of microphone - are a) waterproof, b)
would cope
with the pressure of the coolant and c) wouldn't get confused
by the sound
of the coolant rushing past the diaphragm. The circuit does
include a high
pass filter to remove unwanted noises from those to be sensed
but My
feeling is it wouldn't filter that out.
Of course it's only guessing on my part.
Bosch ones are shown here
http://www.bosch.com.au/content/lang...sors_knock.pdf
and shouldn't have any problem with bits getting wet from the
look of it if you tapped right through into the water jacket.

That's the type I'm thinking about, but ideally they should be
bolted to a flat surface. Unlikely with a cast block. Another
disadvantage is that replacing them for whatever reason would
allow water to leak from the cooling system.
The brass adaptors idea overcomes both those problems.
Apart from that it's a much more elegant solution. :-)
Mike.
Mike.

On Fri, 19 Sep 2008 13:47:17 +0100, David Billington
wrote:

Dave Plowman (News) wrote:
In article ,
David Billington wrote:

Thanks for the heads up - despite using electronics suppliers I never
thought to try them. Got exactly what I wanted from Farnell - at about
15 quid rather than the 75 or so for 'car' ones. Only difference is it
has Molex connectors rather than an automotive one.



That's good. I used to have an account with Farnell but as their printed
catalogues dried up, and they pushed more to the website I stopped
buying from them and switched to RS. I didn't have a RS catalogue but I
found RSs website vastly superior to Farnells and it still is by the
look of it.


I'm not sure there's much between them once you suss them out. They are
both slow if you have a slow connection or computer.


It was mainly that the printed catalogue had the data in it with the
component so I could make a decision quickly, I found the Farnell site
presentation poor and the data had to be downloaded if present. RS at
least had quite a bit of data on the webpages detailing many of the
components so was far quicker to get an order together.

I found using Farnells website a waste of time when it might
take an hour to get an order together that would take 10 minutes with
the printed catalogue.


I tend to use Farnell/CPC cost wise. And Rapid. RS tend to be a last
resort. ;-)


Must look at CPC as I haven't in awhile. Got a nice shiny new Maplins in
Bath now so for odds and ends I can pop in there and pick them up.

CPC *is* Farnells...

Maplins is useful and convenient, but not as cheap, and just doesn't
have the range of Rapid & CPC. Like Dave, RS is a last resort!
--
Regards, Chris (Please take out my car to reply by plain text email)
------1967 Riley Elf------1978 Mini 1000------1971 Mini Clubman------
--1972 Mini Clubman estate--1979 Ford Capri--1984 VW Type 25 camper--