efi A Cam Position Sensor design - please critique

[jimk]

1 hour ago, uai said:

is this really billet?
Looks printed to me. 
So much effort (and money) for such an easy to tackle task.
If you have static ignition you might as well take one tooth off from your gear at the end of the cam and use the butchered cam gear as trigger wheel.
 

I considered a pickup from the distributor drive gear back then but if it's not successful, one wasted cam and much work to put in a good cam.   I went with the hacked distributor for several years since no signal accuracy is required. 

 

The sensor in the photo may needed the tooth length because of the sensor orientation on the cover.  Data sheets for sensors show the orientation relative to the tooth.

 

A cam lobe may not be usable without grinding a step into the lobe to trip the sensor if a hall is used.  A vr sensor would not at all without a defined tooth profile. 

[NickVyse]

2 hours ago, uai said:

is this really billet?

 

 

that's what he told me.

[AustrianVespaGuy]

On 2/22/2024 at 9:34 AM, jimk said:

A cam lobe may not be usable without grinding a step into the lobe to trip the sensor if a hall is used.  A vr sensor would not at all without a defined tooth profile. 

Yeah I agree a VR sensor probably would not work that well, but a Hall triggers nicely off a cam lobe; we've done it in a Slant 6!

Adding a camshaft and crankshaft position sensor to an older engine

WWW.DIYAUTOTUNE.COM

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Older engines typically do not have provisions for cam and crank position sensors. Here is an example of adding these on a Chrysler slant six.

At least as long as you're not using an aluminum camshaft anyway! XD

[veronatii]

I'm prototyping a fuel pump lobe cam position sensor using this 6.5mm hall effect with a 2mm sensing distance. Its held in place with an 8mm OD/6.5mm ID stainless rod. Its working well while hooked up to the multimeter.. we'll see how it does when I fire it up!

 

I plan to epoxy the sensor into the tube, but not sure on how I'll keep the tube in place. Any ideas?

 

https://www.automationdirect.com/adc/shopping/catalog/sensors_-z-_encoders/inductive_proximity_sensors/6.5mm_tubular/ahs-cp-3a

 

 

 

 

 

Edited March 5 by veronatii

[2002iii]

1 hour ago, veronatii said:

I'm prototyping a fuel pump lobe cam position sensor using this 6.5mm hall effect with a 2mm sensing distance. Its held in place with an 8mm OD/6.5mm ID stainless rod. Its working well while hooked up to the multimeter.. we'll see how it does when I fire it up!

 

I plan to epoxy the sensor into the tube, but not sure on how I'll keep the tube in place. Any ideas?

 

https://www.automationdirect.com/adc/shopping/catalog/sensors_-z-_encoders/inductive_proximity_sensors/6.5mm_tubular/ahs-cp-3a

 

 

 

 

 

I would buy a fuel pump block of plate and drill a hole in it. Then  attach your tube to that so it bolts on.

[veronatii]

4 hours ago, 2002iii said:

I would buy a fuel pump block of plate and drill a hole in it. Then  attach your tube to that so it bolts on.

I was thinking the same thing. I drilled half way through the block off plate, then drilled the cable hole in from the bottom. After epoxying the sensor into the tube, I pressed it in and used feeler gauges to create a 1mm gap between the sensor and the fully extended lobe. Then added epoxy into the filler cap hole and bolted it on. I
masked off the area behind the filler plate so the epoxy wouldn’t stick to the head. 

Here’s how it turned out! 

 

 

 

 

 

[uai]

1 hour ago, veronatii said:

I was thinking the same thing. I drilled half way through the block off plate, then drilled the cable hole in from the bottom. After epoxying the sensor into the tube, I pressed it in and used feeler gauges to create a 1mm gap between the sensor and the fully extended lobe. Then added epoxy into the filler cap hole and bolted it on. I
masked off the area behind the filler plate so the epoxy wouldn’t stick to the head. 
Here’s how it turned out! 

That looks nice, however I'd have a second one on board just in case the sensor doesn't like the heat

[tzei]

Make it so that air gap can be adjusted. E.g. shims under plate.

Edited March 6 by tzei

[tzei]

Actually a couple of collars over the shaft might be easier to fine tune air gap.

[jimk]

7 hours ago, uai said:

That looks nice, however I'd have a second one on board just in case the sensor doesn't like the heat

Agree, hall effect sensors have a transistor in them and switch to the reference voltage in square wave pattern.  The sensor specs should list suitable up to 300F at least for engine internal mounting.  

[veronatii]

2 hours ago, jimk said:

Agree, hall effect sensors have a transistor in them and switch to the reference voltage in square wave pattern.  The sensor specs should list suitable up to 300F at least for engine internal mounting.  

Operating temp is definitely my main concern for this design. 

[AustrianVespaGuy]

23 hours ago, veronatii said:

I'm prototyping a fuel pump lobe cam position sensor using this 6.5mm hall effect with a 2mm sensing distance.

Ooohh, I LOVE this, good find!  I'm slightly worried about oil getting out through that hole in your block off plate, but I'm sure you'll solve that if it's an issue.  Also, it does seem that the spec sheet lists operating temperature from -13 to 158F, so. . . we might need to find a more 'robust' candidate, but I might be inclined to take another shot at this also!

[Son of Marty]

That's not a particularly hot area of the engine but 158' is going to be close. 

[AustrianVespaGuy]

5 hours ago, veronatii said:

Operating temp is definitely my main concern for this design. 

117 Euro ain't cheap but gets  you up to 248F. . .

https://xecro.com/shop/inductive-high-temperature/ihtd6-s2anc45-a2s/

[veronatii]

17 minutes ago, AustrianVespaGuy said:

117 Euro ain't cheap but gets  you up to 248F. . .

https://xecro.com/shop/inductive-high-temperature/ihtd6-s2anc45-a2s/

Ya there's definitely more robust options, but I figured I'd prototype with the $29 sensor  

 

This one is good to 120°C and claims to be "oil resistant" 
 

Inductive proximity sensor - IGMF 202 GSP - EGE-Elektronik Spezial-Sensoren GmbH - cylindrical / M8 / PNP

WWW.DIRECTINDUSTRY.COM

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Small Inductive Sensor for extreme Conditions, 120° / IP 69 / Temperaturexchange-Proof If the installation space is limited and the ambient temperature can reach 120 °C, this inductive proximity switch is the problem solver. In the flush design, it offers a switching distance of 2...

 

Edited March 6 by veronatii