Diesel timing light
Diesel timing light
1987 Mercedes 190TD
So I'm looking at an old timing light and a crank position sensor from a W210. Can the crank position sensor be used in place of the inductive pickup on the timing light? If so, it would be a neat solution for timing a Bosch injector pump. Anyone know if this would work?
1987 Mercedes 190TD
(06-30-2013, 12:52 PM)mantahead hi,
could he use the sensor to read the pump timing pointer inside the pump through the hole?
i think there was a tool mercedes used checked the timing this way.
Yup that's exactly right. On the 60x engines there's a bung in the side of the injection pump, which allows you to access a timing lobe on the cam. The peak of the lobe is the start-of-injection point for cyl 1. I would cut a hollow bolt to fit whatever thread size is on that plug, and mount the CPS in the center of it. If it's powerful enough to trigger the light, I think that's all there is to it. If not, then it's an engineering project to figure out how to match the CPS to the light. Mercedes CPS's are inductive, so I'm thinking I might just get lucky here. If I could find some electrical specifications for the various sensors somewhere, it would help. But probably too much to ask. I guess I'll leave it for a rainy day experiment.
1987 Mercedes 190TD
(06-30-2013, 12:52 PM)mantahead hi,
could he use the sensor to read the pump timing pointer inside the pump through the hole?
i think there was a tool mercedes used checked the timing this way.
Yup that's exactly right. On the 60x engines there's a bung in the side of the injection pump, which allows you to access a timing lobe on the cam. The peak of the lobe is the start-of-injection point for cyl 1. I would cut a hollow bolt to fit whatever thread size is on that plug, and mount the CPS in the center of it. If it's powerful enough to trigger the light, I think that's all there is to it. If not, then it's an engineering project to figure out how to match the CPS to the light. Mercedes CPS's are inductive, so I'm thinking I might just get lucky here. If I could find some electrical specifications for the various sensors somewhere, it would help. But probably too much to ask. I guess I'll leave it for a rainy day experiment.
1987 Mercedes 190TD
Make sense?
Its might be possible to do but you will need to do a couple of things and even then it might not be that accurate if it even works. You will need to get the end of the sensor very close to the pump timer. You will need to build an amplifier for the signal from the pickup. Simple enough to do if you know anything about Arduinos. Even if you don't there are tons of examples out there. The part where it might not be very accurate is these sensors generally work with teeth and then a missing tooth for the timing point. In the pumps case there is a single hole/slot and the rest is just metal. Normally you would get a wave for each tooth which is the high point and a hole in the wave where the tooth is missing. In your case though there will be no wave generated because there aren't any teeth. I am not even sure if it will generate a signal at all as its the metal no metal that generated the electric field.
Make sense?
http://www.ebay.co.uk/itm/Sealey-TL95-Ti...43b3549230
and this
http://www.ebay.co.uk/itm/Sealey-Timing-...1e5f5740b7
easy way.
you need this
http://www.ebay.co.uk/itm/Sealey-TL95-Ti...43b3549230
and this
http://www.ebay.co.uk/itm/Sealey-Timing-...1e5f5740b7
easy way.
That said its probably even easier to get the proper timing pin for the pump and use that. Good project though.
This would probably be easier to achieve using a knock sensor attached to the injector pipe. You can probably get a sensor for pennies in the scrap yard since just about every engine has had one for the last 10 years.
That said its probably even easier to get the proper timing pin for the pump and use that. Good project though.
I don't see how a knock sensor would be "easier", and I'm not sure that the pulse would produce enough energy to be picked up. A knock sensor is a microphone, and I would almost certainly need an amplifier to make it drive a timing light. By contrast, a Mercedes CPS is an inductive pickup, which can produce a spike of up to 60V if I can get it positioned correctly. The inductive sensor in a spark timing light has similar characteristics.
I have a timing pin device. The problem with these is that they measure static timing, and I suspect that dynamic timing is not going to be the same. The FSM specifies timing the engine while running, using an inductive sensor on the timing cam. I'd like to try that, if only to see if it makes a difference. I expect a 2-3 degree difference due to dynamic forces on the chain, gears and bearings. That's quite a lot in a Diesel.
There should be no problem locating the sensor...I will make an housing similar to the one used on a pin device, but large enough to accommodate the sensor. Then it's just a matter of measuring the distance to the tip of the cam, and locking the sensor into place.
No arduino is needed here. The only question is whether the CPS can produce enough amplitude to trigger the light. If not, a one transistor amplifier should be enough. Worst case, I may have to go further afield to identify an appropriate sensor.
If the sensor was Hall effect, that would be a different story. A Hall effect sensor is a switching device, so I would need something a little more sophisticated behind it to produce an appropriate spike. But an inductive CPS should be compatible more or less out of the box.
1987 Mercedes 190TD
Some replies, in no particular order:
I don't see how a knock sensor would be "easier", and I'm not sure that the pulse would produce enough energy to be picked up. A knock sensor is a microphone, and I would almost certainly need an amplifier to make it drive a timing light. By contrast, a Mercedes CPS is an inductive pickup, which can produce a spike of up to 60V if I can get it positioned correctly. The inductive sensor in a spark timing light has similar characteristics.
I have a timing pin device. The problem with these is that they measure static timing, and I suspect that dynamic timing is not going to be the same. The FSM specifies timing the engine while running, using an inductive sensor on the timing cam. I'd like to try that, if only to see if it makes a difference. I expect a 2-3 degree difference due to dynamic forces on the chain, gears and bearings. That's quite a lot in a Diesel.
There should be no problem locating the sensor...I will make an housing similar to the one used on a pin device, but large enough to accommodate the sensor. Then it's just a matter of measuring the distance to the tip of the cam, and locking the sensor into place.
No arduino is needed here. The only question is whether the CPS can produce enough amplitude to trigger the light. If not, a one transistor amplifier should be enough. Worst case, I may have to go further afield to identify an appropriate sensor.
If the sensor was Hall effect, that would be a different story. A Hall effect sensor is a switching device, so I would need something a little more sophisticated behind it to produce an appropriate spike. But an inductive CPS should be compatible more or less out of the box.
1987 Mercedes 190TD
(07-03-2013, 09:49 PM)mxfrank I don't see how a knock sensor would be "easier", and I'm not sure that the pulse would produce enough energy to be picked up. A knock sensor is a microphone, and I would almost certainly need an amplifier to make it drive a timing light. By contrast, a Mercedes CPS is an inductive pickup, which can produce a spike of up to 60V if I can get it positioned correctly. The inductive sensor in a spark timing light has similar characteristics.
Not that I have a clue about this but just FYI I'm using a Merceders CPS to obtain a signal for my rev-counter. That had to be run through the amplifier side of a W201 ignition unit to make it work.
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(07-03-2013, 09:49 PM)mxfrank I don't see how a knock sensor would be "easier", and I'm not sure that the pulse would produce enough energy to be picked up. A knock sensor is a microphone, and I would almost certainly need an amplifier to make it drive a timing light. By contrast, a Mercedes CPS is an inductive pickup, which can produce a spike of up to 60V if I can get it positioned correctly. The inductive sensor in a spark timing light has similar characteristics.
Not that I have a clue about this but just FYI I'm using a Merceders CPS to obtain a signal for my rev-counter. That had to be run through the amplifier side of a W201 ignition unit to make it work.
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Looking forward to seeing your results though.
I hope I am wrong but I don't think it is going to work like you think. This is a VR type sensor and as such puts out scary spikes a noisy signal and generally involves conditioning circuits before it can be used. If you need a transistor in there your going to need atleast a zener as well or you will blow the transistor. I had all sorts of problems using them in megasquirt projects (This is sorted now since the circuits to use a VR sensor are incorporated now) where Hall sensors were pretty simple to use in comparison. The signal might be weaker on them but its clean and easily used. You can buy pre made VR interfaces now as well easily.
Looking forward to seeing your results though.
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