Tractor Chat - subject is tachometers

[roscoemi 245]

Amen brother! Give me an anolog tach and maybe a hour meter and I'm happy. And $80 for one is not worth thinking about, I'll pass. Something simple and cheap that fit's the charactor or the machine.

[Save Old Iron 1,565]

Time to drag this one out of the archives:

Good one Mike. Takes me back years to the "old" red square days when you could pull out your smokes

and run around half naked

I'm not ignoring the comments or questions all you good folks have generated so far. And in no way am I advocating anyone make their C series dask look like the cockpit of a Blackhawk helicopter. I would like to fit a few gauges to answer a few age old questions and statements.

"You must run your engine full speed for proper cooling".

"I prefer voltmeters over ammeters."

"I prefer ammeters over voltmeters."

"My engine runs a lot hotter since...."

"Are 520 belt guards mods actually helping any?"

I'd like to put some numbers to all these questions.

And most of all I would live to get rid of that gosh darn awful maintenance sticker on the hood of my 416!!

Maybe I can blast out a quick readout for someone who wants to test the benefit of holes in a 520 belt gaurd. I could easily put together a readout which displays both head temps at the same time or even a differential reading. If anyone wants to be test bed, let's talk about the sensors you would like to use and we can go from there.

[sadixon49 11]

I bought a tach/hourmeter off of evil-bay a couple of years ago. A generic tiny-tach, I believe I spent less than $20.00 with shipping. The tach was installed on my new Toro 726OXE snowblower to keep track of service hours. It is a very simple induction tach, just wrap the pickup wire around the spark plug wire and mount the tach on the dash. I used double sided tape to mount mine. At those prices I can't imagine why more people don't do this. It shows hours of service when not running and rpm when running.

steve

[sorekiwi 761]

Maybe I can blast out a quick readout for someone who wants to test the benefit of holes in a 520 belt gaurd. I could easily put together a readout which displays both head temps at the same time or even a differential reading. If anyone wants to be test bed, let's talk about the sensors you would like to use and we can go from there.

Now there is a great idea!

Much more accurate than putting my hand on the cylinder head and deciding if the rear cylinder burns me more than the front.

And I will say that I like the idea of a temporary sensor for testing purposes rather than a hardwired in sensor that I would have to maintain on an ongoing basis.

Is there a generic surface temp sensor available (similar to the OEM onan/Toro one) that is not ridiculously expensive? I do remember Go-karts running a thermocouple washer underneath the sparkplug to measure cylinder head temp.

[Save Old Iron 1,565]

Is there a generic surface temp sensor available (similar to the OEM onan/Toro one) that is not ridiculously expensive? I do remember Go-karts running a thermocouple washer underneath the sparkplug to measure cylinder head temp.

Mike, there are several options these days - not only the 14mm ring terminal style for under the spark plug but also bayonet mounts to allow easy removal from any area where an 11 mm hole can be drilled to mount the sensor.

a few styles are pictured below

these are easily acquired for $7 - $8. Quality is unknown at this time but I do have a few on order to test them out.

There is also a style with a bent stainless probe for insertion into exhaust pipes for EGT measurements.

If you want to make quick temp measurements or comparisons with a handheld device - take a look at

http://www.ebay.com/itm/130704707788?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

It all looks very promising.

[JackC 617]

"Maybe I can blast out a quick readout for someone who wants to test the benefit of holes in a 520 belt gaurd. I could easily put together a readout which displays both head temps at the same time or even a differential reading. If anyone wants to be test bed, let's talk about the sensors you would like to use and we can go from there."

OK, now we are on topic I am very interested in. I have 3 running ONAN P series engines and would like to avoid the valve seat problem and broken rod problem others have experienced. The ONANS on a wheel horse are run hard driving 60 inch mowing decks and 2 stage snow throwers. I believe there are a few issues with the application of the ONAN P series engines in wheel horse tractors.

First, the back cylinder is in a tight spot in the back of the engine compartment compared to the way the ONAN is positioned on a D-160. The biggest issue that I see is the location of the oil filter. The flywheel fan blows significant air onto the engine and the engine tin keeps the air moving over the cooling fins on the cylinder heads. The front cylinder gets the full benefit of that cooling approach. However, the back cylinder has the oil filter in a location that blocks some of that air flow over the cooling fins on the back cylinder. To compound the problem, oil and grass can build up on the back cylinder further decreasing air flow. The block is aluminum and the valve seats are iron. If the back cylinder overheats, the valve seat can pop out of the head due to the different properties of the two metals.

I believe the P series is one of the best engines ever developed and has gotten a bad wrap due to poor application in some tractors. I suspect the belt guard mod provides little cooling benefit. Heat rises and the belt guard is on the side not above the head.

I believe a remote oil filter and a cover over the oil filter hole on the back engine tin would provide a major cooling benefit by increasing air flow over the cooling fins on the back cylinder. The twin cylinder Kohler Series II engines have the oil filter on the other side of the block so as not to block flywheel fan air flow over the cylinder head.

Some tractor brands put oil coolers on the P series engines which was a very good move.

At a minimum, I believe all P series engines in wheel horse tractors should have temp sensors on both cylinders with alarm function if a set temperature is exceeded. Next, a remote oil filter with a cover over the oil filter hole would be the best mod to avoid engine failure. Next, an oil cooler would help keep the engine cool. The belt guard mod can't hurt and some testing to measure the benefit would be a great idea.

Let me know when I can order the temp monitoring instruments. I need 3 for my P series engines and maybe two for my BF-MS engines on my D-160s, although both cylinders hang out in moving air on the Ds.

[rick 231]

I set the carburetor and governor with the RPM function on my Fluke multimeter and let 'em go. The hourmeter is nice to have, but I usually service my machines more frequently than specified. It is nice to know how many hours I used the machine since purchased, however, I keep no records.

The simpler, the better!

[Save Old Iron 1,565]

Let me know when I can order the temp monitoring instruments.

Jack, thanks for the vote of confidence this is all going to work out. I posted questions on the tachometers not so much to generate sales interest but to get a feel for how different folks interpret and use the data from their tractor gauges. Putting to rest (or comfirming) old wive's tales about how to run these engines and the effects of modifications like the belt guard are also of interest. Who knows, with these controllers being able to activate solenoids and actuators, we may even be able to design a moveable air vane to direct additional cooiing aiir to the rear head when needed (think old type bimetal choke mechanism on your 70's era auto). This is all very easy to accomplish when the right sensors are mounted and the right mechanics are in place.

For right now - since this will be my "winter of 2012 project" - I would direct you back to the last post I made. Check out the eBay link to a dual sensor, hand held digital thermometer for less than $25. If you would like to begin preliminary testing on your setup and don't mind the small investment, this thermometer has 2 channels ( front and rear heads on the Onan) and captures summaries for minimum, maximum and AVERAGE readings for the two channels. Velcro the meter to the tractor dash area, turn on the meter and plow your driveway. The meter will record min, max and average readings for both front and rear head temps over your plowing session. Write down the summary readings and on the next snowfall, do your belt guard mods and recapture data from a similar plowing session.

All said, I will be happy to have you check out a prototype when they become available.

[JackC 617]

Great, thanks, will do.

I am a big fan of instrumentation in general and for the purpose of keeping the old horses healthy in particular.

Sometimes we get busy and do not give the machines the proper maintenance and care.

Two conditions that I have seen that have destroyed engines are low oil level and over heating.

We talked about the temperature monitors but maybe some thought should be given to monitoring low oil level as well.

If oil level is low I am not sure if the block heats up enough for temperature to warn of the low oil level.

Maybe a dip stick with some sensors on it would be an easy retro fit for the old horses?

That may even be worthy of a patent.

Actually, "saving old iron" could be the goal of a line of instruments and how to manuals.

Give it some thought.

[Save Old Iron 1,565]

All great comments.

Jack (and anyone else interested) , consider how these monitors are "assembled"

In the pic below, computer building blocks and sensors are plugged together to form different sensors for different needs,

and with some relatively simple programming, you get a custom readout.

JackC, for your 520 head temp monitor, we can either use a display that shows 2 lines of text or 4 lines of text. The example below is a 4 x 20 display ( 4 lines of 20 characters each line). I added in the faded white grid over the display to show how the characters would be divided up on the screen.

The display could be programmed with any text you want and the text could be placed in any format on the screen, as long as it fits in a 4x20 grid. Each character you want to display takes up 1 space.

In the pic shown above, each head temp is monitored individually, and in my example, a delta or difference is constantly displayed indicating the difference in the two head temperatures. The little arrow after the delta reading will either be an up arrow (meaning the TREND of the difference is increasing), a flashing dot (the difference is not increasing or decreasing), or a downward arrow (the difference between readings is decreasing).

With the custom program ability of the microprocessor, you can show any calculations or trends you would like to see. As long as it fits onto the 4x20 grid of characters. It is possible to set "trip points" - say anything over 450 F will change the entire display to a flashing warning in big text saying "EXCESSIVE HEAD TEMPERATURE" and trigger a piezo beeper like you hear when a truck is backing up. The beeper will immediately catch your attention even if the gauge does not.

You could have a graph displayed using a different style readout. The additional cost might be about $20 more for a graphical readout. With the microprocessor outputs, you can act on temperatures that are too high by simple warning lights, or more complex actions like moving cooling panels to direct more air to the rear cylinder, etc. Think big thoughts. How BIG? Big like with a $12 attachment, the tractor can send you an email or place a call to your cell phone if the oil level gets low or the rear head starts to overheat. Big like remote starting capabilities where you can point a remote out the window on a cold winter morning and have the tractor start itself. Much can be done with this small micro units.

So spend some time and think about how you would want your display programmed. While I wait for some parts to arrive, maybe I can get started and at least get the display formatted to your preferences.

[JackC 617]

Based on a quick review, your proposed display format looks excellent. The beeper would be an important addition. I will spend more time reviewing it tonight.

[JackC 617]

SOI, the 4 line display would be much preferred over the two line display. For the C, 400 and 500 series with twin Kohlers or ONANs it would be FRONT and BACK. For the D series or other tractor brands it would be LEFT and RIGHT. The approach you are using offers numerous combinations for temperature sensors and information displayed. Engine oil temperature and transmission temperature monitoring could also be easily added to the older machines. I will get that dual channel hand held monitor on eBay and see if I can collect some temperature data from my engines. I have the twin ONANs, Kohlers, and a twin Briggs, and I have the single cylinder Kohlers.

There would need to be a method to attach the sensors to the heads without them falling off due to engine vibration. Possible clipping the sensor leads to the spark plug wires or boots would work. Picking up the temperature somewhere near the spark plug is probably a good pick up point. It would be helpful to be able to move the device from one machine to another if desired.

It will be good to keep things simple and economical at first but at some point more sophisticated sensors and user interfaces could be developed including using devices like ipods, ipads, and smartphones with touch screen control and apps that process the sensor information for particular needs. If I were in the mowing business I may want to record engine run time for each customer that I visit. If I am a puller I may want to record max temperature and max RPMs for each run. A wireless interface option between the sensors and the operator interface would be a plus. A wireless interface option would allow the display to be mounted wherever desired or taken off and plugged into a computer for some analysis and post processing.

My main concerns are to have information on the health of my engines to avoid an engine failure for the older engines that are no longer made. Temperature and oil level are two key parameters. RPMs are helpful for setting idle adjustments and setting engine speed before engaging attachments. There are smart dipsticks for other equipment but none for small engine equipment that I know of. It would be nice to turn the ignition key and see oil level without having to open the hood, get out a rag, and pull out the dip stick, not that that is a big job but some people do not take the time to do it and there are numerous cases of engine failure due to low oil level. Some newer engines have low oil level sensors but the older ones that we want to preserve do not.

The Kohler single cylinder service manual has a section on the importance of doing a crankcase vacuum test on a running engine to determine the health of the engine, especially those with ACR where it is hard to do a compression test. A vacuum sensor with a real time display of crankcase vacuum could be very helpful to warn of developing conditions including valves going out of adjustment. Engine timing could also be displayed. The possibilities seem endless. Displaying information in forms that people can relate to is important and now easier to do with programmable micro processors.

Maybe some day we can mount our smart phones on the dash and find out just about everything there is to know from multiple sensors.

[Save Old Iron 1,565]

Maybe a dip stick with some sensors on it would be an easy retro fit for the old horses?

That may even be worthy of a patent.

Actually, "saving old iron" could be the goal of a line of instruments and how to manuals.

Give it some thought.

Years back I read a technical paper on how lubricating oil could be monitored for change in conductivity and ph. Several testing labs would use conductivity tests for checking the amount of additives left in the oil. Another test would be made for the pH (acidity) of the oil and results could be monitored as a reliable "end of life" indicator.

Both of these measurements could be made in the oil pan or on a dipstick - with the right sensor. It would have to be the equivalent of several "miniature probes" being placed across the ADD xxxxxx FULL area of the dipstick. Interesting. I need to look into micro minature resistors and create a resistive analoge to digital "ladder". Interesting. More later ......

[Save Old Iron 1,565]

Jack,

I just received the dual channel K thermocouple meter I pointed you toward on eBay. I am very satisfied with the meter for $22 The thermocouples are calibrated accurately and agree with each other at room temperature. The meter (although not the build quality of the Fluke thermometer I have) looks substantial enough to weather some rough use.

I'll have to putz with the meter a little this weekend to see how the thermocouples agree with an infrared thermometer.

Stay tuned.

[JackC 617]

SOI, I just received mine also. It looks good and seems to work fine. Nice big numbers on the display but it does display only one channel at a time. For the ONANs and other twins, the delta may be the most useful measurement for now. I am anxious to take some temperature measurements on the various engines I have and especially the back cylinder on the ONANs compared to the front. The leads appear to be long enough to attach them to the heads and have the display in the dash area. I need to try a few options for attaching the ends of the probes to the various points on the heads and to points on the block without damaging the leads. It looks like the leads can tolerate some heat. I will look to see what other probes are available but the ones that came with it should work fine. I will keep a log book of all the temperature date that I collect and take pictures of the attaching means I come up with. I also have an infrared thermometer and will compare results. The company that made these could probably build something to specs that are more suitable for use on the small engines and garden tractors and that could be sold for a reasonable price. Once I have collected some data and see how useful it is under varying operating conditions I can start a thread on it.

[perry 82]

good price lazer tach. check out the vid -

[JackC 617]

perry, Thanks for the video.

Any one with any horizontal engine wheel Horse can put the reflective tape on the PTO and check idle and full throttle RPMS.

Very good point about if idle RPMS are too low the engine will not get lubricated properly. That is probably true for both splash lubricated engines and oil pump lubricated engines.

You should get a commission, I just bought one.

[sorekiwi 761]

Very good point about if idle RPMS are too low the engine will not get lubricated properly. That is probably true for both splash lubricated engines and oil pump lubricated engines.

I'm not sure of the threshhold pressure of the genuine Onan oil pressure warning light switch, but I have a generic one on my Onan which turns the light off at 8 psi. The light doesnt come on at idle so it must have more than that, and I would think that would be plenty of lubrication (for a short time idling).

However the fan probably isnt flowing enough air for adequate cooling at idle speed, which is the main reason for not letting them idle too slow for too long.

[JackC 617]

I would assume the higher the idle the higher the oil pressure which should be good for lubrication and cooling.

We know the higher the idle the higher the cooling air flow produced by the flywheel fan. Both are good reasons to be sure the idle speed is set properly and high enough. The magic number for a lot of engines seems to be 1100 RPM.

I have always tried to get my engines to idle at low RPM thinking that was a good thing. Now I realize it is actually a bad thing.

[sorekiwi 761]

I have always tried to get my engines to idle at low RPM thinking that was a good thing. Now I realize it is actually a bad thing.

Thats funny, I do the same thing! I actually think its an ego thing - its really satisfying to get that engine purring really smooth and slow. I still try to get them there, but once I've proved to myself that I can do it, I wind the idle back up again. :)

[Save Old Iron 1,565]

I have always tried to get my engines to idle at low RPM thinking that was a good thing. Now I realize it is actually a bad thing.

It certainly sounds logical, but then you start to think -

low RPM = lower heat output from engine

lower heat output = lower requirement for cooling

and for the sake of more "tractor chat", I'll throw this one out too -

lower RPM / idling without load = lower load on engine

lower load on engine = less need for high pressure lubrication to maintain film between moving surfaces

[JackC 617]

My belief has always been that in general it is not a good idea to let any engine idle for very long due to the risk of carbon build up.

I Googled the issue and this is one of the first articles on the subject.

Apparently there is not only more wear but also less efficient combustion.

I would assume the same applies to small engines but on a smaller scale?

http://www.epa.gov/region1/eco/diesel/pdfs/Diesel_Factsheet_Truck_Idling.pdf

[JackC 617]

Actually, if engine wear increases and combustion efficiency is reduced due to idle speed being too low, then the tachometer becomes a much more important tool to help avoid engine failure. If I were specing a tachometer for garden tractors I would incorporate an alarm function so for example if the RPMs go below a user specified set point such as 1100 RPMs, an audible alarm would be generated.

[SousaKerry 501]

Hey since we're spitballing ideas here....

How bout a gps guided auto steer system like them lazy megafarmers.use.now. then we could have perfectly strait mow lines in our yards.

Hell when I was on the farm we didn't even have a cab on the big tractor let alone them luxury skyboxes they call tractor cabs now.

But tachs are just plain cool as long as they are durable enough to stand up to water and vibration ip65 rating would be nice