Making an adapter for GPs

[libbydiesel]

That looks much less deadly.

The Snap-on Lumy adapter looks remarkably like my snap-on piezo pulse adapter.  I posted the circuit and components in this thread:  http://www.vwdiesel.net/forum/index.php/topic,34340.msg337634.html#msg337634

Unfortunately, the image I attached with the component list and a better view of the board seems to have disappeared.  You might open yours and see how closely the circuit matches.

Your timing light looks like a typical advance timing light.  Is there something special about it that allows it to alter the flash the other direction?

[ORCoaster]

I turn the light upsidedown.   LOL... No way to change the way the light works but knowing that the flash occurs after TDC the Zero mark would show the flywheel with the TDC mark way over to the right correct?  So by turning the knob to advance the time of the flash you sync it in on TDC and read the number of degrees of advance you needed to get there.  Knowing it should light at 23 degrees and doing the math you can determine the actual advance.  Or at least I think that is the way I use it. 

Snap on adapters are the same as far as I know.  Just the way it sets it off is now different the piezo signal replaces the photo cell trigger. 

[RustyCaddy]

Thanks for posting this!

 

Didn't know about using the timing light method but was familiar with using a MT 480 with a holder for a magnetic pickup.  Checked a couple of spare blocks in the garage and can't find anything that looks like a magnetic pickup holder on either a mechanical or hydro 1.6l so am thinking your method was most likely to have been the standard for diesels, otherwise why would they have made a MT 162 specifically for VAG applications?

Going to do some web searching on that.

[ORCoaster]

I am just guessing here but I think Snap On saw a market for timing diesels in place of the dial method.  You have to figure that their clients are all those guys pulling timings on the typical gassers.  In comes a diesel and crap I have to get out my manual stuff and actually measure something.  Not normal, not fast.  So they might have approached Snap On and asked, can't you guys come up with something better?  And they tried, and now they have refined that with the Piezo pickup.  Snap On had a big device that had a way that it sensed the timing area on the flywheel and measured the flash in the combustion hole.  Can't remember the name of it but it was an MT 480 something.  Measured RPM too. 

So it is my guess that they tried to make it simpler and faster for the diesels to get timed.  They made adapters for the Izuzu Pup, GM, Ford and Cat engines in addition to the VW/Audi  one.  Which reminds me,  Ebay auction ends soon, best go look for that VW one.

Later glad to have provided something of interest to ya.

[vanbcguy]

Fact is the dial method isn't actually measuring what's going on, it's just telling you what the pump is up to. Have worn injectors? Dial method is wrong. Have a worn pump? The dial method is wrong.

No matter how worn or not standard parts are in your setup the luminosity or pulse adapter tells you what is actually going on rather than what SHOULD be going on.

[libbydiesel]

No way to change the way the light works but knowing that the flash occurs after TDC the Zero mark would show the flywheel with the TDC mark way over to the right correct?  So by turning the knob to advance the time of the flash you sync it in on TDC and read the number of degrees of advance you needed to get there.  Knowing it should light at 23 degrees and doing the math you can determine the actual advance.  Or at least I think that is the way I use it.

I'm not sure what you mean by 'way over to the right'.  That depends on where you're standing when you're looking at it.  If the knob on the light is at 0 and the flash of the light shows the TDC mark toward the manifolds then the triggering event is BTDC.  If turning the knob UP moves the TDC mark toward the pointer then the knob retards the flash of the light.  The number of degrees required to sync TDC with the mark are the number of degrees the triggering event is advanced BTDC.

[RustyCaddy]

Well...this was probably obvious to most folks but finally realized how the magnetic pickup on the MT 480 works with a lumy probe.  This answered another question that had wondered about.

The crank pulley bolts have one that is offset from the crank nose and at TDC that bolt is up (or maybe down...need to look).  Apparently the magnetic pickup can sense the crank position from the offset bolt from some Chrysler models.  Am thinking that is how the VW's were set up.

But your meter and timing light seem more precise and controllable.

[ORCoaster]

Just got off Ebay purchasing a Snap On MT 480 and all the sensors, manual, never used Audi/VW adapter and several others.  Might be looking to sell the MT 254 and Timing light now. 

[RustyCaddy]

That is really a great find...i am very envious

 

Please let us know how you like it when you get the chance.

Where does the magnetic pickup sit BTW?

[ORCoaster]

I believe that the magnetic pickup sits in an adapter for the transmission hole.  It senses the tabs on the flywheel that are raised up at before and after TDC.  I should get it next weekend if all goes well.  Another deal I couldn't resist, and my wife will be frowning about.

[ORCoaster]

Update if you are interested.

I was after a VW/Audi adapter that goes in the glow plug hole for awhile.  There were several on Ebay that were just too pricey for me to consider and the sellers were convinced that 100 dollars was reasonable.  So, last week I finally found one. 

It had never seen the threaded hole in the block and it came with several others for Chevy and Oldsmobile engines.  So my hand crafted one that works very well mind you now has the real McCoy



But it also came with some other items:

Tah DAH!!!!  Yepper Jimmy that is old school stuff, but you watch it work.



And so I spent some time in the drive with it and only pulled the IP back a bit to make it run at 3 degrees before TDC. 

Going to try it there for a bit.  The dial method reading prior to starting was .93 mm and that gave me 6 degrees BTDC and it did run well but I wanted to see if pulling it back some to TDC would quiet it down a tad. 



This thing is so cool to use.  All you do is pull the glow plug out and put the adapter in, then take the plastic cap off the tranny and set up the Harmonic pickup.  Then slide the optical pickup over the adapter and juice it up with the leads to the battery.  Start the car and instant reading.  To adjust IP is like always, shut car off, undo 4 bolts leaving one up front a bit tight.  Start the car, loosen the front bolt while pulling or pushing on top of IP and watch the needle move.  Once at the setting you desire, lock the front bolt on the IP, shut off the car to tighten the rest and voila.  All done.

Opps forgot to pull adapter and reinsert GP and hook up wire.  Won't start so good in the cold that way.   

[92EcoDiesel Jetta]

Cool you found what you need. How much was it? How would you compare the luminosity probe to the diesel pulse adapter in ease of use, accuracy and repeatability?

[RustyCaddy]

Thanks for the posts.  That is really great!

It is funny how obvious the pickup adapter works now that you explain it.  Have always wondered why that plastic plug was there at all

D'oh!

 

Made in Wisconsin too...worth whatever you spent just to buy old school MADE IN USA (Yeah!!!)

Have a great 4th !*~*~*~!*

[ORCoaster]

The best thing I ever got out of Wisconsin is neither this meter or a bunch of cheese.  It is my wife, Milwaukee girl.  LOL

But the meter is pushing a close second. 

[vanbcguy]

What I'm REALLY interested to see is what the advance curve looks like overall. I can't remember what all you have vehicle wise...