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#90
by
ORCoaster
on 19 Mar, 2014 20:37
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I found a manual for the MT 480 Snap on tool and they describe a proceedure for the GM and Chevys but then another for the VW/Audi engines. They talk 12 BTDC on the pluse adapter and 20 degrees on the Luminosity detection. One is getting signal at the top end of the injector and the other senses the actual flash in the combustion chamber. Well after TDC or you would be on the upstroke of the piston and we all know that noise don't we.
I did get an advancing timing light today in the mail. Craigslist special, Snap on early version, no tach.
Lumy gets it to flash on the bench.
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#91
by
vanbcguy
on 19 Mar, 2014 23:48
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Oops, backwards math on my side I guess!
Sent from my HTC One XL using Tapatalk
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#92
by
fatmobile
on 20 Mar, 2014 14:10
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I would think accuracy of the light has more to do with the brand and the age of the equipment. I bet you could verify the accuracy pretty quickly by running it in comparison with a light that doesn't have the fancy adjustment. Shoot a gasser engine with the degree scale with the low tech light and read the number. Then connect the hight tech and zero out the light on the scale by moving the knob. Read the dial and see what you get between the two.
Or am I messed up on this?
The accuracy can be easily checked if you have timing marks on the flywheel.
Just set it for 0 degrees advanced and see where it points. Then advance the timing light until it shines right on the timing mark and compare.
It would be easy to see if my mechanic is right. He was selling me his timing light when he mentioned the noticed inaccuracy of the advance setting on the snap-on timing light.
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#93
by
Tintin
on 31 Mar, 2014 11:26
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The pulse adapter & strob is only usefull if you have a stock engine in good shape and a stock pump in good shape, it can be accurate for the mechanical timing but not optimal for the timing curve, but close enough if all is in good shape, a good tool overall for stock or lightly modded IDI engine.
If you have an E TDI, you don't need it, Vag-Com do it for you.
Now if you'r into M-TDI, it's completely useless, since what matter is the dynamic timing at the end, and the timing curve you need will be very different from a stock set-up to a modified one.
To first find the proper curve you need, you have to look at how much fuel you need for your goal/set-up and how much time (crank degrée rotation) it take to inject the amount you want, and then do your calculation, your goal is to not to inject too much fuel after TDC, if timing need to be too advanced, then increase inj. pressure or enlarge nozzle hole.
I've found the pulse adaptor does not work very well past 1500rpm, and even.... you need to take into consideration the load on your pump when you check the timing, it's impossible to do at neutral, you have to drive the car at various rpm and load.
Best to do if you have an M-TDI, is to tune an ECU in a way to be able to use it for timing reading only and with the help of vag-com log to tune your pump dynamic timing.
Another way is to bench test the pump and tune it according to the curve you need.
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#94
by
bbob203
on 31 Mar, 2014 11:33
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If you know your timing advance curve is correct then it is totally helpful to set the static timing.
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#95
by
Tintin
on 31 Mar, 2014 11:41
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If you know your timing advance curve is correct then it is totally helpful to set the static timing.
Exactly, yes, that's what this tool is for.
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#96
by
vanbcguy
on 02 Apr, 2014 13:36
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I received the TinyTach line clamp today - it looks IDENTICAL to the Snap-On one in the user manual (at least from the line drawing). Hopefully they really do work together!
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#97
by
ORCoaster
on 02 Apr, 2014 21:22
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The clamp that came with my Tiny Tach was not like that. It was not meant for quick removal I guess. Two small hex head screws it had. That one looks more like the one on the MAC pulse adapter. Funny that I have the Lumy Snap on pulse adapter MT 254 and it looks every bit like your MT 257, but works on a different principle for the flash in the cylinder to set off the timing light. That has me thinking that it might just be possible to hook a secondary wire to the ones where the optical ends and see if the Tiny Tach clamp will fire it off. I may just have a combo adapter. I can check the fire in the hole and the click on the top side too?
Across the states for awhile so not near the tool to find out. Going to be a weekend experiment when I get back for sure.
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#98
by
fatmobile
on 05 Apr, 2014 21:58
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Found an '84 flywheel:
As you can see the 12 degree mark is right in the middle of the metal block/standoff.
The distance from 0 to 20 degrees was 41.25mm.
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#99
by
smokeinmirrors
on 06 Apr, 2014 13:47
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I've found the pulse adaptor does not work very well past 1500rpm, and even.... you need to take into consideration the load on your pump when you check the timing, it's impossible to do at neutral, you have to drive the car at various rpm and load.
I am having this problem as well with my newly acquired Mac pulse adapter. I'm using a known good Ferrett 84 advance light with tach, but for some reason I'm not getting accurate rpm readings while using the pulse adapter. At idle it reads a steady 940 rpm which seems correct to me, but with even the slightest increase in speed that reading quickly doubles and by the time mid-range rpm is reached i'm seeing a reading of 6k+. I'm using the 6mm piezo clamp as tight as I can get it by hand and have it mounted at the #1 (timing belt side) injector on a well sanded fuel line. Does anyone have any ideas as to what the problem could be, and would it be safe to say that timing readings above idle can't be trusted with it acting like this?
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#100
by
745 turbogreasel
on 06 Apr, 2014 17:04
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I'd guess noise, maybe try damping the lines.
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#101
by
rbremiller
on 06 Apr, 2014 17:59
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Be sure the pick-up is clamped next to the line nut where it leaves the pump. Line clamps should be in place also.
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#102
by
ORCoaster
on 06 Apr, 2014 22:55
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Since the #1 and #4 hit TDC at the same mark you might get less vibration. Just my thoughts.
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#103
by
fatmobile
on 08 Apr, 2014 00:44
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Now that you mention it.
I've read better than 1500 before but not much.
I think the line expands then might not have time to shrink at higher RPMs.
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#104
by
smokeinmirrors
on 08 Apr, 2014 22:40
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Thanks for the suggestions, I experimented with it a bit this evening and never could get accurate rpm readings above about 1500, but at idle my light seams to give very precise advance readings. The light even jived with the 0 - 15 degree marks that I just etched onto my crank pulley, so with fair confidence in my equipment and method, here is an overview of my findings. - This is an AHU with a stock Land Rover 300 pump.
My dial indicator timing setting when I first installed the pump was 1.25mm. I had only previously experimented with it in the 1.15 - 1.25 range. The engine had always pulled very strong almost right off idle, but quickly fell on it's face just past mid-range with egts always sky rocketing to an easy 1500+ with high load high rpm accelerations.
Unfortunately I didn't think to take a dial indicator reading before messing with it again, but I think last time around I had set back to 1.25. Whatever that setting was I got a strobe light reading of only 9° BTDC when I checked it today which confirmed my growing theory that all along I had been suffering from (injection timing) retardation. Since I had been thinking about advancing my timing anyway, I decided to give this 12° thing a go that everyones been talking about.
I cranked my pump back to a strobe reading of 12 BTDC, unstressed all the lines, then proceeded to put my dial indicator on and take a reading the old-fashion way. This gave me a result of exactly 1.40 mm which seems to be the upper range of what I had heard from a few other people and way out of the range I had ever used.
Just getting back from a quick test drive, I am very impressed with the results. Right off the batt I do notice more turbo lag at low rpm but this is more than made up for in mid-range thrust. Power delivery is still linear but it now has more of that turbo-car kick and in a more usable rpm range to boot. Torque steer is more pronounced, it accelerates noticably faster and EGTs are noticably lower at high speeds.
I think I will leave it at this and see how it does for awhile. When I install my bigger turbo and a taller 5th gear though, a slightly lower setting might be ideal so I will definately revisit it later.