diesel flywheel timing marks

[92EcoDiesel Jetta]

I found this nice diesel flywheel pic and borrowed it.

We know circled in green is TDC

Anyone know how many degrees before TDC is the red tooth?

What is the blue tooth used for? It is way after TDC

[ORCoaster]

From what I know the first tab is 12 degrees BTDC and the second one is 20 degrees ATDC.  I get that from the Pulse adapter literature I had.  There are two ways that the adapters work.  One sensed the mechanical ping off the injectors and uses the BTDC nub and the other adapter used the actual flash of the fuel to switch on and off the electronic device by means of a photo cell, hence the name Luminosity adapter.  LUMY for short. 

I own a Lumy and was provided the Pulse adapter by RBREMILLER, thanks man, so I could measure out my IP and get readings on both nubs.  Did a compare chart here someplace. 

DAS

[TylerDurden]

As I recall, there are 125 teeth on the typical 1.6D flywheel, so the red looks close to 12^o BTDC and the blue looks close to 20^o ATDC.

[92EcoDiesel Jetta]

From what I know the first tab is 12 degrees BTDC and the second one is 20 degrees ATDC.  I get that from the Pulse adapter literature I had.  There are two ways that the adapters work.  One sensed the mechanical ping off the injectors and uses the BTDC nub and the other adapter used the actual flash of the fuel to switch on and off the electronic device by means of a photo cell, hence the name Luminosity adapter.  LUMY for short. 

I own a Lumy and was provided the Pulse adapter by RBREMILLER, thanks man, so I could measure out my IP and get readings on both nubs.  Did a compare chart here someplace. 

DAS

So VW put those flywheel marks at 12 deg BTDC and 20 ATDC specifically for diesel pulse adapters and luminosity probes? When you use the pulse adapter, did you try placing the piezo near the delivery valve and near the #1 or #4 injector nut? How many degrees of difference did you notice and which is the correct one?

[ORCoaster]

I am not sure VW was that forward thinking on the tab placement.  Maybe, but the tabs are used by others.  The SnapOn Tools I was using convert mechanical or light signals into and electrical pulse that then can fire off a regular timing light.  Like a gasser does with the spark plug.  EWww what are those things?

When I used the pulse adapter I placed the piezp pick up about 1/2 inch from the nut.  I tried it at several other places back down the line but there were few choices to get it on and once I got close to the IP I started getting too much interference from other sources.  Some say it picks up the swell in the line but I don't agree with that.  Why?  Because when I first was loaned the equipment I didn't have a proper advance type timing light but I did have the old school Sears light from the 70's with an inductive pick up.  So I just clamped the pickup on a 1/4 inch bolt and hit it lightly with a screwdriver tip.  That is all it took to make the timing light fire off.  I believe the pickup senses mechanical pings. 

Back to the questions;  I tried the pickup on both the #1 and #4 cylinders.  Got the same readings on both so I would use #4 as it is much easier to get to and not have to work around the IP.  The degrees of difference between the two cylinders is nada.  Both TDC at the same mark just 180 degrees between them  TDC is TDC for any given cylinder.  SnapOn has a monster device that you can use with these adapters that actually can offset the other cylinders too.  Not sure what all that device was used for.  Charging 150 extra dollars for a tune up? 

So, using a pulse adapter, which is way handier than the one that goes in the Glow Hole.  Use the 12 BTDC mark and place the pickup close to the nut.  In my hunting around for proper numbers and proceedures I think I only found one mention of a degree or so of difference when placing the pickup on the line.  I tried to simulate that and was foiled again by a shaky IP I think.  Time to check that bottom or engine ward most nut I think. 

[92EcoDiesel Jetta]

I have the Mactools diesel pulse adapter and have been getting readings (TDC mark and RPM )that jumps around and not steady. I took a closeer look when the thumbscrew is tight around the line (not too tight) and there was no gap at all on the thumbscrew end (probably from over tightening by the PO). I proceeded to make a gap with  a file to remove some of the aluminum and lo and behold, it reads steady as a rock now. I have to experiment with piezo placement on the 2 ends of the injection line and see what differences I get now that it is working well. Timing per the pulse adapter is around 14 deg BTDC, maybe a little more. I took a better video and will post later. I have been driving it for a few days now with the advanced timing and noticed going up the same 1/4 mile long hill in 5th gear, the EGT is about 200 degrees lower with more torque to make it up the hill without the need to downshift to 4th. Before I advanced the timing, EGT would creep up to 1100 to 1150 F at the top of the hill but now it creeps up to about 900F at the top of the hill. I am hoping this better running will translate to better fuel economy. I will know after a few tanks.

[ORCoaster]

The Mac Tool that was loaned to me had to have the clamp modified as well by the owner.  It really was meant for a 1/4 inch line and not the 6 mm ones we have on the IP.  I had a Tiny Tach piezo on my lines and I tried that as well.  It did a lot better job than that thumbscrew job on the Mac unit. 

When I first started the dial measure compared to BTDC with the light I was running about 19 BTDC.  It was a little naily but I think it got me better mileage that way.  I was getting 34 in town, all stop and go.  Didn't have a reason to test on the highway but now I think I get a bit less with it set at 15.  Time and miles will tell. 

I may have an injector fouling out as well because I see the blue cloud lightly run out the pipe and if I jump on it between 2nd and 3rd I see the same.  Without a means to pop test my current injectors I will likely have to have a set rebuilt and replace all of them.  Then rebuild or have the shop test the others and rebuild what is needed. 

Good luck on the tweaking.  Or is it considered Mods or Eco.

[92EcoDiesel Jetta]

The Mac Tool that was loaned to me had to have the clamp modified as well by the owner.  It really was meant for a 1/4 inch line and not the 6 mm ones we have on the IP.  I had a Tiny Tach piezo on my lines and I tried that as well.  It did a lot better job than that thumbscrew job on the Mac unit. 

When I first started the dial measure compared to BTDC with the light I was running about 19 BTDC.  It was a little naily but I think it got me better mileage that way.  I was getting 34 in town, all stop and go.  Didn't have a reason to test on the highway but now I think I get a bit less with it set at 15.  Time and miles will tell. 

I may have an injector fouling out as well because I see the blue cloud lightly run out the pipe and if I jump on it between 2nd and 3rd I see the same.  Without a means to pop test my current injectors I will likely have to have a set rebuilt and replace all of them.  Then rebuild or have the shop test the others and rebuild what is needed. 

Good luck on the tweaking.  Or is it considered Mods or Eco.

1/4" is 6.35 mm so if the MacTools piezo clamp is really made for 1/4" line I see why it's fitting loose. If I continue to have problems I will shim it with lock tumbler shim stock which is very thin stainless and is already curved. Do you have a pic of your Tiny Tach piezo?



Too bad I hadn't fixed the jumpy diesel pulse adapter and get a good reading of the timing with the light before I advanced the pump. I had it timed 2 years ago to factory spec (1.05 iirc) using a dial indicator.

[92EcoDiesel Jetta]

Here's a video of the current timing. How many degrees before TDC does that look like to you?

CLICK TO PLAY!

[ORCoaster]

Boy that is one jumpy video.  Took me a couple of times watching it to figure out what was where.  If I had to guess, and that is what you are asking me to do, I'd go 10 BTDC.  The center of the pointer seems to be just in front of the 12 degree tab so that is what I'd call it. 

Tiny Tach picture.  Hmm  Photobucket maybe?  From the side and from the 45 degree angle.  You can see that there are two hex head screws that do the clamping and there is a gap between the blocks as the clamp is tight to the pipe.

[TylerDurden]

If the green mark is 12^o, I'd say the timing is a tooth or two ahead of that... 16^o-18^o BTDC

[92EcoDiesel Jetta]

Sorry about the jumpy video. I should have explained the orientation. You are watching as if you are standing in front of the car. The triangular pointer of the tranny housing opening would be on the left. 16 - 18 deg BTDC is very advanced. Does it sound that way? Can you hear a lot of diesel clatter?

[TylerDurden]

I'd say you got some clatter. These IDIs almost always have some... I find the difference is how loud, which is kinda hard to tell on recordings due to auto record levels.

[92EcoDiesel Jetta]

................
When I used the pulse adapter I placed the piezp pick up about 1/2 inch from the nut.  I tried it at several other places back down the line but there were few choices to get it on and once I got close to the IP I started getting too much interference from other sources.  Some say it picks up the swell in the line but I don't agree with that.  Why?  Because when I first was loaned the equipment I didn't have a proper advance type timing light but I did have the old school Sears light from the 70's with an inductive pick up.  So I just clamped the pickup on a 1/4 inch bolt and hit it lightly with a screwdriver tip.  That is all it took to make the timing light fire off.  I believe the pickup senses mechanical pings.  
........

I have similar experience as you and find the pulse adapter very sensitive. With the piezo clamped on a line and engine off, I can tap lightly on the line and I can get the strobe to flash (and the LED on the pulse adapter to flash). The piezo has a very wide output proportional to the mechanical force input and I am thinking the pulse adapter circuitry must be able to discriminate the higher output (line expansion) from the noise (adjacent cylinder firing and other vibrations). To give you an idea of the range of piezo's output, consider the piezo barbecue grill lighter, it can generate thousands of volts from a small hammer striking it when the trigger is pulled, yet will put out a few milli-volts when tapped lightly with a screw driver, which I have verified with an oscilloscope.

A large part of how well a diesel pulse adapter works is how good the circuitry is to filter and pick out (discriminate) the signal. I have looked at the raw piezo output while clamped around the injection line. It is a very wide and noisy signal if you can call it a signal at all.

[92EcoDiesel Jetta]

Interesting that ORCoaster sees it at 10 deg BTDC and TylerDurden sees it at 16 to 18 deg BTDC. With the orientation I just explained, can you look at it again and explain how you arrived at it?