Timing Gauge DRF 35169 for 6.2 Diesel

Jake59

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Hello,

The Timing Gauge DRF 35169 DIESEL TIMING GAUGE - NAN 4910-01-231-3671 is just about unavailable anywhere and if/when, then heavily overpriced for what it is.
Anyone know the dimensions? Distance between center of the strobe tube and the 0 Degrees mark?
Once this is verified I plan to lock/weld the strobe tube in place so no future checking is required
Thanks,
Jake

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Barrman

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You don't really need that part. The probe holder is supposed to be 9.5° offset from the 0° or TDC notch on the timing tab. I just held a tape measure up to one and it is about 1/2 inch from the 0° notch to the middle of the timing probe holder.

How are you going to get a timing signal? I ask because the tolerance is plus or minus 2°. So, the probe holder being on the engine pretty much gets you within tolerance. By the way, 3° at 1400 rpm using a lumy mag is the listed timing point.
 

Jake59

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Hi Barrman,

Thanks for that!
Will check those measurements on my 1985 M1009.

I have 2 sets Tach-n-Time so the timing signal should not be an issue. And if the magnetic probe does not work or if I do not trust the position of the probe holder, I can always use an inductive strobe light as well, right!?

Timing adjustment must be: 3° at 1400 rpm using a lumy mag?
On the chart provided with the Tach-N-Time, it says: +4° at 1300 RPM.
Pic attached.

Which value to follow?

Thanks,
Jake
 

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Barrman

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Are you stock or with a turbo? Stock you could probably step it up to 5° or even 6° advanced. I haven't pushed my turbo motor more advanced that 3° yet. Notice that your chart is for clamp on sensor timing. Not lumy probe. Put the probe as close to the injector as you can get it.

The DB2 pump actually retards timing as the rpms increase because diesel fuel lights on fire quicker the more heat and pressure it is under. Kind of backwards compared to a spark plug ignition set up. Diesel being slower to catch fire needs some advance. However, since we are going into winter and the fuel chemical adjustments that go along with it. The winter blend will light on fire faster than the summer. So, whatever set up you do now and think works. Be aware winter fuel might tell you through sound that it needs a little less advance.
 

Jake59

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Hi Barrman,

I have a 6.2 N/A in a 1985 M1009, which I am still restoring at this stage.
Adding a turbo may be something for later on, once it is on the road...

I had white smoke at idle and most engine speeds actually, so checked the timing and it was -4°.
I assume this is caused by timing chain stretch/slack (?)

So I advanced the IP about 5mm which should correspond to 10° crankshaft rotation and now am at + 5.5° at 1300 RPM.
No more white smoke at this stage, at idle rattles a bit more.

You are right, the DB2 retards timing as RPM increases, I noticed this as well when using the Tach-N-Time, which is quite surprising actually. While your explanation does make sense, diesel timing is normally additionally advanced in relation to RPM increase. Timing advance on diesel engines is normally even more then gasoline engines, because the combustion of diesel fuel takes a little more time, due to the properties of diesel fuel itself as well as the method and time of mixing and vaporizing.
Generally speaking static diesel timing advance on German engines averages around 15°, which is a lot. This is although for old diesel engines and when manually setting the timing, without testing or measuring equipment and done as follows:
  1. Disconnect high pressure line at the IP for injector No 1
  2. Manually rotate engine and observe the exact point when the first drop of fuel is pumped out.
  3. This should be 15° BTDC.
Obviously this is not the exact point when the nozzle valve opens, nor when combustion starts as the crankshaft will have turned a number of degrees further towards TDC before fuel is actually ignited and combustion starts. First off, the nozzle will only spray into the pre-combustion chamber as and when the opening pressure of 125Bar is reached, which takes a few crank degrees. Next there is the actual combustion delay, which will add a few more degrees of crank rotation before combustion really takes place. One can imagine this takes us down to 4° BTDC at 1300RPM.

I'll have to do a comparative test on a few of the German diesel engines I have here (1957 MWN AKD 112 Z (MWM=Motoren Werke Mannheim), 1968 MWM D-322-3, 1969 MWM AKD 10 V and a Henschel D4 5.200cc) and then compare with the readings from my Tach-N-Time, just to see how many degrees difference there is between the manual timing advance setup and the actual/Tach-N-Time measured timing advance. Could be interesting....

On the other hand, I recently read this chapter in the GM 6.2 Diesel Engine Manual: page 208 or 4-106 gives a typical, unretouched, four channel oscilloscope photograph of a Stanadyne fuel injection pump operating at full speed and full load on a 219CID turbocharged diesel engine. On this engine, the pump discharge begins at 28° BTDC engine timing. This is 14° pump timing. The advance mechanism was adjusted to produce an 8° pump speed advance (16° engine) with a 12° BTDC static engine timing.

According to the manuals, my MWM diesel engine the AKD 112 Z has a timing advance of about 28-29° BTDC and the AKD 10 V has 29° to 31° BTDC advance. These are both IDI and slow running diesels, with maximum 2000 RPM governed speed and no dynamic timing advance with RPM, so fixed timing . Obviously these have a humongous large and heavy flywheel, too heavy for a single person to lift. One would assume that when running at such low RPMs, timing advance should be even less then with faster running diesels to avoid harsh idle and piston knock...
Note that these old MWM engines however will run on anything from diesel fuel to heavy (waste/vegetable/gear/...) oil, (well filtered of course)

Intersting topic, perhaps more Q's then A's but interesting nevertheless.

Jake
 

Barrman

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You have found the black hole of 6.2/6.5 Diesel engine tuning. There are no published numbers from the manufacturer to do a static timing set up, GM never put out timing specs or timing methods. Snap-On, Kent-Moore and Ford all made a timing/rpm reading machine that works on the engine. Yet, nobody put out real specifications. Your chart only list a clamp on pulse detector timing spec. GM put out nothing. AM General in one M998 TM said 3° + or - 2° at 1300 rpm with the Snap-On Lumy/mag machine. Totally different number considering fuel burn rates than your spec. Yet, they a amazingly the same. We are all test pilots when it comes to these engine.

Welcome to the party pal.
 

Sharecropper

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You have found the black hole of 6.2/6.5 Diesel engine tuning. There are no published numbers from the manufacturer to do a static timing set up, GM never put out timing specs or timing methods. Snap-On, Kent-Moore and Ford all made a timing/rpm reading machine that works on the engine. Yet, nobody put out real specifications. Your chart only list a clamp on pulse detector timing spec. GM put out nothing. AM General in one M998 TM said 3° + or - 2° at 1300 rpm with the Snap-On Lumy/mag machine. Totally different number considering fuel burn rates than your spec. Yet, they a amazingly the same. We are all test pilots when it comes to these engine.

Welcome to the party pal.
Ditto what Barrman said. I’ve been trying to develop a good way to time the 6.2 for over 35 years and can now say there is no good way. Nothing beats a process of trial and error, that is to say, setting the mark on the pump slightly ahead of the mark on the engine. Then running it to see how it feels and sounds. From my experience the engine is most efficient when the pump is advanced the thickness of a matchstick between the marks. Yeah I know this sounds kinda redneckish but hey - it works. This is how I plan to time my P400 with the Bullet Supercharger and 250 HP marine pump. I will set the pump and then run the truck on the road over and over with different pump settings until I feel it is running it’s best. When I think I have got it the way it should be, I will then hook up my DTI Tech Time 3300-S to see where the timing light hits on the crank gauge. This will be noted in the engine’s notebook so it can be duplicated later, or revised if necessary. This method is really the only way to get the timing set for a specific engine.
Hope this helps.
 

Jake59

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You have found the black hole of 6.2/6.5 Diesel engine tuning. There are no published numbers from the manufacturer to do a static timing set up, GM never put out timing specs or timing methods. Snap-On, Kent-Moore and Ford all made a timing/rpm reading machine that works on the engine. Yet, nobody put out real specifications. Your chart only list a clamp on pulse detector timing spec. GM put out nothing. AM General in one M998 TM said 3° + or - 2° at 1300 rpm with the Snap-On Lumy/mag machine. Totally different number considering fuel burn rates than your spec. Yet, they a amazingly the same. We are all test pilots when it comes to these engine.

Welcome to the party pal.
Thanks!
I’ll be doing some measurements on my German made diesels and search for commonalities in diesel timing. Best chance will be with my Henschel 4 cyl 5200cc I guess…

cheers,
Jake
 

Jake59

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Ditto what Barrman said. I’ve been trying to develop a good way to time the 6.2 for over 35 years and can now say there is no good way. Nothing beats a process of trial and error, that is to say, setting the mark on the pump slightly ahead of the mark on the engine. Then running it to see how it feels and sounds. From my experience the engine is most efficient when the pump is advanced the thickness of a matchstick between the marks. Yeah I know this sounds kinda redneckish but hey - it works. This is how I plan to time my P400 with the Bullet Supercharger and 250 HP marine pump. I will set the pump and then run the truck on the road over and over with different pump settings until I feel it is running it’s best. When I think I have got it the way it should be, I will then hook up my DTI Tech Time 3300-S to see where the timing light hits on the crank gauge. This will be noted in the engine’s notebook so it can be duplicated later, or revised if necessary. This method is really the only way to get the timing set for a specific engine.
Hope this helps.
Hi Sharecropper,

And thank you for the good advice!
I have advanced my IP a lot more then just a match at present. Would chain stretch have anything to do with that? I have nearly 25.000M on the speedometer but it did not work when I purchased it so could be a few 10000’s more…

Not sure if this is relevant or helpful, but I will attempt to attach a recording which hopefully will allow you to hear and evaluate engine idle sound.

thank you once again,

Jake
 

Sharecropper

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Hi Sharecropper,

And thank you for the good advice!
I have advanced my IP a lot more then just a match at present. Would chain stretch have anything to do with that? I have nearly 25.000M on the speedometer but it did not work when I purchased it so could be a few 10000’s more…

Not sure if this is relevant or helpful, but I will attempt to attach a recording which hopefully will allow you to hear and evaluate engine idle sound.

thank you once again,

Jake
Jake - I believe if your timing chain was stretched so much that it affected the timing position of the pump, your engine would probably not run at all. Not to mention that the chain would hardly stay on the gears. If your chain is wore out, probably your whole engine is too. In all my years I have never seen a stretched chain in a diesel. That’s not to say it can’t happen but I have never experienced it. And in my opinion, if you have advanced your pump more than the thickness of a match stick between the lines, you are at or near being advanced too much.

Regarding an audio of your engine, I apologize but there is no way anyone could listen to a recording through the internet and determine where the timing should be set. I mean, I am pretty good but dayum, not THAT good.

Everyone is looking for a book or chart to indicate where to set the timing on a 6.2 so that it runs line a scalded dog and gets 35 mph. It just ain’t out there. Every engine runs slightly different based on how it has been maintained and various wear patterns on all the moving parts. A 5 degree advance might be the ideal setting on one particular 6.2 but may not be ideal on a different 6.2. That is why I suggested what I did in my earlier post. Start off with the marks aligned or slightly advanced and then run the truck a while and see how it performs. Having said all this, I believe you may be asking for more than your 6.2 is capable of giving.

I own the best diesel timing light money can buy, but I will only use it after I have found the sweet spot through trial and error of changing the pump position. And the only reason I will use it then is to document the indicated advance for my notebook.

Adjusting the pump position over and over is time-consuming and requires special tools. Most guys either don’t have the skill, tools, or patience to do it several times to find the ideal timing for a particular engine. I am not going to be able to help you more than I already have tried to.

Good luck, let us know your results.
 
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Jake59

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Good morning Sharcropper,

Once more thank you for the advice. Will follow your direction and see where I get from there.

2 weeks ago I finally got my new timing sprocket and chain set with the last (container) shipment form USA (took 16 months to get here....), so replacing the old one is on my To Do list. I decided to order a new set because I read on various websites the chain stretches considerably in time. This instigated me to do a few measurements a while ago on my engine before deciding to get a replacement. Although I know I could not do any meticulously accurate measurements, I did find that the actual stretch of the timing chain is beyond the maximum allowed, which is why I will replace it. Also based on these measurements, I found the timing was off by ~9 degrees, which kind of was confirmed when I used the Tach-N-Time J33300-A. I'll have to do a few confirmation measurements and calculations, based on the new sprocket and chain set I now have here to confirm my earlier assumptions/estimations.

You're right, just listening to a recording of a diesel engine does not provide a good basis for any sound conclusions. I was just hoping that there was this unlikely but narrow possibility...

As said, I will be following your path and adjust the timing based on trial and error and listening/feeling my engine. I have measured up the IP quite thoroughly and calculated that for every 1mm of pump rotation (to be exact I believe it is 1.07mm), this corresponds to 1° pump timing change, which naturally shows as 2° actual timing change on the crank shaft.

Also made me an IP rotating tool which is very simple: took just a 25" long piece of 1"x1/4" flat bar, 2-3" of 8mm rebar or bolts which you weld on either side of the flat bar and distanced so they fit into the two IP adjustment holes, just grind a slight arch on the side of the flat bar to clear the IP body and you have your adjustment tool.

Cheers,
Jake
 

Barrman

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Just to re state that every engine is different. I have 4 6.2 or 6.5 engines that get driven just about daily. Each one starts different, sounds different and for sure runs down the road different.

German and agriculture diesels have a precise tooth to tooth alignment for the camshaft to crank and injection pump to cam or crank. You set it up right and you know your exact timing. Because the manufacturer gives you numbers they figured out. You can then fine tune the timing by IP movement using factory specs. 6.x diesels you don't have that initial set up with any kind of comparable accuracy. Just the line on the IP that might or might not be in the same place as the line on the last IP. That is why I applaud your effort to get it exact but am shaking my head in frustration that your quest might end in "close enough for government work."
 

Barrman

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Do you know about the screwdriver test to check timing on the 6.2? With the engine warm and running. Put a large screw driver against the advance arm on the lower passenger side of the IP. Push the arm in. Then you have to figure out if is now running better/louder, worse or just kind of not happy.

If it dies, you were for sure too retarded on the timing. Turn it off, advance the IP some and try again.

If nothing changes then you are probably too far advanced and should move the IP toward the passenger side a bit to retard the timing.

"Sounds like a power stroke" and jumps around a bit is the best way to describe real close to right on.

Of course, a test drive is needed to confirm. Check smoke and cold starting too.
 

Jake59

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Do you know about the screwdriver test to check timing on the 6.2? With the engine warm and running. Put a large screw driver against the advance arm on the lower passenger side of the IP. Push the arm in. Then you have to figure out if is now running better/louder, worse or just kind of not happy.

If it dies, you were for sure too retarded on the timing. Turn it off, advance the IP some and try again.

If nothing changes then you are probably too far advanced and should move the IP toward the passenger side a bit to retard the timing.

"Sounds like a power stroke" and jumps around a bit is the best way to describe real close to right on.

Of course, a test drive is needed to confirm. Check smoke and cold starting too.

I know about the test as such, but never had it clarified to this extent.
Thanks,
Jake
 
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