Injection pump timing
#1
07-30-2005, 10:26 PM
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#2
07-30-2005, 11:22 PM
-Diesel Timing-
When adding fuel and boost in the quest for better performance, a key component, timing, is often overlooked. Timing mechanically injected diesels like the General Motors (Detroit Diesel) 6.2L, 1993 6.5L, and the Ford (Navistar) 6.9L and 7.3L diesels (all of which use the Stanadyne DB2 rotary injection pump) is simple in practice, but understanding the why and where to time is what this article is all about.
Most light-truck diesels come off the line tuned for moderate power and little or no smoke, and as miles are added and power drops off, the general wisdom has been to advance the pump to reclaim some of those lost horses. We'll look deeper into the idea of diesel timing, and its practical application on the project 6.2L engine.
Diesel Timing: an overview
Conservative timing results in low nitrogen oxides (NOx) emissions. For our 6.2L project engine, that resulted in the timing marks perfectly aligned which was top dead center (TDC) at 1400 rpm. While lower timing figures like these are best for NOx levels, brake specific fuel consumption increases, as does carbon monoxide; hydrocarbon levels decrease. In addition, lowered timing decreases cylinder pressure and reduces peak flame temperature since the fuel charge is injected once the piston has past TDC and is already on its way back down the cylinder in the power stroke. This is why it is more difficult to get a complete burn, and it is this hot, unspent exhaust gas that gets past the valves and decreases turbo lag.
On the other hand, advancing the timing results in increased cylinder pressures and higher peak flame temperatures which leads to a more complete burn of the fuel injected. This is demonstrated by a drop in exhaust gas temperatures, and increased turbo lag. The effect on emissions is significant. The NOx level increases dramatically past just a couple of degrees of advance, while hydrocarbons increase and carbon monoxide decreases. Brake specific fuel consumption drops off quickly as well.
As always, there is a happy medium between fuel rate and ingnition timing. A general rule to follow, and a good starting point for tuning, is that the more fuel you're running, the more conservative the ingnition timing. It all goes back to cylinder pressure. Adding fuel increases the combustion pressure since there is now more gas trying to expand rapidly during the power stroke.
How to adjust the timing:Fully warm the engine, and shut it off. Remove the appropriate glowplug (#3 for 6.2/6.5 diesels, #1 for 6.9/7.3 Ford truck diesels, and #4 on Ford vans), and install the MT161 luminosity probe. For Chevrolet diesel, #3 cylinder is chosen since combustion could start close to 9.5° ATDC thus making the first cylinder unusable. Another 90° of crankshaft rotation is available for signal processing. Install the magnetic probe in the holder on the front cover. Power the meter via one of the batteries. Make sure that there are no wires dangling in the way of the engine fan; zip-tie if necessary. Restart the engine, and check timing at selected intervals to establish a baseline.
To adjust the timing figure, rotate injection pump to increase or decrease the timing. To do so, Loosen the three bolts (15mm nuts on GM trucks, and 9/16 for Fords) and rotate appropriately. For 6.2/6.5 diesels, advance is towards the driver side; for 6.9/7.3 diesels, advance is toward the passenger side. NOTE: Do not adjust the timing with the engine running as this will cause severe damage to the injection pump geartrain.
Use the same RPM for each timing session to ensure the comparability of readings throughout the tuning process.
Our Results:
- Round 1: experimenting with timing advanceWe went to 3.5° BTDC @ 1300 RPM. The engine clack is noticabely louder at idle to about 1500. Beyond that, the volume and quality of the clack sounds normal. As predicted, turbo lag increased slightly, and boost levels were down by about 1/2 psi. There was a substantial increase in smoke throughout the rpm range, but cruising EGTs were lower by 50-75 degrees.
- Round 2: experimenting with timing retard
We turned the timing down to 2° ATDC @ 1300. There is nearly zero black smoke unless you're really hammering down on it. Boost is more responsive throughout the rpm range, but power is down just slightly. All this at the cost of EGTs. They are much higher than desired at around 750° cruising at 60 mph. They rise quickly on any hill, too.
- Round 3: trying to find the sweet spot
We bumped the mark forward to 2° BTDC @ 1300 rpm. There's hardly any smoke, power is good, and turbo lag is almost non-existent. Fuel economy increased slightly by an average of .75 mpg. This is a goodl setup for a conservative fuel rate (less than 60 cu mm) and low pressure injectors like the 1800 psi 6.2L long style.
#5
07-31-2005, 09:09 AM
Originally Posted by Tim Lamkin
Please post in normal font, thanks.
Much easier to read.
BTW great article
Much easier to read.
BTW great article
Yep, I just found that article myself, good information there. Too bad that Snap-On timing kit is over $300, (ouch), but I guess it might be worth it if you're keeping your rig for any amoung of time.
#6
07-31-2005, 12:23 PM
#7
08-01-2005, 12:21 AM
No problem, glad to help. It is an interesting article and the more info on our IP timing the better. Seems like that's about the most sensitive item in these trucks.
I checked out mine today, it was still set to the factory marks so I bumbed it up a hair. Anyone have any tricks on getting to those lower IP bolts? What a pain, I managed it, but I had to grind a lot off my 9/16 wrench just to get it in there.
I replaced the bearing that froze in my alternator, tomorrow I'll get the new fan belts and test it out and see if advancing the IP helped power and/or fuel economy any.
I checked out mine today, it was still set to the factory marks so I bumbed it up a hair. Anyone have any tricks on getting to those lower IP bolts? What a pain, I managed it, but I had to grind a lot off my 9/16 wrench just to get it in there.
I replaced the bearing that froze in my alternator, tomorrow I'll get the new fan belts and test it out and see if advancing the IP helped power and/or fuel economy any.
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"In one sitting, three different positions were tested. Although the pump was moved each time, the timing marks on the pump and front cover stayed in relatively the same place. There is no strong correlation between the position of the timing marks and the timing figure. Depending on how the pump was jiggled, it was possible to get two timing results that were as much as a 5° apart, yet were at the same physical location according to the timing marks. This just confirms that the factory-provided timing marks are a great ballpark figure for factory timing when one replaces their injection pump, but adjusting based on the "dime method" is hit and miss for tuning."
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another good link:
http://arrc.epnet.com/autoapp/8978/8...ION_TIMING.htm
(thank you Dark Horse for sharing in a different thread.)
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"I'm not a fan of timing above 9 degrees. I've had issues with it and WMO eating glow plug tips. I stick to the 8.5 and even with the newer fuel, I haven't gotten any unfavorable results. The changes in fuel have decreased the energy in it, but not the flash point. If you want more energy, just push your foot down further.
The Cetane rating is Higher thus, it combusts Sooner so theoretically, we should be retarding our timing. Not advancing it, if your trying to compensate."
-Mel (the Moose pump builder,when discussing the new ULSD fuel.)
"The problem with the lumy method is it relies to heavily on the injector, and the readings can be erratic. In theory the method is sound, but in application it falls short. Just ask anybody who has every done both, and your going to hear pulse is the way to go every time. Todd was over my place last night, and I timed his truck to 8.5 PBTDC on the nose. He was 3 degrees retarded. Man that thing will scoot now!"
-Mel
Todds reply:
"Thanks again Mel!
I'll post next week after I run a tank or two through to see how my mileage is. My truck definitely likes 8.5 deg timing!
5.5 degrees was with the marks lined up on the pump, for what it's worth. It seems like 3 degrees has made a big difference.
BTW if you're considering any Moose products, I highly recommend them. The service can't be topped
-Todd
"If you were burning waste motor oil or could (potentially illegally) find leftover old fuel you'd probably want to retard the timing in the general vicinity of the book timing specs and those were 8.5 BTDC at 2000 RPM +-2 degrees with the pulse method or anywhere from 1.5-5* ATDC with luminosity depending on cetane rating. "
-Diesel JD
i had to "borrow" a few posts,as most here so far,use the "by sound" method.-im trying to help discourage that madness lol.engine timing is not hand grenades and horse shoes.
i see this often recommended in searches:
Ferret Instruments V765-01 Injector Tester - Fuel System Tools
oh cool! i found my favorite from Mel:
"Get a meter on it! Why waste your time setting it from one "guess" to another? Glow plug damage, and hammering of the wrist pins can result from too much advance. Not only that, but you will never know if your IP is working properly, because someone who does it properly will know what the timing looks like at idle, and through the RPM range to the target speed. Timing by ear will only get you close. 2 degrees makes a BIG difference, and that is about as close as you can get it by ear... if your good. If you land it at 8.5, it's not because your good. It's because your lucky. "
-Mel
oh double cool! i found the other post i really liked from Mel too,thats good to know:
"It's not a bad idea to have your timing checked every 20-30K miles. It's going to creep in the retarded direction as things wear, and fuel delivery for any given throttle setting is going to decrease. Fortunately as injectors wear, their pop presure lessens so things can sort of stay even, but there are no guarantees. "
-Mel
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................
this must be an older version of this book,because mine has no such chart (found via google) it does match Jens info provided above:
.........................
this was found searching cetane ratings via google in Maine:
(also have a friend who works at oil co.and he made some calls recently,that verifies the info below.he there are only 2 terminals in Maine,and most,including the diesel they sell has a 40-42 cetane rating.)
........
caution! too much timing advance will kill glow plugs!,as well as potentially harming your pistons wrist pins!
caution! when looking for meters on ebay,etc.without the correct lumy,crank sensors,and or pulse probes specifically for your diesel engine,the tool is no good to you! most of which are no longer in production,and RARELY(don't be surprised to wait for years,and never see one come up) sold separately.know what your buying/bidding on first.caution!
.......
more timing reference links:
https://www.ford-trucks.com/forums/5...-on-mt480.html
https://www.ford-trucks.com/forums/8...ime-meter.html
when is it timing required as part of the diesel tune up for 6.9l and 7.3l IDI engines?
1.whenever fuel injectors are replaced.
2.whenever the ip is replaced.
3.whenever the fuel is adjusted.
4.whenever a turbo and more fuel is added (doesn't make sense to add a turbo,and just supply more air only.your pump was too high for n/a to start with,or your missing out on the proper fuel to air ratio if you don't tune the mixture.)
5.whenever using alternate fuels,or switching to a fueling station that now offers higher cetane rated fuel.
6.once every 30 thousand miles,or more often in your quest for peak performance,fuel economy,lower egts,less turbo lag etc.
reading through,we can see the "more is better" is not always best.so many variables such as fuel flow and quality,altitude etc all play a part on hitting your particular engines optimal timing setting.
we read a lot of debate as to which timing method is best.
personally before my meter has even arrived,based on research i think this focus is of lost concern.
what seems to have gotten lost,is that "one setting" fits all vs each individual setup.
for a brief example,we can't expect the guys idi set in the Rockies to be the same optimal setting for the guy who runs his truck down at sea level in Florida with all things being equal (ok,so there are high alt,and norm ip's to compensate for this.but what about everyone in between,and of course all the other variables too long to list examples of.)
where the focus should be,is setting the timing where it works best for you rather than focusing on one particular setting.
this is why the older more experienced back along tossed the book,and began to tune by ear is my theory.
however,we know this method is not sound either,because the placement alone on the ip is not strict enough to follow.
a meter will help determine where you are at all times,and allow you to move correctly in each direction while driving the truck,and testing for fuel economy along the way and for peak performance.
with no meter in hand yet,this is my theory only and should be taken with a grain of salt,or dismissed all together,whichever you see fit lol.
this info posted above is NOT to discourage you from having your timing properly adjusted at the shop,from a friend,or other means with a meter!nailing it to the average preferred setting(s) is,as we know most important.
if you have have looked in on my particular fuel economy records here:
https://www.ford-trucks.com/forums/i...vehicleid=1301
you'll soon see me posting with different timing settings.however,remember mine will not necessarily be your best,and because i travel different routes,and with various load combos,i will not be the best person to follow along with to determine even my own optimal timing setting,let alone anyone else.so keep that in mind when your searching for yours.also keep in mind,iv always been happy with the performance from my idi(keeping in mind most rural roads have posted speed limits of 45 mph here) so i will tend to sacrifice performance slightly,should i see the fuel economy rise at the same time.i figure it will take me a long time to nail my trucks happy point with such variances.but im going to have fun with it just the same.
http://arrc.epnet.com/autoapp/8978/8...ION_TIMING.htm
(thank you Dark Horse for sharing in a different thread.)
Here are some infos for the dymamic timing:
Dynamic timing
Note: Diesel engines are very sensitive to slight changes in timing, and dynamic timing is more accurate than static timing. Although the dynamic timing procedure is not extremely difficult, the procedure requires several expensive tools. If you don 't have ready access to these items, we recommend you take the vehicle to a dealer service department or diesel specialist for dynamic timing.
1. Obtain a fuel sample and check the cetane value using Ford Rotunda Tool no. 078-00121 supplied with Ford Rotunda Tool no. 078-00200 or equivalent (6.9l_ engines only). Cetane value is determined by measuring the specific gravity {desity) of the fuel with the fuel temperature between 75 and 95-degrees F. Poor quality fuel can affect diesel engine performance. Check the cetane value as follows:
a) Fill the hydrometer Container with fuel until the hydrometer floats.
b) Gently spin the unit to break surface tension. Read the number at the Iowest point of the fuel level in the hydrometer. Record the number and refer to the cetane value conversion chart.
Hydrometer Reading Getane Value
.837 50
.846 47
.849 46
.858 43
.862 42
.876 38
Fuel hydrometer reading-to-cetane value conversion chart
2 Run the engine to bring it up to normal operating temperature (192 to 212-degrees F). Note: Temperature is critical to obtain accurate timing.
3 Stop the engine and install a Dynamic Timing Meter (Ford Rotunda no. 078-00100 or equivalent for 6.9L engines, or no. 078-0020 for 7.3L engines), by placing the magnetic pickup in the hole on the timing pointer scale. Insert the pickup until it almost touches the Vibration damper. Note: To ensure accurate readings, clean the damper and remove any rust.
4 On 6.9L engines, disconnect the glow plug from the number one cylinder using Ford tool no. D83T-6002-A or equivalent. Install the luminosity probe and tighten it to 12 foot-lbs. Install the photocell over the probe.
5 On 7.3L engines, connect the clamp of the Timing Meter Adapter (no. 078-00201, or equivalent) to the pressure line sensor on the injector nozzle (no. 1 on F-series, no. 4 on E series).
6 Connect the dynamic timing meter to the battery and dial in 20-degrees of offset on the meter. Unplug the cold Start advance solenoid connectorfrom the solenoid terminal. Caution: Keep the wiringawayfrom the drivebelts.
7 With the transmission in Neutral and the rear wheels raised off the ground, startthe engine. Using Ford Rotunda tool no. 014-00302 or equivalent, set engine speed to 1400 rpm (6.9L) or 2000 rpm (7.3L) with no accessory load. Observe injection timing on dynamic timing meter.
8 Using jumper wires, apply battery voltage to the cold start advance solenoid terminal to activate it. Note: Activating the cold Start advance solenoid can result in engine speed increase. Adjust the throttle control to maintain 1400 rpm (6.9L) or2000 (7.3L) (if necessary).
9 Check the timing. The timing should be advanced at least 2.5-degrees on 6.9L engines or 1 -degree on 7.3L engines before the timing obtained in Step 7. If the advance is less than 2.5-degrees, replace the fuelinjection pump top cover assembly.
10 On 6.9L engines if the dynamic timing is not within 2-degrees of specification (see Illustration), adjust the pump timing. On 7.3L engines, it should be 8.5-degrees BTDC (before top dead center), plus-or-minus 2-degrees.
11 Shut the engine off and note the timing mark alignment. Remove the fast idle bracket and solenoid from the injection pump. Slightly loosen the injection pump mounting nuts with Ford tool no. T86T-9000-C or equivalent.
12 Install the pump rotating tool (Ford no. T83T-9000-C or equivalent) on the front of the injection pump. Rotate the pump clockwise (when viewed from the front) to retard the timing and counterclockwise to advance it. If necessary, tap the tool lightly with a soft-face hammer if the pump sticks.
Note: Two degrees of dynamic timing is approximately 0.030 inch of timing mark movement.
13 Remove the rotating tool and tighten the pump mounting nuts securely. Start the engine and recheck the timing. Repeat the procedure äs necessary until timing is within one degree of Specification.
14 Turn the engine OFF and remove the test equipment. Install the glowplugs äs described in the Electrical System portion of this Chapter.
15 Run the engine and check for power and smoothness.
have fun
Jens
Dynamic timing
Note: Diesel engines are very sensitive to slight changes in timing, and dynamic timing is more accurate than static timing. Although the dynamic timing procedure is not extremely difficult, the procedure requires several expensive tools. If you don 't have ready access to these items, we recommend you take the vehicle to a dealer service department or diesel specialist for dynamic timing.
1. Obtain a fuel sample and check the cetane value using Ford Rotunda Tool no. 078-00121 supplied with Ford Rotunda Tool no. 078-00200 or equivalent (6.9l_ engines only). Cetane value is determined by measuring the specific gravity {desity) of the fuel with the fuel temperature between 75 and 95-degrees F. Poor quality fuel can affect diesel engine performance. Check the cetane value as follows:
a) Fill the hydrometer Container with fuel until the hydrometer floats.
b) Gently spin the unit to break surface tension. Read the number at the Iowest point of the fuel level in the hydrometer. Record the number and refer to the cetane value conversion chart.
Hydrometer Reading Getane Value
.837 50
.846 47
.849 46
.858 43
.862 42
.876 38
Fuel hydrometer reading-to-cetane value conversion chart
2 Run the engine to bring it up to normal operating temperature (192 to 212-degrees F). Note: Temperature is critical to obtain accurate timing.
3 Stop the engine and install a Dynamic Timing Meter (Ford Rotunda no. 078-00100 or equivalent for 6.9L engines, or no. 078-0020 for 7.3L engines), by placing the magnetic pickup in the hole on the timing pointer scale. Insert the pickup until it almost touches the Vibration damper. Note: To ensure accurate readings, clean the damper and remove any rust.
4 On 6.9L engines, disconnect the glow plug from the number one cylinder using Ford tool no. D83T-6002-A or equivalent. Install the luminosity probe and tighten it to 12 foot-lbs. Install the photocell over the probe.
5 On 7.3L engines, connect the clamp of the Timing Meter Adapter (no. 078-00201, or equivalent) to the pressure line sensor on the injector nozzle (no. 1 on F-series, no. 4 on E series).
6 Connect the dynamic timing meter to the battery and dial in 20-degrees of offset on the meter. Unplug the cold Start advance solenoid connectorfrom the solenoid terminal. Caution: Keep the wiringawayfrom the drivebelts.
7 With the transmission in Neutral and the rear wheels raised off the ground, startthe engine. Using Ford Rotunda tool no. 014-00302 or equivalent, set engine speed to 1400 rpm (6.9L) or 2000 rpm (7.3L) with no accessory load. Observe injection timing on dynamic timing meter.
8 Using jumper wires, apply battery voltage to the cold start advance solenoid terminal to activate it. Note: Activating the cold Start advance solenoid can result in engine speed increase. Adjust the throttle control to maintain 1400 rpm (6.9L) or2000 (7.3L) (if necessary).
9 Check the timing. The timing should be advanced at least 2.5-degrees on 6.9L engines or 1 -degree on 7.3L engines before the timing obtained in Step 7. If the advance is less than 2.5-degrees, replace the fuelinjection pump top cover assembly.
10 On 6.9L engines if the dynamic timing is not within 2-degrees of specification (see Illustration), adjust the pump timing. On 7.3L engines, it should be 8.5-degrees BTDC (before top dead center), plus-or-minus 2-degrees.
11 Shut the engine off and note the timing mark alignment. Remove the fast idle bracket and solenoid from the injection pump. Slightly loosen the injection pump mounting nuts with Ford tool no. T86T-9000-C or equivalent.
12 Install the pump rotating tool (Ford no. T83T-9000-C or equivalent) on the front of the injection pump. Rotate the pump clockwise (when viewed from the front) to retard the timing and counterclockwise to advance it. If necessary, tap the tool lightly with a soft-face hammer if the pump sticks.
Note: Two degrees of dynamic timing is approximately 0.030 inch of timing mark movement.
13 Remove the rotating tool and tighten the pump mounting nuts securely. Start the engine and recheck the timing. Repeat the procedure äs necessary until timing is within one degree of Specification.
14 Turn the engine OFF and remove the test equipment. Install the glowplugs äs described in the Electrical System portion of this Chapter.
15 Run the engine and check for power and smoothness.
have fun
Jens
With the last timing adjustment I made using the MT480 luminosity style probe (now at 2* ATDC @ 2000 rpm) I can tell you this: I started it this morning, overnight low in the low 30's and not plugged in, and it smoked very little. The light blue smoke was not even a quarter of what it used to be at idle even when it was at full running temperature. It does rattle more than it did before when cold, once it comes off the cold advance then quiets down. Once the truck is up to running temp (I drove around for a while then parked it) it does not smoke at all anymore. The throttle response seems a lot better. When I gun it while parked I get a puff of black smoke, about a lungs worth - LOL. While driving with the seat-o-meter hooked up, there does seem to be more power and better acceleration now. Once in overdrive I slowed back to about 35 miles an hour, but still in OD, if I give it as much throttle as I can without kicking it down into passing gear the truck accelerates with a light amount of black smoke – I think that’s pretty good for OD. I’m going to leave the timing here and see what I get for mileage.
As far as recommending a setting I’ll say this: Either buy a meter (either the luminosity style or the pulse type) or find someone that has one. Then I would start out at either 2* ATDC @ 2000 rpm using the luminosity probe or 8* BTDC @ 2000 rpm using the pulse adapter. Take it for a test drive and then make adjustments as needed. Again my van is a 1993 with the 7.3 NA IDI.
<O
Cetane hydrometer: I’m going to get one. I’m going to take a sample out of my fuel tank for a sample that way I can measure the additive effects as well. It will probably be a few weeks before I do this but once I do I’ll give you an update.
<O93
As far as recommending a setting I’ll say this: Either buy a meter (either the luminosity style or the pulse type) or find someone that has one. Then I would start out at either 2* ATDC @ 2000 rpm using the luminosity probe or 8* BTDC @ 2000 rpm using the pulse adapter. Take it for a test drive and then make adjustments as needed. Again my van is a 1993 with the 7.3 NA IDI.
<O
Cetane hydrometer: I’m going to get one. I’m going to take a sample out of my fuel tank for a sample that way I can measure the additive effects as well. It will probably be a few weeks before I do this but once I do I’ll give you an update.<O
93Normally the 7.3 was timed by the Pulse method only........
DieselDon's info
If you have the original emission label on your valve covers, they gave the max pump fuel flow rate in mm3 at rated HP.
As I recall 6.9 was about 48mm3 sea level and 44mm3 for high altitude pump
7.3NA was about 54mm3 and 49mm3 for high altitude
7.3 IDI Turbo - 58 mm3 ( this is out of the Ford book )
Optimum timing: 6.9IDI ( Ford method ): .5-1.5 degrees ATDC
6.9IDI ( Navistar method ): 6-7 degrees BTDC
7.3 NA: 8-9 degree BTDC*
7.3 IDI Turbo: 8-9 degrees BTDC*
Anything above these, the engine get's pretty noisey.
* helps engine starting. Original timing was 5-6 BTDC and engine cranked a long time ( at least in comparison to 6.9 ) before starting.
DieselDon's info
If you have the original emission label on your valve covers, they gave the max pump fuel flow rate in mm3 at rated HP.
As I recall 6.9 was about 48mm3 sea level and 44mm3 for high altitude pump
7.3NA was about 54mm3 and 49mm3 for high altitude
7.3 IDI Turbo - 58 mm3 ( this is out of the Ford book )
Optimum timing: 6.9IDI ( Ford method ): .5-1.5 degrees ATDC
6.9IDI ( Navistar method ): 6-7 degrees BTDC
7.3 NA: 8-9 degree BTDC*
7.3 IDI Turbo: 8-9 degrees BTDC*
Anything above these, the engine get's pretty noisey.
* helps engine starting. Original timing was 5-6 BTDC and engine cranked a long time ( at least in comparison to 6.9 ) before starting.
The target plate on the front of the engine is offset by 20*. With my Kent Moore timing meter I found that at idle 640 rpm timing (pulse method) is at 14.4* BTC, then at 2000 rpm it retards to 8.5* BTC.
At this piont you will get a slight rattle to the engine as you accelerate when the cold advance is still on. After the advance cuts off, the rattle will be gone.
At this piont you will get a slight rattle to the engine as you accelerate when the cold advance is still on. After the advance cuts off, the rattle will be gone.
"I'm not a fan of timing above 9 degrees. I've had issues with it and WMO eating glow plug tips. I stick to the 8.5 and even with the newer fuel, I haven't gotten any unfavorable results. The changes in fuel have decreased the energy in it, but not the flash point. If you want more energy, just push your foot down further.
The Cetane rating is Higher thus, it combusts Sooner so theoretically, we should be retarding our timing. Not advancing it, if your trying to compensate."
-Mel (the Moose pump builder,when discussing the new ULSD fuel.)
"The problem with the lumy method is it relies to heavily on the injector, and the readings can be erratic. In theory the method is sound, but in application it falls short. Just ask anybody who has every done both, and your going to hear pulse is the way to go every time. Todd was over my place last night, and I timed his truck to 8.5 PBTDC on the nose. He was 3 degrees retarded. Man that thing will scoot now!"
-Mel
Todds reply:
"Thanks again Mel!
I'll post next week after I run a tank or two through to see how my mileage is. My truck definitely likes 8.5 deg timing!
5.5 degrees was with the marks lined up on the pump, for what it's worth. It seems like 3 degrees has made a big difference.
BTW if you're considering any Moose products, I highly recommend them. The service can't be topped
-Todd
"If you were burning waste motor oil or could (potentially illegally) find leftover old fuel you'd probably want to retard the timing in the general vicinity of the book timing specs and those were 8.5 BTDC at 2000 RPM +-2 degrees with the pulse method or anywhere from 1.5-5* ATDC with luminosity depending on cetane rating. "
-Diesel JD
i had to "borrow" a few posts,as most here so far,use the "by sound" method.-im trying to help discourage that madness lol.engine timing is not hand grenades and horse shoes.
i see this often recommended in searches:
Ferret Instruments V765-01 Injector Tester - Fuel System Tools
oh cool! i found my favorite from Mel:
"Get a meter on it! Why waste your time setting it from one "guess" to another? Glow plug damage, and hammering of the wrist pins can result from too much advance. Not only that, but you will never know if your IP is working properly, because someone who does it properly will know what the timing looks like at idle, and through the RPM range to the target speed. Timing by ear will only get you close. 2 degrees makes a BIG difference, and that is about as close as you can get it by ear... if your good. If you land it at 8.5, it's not because your good. It's because your lucky. "
-Mel
oh double cool! i found the other post i really liked from Mel too,thats good to know:
"It's not a bad idea to have your timing checked every 20-30K miles. It's going to creep in the retarded direction as things wear, and fuel delivery for any given throttle setting is going to decrease. Fortunately as injectors wear, their pop presure lessens so things can sort of stay even, but there are no guarantees. "
-Mel
this must be an older version of this book,because mine has no such chart (found via google) it does match Jens info provided above:
Haynes Diesel Engine Repair Manual
(book # 10330), page 3-34.
3.66a Fuel Hydrometer Reading-To-Cetane Value Conversion Chart
Hydrometer Reading -- Cetane Value
-----.837 -- - ------50--------
-----.846 -- ------ - 47--------
-----.849 ------ -- - 46--------
---- . 858 ------ -- - 43--------
----- .862 ------ -- - 42--------
----- .876 ------ -- - 38--------
(book # 10330), page 3-34.
3.66a Fuel Hydrometer Reading-To-Cetane Value Conversion Chart
Hydrometer Reading -- Cetane Value
-----.837 -- - ------50--------
-----.846 -- ------ - 47--------
-----.849 ------ -- - 46--------
---- . 858 ------ -- - 43--------
----- .862 ------ -- - 42--------
----- .876 ------ -- - 38--------
this was found searching cetane ratings via google in Maine:
(also have a friend who works at oil co.and he made some calls recently,that verifies the info below.he there are only 2 terminals in Maine,and most,including the diesel they sell has a 40-42 cetane rating.)
Only certain states mandate cetane numbers on the pump. For the most part though, all the fuel in your area is going to be fungible #2 that travels down the pipeline to the local terminal, at which point it's separated into branded trucks and additized if that company chooses to. Basically all the stations in most people's areas are serving the exact same fuel, typically 40-43 cetane. Hess does typically carry a minimum cetane of 42-45, and is probably the best choice in your area.
I don't know of any suppliers of true premium diesel in your area, although possibly Irving fuels make it down that far. I am spoiled being in one of very few states lucky enough to get 50 cetane minimum BP Diesel Supreme.
I don't know of any suppliers of true premium diesel in your area, although possibly Irving fuels make it down that far. I am spoiled being in one of very few states lucky enough to get 50 cetane minimum BP Diesel Supreme.
Shell 'premium diesel' is the same as most generic 'premium' diesel fuels. They do have a premium in Canada that is actually decent compared to #2. Most generic premium diesel fuels are regular #2 that has been additized at the terminal. All it has to meet is 2 of 5 characteristics of premium diesel to be legally called premium. Typically the fuels just have an added detergent and stabilizers, or antigels in the winter. Most premium diesel isn't worth the extra cost associated, unless it's the real deal like BP supreme or Amoco premier, which are 50 cetane minimum, start from more refined/better basestocks, and are kept separate from #2 the whole way, from refinery to pump. There are some smaller regional companies that do sell 50 cetane true premium fuel, however they are few and far between.
caution! too much timing advance will kill glow plugs!,as well as potentially harming your pistons wrist pins!
I burned out 2 sets of beru's(200 bucks down the drain) before I realized my timing was way to far advanced. Anything over 10 degrees will toast them quickly...
when I bumped my timing up a bit, then there went my glow plugs. Ill take the timing back to the original spot till I get a timing meter here soon so it can be dead on!
When i killed glow plugs due to timing they actually looked like they had started to melt or something and some of the tips were gone not because i broke them but because the burned off
"Get a meter on it! Why waste your time setting it from one "guess" to another? Glow plug damage, and hammering of the wrist pins can result from too much advance. Not only that, but you will never know if your IP is working properly, because someone who does it properly will know what the timing looks like at idle, and through the RPM range to the target speed. Timing by ear will only get you close. 2 degrees makes a BIG difference, and that is about as close as you can get it by ear... if your good. If you land it at 8.5, it's not because your good. It's because your lucky. "
-Mel
-Mel
.......
more timing reference links:
https://www.ford-trucks.com/forums/5...-on-mt480.html
https://www.ford-trucks.com/forums/8...ime-meter.html
when is it timing required as part of the diesel tune up for 6.9l and 7.3l IDI engines?
1.whenever fuel injectors are replaced.
2.whenever the ip is replaced.
3.whenever the fuel is adjusted.
4.whenever a turbo and more fuel is added (doesn't make sense to add a turbo,and just supply more air only.your pump was too high for n/a to start with,or your missing out on the proper fuel to air ratio if you don't tune the mixture.)
5.whenever using alternate fuels,or switching to a fueling station that now offers higher cetane rated fuel.
6.once every 30 thousand miles,or more often in your quest for peak performance,fuel economy,lower egts,less turbo lag etc.
reading through,we can see the "more is better" is not always best.so many variables such as fuel flow and quality,altitude etc all play a part on hitting your particular engines optimal timing setting.
we read a lot of debate as to which timing method is best.
personally before my meter has even arrived,based on research i think this focus is of lost concern.
what seems to have gotten lost,is that "one setting" fits all vs each individual setup.
for a brief example,we can't expect the guys idi set in the Rockies to be the same optimal setting for the guy who runs his truck down at sea level in Florida with all things being equal (ok,so there are high alt,and norm ip's to compensate for this.but what about everyone in between,and of course all the other variables too long to list examples of.)
where the focus should be,is setting the timing where it works best for you rather than focusing on one particular setting.
this is why the older more experienced back along tossed the book,and began to tune by ear is my theory.
however,we know this method is not sound either,because the placement alone on the ip is not strict enough to follow.
a meter will help determine where you are at all times,and allow you to move correctly in each direction while driving the truck,and testing for fuel economy along the way and for peak performance.
with no meter in hand yet,this is my theory only and should be taken with a grain of salt,or dismissed all together,whichever you see fit lol.
this info posted above is NOT to discourage you from having your timing properly adjusted at the shop,from a friend,or other means with a meter!nailing it to the average preferred setting(s) is,as we know most important.
if you have have looked in on my particular fuel economy records here:
https://www.ford-trucks.com/forums/i...vehicleid=1301
you'll soon see me posting with different timing settings.however,remember mine will not necessarily be your best,and because i travel different routes,and with various load combos,i will not be the best person to follow along with to determine even my own optimal timing setting,let alone anyone else.so keep that in mind when your searching for yours.also keep in mind,iv always been happy with the performance from my idi(keeping in mind most rural roads have posted speed limits of 45 mph here) so i will tend to sacrifice performance slightly,should i see the fuel economy rise at the same time.i figure it will take me a long time to nail my trucks happy point with such variances.but im going to have fun with it just the same.