6.9 timing specs

[rjdaaa]

I just read the tech on how to time the IDI with the ferrett intstruments and the digital timing light, it looks like when the light is firing the rpm is 660 and you can adjust the injection pump rotation to achieve the mark on the balancer lining up when it fires so 0 degrees at this point. After that assumption I get confused, then you dial up 8.5 degrees and go to 2080 rpm with the light, then what if the light is not firing at the mark on the balancer, and you again adjust/rotate the injection pump to make it line up, does this mess up your first setting of adjusting the pump at 660 rpm ?
Also, are the correct timing specifications for say a non-aspirated 6.9 which is used in light duty on the highway, versus a hypermax 6.9 which pulls a 6,000 pound trailer the same?
I haven't studied the postings here in a while, so if this has already been covered sorry about that.
Thanks for any advice here, correct timing for best fuel economy would be nice but if other specifications are better for the engine, that's what I would want.

 

[gatorman21218]

I just read the tech on how to time the IDI with the ferrett intstruments and the digital timing light, it looks like when the light is firing the rpm is 660 and you can adjust the injection pump rotation to achieve the mark on the balancer lining up when it fires so 0 degrees at this point. After that assumption I get confused, then you dial up 8.5 degrees and go to 2080 rpm with the light, then what if the light is not firing at the mark on the balancer, and you again adjust/rotate the injection pump to make it line up, does this mess up your first setting of adjusting the pump at 660 rpm ?
.

You set the timing at 2000 rpm so dont worry about what it is at idle. How i do it is I adjust the meter while its strobing until the mark aligns on the balancer. Then make the adjustment and check again.


So first you get up to speed, and start the meter at zero. keep dialing the meter while the strobe is on and you will see the mark on the balancer move. When the marks line up, stop, and look at the meter. that number is where your timing is currently. then you can adjust the IP accordingly

 

[stumiister]

The method of timing your trying to use is with a meter that has a clamp on sensor that goes on either #1 or #4 fuel line and the other magnetic pick up goes in the hole on the front cover to see where the crank is for timing.
It is timed at about 2000rpm to about 8.5*btdc.

 

[swervyjoe]

Do you advance more for altitude like on a gasser?

 

[icanfixall]

I feel I need to add this about timing.. Its been talked about for many years now that 9.5 degrees before top dead center is a better degree because of the low sulfer fuels we are forced to use. Moving the injection pump counter clockwise advances the timing. Thats moving the pump towards the passenger side of the engine compartment. Retarding it any amount is going the drivers side. So think of it this way... You find your timing is 15 degrees advanced.. Thats 15 dbtdc. So you have to retard it back 5.5 degrees retarded. But its not retarding the timing past the zero mark. Thats where the timing has become a negative degree and no longer a plus degre. When you move the pump you are advancing or retarding it. This is when you are using the line clamp timing method... Using a luminosity probe in the number one glow plug hole is when you need to see an actual retarded timing degree on the meter or timing lite. Thats how the lumi method of timing works.. Its still going to be the same timing in advance degrees as the clamp type timing method. Funny how that works the same... Not many owners will use the lumi method of timing because there is more work involved doing that kind of timing. You really need the hydrometer to tell you what the fuel cetane is for that type of timing plus removing a glow plug. Thats not usually a fun project either. The lumi timing uses the combustion flash to trigger the timing responce that tells the meter and lite what the timing is...

 

[rjdaaa]

Thanks for the advice, I think I understand how to time now, I will set at 8.5 btdc as I try and improve fuel to what it used to be be by running Redline diesel fuel catalyst.

 

[icanfixall]

The factory specs for timing with the pulse timing method was 8.5 dbtdc plus or minus 2.5 degrees. So a timing of 6 to11 degrees was correct. Or anyplace in that range would do.. We have figured out thats not going to work for most of us in this forum The high end is 10.5 degrees advanced at the most. Now some will run less and very few will run more. I like how my engine runs at 9.5 advance. If when you set yours to 8.5 advanced and its lack luster in proformance and mileage try advancing it to 9.5. Testing is what you want to do or settle for the feeling you get when you time it.. You are not "required" to test out all thats posted here. I post what I have found to be whats happening in real life with our engines. I will change as new information is proven here. I feel this forum as a collective is far advanced of any other source no matter it be a dealer or another idi fourm. We do more here by 8am than most do in a day..

 

[RLDSL]

Do you advance more for altitude like on a gasser?

As mentioned, with the new fuel, baseline really needs to be at around 9.5- ( optimally 9..7 deg btdc if you want to split hairs ) and yes, that is for those of us at average altitude. If running at extreme altitude all the time, you would benefit from a bit above that , Now heres where it gets murky. By the OLD figures with 50 and 500 ppm sulfur fuel 10.5 btdc was considered the max as glow plugs begin to suffer ill fates beyond that, but with the 15ppm sulfur fuel we have now, the burn rate has significantly been altered ( hence the need for the timing change , when the new fuel first came out, we all lost power and had fuel mileage go in the toilet, the increase in timing simply brought it back up to factory standards and was based on european ultra low sulfur diesel fuel timing settings that have been in existance for many years) in other words, ULSD burns slower ( take the head off a match, all you have is a stick ) So we dont know exactly what the high end limit might be raised to . Theoretically , it should be 11.7 given teh calculations used , but weve all basically chosen to take teh safe path and stay below the original 10.5 mark due to the fact that digging broken glow plug tips out of one of these things is no fun chore I wish I had an extra beater to experiment with as I would kick the timing up to 11.2 in a heartbeat just to see what happens., But anyway, I ran at 10.5 before for quite sometime and experienced no problems.

While you will see many guys wanting to turn fuel up, at altitude, you want to do the opposite and turn it down. ( many bosch pumps have little gadgets that do this automatically at a certain altitude, they advance the timing and reduce teh injected volume of fuel , Stanadyne wasnt quite that sharp )