Interesting Timing info

[WrickM]

so now that i at least have a mt480 working i have found some interesting results. once the engine is good and warmed up i get ~7.5ATDC at 1400 rpms. This is pretty far retarded so i am thinking i need to advance the timing a bit. Then i switch over to WVO and at 1400 rpms the timing is now ~2-2.5 ATDC! That's quite a change between the dino-diesel and WVO! It presents some real questions in tuning. I want to advance it so my cold start is better and so i have less gray smoke, but if i do when i run on WVO my timing will be too advanced and too ******* the engine.

I need to see how some B20 effects the timing.

Also i should note that during the switch over to WVO the timing becomes extremely advance up to 8BTDC for about 20 seconds. then when switching back to dino-diesel the timing goes extremely retarded 12atdc for about the same period of time. all very interesting.

 

[LCAM-01XA]

Just a quick note: ain't you actually supposed to measure timing at 2000 rpms? As your engine speed increases the IP will back off the timing, so your truck may actually be even more retarded than you now think...

 

[WrickM]

2000 rpms if you are using the mt1480 and the pulse timing method. i am using the luminosity method on a mt480. As per the instructions using 1400 rpms i was targeting 2-3 atdc but now i am just not entirely sure where i am going to tune it to.

 

[LCAM-01XA]

Also, have you though of measuring the timing advance that's achieved by the factory solenoid on a warm engine (you'll need to manually jump the solenoid for that)? I'm thinking you may be able to set your timing based on WVO (since that's the more advanced number) and then wire up a manual switch for the advance solenoid for whenever you're running straight diesel fuel and the timing falls back due to the different fuel properties...

 

[WrickM]

guess i am the only one really interested in the massive timing difference between wvo and diesel lol

 

[OLDBULL8]

guess i am the only one really interested in the massive timing difference between wvo and diesel lol

Hey! It's Sunday and some are in Church or waiting for NASCAR race to start.

 

[towcat]

Hey! It's Sunday and some are in Church or waiting for NASCAR race to start.

you forgot one more thing, recovering from a hard drinking night and trying to remember what the hell happened.

 

[THECACKLER]

IIRC the Cold Advance mechanism on the I/P gives 6* Advance. That might be just right for Pump Fuel.

 

[jwalterus]

Just a quick note: ...... your truck may actually be even more retarded than you now think...

after spending all this time fixing my truck from the PO's "fixes", I don't think MY truck could GET any more retarded

 

[Diesel JD]

Hey WrickM you are using the correct method I think. Which port did you use on the engine front? The one at 0 ATDC or the one at 20ATDC? Does the MT480 requirere you to dial in advance like the `1480 does? You seem to unerstand these meters so I'm assuming you did all this stuff right. f that's the case I would shoot for being in timing spec with the WVO if that's what you use the most. That will leave your timing on diesel very retarded, but you could run a trigger wire to the cold timing advance and that way you could gain about 2 * of advance to help you warm up faster and keep you closer to spec when on diesel. I'd actually shoot for about 0-1*ATDC with the wvo since it is a higher cetane and lower BTU/unit fuel compared to diesel. If you were running waste motor oil you'd be wanting to be at the retarded end of the timing specs because compared to D2 it is a high BTU/unit and low cetane fuel. You're right this burn rate stuff is fasinating! I'm at around 0-1 ATDC with luminosity at 1400 and burn B100 99% of the time. The fuel economy could be better but I think there are other reasons behind that. I don't chew glow plugs or have excessive smoke and it does what I ask of it power wise.

 

[WrickM]

I use the port that the pickup fits in at 20atdc and #1 cylinder. the mt480 has a switch that toggles 20 degree offset and 95 degree. it is of course set to 20.

i agree i was going to aim for 0-1 atdc with the wvo and see what that does with the diesel. I need to figure out the wiring on the cold timing advance, but my guess is that would be on anyway when the truck is warming up and when i am purging the system the timing doesn't matter much. though the switch could be handy for those occasion when the WVO filer is clogged. . . hmmmmm i need to research how that would work.

 

[Sycostang67]

I am curious to see if there is a difference with biodiesel. I recently found a few stations that carry it was gonna give it a try.

 

[WrickM]

Syscostang67. . make sure any rubber you have in your fuel system has the vitol inside coating inf you are going to use anything over B20.

i am going to refuel on b20 this week and have one tank b20 one tank dino-diesel and the aux tank wvo and do another round of testing. i edged the timing up an hair so we shall see soon enough.

 

[Sycostang67]

Thats good to know, I'll make sure to check and see what kind of bio it is before I pump it.

 

[Agnem]

The cetane rating of WMO cannot be estimated. What's that mean? Well... luminosity timing figures are based in totality on the cetane rating of the fuel. You can not know what the timing should be set at unless you are running diesel fuel and know the cetane rating. It would take a whole nother' chart and dyno research to find out what the correct luminosity timing figures would be for WMO (and even then, every batch would be different... you'd have to time on a per tankfull basis unless you were using only 1 kind of waste motor oil, aged the same amount each time. Naturally your timing readings are going to change between diesel and WMO, because the cetane rating is different between each. But, if you had such a chart, you may find that where it is set, is exactly where it is supposed to be. Do not assume it is retarded just because the numbers are different. This is why I prefer the pulse method so much better. However, as you've clearly indicated, ignition does begin at different times for each fuel. The question though that the timing meter can't answer is when does it STOP burning. The length of the burn is going to be a significant factor.