New insight in IDI burning WMO - need high compression or turbo

[ut99dot1]

hi all, every single time, my car starts losing power after 3-5k miles, lots of smoking too. Definitely incomplete combustion. No matter the WMO - diesel/kerosene ratio it happens around 3-5k all the time.
I found out the reason: the injectors heatshields get plugged;

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After replacing them power is restored (temporary).

That was last time, all were equally plugged. This time 2 were ok'ish, and the other 2 were plugged like above. What was the difference? The 2 cylinders with the fouling had lower compression (325 vs 400 psi)! Made me think, with the IDI the air that's forced in the pre-chamber is used to mix fuel and air, see for example this old bosch movie:

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Less compression = less mixing, worse combustion

I will put a turbo on it, low boost (5 to 10psi), and see how it fares!

 

[kbenz]

Rug will thin the oil better. Not sure if that will help you or not but thinner oil can't hurt

 

[Jesus Freak]

I agree with both of you. But we all can agree that of all the science experiments you can do with our vehicles, WMO is the one for us! Thanks for the input and update.

 

[Far Right]

I have a NA6.5 chev, she’ll run fine on 50/50, but full mix will only go a few tanks till my injectors are proper coked, I’m also in the process of turbo install, I’m absolutely no expert but all the advice on here says you need to give ya rig a good hard heavy run here and there to keep it all clean. I tried this with my N/A n the lack of boost meant I just cokes the injectors sooner,

 

[Black dawg]

Had this same problem with a healthy 6.5 with turbo. Never checked compression, but was a very easy starting one down even below zero, so I think compression was probably good.

I did try healthy vs pissy injectors, and also much higher pop pressure. Didnt make much difference, roughly same amount of time until coked.

 

[Far Right]

Hmmmm, not what I wanted to hear. Wonder what it is with the 6.5 set up compared to the 7.3? heads look very similar in design from pics I’ve seen

 

[Black dawg]

I have never seen even a little bit of coking on the end of a 6.9 7.3 injector, and I have seen some that were treated really poorly with 100%wmo.

The ends of the injector is shaped completely different.

 

[ut99dot1]

Update after installing the turbo. Difference is night & day. The car retains its power regardless of the oil I put in it. Also the smoke is mostly gone, only a slight haze.
I've come to the two improvement points :

1. Need to get the fuel to the pump & injected
Very thick oil flows very badly, so it needs to be thinned in order to be injected. I've done some calculations for my engine and these are the figures I've come up:

10F (-10C) 15% RUG
30F (0C) 10% RUG
50F (10C) 5% RUG
Everything more 0% rug

This assuming a bad batch of +- 50% heavy oils (20W50). It will be less pessimistic if more lighter oils are mixed in (0W30 etc)
The RUG will dilute the mix down to +- 300-350cSt (consistency of castor oil) from +- 2000-3000 cSt (e.g. honey) at 10F

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(Couldnt find any high resolution movies) Not ideal, but good enough to get it started. There's a small heater core (runs on engine coolant) which will heat up the oil along the way. Should reduce it to 50cSt down the line.

2. Turbo to improve burning
The autoignition temperature is the temperature where fuel automatically ignites (without any flame / spark).
For diesel this is: 210C / 410F
10W40: 320C / 608F
Gasoline: 280C / 540 F

So not only the oil, but also the gasoline actually makes it harder to ignite. This leads to incomplete burnt fuel, which sticks together and forms deposits.
The turbo I run spools up super quickly (about +- 1200rpm), and delivers a steady 7psi (1.5 atmosphere)
- so 50% more air, where 50% more ignition temperature is needed (600F vs 400F). Seems to cancel eachothers out,lol.
- IDI relies on compressed air to break up the injected fuel droplets. So even if the thicker oil is squirted in (not atomized as it should be) due to the extreme thickness, the higher pressure should break it up, leading to a better combustion.

 

[Jesus Freak]

Good stuff. It really does come down to viscosity. My current engine is freshly overhauled with rings and gaskets. It's a NA 7.3, and with the overhaul I put a new IP and injectors in it. The IP isn't rebuilt or souped up, it's a brand new stenodyne and the injectors are brand new BB something or others, like Bosch or something.

I get ever so slightly haze at idle, but none while driving. I have to really get on it or be under lots of pressure to make smoke.

So yeah, I agree that a turbo definitely helps the burn, but it really appears that a tight fuel delivery system is important too.

I didn't time my engine with a device, I really just kinda put it where it is and I'm pretty sure that I hit the sweet spot because I have power where it's supposed to be and no smoke except where you expect it.

 

[Bart F-350]

A few additions: Lubrification! the bosch pump on your golf needs it! so whatever you do, take care that the fuel you use lubrifies!

Please help me out here, what do you mean with RUG?

I would suggest (if possible) try a batch where you are sure the WMO is MINERAL oil!
I've seen WMO heaters, where they burn Mineral oils, they can burn the whole week long before cleaning their heater, and where they use WMO with synthetic oils, they need to clean out the ash every night!

So I think it makes a difference in how quick your burn plates are clogged as well, don't you?

 

[ttman4]

A few additions: Lubrification! the bosch pump on your golf needs it! so whatever you do, take care that the fuel you use lubrifies!

Please help me out here, what do you mean with RUG?

I would suggest (if possible) try a batch where you are sure the WMO is MINERAL oil!
I've seen WMO heaters, where they burn Mineral oils, they can burn the whole week long before cleaning their heater, and where they use WMO with synthetic oils, they need to clean out the ash every night!

So I think it makes a difference in how quick your burn plates are clogged as well, don't you?

@Bart F-350 RUG means Regular Unleaded Gasoline.
Over here some folks cut WMO with RUG different % depending on their rig or the weather. I have used it in the past early on when I first started running WMO or WVO back in 2003. For several years I just use WMO/Diesel mix to run on.

And I think your assumptions about Mineral Oils vs Synthetic Oils straight or mixed could be very true.

Soon as I get my 40x64 shop up & finished I have a big shop oil heater that was given to me that I plan on getting mounted & learn about & running.

 

[Bart F-350]

@Bart F-350

And I think your assumptions about Mineral Oils vs Synthetic Oils straight or mixed could be very true.

Hello James,
Thanks for explaining RUG. I did use that in the past, I need now to inform myself about "better"? ways to use WMO.

Those above are not assumptions. experiences with batches from which we were sure they were pure mineral or pure synthetic. over a few weeks.

 

[ttman4]

@Bart F-350 I have a centrifuge for my WMO, currently it is down. However with it I've always been worried about other unseen containments the centrifuge don't get out.

On my '90 F350 & my '92 F250 I use WMO Mix in one tank, diesel in the other tank. I start on diesel, warm up or go 2-3 miles, get warmed up, then flip over to my WMO tank. At least 2 miles before I get home I flip back over onto my Diesel tank.

I also have my fuel return lines on a manual valve I have mounted thru the floor just inside the door beside the seat. When I'm running my diesel tank my return is returning to my Diesel tank. When Im running on my WMO mix tank I manually turn the valve handle to return to the WMO tank.

I want to do some experimenting with some Synthetic used oil and regular WMO. Maybe just have a coffee can of synthetic and can of regular WMO & set fire to both and watch to see what's left in the cans. I don't know. hahaha

In my signature below i mentioned
"WVO & WMO set-up (learning curve was tremendous!)"

I been playing with WVO & WMO since early 2003 & still learning stuff daily!!! However I haven't run any WVO for 10-11 years now.

 

[Jesus Freak]

@Bart F-350 I have a centrifuge for my WMO, currently it is down. However with it I've always been worried about other unseen containments the centrifuge don't get out.

On my '90 F350 & my '92 F250 I use WMO Mix in one tank, diesel in the other tank. I start on diesel, warm up or go 2-3 miles, get warmed up, then flip over to my WMO tank. At least 2 miles before I get home I flip back over onto my Diesel tank.

I also have my fuel return lines on a manual valve I have mounted thru the floor just inside the door beside the seat. When I'm running my diesel tank my return is returning to my Diesel tank. When Im running on my WMO mix tank I manually turn the valve handle to return to the WMO tank.

I want to do some experimenting with some Synthetic used oil and regular WMO. Maybe just have a coffee can of synthetic and can of regular WMO & set fire to both and watch to see what's left in the cans. I don't know. hahaha

In my signature below i mentioned
"WVO & WMO set-up (learning curve was tremendous!)"

I been playing with WVO & WMO since early 2003 & still learning stuff daily!!! However I haven't run any WVO for 10-11 years now.

Hey, keep us posted on your experiment. I have no idea what most of the stuff I run is I've gotten stuff from so many sources. I only filter and settle and mix with diesel.

But I tell you what! You are absolutely right about the learning curve! And people need to realize that. If you're not interested in sitting on side of the road from time to time because you're in the learning curve PLEASE don't get into alternative fuels! Alternative fuels and getting old is NOT for wimps or sissys!

 

[ttman4]

Hey, keep us posted on your experiment. I have no idea what most of the stuff I run is I've gotten stuff from so many sources. I only filter and settle and mix with diesel.

But I tell you what! You are absolutely right about the learning curve! And people need to realize that. If you're not interested in sitting on side of the road from time to time because you're in the learning curve PLEASE don't get into alternative fuels! Alternative fuels and getting old is NOT for wimps or sissys!

Couple LEARNING CURVE RULES:
NEVER run inside lanes, especially in big cities!!! Bessie quits I want to get to the shoulder!! & carry extra fuel filters.....7-8-9 extra fuel filters in back floorboard, even running up to 7Eleven & back!!!!

It's supposed to get a bit chilly this evening & tomorrow....... maybe I'll set couple cans on fire & get warm while I watch 'em burn. We live bout 7 miles out of town so maybe fire department will leave me alone?????