WMO and Coking

[mikepotts]

i figured i would start a thread about this specifically, making it easier to find later. so im wondering, i heared about people having problems with "coking" on the tips of their injectors while using differing WMO blends, if im understanding this correctly "coking" is a term used referring to a build up of residue which can adversely effect the performance of the injectors and in extreme situations block the injector tip completely. so my questions... have you guys had this issue? if so, what blend were you using? what did you do to counteract this (additives, ect)? the guy selling the ebay pump and filter setup for $500+ in his description mentioned using 85/15 WMO/RUG and adding "X" amount of seafoam and not having any coking issues.... so im wondering if the seafoam could be the key?

 

[The FNG]

You are correct on what coking is. Essentially, the oil that does not burn completely eventually builds up in the form of carbon deposits (coking), usually on the injector tips. This can cause a poor spray pattern and poor performance. The key is to help the WMO burn more efficiently. The w85 (15% gas) blend is usually thin enough to get close to the viscosity of diesel. If it is too thick, you may have 2 issues. The first, you will starve your fuel pump and ruin it. The second, you will have a poor spray pattern from the thick oil and will develop coking issues as a result and the issue will compound very quickly. I like seafoam, but I personally use power service diesel kleen. I also use it as a double dose. The idea is to help clean the coking when it forms and reduce smoke. Also, it ups the cetane number which is known to help fuel burn more efficiently in Diesel engines (up to a certain point). So yes, it is a good combination to use a w85 blend with a strong shot of injector cleaner and cetane booster.

 

[mikepotts]

thanks for the reply! so what kind of ratio do you use when adding your diesel kleen? just the directions on the bottle? and how often do you use it?

 

[The FNG]

Diesel kleen is .66 oz per gallon of total fuel. That will make a double dose. I use it every batch. Basically, I measure it by the cup since I know there are 8 fl. Oz. per cup.

 

[mikepotts]

okay, thanks bud!

 

[Josh Carmack]

I use DK as well, dump a half a small bottle in a 45 gal batch. I have no clue what that ratio is, and I call a small bottle the one that runs about 16 bucks or so, I don't recall the capacity, perhaps 32, or 28 or even as much as 64 oz a bottle. It doesn't seem to make any difference in my cars or truck, but It makes me feel better about force feeding them "substandard" fuel. Well, it may smoke a little less, but I have never taken the time to notice the difference with or without, but I have run many batches without it and didn't see any huge deficiencies.

With my specific situation, I have more opportunity to put more miles on WO than probably anyone else here. I was averaging about 1300 miles per week on little blue. That average is probably closer to 950 now. My wife averages about 500. 75 miles round trip to school and back, and her daily running, it's all highway miles for her with very little stop and go. My car see's some of the harshest conditions anyone's car will ever see. Lots of idling, lots of hard acceleration and lots of slow acceleration. My car only see's highway miles for the brief trip to and from work, unless I'm being loaned out to another office, which happens about 30% of the time. When i am being loaned out my highway miles can be as much as my rt miles. Once I'm out on the rt, the car will be shut down and restarted as many as 50 times in one day, see's about 4 hours worth if idling and slow running broken by brief periods of higher speed running. I would say for coking, if anyone's car is gonna coke up it'll be mine. While we are currently burning some really really clean oil, so clean it actually looks like diesel. So my comparison may not be the norm. I keep saying I am going to do this and that, but very soon I will replace the injector and valve seals and when I do I'm going to pull the injectors from my parts car that has never seen any WO and compare them to my injectors that have a few thousands of miles of wmo on them now as well as having probably 200,000 D2 miles beforehand. I have a feeling that coking is more of an engine design issue more than it a fuel issue, but thats only an assumption.