Why does it matter if full reaction happens?
 

I am not making bio yet, And I am still getting info on it, I understand everything that has to be done but have lots of questions. I won't bother with them yet just one to start. I have seen and worked with vehicles that are set up with line and tank heaters so you can just put filtered oil in the tank and it runs fine. So my question is, Everyone seems to make a point of the lye and methanol having a complete reaction, Why would this matter? My truck will run off of used oil in the summer with no processing of the oil, just filtered, So wouldn't any uncomplete reaction just stay as used oil and the truck would run it anyway. What I am looking at is not have to titrate and just add the same percentage of lye and methanol to every batch, And not have to worry about all the other bull that everyone says I will have to do.

I'm not sure but I think the unreacted oil, DG and TG will coke up injectors. plus any glycerol that gets left behind I'm told isn't good either. left over methanol will cause a diesel to preignite or detonate kindof like a spark knock in a gasser. this is all what I've been told and read so with two very expensive engines, I shoot for a complete reaction.

i have wondered about this a lot. i still test my bio and most all my batches pass the 3/27. i have had a few show a couple drops in the test, but i wasn't too concerned. it looked very good and ran through the 1 micron filters just fine.

even in my completed bio, i can still smell a little methanol. i figured this was normal since i wasn't doing any recovery. i never read any warnings regarding this.

i blend every batch i make to a b80. i have been running this way for months already and my truck runs so much better on this stuff. i figure i am still way better off than the guys running a filtered wvo blend, used motor oil, or diesel secret.

Incomplete transesterification reaction leave a lot of Free Fatty Acids in the mix.
These acid, while not strong acids, are strong enough to attack metal parts in the fuel system and will cause significant damage over time.

Whiteaddiction
burning unheated VO, even in the summer, is a recipe for engine failure. There have been many studies done and they all point to eventual inevitable significant damage.

A couple of drops can be about 5% FFA's that are unreacted and that is not good. The accepted minimum is 0.5%

I think you mean the accepted maximum is 0.5%, don't you?

How right you are!