Hey Glort,
I have run RUG with the WMO, on several occasions in fact... Overall, I found that unless you mix up a large batch, more than 200L, it is not worth it... My reasons were as follows:
A small batch of WMO, when dried, can vary dramatically in burning rate from the next, this is because of the hit and miss on what you get blended in with it... At an average injection timing that is slightly advanced from Dino, these random batches work quite well, particularly if you add about 15-20% Dino to help with thinning and initial combustion... to keep the carbon down, water is the miracle tool that solves all ills, from preventing carbon buildup to rings sticking in grooves, to carbon building up on valve stems, to even carbon clogging in the exhaust pipes themselves...
When I tried a few small batches of RUG mix, carbon and associated ills were indeed less, but I was concerned about the "knockiness" while running, usually OK for mid early morning and evening to nightfall, where temps were around the 5 to 12C, but midday heat around 28+ C did make the monster quite a bit "lively" shall we say... And he voiced it quite audibly... It was hit and miss to find a timing position that would work satisfactorily, eventually I gave up on the RUG mix and went to Dino and water... Much more user friendly over a wide range of temperatures, albeit a little difficult to start.... But no problem with a mains powered starter motor.. I just wouldn't try and run it up cold by hand.
If I were located in a more even temperatured and cooler climate, I have no doubt that RUG would work well, just doesn't suit me in my area in summer....
I did find RUG mix much easier to start, a bit cleaner burning, and less smokey when cold....
While I am at basic diesel spec for the timing, I have both advanced and retarded it significantly and found little benefit of going beyond 22 degrees... as soon as you go more than this depending on your fuel makeup, you have to watch for knocking becoming bad.. less than 22 deg and knocking is within limits, and as a bonus, a wide variance in air temps can be handled...
I have now installed a fuel preheater, tapping heat from the cov plug to warm the juice up really hot just pre injector... initial tests seem positive, but a mech failure has got in the way of the final verdict, so the jury is still out on this one... as soon as I get the crank in, I will continue the testing, if it works out as planned, very little dino will be needed for the day's run... The only problem I for see, will be the fuel filter being a bit "slow" with the thick oil... I might have to run parallel filters to use the 40-50W oils ... Unsure as yet...
One thing I will say about WMO over Dino - Smoother running with apparently more power- I way prefer it, so much so, that even a lady who works on the premises here remarks every now and then when the dino ratio is a bit higher than normal, she can pick it up by ear!
I juiced up my pop tester with WMO and compared the patterns... there is little difference to dino when the fuel is warm, and only minor difference when it is cool.. I didn't compare with refrigerated fuel, as my thinking is that the initial bit of the run is going to be sub normal temp only... once warmed up is my main concern... (and of course, it rarely, if ever, gets below 0C here anyway, I can only remember one winter in the last 22 when it actually hit freezing point, and that was for less than a 4hr stretch)... As to injector pressures influencing spray pattern to any large degree, they definitely don't from what I saw.... but... they do affect the size of the droplets in the pattern... I cannot say for certain as to the percentage of atomisation that occurs from one pressure to the next, but it does make a mild difference on WMO between 1500 and 2500psi... not enough I don't think to be of concern for combustion, but a bit of concern when the upper pressures were on test for me to worry about the mechanical stresses involved... when I saw the small amount of difference I could perceive between upper and lower pressures, I simply went back to my original factory standard of 2000 psi as the injector was set when it arrived... There might be a much larger difference that is found on Dino, this I have not tested as yet... Methinks the heavier oils are a bit more "forgiving" if I might put it that way...
I did a bit more prepping of the beast this afternoon, I am now just waiting the crank and big end replacement to arrive so I can do a bit of fine balancing and install... At the same time I am going to install a double top ring... The reasons are twofold, one, more of a convoluted path for the residue to follow to get to the second ring, and two, a harder "seat" for the top ring to rest on, this should also slow down the groove wear I am experiencing...
I did notice that the top oil control ring was sticking somewhat, it is a spring assisted ring.. What I am thinking of doing is moving the lowest oil ring up a slot and installing the new bottom ring in place... the bottom oil control ring isnon spring assist and seems to fare a bit better with crappy fuels... interestingly, there is little to no wear on these rings, just a stuck spring was evident...
Ring wear is readily apparent on the top ring, less apparent on the second, even less on the third, hardly apparent on the forth, and almost non-existant on the fifth.... From this I surmise that the abrasive residues are not making it past the third, probably only just making it past the second.... Of blow-by there was very little, compression was reasonable to good, and all of this on over 1500 hrs of sump gunk fuel... I am sure that if the lube standpipe hadn't let go, rubbed against a bearing cage, and spat filings into the journal feed ring, I would still be running quite reasonably...
I did notice something I wasn't happy with while checking things over today... there is no stop in place to prevent the oil pump cam follower rotating... also, the follower was rough as a bears arse and had started to pit the cam... I pulled it, reground the profile, polished it and the cam, and reinstalled... the original listers had a oil priming lever which probably prevented the follower from rotating to any large degree... might be worth looking at in the future...
Another thing I noticed, from first startup in fact, was a "knock cum rattle" every now and then... I think I have found it... the covered end of the camshaft has a retaining bolt.... on my unit, the shaft is about 1/10mm below the level of the bushing... what our Indian friends did was install a spacer washer of about 1mm between the thrust washer and the end of the camshaft to allow things to turn without binding... I have now removed the washer, top-hatted the thrust washer by around 2/10 mm for a more reasonable working clearance, and zapped it all together... hope that damn rattle is now gone!
I also had a poke around the inside of the case today with a screwdriver and a hammer... there was only one piece of slag/sand that was readily found, in the one web corner of the IP side of the case... much hammering later, I dislodged it and removed the offending junk.. Overall, I would at this stage, label these castings as excellent in comparison to what others on this forum have found... maybe I am just lucky!
I can say, the red paint/loctite/cement/gunnite that the insides are coated with is TOUGH! After 1500 hrs, there is no flaking evident, all is intact...
Incidentally, the timing idler gear shows no discernable wear, on bushing or teeth... so that's a plus!
The only parts showing appreciable wear at this stage are the rings/piston grooves and the oil pump cam...(excluding the big end of course, that was an induced fault because someone in India didn't know that to braze piping, you actually need to use a brazing rod....)
Enough rambling.....
Keep it spinning...
Regds
Ed
PS - I just did a quick calc of the imbalance on the flywheels I had... Around 290g total imbalance at a radius of 300mm or so... Running at 750rpm that gives a centrifugal force of 55kg... I wonder if that could be why I had to go to the dentist to replace my fillings every time I stood next to it for more than 5 mins.....?
