its the base additives in hd oils that remove sludge that cause worn gaskets to now leak. These base additives are there to fight acid build up and keep the oil from harming the engine. Howerver some gasket materials built in the 70s were silicon based and the alkali base materials will leach out the silicone and the gasket will get hard and crack. These types of gaskets were removed later as it was found out they were not compatable will modern motor oils.(cummins.fleetguard). Its this base additive that also cleans and dissolves the sludge.FAST FRED wrote:e3steve, I HAVE RUN SEVERAL TYPES OF OIL IN MY CL77. I HAVE FOUND THAT ANY OIL CONTAINING ANY SYNTHETIC COMPONENT TENDS TO ACCELLERATE ANY PRESENT OIL LEAK YOU HAVE ALREADY AND GIVE YOU A COUPLE MORE. IT SEEMS THE MOLICULE STRINGS IN SYNTHETIC OIL ARE VERY SHORT COMPARED TO PETROLEUM. THIS MAKES THE OIL THINNER AND LETS IT WEEP THROUGH WORN OIL SEALS OR GASKETS LONG BEFORE STRAIGHT PETROLEUM WILL. I HAVE USED SOME BLENDS IN MY BIKE (MOTULE 5100 PETROL-SYNTHEIC BLEND) BUT WAS FORCE TO RETURN TO STRAIGHT PETROLEUM (HONDA GN4) TO STOP THE WEEPS AND LEAKS. I AM NO EXPERT, THIS IS ONLY WHAT I HAVE EXPERIENCED.
FAST FRED
When I was a youngster and worked in a machine shop, we have a giant vat that we boiled engine blocks and heads clean so we could then rebuild them. I always though it was acid, but every 6 months, we drained the vat, washed it out, then added 50 lbs of special lye or akali powder and then fired the vat back up again. The high base solution dissolves all grease and grime. Modern hd oils have a very high tbn or total base number.. lots of them are 13 and above... so yes,, if your engine is gunked up, new modern oils will by nature clean and suspend the dirt.
add any modern oil and it will "clean" you engine,, and then if you have any "lazy" gaskets, the will certain start to ozose or leak.. If you have old silcon gaskets, the modern oil will leach out the silicon and make the gaskets hard, although those gaskets were supposed to be gone.
non detergent single weight oils are made from heavy mixed parrafins chains, will wax up and fall out and sludge up the engine.. while it will not leak, it will provide poor lubrication, the heavy and long molecule chains will shear out and cause the sludge to form, the lighter molecules will then vaporize out the breather creating 10 to 20 percent loss, the residual viscosity will continue to thicken up dramatically, and offer less and less lubrication, Especially on start up. The lack of additives means that compustion gases will form acids that will eat away at bearings, and linners, epecially the mains and rod inserts. Piston scuffing will accellerate, lack of moly and high wear zzdp additives means the cams will start to peal off and score.
I was rebuilding a massey harris 33 tractor with a old engine. I clean about 1/2 inch of sludge out of the pan and found out the whole bottom of the pan was full on pin holes but the sludge had prevented it from leaking for years. As the pan was a low grade pot metal, it could no be soldered welded or brazed so I had to jb weld it. had to go 30 over on the crank and manufactor new oil pump gears to get this old beast back into service as an antique... The old tractor probably never saw 4000 hours on the clock where today, 12000 hours are common. remember that a mechanical rpm driven hour on a tractor is about 60 miles as its based on 114000 revolutions per hour on the engine give or take pending on max torque curve. Remember that when the honda 305 was built, car engines didnt last but 60,000 miles between overhauls and valve jobs were often done at 40,000 miles and oil changes with 30 wt oils had to be every 3000 miles and spark plugs every year or 10,000 miles if not sooner. I worked my way through college doing machine work and rebuiding autotranmissions.. which only did 40 to 50,000 miles in those days,, till the draft got me.
Sorry, got a bit carried away... There is no reason in the world to run 30wt non detergent oil in anything today.. No scientific reason. If there is a 'stamping" on the housing, it must have been left from when the honda hawk was made and there simply was no other oil choice availible, and doctors were still using bleeding and leaches to treat illnesses. no owner's manual for a 305 or newer will show that. the 450 shows to use multiweight and oil rated api SE or higher and it has the same spinner oil filter.
You have to remember that the cold war and going to the moon, both in that time frame cause a huge leap forward in technolgy. The need of oils to perform in the the artic to stop the ruskies from comming and fluids that would work in the cold of space caused a huge change in the world right about then. new additives and formulas were being tested and put into service almost everyday. Kinda like one day you have a kerosine latern and the next day you have electric lights. One day they did labotamies and used camphers that caused cancer for cuts. The honda used crude germanium diodes. its was just a few years later that the later model 450 used silicon and solid state zenor diode voltatge regulator.. all in a couple of years time.
GE delveloped the top secret 50 amp submarine diode the allowed submarines to charge their batteries faster and stay under longer.. wow, I remember they were first sold for around $2000 if you could find em. wow, what a battery charger one could build out of a pair of those.
