BDiggity

i thought napa oil was made by valvoline. cant remember where i read/heard this.

mookymonkey

im pretty sure you are correct as i heard that also.

stevesxm

thats not a solution. and at 240 deg, the viscosity is that of 5 wt anyway. all heavy oil does is cost you hp. lots.

baja36ft

did not say that was the SOLUTION i said see if it helps....
don't put words in my mouth.....

stevesxm

okaaaaaaaay... just out of curiosity, if you believe the oil is too thin and getting by the rings because of that ( a million to 1 chance ) and you put in heavier oil which then becomes.... well, just as thin when it gets hot, what's your theory on how this is going to indicate anything ? silly me for thinking about actually identifying the problem rather than just treating the symptom.



on the other hand , IF the oil is getting fuel diluted for some reason like maybe its injected and running too cold and fooling the ecu or even if its carb and running too cold and the clearences never close up... the motor could be just fine mechanically and still use oil like this...

i think i would have the plugs out and see if they are really dark which they shouldn't ever be on an injected motor and maybe sniff the oil and rub it between my fingers to see if there is fuel in it...or maybe do a leakdown and see if the valve covers try to lift off or something...

or you could just put straight 90wt in it. oh... sorry... thats already been suggested.

baja36ft

maybe you should call merc and see why they use 40wt in the
hp 500's??? i am not saying it will stop his problem it might help...

baja36ft

on the other hand , IF the oil is getting fuel diluted for some reason like maybe its injected and running too cold and fooling the ecu or even if its carb and running too cold and the clearences never close up... the motor could be just fine mechanically and still use oil like this...

i think i would have the plugs out and see if they are really dark which they shouldn't ever be on an injected motor and maybe sniff the oil and rub it between my fingers to see if there is fuel in it...or maybe do a leakdown and see if the valve covers try to lift off or something.

yup your right maybe even check the oil cooler...

GO4BROKE

iTrader: (1)

QUOTE=mookymonkey;2622043]isn,t rebuilt stock. pushed it up to 550 hp. cam, heads, stainless marine exhaust. the motor only had 300 hours on it so we did reuse the stock pistons with a hone. new rings, new mains. i had heard that they are built to run a little wet. we also are running a 150 degree thermostat but i really don,t think thats the cause. i understand the 40 wt option but i am trying to keep with the program that the mechanic told me to follow. just trying to learn and get fresh ideas.[/QUOTE]

Was it blue printed? With just a hone the cylinders probably aren't perfectly round anymore, and with new rings that are true, may allow some oil consumption. A leak down test may not show anything, the oil control ring doesn't hold compression.

mookymonkey

i will pull the plugs first chance and check them. boat runs strong and doesn,t seem to miss. idles nice also. i don,t run it too hard, but i don,t sit around either.

69-CHVL

My 454HO used alot of oil right from new - like quarts. After trying everything (blocking PCV, different oil, another carb(s), and different valve seals), I finally dug in. Part of the problem is the metric ring package as mentioned. The oil rings are a "shallow" design, which I guess makes them low tension. The compression rings are normal however.

Not wanting to replace pistons on essentially a new motor, I had the block plate honed, and replaced the rings with a new set. Oil burning has ceased. Only thing I see now is some oil on the threads of the plugs, and that I can deal with. My machinst said that the cylinder wll distortion was really bad.

So, if you want to use low-tension rings great, but cylinder prep becomes more important than even IMO.

Look how bad the cylinder walls are distorted. I guess this is a Gen 5/6 issue as they are lighter weight casting. You can see how the rings never even touched the cylinder walls by the bolt heads, as the bolts pulled the cylinder walls "in" towards the bolts. Check out the "shallow" oil rinngs vs the compressions.