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Diesel oil (RotellaT4) vs. all-fleet (Valvoline conventional 'Super Blue'), in gasoline engines?

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Any opinions on which bottle for the crankcase on my Z24?  Also, intend to use the same bottle on non-hydro lifter '75 Toyota 2F gasoline motor.


Valvoline is listed for both gas, and diesel.  Rotella is listed for diesel only.


Is there any reason to not use Super Blue non-synth, particularly in the Land Cruiser 2F without a cat converter, and stick with T4?  I'm kinda hung up on the print that is actually on the bottle.  However, I'd like to deal with sludge first, and maybe get a bit more protection on the lifter/cam side of things, but, sludge is a particularly a concern.

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Diesel oil is higher in detergent that any gas engine oil. You may find that after switching, the oil darkens quickly as it 'dissolves' years of deposits. The oil is fine it's just holding more in suspension. Slowly the engine surfaces will clean up after a few oil changes. Find out which has the higher ZDDP level. Most diesel oils are over 1,000 ppm even 1,200 while gas oils are under 700 ppm. Oil is oil, but the higher ZDDP is what makes T4 attractive for use with our cam rocker contact areas. I want the most protection for my irreplaceable valve train. The wear is accumulative and could take years and the oil company saying "Ooops, sorry" later is no help to me. These engines were made when all oils were in the over 1,000 ppm range. Reducing them to almost half that does not inspire confidence. 

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As always, thanks Mike.  I didn't know that Rotella had the greater wear resistance factor.  Folks on the Land Cruiser forum report adding a bottle of Rislone Zddp (the Land Cruiser has a capacity of about eight quarts) to their Rotella T4.  I guess that I could just get some additive for the Valvoline?  The Rotella is less expensive, but again it isn't specified for gasoline engines


When I replaced the valve stem seals in the Toyota, I soaked parts in gasoline, overnight.  It was amazing how much fine red rust is under the black sludge.  After the gasoline dried off, a wire brush would produce quite a bit of red dust that was hard not to breathe in a little of it.  The worst wear on the four rocker assemblies that I've worked on, was the rocker arm shaft/spindle, on the friction side (bottom side of the rocker arm).  All four have serious wear.  These parts are also, NLA from the OEM.  It is so bad that if the valve is adjusted to where the rocker arm could ride just outside the groove (factory specs in some cases) created from earlier wear, there will be an annoying click from the arm jumping around.


For me, it is still the sludge factor, and the detergent that I'm after.  Why, I've only put on 10K on the Z24 in almost five years of ownership, and much less since I put the Land Cruiser on the road, so it isn't like I'm running the camshaft much thru the modern oil's pencil sharpener treatment on my lifters, etc.  I don't like the idea of holding on to the PO's sludge, and, I'm not firing up the 720 that much.  My guess is that the Z24 is aging slower than I am, even with low ZDDP oil, but why not improve the situation - I have to change the oil anyway, so why not get out as much junk as I can?  And, even better if I can prevent wear.



Edited by DIY 1985
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I would rather use something that you don't have to add something to. Adding ZDDP to an oil with already high levels is silly. Any amount added that is not needed, displaces valuable oil for lubrication.


Not sure what the red stuff is, doubt it's rust, probably combustion by products from what little blow by there is. Normally the oil holds it in suspension and it is removed every oil change. However owners rarely stick to regular intervals and it slowly plates onto everything.




You can see the reddish deposits even where the rocker pad doesn't contact the base circle of the cam. This engine missed a few oil changes. Possibly the "emissions crap' was removed by a previous owner and the PCV valve was left off the block off plate for the EGR. Really sad.


Finding TDC L28 with head installed - YouTube


Here's what it should look like, no matter the mileage. Even with dirty oil the shiny metal shows through.  




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