UCL (MMO or TCW3) use in new engine

[barnstormer]

I'm considering using an UCL in the 92 Montero I recently rebuilt the engine in. My motivation is longevity and improvement in MPG (if possible).
Will the use of an UCL compromise the break-in of the engine? I've got almost 750 miles on the engine now, so it's not as though it's BRAND new, but I just want to make sure there is no reason to wait for more break-in before using it. Any reason to not use it? Ring seating?

Thanks for any input

 

[getnpsi]

If by saying UCL you mean adding it to the fuel in 2-4oz doses i see no harm, and the other components of the vehicle if not new may find benefit. Now adding lots to the oil we can argue it dilutes the additive package of the first fill. Is the break-in regular oil or something 'special' your builder put in? I'd not wanna make him mad and he turn his back if you have any early onset oil burn or leak issues. MMO could be something he could try blaming.

 

[barnstormer]

Well, I'm the builder, so I can't get too mad at myself.
The initial fill of the engine was 30wt ND oil for about the first 250 miles, Shell 10w30 for the next 500 or so.
I recently changed it again, using the Supertech Synthetic 10w30, which will stay in there until winter arrives.

I'm not overly concerned with the longevity of the engine. Only the best stuff went into the engine rebuild, and I feel like I'm breaking the engine in appropriately. I expect it will go another 150-200k without any drama. I doubt I'll even own the truck anywhere near that long.

My only concern is that the addition of MMO or TCW3 might impair ring seating by being too slippery, in the same idea that people (rightfully or otherwise) think synthetic oil should not be used for break-in, as it is too slick to allow the rings to seat.

?

 

[ekpolk]

In earlier days, based upon word of mouth, I used to use MMO ONLY for break-in. I had a couple cars live nice, long lives after having been infused with MMO only for the first 2k miles of their lives. Of course, I can offer no proof that the MMO made any difference one way or the other. But it certainly seemed it did no damage.

 

[demarpaint]

MMO in the gas won't hurt with the break in of the engine. In fact years ago I was told by several avid MMO users that it helped. I've done it to about 4 new cars w/o any issues, that is add it to the gas. HTH