Hey guys, I have about 4k miles on my Vitara rebuild. Ever since first startup it has had a "problem" where it smokes slightly during warmup, a little blue smoke. I chalked it up to high oil pressure possibly pushing past the valve stem seals, or possibly my ring gaps...

Anyways it only smokes for a minute or so with conventional 5w-30, starts smoking usually at 110* and stops at 150* coolant temp, so while something is warming up it gains its seal I suppose

I want to switch over to synthetic oil, I want to use the 0w-40 I found at autozone as i feel I will have the best oil pressure with that weight with my slightly loose bearing tolerances.

Would I make the smoking problem worse? Completely unbearable? No difference?

I dont want to switch the motor to synthetic and then switch back if I dont like the results as I heard once you go synthetic you cant go back.

Thanks alot

 

You'll probably have to list what you're clearances are to get the best answer. Also, where do you live? Why would you need a 0W? If anything, it sounds like you need a higher cold viscosity. Something like a 15w-40 would work better for you possibly (if your clearances allow).

 

I want 0W, Im in Canada. 50 degrees is common in summer, its 35degrees today. And my oil pressure is sky high during warmpup and Im hoping to help that a little.

Not positive on clearances anymore, they are standard ACL race bearings though so they are loose.

 

You may have some leaky valve stem seals like you has brought up before. It's really hard to tell what you might have going on without the PTW clearances and bore size too.
Sorry it's harder to lock down a definite answer in this type of situation. I'd try doing a cold vs. hot compression/leakdown test to see how much air is going past the piston in both situations. This should let you know how much expansion you have of the pistons (an idea at least).