So I'm putting together my 05 S engine now that all the machine work is done. My question is should I use some kind of break in oil or just run 5w 30 Castrol synthetic?

 

Personally I use it, simply for the "why not" factor, the extra zinc can do nothing but help and it's only about $5-10 more for the entire oil fill.

 

If your rebuilder does not have a SPECFIC reccomended oil, I would just use the suggested oil....a higher than normal zinc oil is good (zinc is an extreme pressure addative that protects a surface if the oil film fails....it has been reduced to help catalytic converters last longer)...
Me...I would do a fairly fast oil change....and filter check....ensure all is good.
And be 100% sure the motor is fully oiled before starting....older motors could be spun with a drill, but in this motor, just cranking without the sparkplugs wires connected should be fine (a trivial amount of gas will get mixed with the oil) if you used a good assembly lube.....sure your book/rebuilder has lots of great info.

 

I haven't asked the machine shop that turned the crank what they recommend. I only used oil on the crank and rod bearings mainly because I put together a VW 1600 air cooled engine and read that why put assembly lube that's thick in there. It just makes it harder for the oil to push through. I used break in oil in it,but its a flat tappet engine. I planned on turning the motor over before I install it. I

 

It seems there there are a million ideas as to what type of break-in oil to use...
I knew a guy who once rebuilt Merlin fighter plane engines for use in race cars....he Liked straight mineral oil...as for most piiston engine rebuiders in aviation (I suspect same with aircooled VW motors too) but with the tolerances bring so tight on a modern liquid cooled engines, and syrnthic oil so good, I have a funny feeling if the motor is assembled right, any oil that meets the engines specs are fine...heck these cars came from the factory with a full synthetic oil....

 

So true. New car owners just drive them. They don't break them in.

 

I'm breaking in a newly rebuilt engine as we speak. I used the below. Just add it in, then fill the rest with conv 5w-30.

I've also used Royal Purples break in oil to great success, but that stuff if around $10 a bottle, and you fill your entire engine with it. The lucas below is only $20 and just goes in with your oil.

 

Are you leaving the TB ZiNC-PLUS and the conv 5w-30 in during the 500 mile break in period?

 

Yes. You put this in, then fill the rest of the way with conv oil. Much cheaper than buying 5qt of break in oil like RP.

 

Well I have just over 500 miles on the rebuild. Should I still run the zinc and conv oil?

 

Yes, I would change it, you don't really want to leave it in too long because of the metals that accumulated during break in, I changed mine at 300, and went to my regular oil, most of the reason for using the break-in oil has past after the first couple of hundred miles.
I would suggest a half normal interval oil change though, just to be extra cautious that all the break-in metals are flushed.

 

Thanks. I better get it changed out very soon.