swerks

Just had my engine rebuilt, I know the turbo likes synthetic but my builder says I need to run regular oil for first 5000 mi. why exactly?????

Localmotion

break in period. I'm not sure why exactly, but it might have to do with the seals settling in or something.

Definitely follow their advice.

19RUNNER86

it helps break in the engine and seal anything with deposits from the dino oil. after breakin use what ever you feel like. personally i would use synth for a turbo application...

waskillywabbit

iTrader: (-1)

Lots of new vehicles wiht new engines come now straight from the factory with synthetic in them...that stuff about break in blah blah blah is old wive's tale junk. I mean if you don't want the engine parts to wear and synthetic is better at preventing wear, why wait until the most damage is done during the "break in" period? I'd use the dino stuff at 500 and 2500 strictly cause it is cheap on $$$, then put some synthetic in it for the regular oil change intervals. I use AMSOIL in all my vehicles and I am an independent dealer.

Definitely use synthetic in trannies, t-cases and diffs as you don't have to change it near as often so the higher price is worth it.

misterzee

I think the significant issue is getting your rings to seat in to the cylinders well. That actually requires some specific steps. Otherwise, especially with synthetic, which is SO effective at preventing wear, you'll retain the hatch marks and never really get an optimum seal in your cylinders. Sure, it'll run ok, but if you're looking to get the maximum performance, do the proper break in for the cylinders.

swerks

Does 5000 mi seem like a lot for a break in????

KillChain

Thats really a long time, my 90 Toy 22re. Its rebuilt too, I was told 500 mil break in. Then at 1500 I get a check up, with oil change after that mechanic said I could use whatever oil choice of oil I want as long I change the oil every 3k.
So I plan at 1500, tell the mechanic I want 10w40 syn. Maybe Royal Purple or just Mobile 1.

imtxn

Recomended, is one grade thinner than you normally use, i.e. like 5w30 instead of 10w30. But more importantly you should install a full oil filter, prime the oil pump and rotate the engine with the starter (no plugs in the head) until there's an oil pressure indication before you start it. This is to fill the oil pick up tube, drillings, cam and crank. The builder probably used assembly lube when he built your engine, but if you neglect the precautions you will sacrifice time, $$$ and Kmiles of use in the long run. What did your rebuild cost, $2,00? Don't waste it. The valve lash should be set .001th larger cold as the metal will expand when it gets hot. If the valves don't close all the way the margins will burn. The engine should be run at 1200 to 1400 RPM for 1/2 hour soon as its started. When the engine is run at idle the crank won't splash enough oil on to the lower cylinder walls you will score the cylinders. After the engine is hot take time to reset the timing and valve lash. The first time you drive the rig be GENTLE, VARY your speed continuously, and DON'T go faster than 35 MPH for approx. 30 minutes. I personally wouldn't go faster then 40 or 45 MPH for the first 1500 miles.

Yotapup

Don't make the mistake of synthetic after re-build. From personal experience I can tell you the rings will never seat.The damn syn. is so slick it will not allow a proper break in. It was a damn expensive mistake I will never make again.

CoedNaked

I would run dino oil for 1000 miles. After 1000 miles do another dino oil change. Run it for another 2000 to 3000 miles (so 3000 to 4000 total after rebuid) and then switch to synthetic. After your first 1000 miles, run the engine a little harder just to help break 'em in a bit more. Feather it for the first 1000 though. Running regular oil isn't going to hurt your engine if you change it regularly. But you obviously recognize synthetic as a suprioer oil and want to run it asap but for the break in period I would listen to your builder. Especially if say you have a problem after a few thousand - he might be more receptive to potentially fixing the problem pro-bono if you followed his advice.