I was getting an alignment done the other day and the tech that was doing my XJ came out to talk to me about it. He explained he was an avid jeep guy and has 3 total in his driveway that he muds, crawls etc. with.

Anyway, he asked me what oil I was using in the freshly rebuilt engine and I told him Mobil 1 5-30 full synth. He said I should be using a Rotella 5-30 or 5-40 due to the added ZDDP that is in the oil and that guys he knows who have built strokers have had difficulty with the low ZDDP content full synth oils.



Any input?

 

U need to find a new tech.....one that doesn't continue to spread/perpetuate oil and ZDDP myths.

 

Give the guy a bit of credit, that one's a little more obscure than "synthetic causes oil leaks"

I assume you're referring to this? http://www.bobistheoilguy.com/forums...Number=1049812

Also, FWIW, Rotella T6 5W40 is a full synth. Mobil 1 5W30 High Mileage is also a full synth with extra zinc.

 

Ok, so would you recommend the Mobile 1 5-30 High Mileage with added Zinc for a fresh engine or just go with the regular Mobile 1 5-30 full Synth? Or am I just being a 4.0 Hypochondriac?

The LAST thing I want to do is to have to redo this motor after 5 or 10k miles are on it.

 

High open/closed valve seat pressures is what wipes lobes off cams. Nobody in their right mind, or any engine builder worth a flip, would install high seat pressure valve springs in a new motor, stroker or otherwise. If u do, u are asking to wipe the lobes off the cam.....ZDDP in the oil or not. Plenty of assembly lube should be used on all moving parts AND the new motor rotating assembly should be spun as little as possible during assembly, prior to initial start-up. A performance motor should be broken-in using stock type, low seat pressure valve springs, thus easing the initial lobe-2-lifter pressures/break-in loads. Then, and only then, after the motor has been run tested and all moving parts have completed their "break-in meet-n-greet" with each other, should the stock type valve springs be removed and substituted with the high performance/high seat pressure valve springs.

At a OE stock +/-65lbs closed seat pressure for the stock 4.0L, wiping the lobes off a cam should be a non-issue as long as the new motor was properly assembled, again with assembly lube, and oil primed prior to initial start-up. That's the way I did it, way before the Internet and BITOG.

On a freshly re-built motor, u want to change both the oil and filter immediately after initial break-in (30 minutes), then again at 500 miles, then go from there and each time using quality name brand oil and filter.

 

Ok. Mine is not a stroker high performance but I appreciate all the info!

I did follow your break-in procedure though, ran it for 30min changed oil, ran for another 500 miles and changed the oil. Everything prior to firing up the first time had lots of assembly lube, even the lifters, push-rods and rockers. The engine runs great, zero noise.

I think I am just being paranoid, I have spent a lot of time on this project and don't want to see it wasted.

 

Sounds like u got a good scald on it to me.......and don't believe everything u hear from an alignment tech as I don't believe Rotella is offered in 5W30. Most clueless so-called engine builders will have difficulties regardless of what/which oil they use.

 

Make sure you use right oil, otherwise your crankshaft will fall apart.

 

im in the 500mi portion of my break in of my stroker, im using conventional castrol 10w30 with a zinc additive

after the 500mi im switching to 10w30 amsoil zrod

 

Yep. 10W30 comes in conventional and the T5 synthetic blend. Apparently there's also a T5 0W30 which doesn't meet many specs (or possibly just isn't certified to them based on target market) and even more ZDDP then T6 5W40 :O

 

I didn't see any 5W30 or 0W30 listed at the Shell Rotella web site, maybe I missed it.

 

Yeah there isn't a 5W30, I found the 0W30 mentioned in a product guide PDF similar to this one: http://www.bluewaveenergy.ca/LinkCli...s%3D&tabid=259

I couldn't even find the 0W40 on their own site.

 

i have a 2001 xj with a rebuilt motor with 3k on it and i too dont know what oil i should use any ideas? i live in wisconsin and its summer at the
moment

 

Oh I LOVE these Oil questions. Mobil 1 is a great oil, BUT NOT FOR BREAKING IN ENGINES. A conventional (dinosaur)base oil motor oil should be used with 10w-30 being the prefered and most commonly used grade. I like WallyWorlds brand SuperTech, because its Cheap and Good for the Money, and You should be changing the oil often anyway during Break-In. I change after the first 30 min of running, then after first 30-40miles of driving(Where You want the majority 80-90% of BreakIn to occur), and the after another 500miles of spirted, but not abusive(not over3500RPM) driving. I have seen engines not breakin right or fully with Mobil 1 in them, and It only makes sense because its so slippery, the parts cant WearIn together.

 

If its a 93 and later 4.0 with the horozontal oil filter mount, use a Oversize filter(FRAMFARM PH8, TG8,. Purolator 30001, Mobil 301, Wix 1515 NAPA 15151, 21515, 31515, and so on), they can hold more oil and contaminants while not costing any extra.