What other parts of the engine are you concerned with?

 

It dont stick like you think it would. like i said its just from exp i have had. my shop has built 100s of engines and i never had a issue. Im sure you can google it to find out more. Everyone is going to say this and that but you have to go off of what works.

 

Rod bearings, main bearings, piston rings. Those are the key components.

 

If a cam manufacturer like Crane says not to use synthetic oil for break in I for one won't use it to break in my motor when it gets back from the shop.

Actually, I encourage everyone to use syn oil for break in. Why not? It seems there are lots of nay sayers on the forum so they must be right...right?

 

It makes me wonder if even the cam manufacturer is just going off of hearsay also, or if they've performed independent tests. Yes, cost would be a driving factor. I just want to know why people think their camshaft is going to grind away to nothing if they break it in with synthetics.

 

Check out bobistheoilguy. There you will be able verify my explanation and find out why not to use syns during BreakIn. Engine parts Need to Wear together. They Need to Wear. Together. Not alot of wear, but enough wear so they "mate" together. The finish surface of all the new engine cmponents are going to be different. Until they have a similar "wear" surface between moving parts,.ie rings/cylinder walls, lifter foot/cam lobe, they will not be broken in. A SYNTHETIC oil, at least a SYN oil with Group 4 or 5 base oil Will prevent these parts from wearing because the SYN oil is so slick. True Story.

 

84z, I've seen you cruising around over there. Can you give us a link to the explanation?

 

Maybe I missed it while scanning this thread, but the first question I would ask the OP is...

What oil does the engine builder recommend? I would stick with that if the engine came with any kind of warranty. No use giving them an easy out on potential warranty engine issues because you didn't use the oil they recommend. I would ALWAYS make sure that, at least for the first year of your warranty, you follow their recommendations to the letter. And document it with dated receipts.

My ATK longblock, with a 3 year, unlimited mileage warranty recommended a conventional 10W-30, so that's what I used. Castrol with a Mopar filter ($6.00 at O'Reilly). I did the initial 20 minute break-in with that, and then actually drove it for 50 miles. Changed the oil and filter with the same Castrol. Changed again at 500 miles and 1500 miles. Then every 3000 until I got to 17,500. Once I reached that point (about 2 months ago), I switched to Castrol Syntec. From here on out I plan for changes every 7000 using Syntec unless I'm subjecting it to hard use like lots of trailer towing or wheeling. She runs and sounds great and keeps good pressure and temps. Always used Mopar filters at every change.

When I sold my '02 TJ (that I bought new) it had 147,000 miles on it and used Castrol Conventional 10W-30 and Fram (yes, FRAM) filters it's whole life. Ran like brand freaking new the whole time I owned it, had never been in the shop, and zipped through emissions tests with ease.

However, thanks to these forums I did learn some important things about filters, and while I'm still not convinced that Fram, provided it is changed every 3K miles will let you down, for $1.50 more each time, and to protect my warranty, I switched to the Mopar filters.

There are as many opinions about oil as there are kinds of oil. Some are slightly better, others worse. From my own experience and the feedback I've seen from others, our 4.0 beasts will do just fine and run for lots and lots of miles on any decent 10W-30 provided it is changed regularly. Unless you really want to, there's no sense driving yourself crazy fretting over one oil being 5% better (in some, but maybe not all categories) than some other oil. Keep the oil changed, keep anything that sucks air into the motor (hoses and tubes) tight and sealed, keep the engine clean so it runs cooler, and keep the air filter clean and you should be good to go.

 

Here is what some ring and cam manufacturers say about break-in oil, links provided:

Total Seal:
http://www.totalseal.com/TechPage.aspx


Hastings:
http://www.hastingsmfg.com/Master_Ca...Master2012.pdf


Crower:
http://www.crower.com/media/pdf/cam_book.pdf

Crane:
http://www.cranecams.com/uploads/instructions/214e_.pdf

I tried to find a manufacturer who specifically recommended using a synth break-in oil and could not.
Comp cams does not appear to care as long as there is sufficient zinc/phosphorous present, recommending their own supplement for that purpose- as do most, and Sealed Power is silent entirely on the subject of break-in oil other than to recommend 'good quality'.
After the initial break-in period, none object to synthetic oil and there is no reason it cannot be used.

 

Your motor is already broken in and most of this thread is irrelevant to your question.
Any good quality 5W30, 10W30, 10W40 or 15W40 is fine.
I'm also in WI and use 15W40 in the summer and 5W30 in the winter simply because the motor runs a bit quieter with the 15W40, but it's a bit thick for cold temps.

 

I say either Castrol GTX, Valvoline White Bottle and Mobil Clean 5000 in a 10w-30 viscosity would be the Highest Quality choice. Personally, I use SuperTech. SupahTech, I mean.