Which would be better for first start? There's going to be some coolant and bits of gasket in the pan from my head install. Just trying to find out what would be best to clean it out andrun for a couple hundred miles. Thanks

 

Do you have new piston and rings? Never break in a engine with synthetic oil. I use cheap 10-30 and change it twice. I switch over to syn after dyno and the to the track for the first time.

 

Run a good filter and conventional oil. Some group V ester based oils have some cleaning ability but its not very well proven or documented. I run Redline synthetic which is a group V. Its about $9 per quart though and I would never dream of using it as a flush oil. I plan to use a good HDEO like rotella for my first 500 miles on the new motor along with a royal purple filter, change again at 1,000 and then at about 1,500. After that its time for the redline.

If the motor has carbon build-up auto-rx.com has a great product for that. Not sure if you know but one of the major benefits of a synthetic oil is its ability to stay in service longer. Draining it early is erasing that benefit. Modern conventional oils are very capable these days and will be more than ok to do what you need. If you need any further info visit bobistheoilguy.com/. I am a member there. It's a great resource for any lubrication based info.

FWIW unless you are using a group v like redline, the whole "dont run a synthetic for break-in" is untrue. Most synthetics are group III oils, meaning they are synthetic hydrocarbons (conventional oil that has been highly refined/processed. The molecular structure is altered so its very robust for lubricating at higher temps and can be run longer but it will not interfere with rings seating. The only real worry when looking at oils is the proper weight being utilized and if its a flat tappet(not an issue here) is ZDDP included in a high enough level to protect the tappets. So whether you pick mobil 1 or Castol GTX your rings will seat. If you wish to look into this further look on the above site. It is also listed on mobil1.com

Either way I would get a inexpensive conventional, do a few short runs and then stick to a reasonable OCI(oil change interval) using your favorite brand.

 

I've seen it happen with Amsoil.

 

Dino, as price is the only real consideration here.

 

Must have been some other issues because its a myth. Mobil 1 and amsoil are not too far off from each other. Both are group IV(PAO) oils. And both companies last time I checked, state that break in on dino is not needed. Along with many auto manufacturers and tribologists. Do whatever makes you sleep good at night. If the motor is built right and break in procedures are followed, the rings should seat regardless..

 

Didnt touch the internals aside from valve springs, pushrods, timing chain, oil pump and heads.

 

Refer to my first post. You will be more than fine running a proper grade dino. I like rotella but also use castrol GTX. Really with group II conventional oils there is very little difference. Mostly brand preferance. Run a good filter and change it with short intervals the first few times. All oils are going to do about the same thing with respect to this kind of junk in a motor, little to nothing. Its cahnging it frequently and when hot along with good filters that will hopefully flush or trap any junk thats left in there. Good luck!

 

Dino oil. On my new motor startup I used the cheapest oil I could get (within reason, name brand). Ran it long enough on initial startup to burp the cooling system; and then changed it and the filter.

Then I put in Mobil dino oil and ran it for 500 miles.

Now its got valvoline synthetic in it, and has been sitting for the winter.

 

Since you stated you have some debris in there, I'd use less expensive regular conventional oil, then change it out to synthetic oil and put a new oil filter on it too. Bob