best oil for rebuilt GM 5.7 V8 TBI engine?

[sr17]

I recently had a remanufactured engine installed in my 1991 GMC Sierra K2500.
First oil change was done by the installer at around 500 km. I am now at around 3000 km total and would like to change oil again.
With a fresh engine, I would like to treat it right from the start.
What brand, type and viscosity would you oil gurus recommend?
Any particular filter recommendations?

 

[jayg]

Now that's it's been broken in, Delco filter and any name brand full synthetic 5w30 would be fine.

To be fair, that SBC doesn't care. Peak conventional 5w30 would do the same job. The only reason I recommend synthetic is to stretch out the intervals and change it once a year if you aren't putting more than 10k on it annually.

 

[sr17]

Originally Posted By: jayg
Now that's it's been broken in, Delco filter and any name brand full synthetic 5w30 would be fine.

To be fair, that SBC doesn't care. Peak conventional 5w30 would do the same job. The only reason I recommend synthetic is to stretch out the intervals and change it once a year if you aren't putting more than 10k on it annually.


The one thing the installer told me was to wait at least a year before using synthetic.

 

[jayg]

Originally Posted By: sr17
Originally Posted By: jayg
Now that's it's been broken in, Delco filter and any name brand full synthetic 5w30 would be fine.

To be fair, that SBC doesn't care. Peak conventional 5w30 would do the same job. The only reason I recommend synthetic is to stretch out the intervals and change it once a year if you aren't putting more than 10k on it annually.


The one thing the installer told me was to wait at least a year before using synthetic.


Your engine can't read a calendar but hey if he is offering some kind of a warranty then ask him what he wants in there. If by a year he means 5k miles, then keep running a high quality conventional until then. Or forever. It really doesn't matter.

 

[daman]

You can start using Synthetic now no need to wait. A good quality 5w30 will work.

 

[sr17]

Originally Posted By: daman
You can start using Synthetic now no need to wait. A good quality 5w30 will work.


I thought it was something about rings not seating properly with synthetic?

 

[JHZR2]

I've always liked PYB for GM iron engines.

 

[Red91]

Don't over think it. These were some of the best small blocks GM ever produced, and a lot of them got to 350K miles with regular conventional oil, SF to SH API spec no less. I'm going to be running some SJ Kendall GT-1 SAE 30 in mine, coming off a run of Delo 400 SAE 30. A 15W-40 from any brand would be a good choice.

 

[Alex_V]

My vote: in anything warmer than a regularly sub-freezing climate, good conventional 10w30. If the engine has a flat-tappet cam Rotella might be a good choice for the ZDDP, but if it was mine and it ever gets used for pulling or other halfway strenuous work after about 5,000 total miles I'd go to a good syn blend like Schaeffer's 7000 or Valvoline Maxlife.

Not sure why your installer said to stay away from syn for the first year - after the 5,000 mi. mark I don't see how there's any more breaking in to be done that a slick oil would prevent. The time for this has apparently come and gone, but in the first 1,000 miles I'd have given it one or two good, hard pulls up to 4,000 RPM or so, and go to whatever oil you want to use at the next change after that.

 

[tig1]

Originally Posted By: daman
You can start using Synthetic now no need to wait. A good quality 5w30 will work.


+1. Living in Canada it would be wise to use a quality synthetic for easier cold temp starting and faster oil flow. Possibly a 0-30 as well.

 

[Garak]

There's nothing wrong with following his directions. Grab your favorite conventional, and any sensible filter, and go to it. We ran many Chevy small blocks to many miles with Quaker State conventional and Wix filters.

 

[FCD]

Would a 1991 engine have a flat tappet cam? If no run Mobil 1 5W30.

 

[jayg]

Originally Posted By: FordCapriDriver
Would a 1991 engine have a flat tappet cam? If no run Mobil 1 5W30.


1987 is when roller motors started in GM cars, 1996 in trucks.

 

[FCD]

So it doesn't have a roller cam in it?
I'd run Shell Rotella 10W-30.
Vancouver has pretty mild winters so cold starting should not be an issue.

 

[GenaFishbeck]

For a 1991 GMC Sierra K2500 5.7L engine, we recommend a quality 5W-30 oil motor oil. For premium performance we recommend Pennzoil Platinum Full Synthetic motor oil in 5W-30. Pennzoil Platinum is formulated using PurePlus Technology, a process that creates base oil from natural gas instead of crude oil. PurePlus base oil won't gel in extreme low temperatures that can be experienced during Canadian winters. Hope this helps! - The Pennzoil Team

 

[FCD]

Originally Posted By: GenaFishbeck
For a 1991 GMC Sierra K2500 5.7L engine, we recommend a quality 5W-30 oil motor oil. For premium performance we recommend Pennzoil Platinum Full Synthetic motor oil in 5W-30. Pennzoil Platinum is formulated using PurePlus Technology, a process that creates base oil from natural gas instead of crude oil. PurePlus base oil won't gel in extreme low temperatures that can be experienced during Canadian winters. Hope this helps! - The Pennzoil Team

Vancouver has a oceanic climate which is quite mild compared to the rest of Canada, a 10W-XX oil would suffice there.