VCCA Home Forums GENERAL DISCUSSION New User Forum Rebuilt 1927 171 cu in engine oil

Hi: I am about to first start a rebuilt 171 Chevy engine and would like to hear input into what oil I should use. Some say any Dino oil, some say diesel oil, some say 30w only. I’m confused! Any clarification would be greatly appreciated, thanks. Ron

Hi Ron,

Welcome to the VCCA's website! This is definitely the best place to ask such questions and hang out with other old Chevy enthusiasts.

There has been a lot of discussions on this topic and the consensus is 10-30w dino oil, any brand. Members who are master mechanics and chemical engineers agree on this.

We have a couple of good references on this website on rebuilding one of these 4-bangers. Each will take you a few cups of your favorite beverage to get through!

1. Ray Holland (aka AntiqueMechanic), a master mechanic, rebuilt a '28 Chevy engine in a series called School is in Session. This story resides in a 250 page PDF on the VCCA's web page of Technical Articles. Go to the main VCCA website and in the Members Only area, you'll find the list of Technical Articles. To access this fine reference document you have to be a club member. Accessing these articles is only one of many great benefits to joining the club.

2. In 2017, I rebuilt the '28 engine in Lurch, my 1927 one ton truck (see the links below for info about Lurch). I documented that journey here: Resurrecting a '28 4 banger

Cheers, Dean

My first choice would be whatever the machine shop which did the rebuild recommends. In the absence of that input, I suggest use a 5W-20 conventional oil as a break in oil. After 250 miles drain and use conventional 10W-30.

Remember that any oil you put in that engine today is way better than whatever was available when it was new.

Hi Skrpbod
Looks like you are in Alberta? :-)

I'm partly in agreement with Rusty and do respect his advice, but...
Machinists aren't necessarily good tribologists. I'd trust their recommendations on "cutting oils", but not necessarily engine oils.

That said, I'd say the 2 most important things are:
Keep it light!
And use a high quality detergent oil, either conventional or synthetic.

You want the oil to get where it's needed as fast as possible on start up, and you want it to carry away heat as well as possible after the engine is running.
That means using a low viscosity oil to cover both bases.

Note that for years and years before multigrades were available the Chevrolet factory fill for break in was straight 10W.
I think Rusty's recommendation of a 5W-20 is a good one. 0W-20 would be better yet.

Remember, on a 4 cylinder Chev, oil PRESSURE is irrelevant except to indicate the pump is pumping. FLOW is the important thing.
And the oil must be thin enough on start up to be broken up into a fine mist by the connecting rods dipping into the oil troughs.
That is the ONLY lubrication the upper part of the engine gets.
On that note, and given your geographical location, I would recommend that straight 30 weight oil should NEVER be used. Not even after break in is done. 10W-30? Sure. But never straight 30.

I know I'm probably opening a can of worms here with what I've said, but I'd like to see you get the best break in possible up here in the great white north. :-)
(It's snowing here again this morning).

PS
Rusty makes an excellent point regarding RPMs in the next post below!

I like Ole’s advice. He and I are thinking along the same lines. For start-up on a fresh rebuild you want to get oil everywhere it should be as soon as possible.

Keep the rpm up maybe around 1200 rpm for good 15 minutes or more. Watch your temperature. Then drive it like you will normally drive it.

Yep thin! 5w20 would be ideal then a switch to 5w30 or 10w30. Frequent changes when breaking it in.