First engine start in many years, which oil to use?

[pafagt]

Hello forum, I’m getting ready to start up the car after many years. My car has 32,000 original miles and has been sitting for around 15 years. Engine turns freely and we’ve cleaned and worked on carbs, fuel tank, lines and a brine head gaskets. Some folks have recommended using a thinner oil like a 10W30 just to start it up and get everything moving and the discarding it and switch to a more viscous 20W50. Would this be correct.? Any suggestions..?

Thank you as always..!!
Pablo

[Simonpfhc]

Hi Pablo,

You would only need to use thinner oil (sae30) to run in a brand new engine and allow the piston rings to bed in to the cylinder bores. Whilst it wouldn’t do any harm to use thinner oil, just go ahead and use a decent 20w-50 oil.
However, before you actually fire it up, make sure you get oil pressure with the plugs out and just using the starter motor. I normally also disconnect the fuel pump and coil. When you see pressure, put back the spark plugs, fire it ip and off you go.

Cheers.

[mgcjag]

Hi Pablo...I would put a squirt or two of oil in each bore and turn by hand.....leave for a day so the oil drains down.......
Then as posted above..plugs out fuel off turn engine on the starter to get oil pressure up...but it can take what seams a long time when cranking....60 secs or there abouts...Steve

[pafagt]

Thanks Steve and Simon. I guess I’ll use the 20W50 then.

[angelw]

Hello Pablo,
An engine sitting for that long. all of the bearings would be fairly dry and in my opinion, cranking the engine to get oil pressure is not best practice.

With all fresh, rebuilt engines, or engines that have stood dormant for long periods, I use the pre-lubricator shown in the following picture. This is an overkill for an individual starting an engine for the first time, or in a long time, where it may be used only once, but I made this pre-lubricator because of the frequency of engine rebuilds or restarts that I encounter in a year. The same can be achieved with a cheap hand pump plumbed into the oil gallery.



In its use:
1. Shop Air is connected to the air regulator at left rear in the picture
2. The outlet hose connected to the oil gallery.
3. The air regulator is set to the max oil pressure the engine would normally experience
4. The Outlet gate valve is opened to allow oil to flow through to the engine.

Oil pressure will be seen on the car's oil pressure gauge, and I look for oil welling up inside the cam covers to determine when job is done.

When using a device such as the pre-luber shown above, some oil needs to be drained off to make way for the incoming oil, and the oil level needs to be checked at the conclusion of its use. For engines that are either new rebuilds, or those having the oil changed before starting after the engine has stood for a long time, I use the pre-luber to fill the sump. Out of sight on the back side of the cylinder is an oil level sight glass. From the bottom line on the sight glass the correct quantity of oil is added to the pre-luber and the device operated with the engine until the oil level in the cylinder is down to the bottom line of the sight glass.

Many will argue that the use of a pre-luber is not necessary. Internal combustion engines can suffer quite some abuse without noticeable damage, so I would argue that some damage may occur when turning over an engine on dry bearings, but as its not that noticeable, the belief is that no damage is done. For the price of a cheap hand pump, I would opt to be safe every time. I would do this just for the peace of mind.

Regards,

Bill