Engine break in with regular oil or synthetic

[Paul G]

Everything I read about engine break in says to do it with regular oil first, then switch to synthetic. If the LT and LS engines require synthetic oil were they broke in with regular oil before they were sent out to the dealers?

 

[motorman]

Everything I read about engine break in says to do it with regular oil first, then switch to synthetic. If the LT and LS engines require synthetic oil were they broke in with regular oil before they were sent out to the dealers?

no but they have roller camshafts and that is where the problem comes if you have a engine with a flat tappet camshaft the syn oil will not work because the lifters MAY not rotate and cause a problem.

 

[C4Tom]

Everything I read about engine break in says to do it with regular oil first, then switch to synthetic. If the LT and LS engines require synthetic oil were they broke in with regular oil before they were sent out to the dealers?

I believe that when the engine is assembled and first started at the engine assembly plant, they use regular oil. When they dropped the engine in at the assembly plant, they add synthetic there.

There are various components in the engine that need to mate properly to seat or seal(rings, valves, bearings). The advance lubrication properties of synthetic oils don't allow for it.

 

[Ken]

I agree with both Motorman and Tom. Use regular petroleum-based oils for break-in.

 

[Edmond]

no but they have roller camshafts and that is where the problem comes if you have a engine with a flat tappet camshaft the syn oil will not work because the lifters MAY not rotate and cause a problem.

So could you break in the motor if you had a roller cam?

 

[RWDsmoke]

I have a friend that put synthetic oil in a new engine. Rings didn't seat and and he had an oil burner.

 

[motorman]

I believe that when the engine is assembled and first started at the engine assembly plant, they use regular oil. When they dropped the engine in at the assembly plant, they add synthetic there.

There are various components in the engine that need to mate properly to seat or seal(rings, valves, bearings). The advance lubrication properties of synthetic oils don't allow for it.

the LS engines are not hot fired at the engine plant they are just spun with a electric motor to see if they have oil pressure and everything fuctions as it should. i have been there to watch it happen. the new ZO-6 enines will be hot fired at their special assy plant.

 

[motorman]

So could you break in the motor if you had a roller cam?

GM does it all the time

 

[Vettefreak100]

Got an engine built for my 1961 Corvette that was a 383 with vortec heads and a solid high lift cam. When we asked the engine builder how he felt about using synthetic oil for break in here is what he said. He was telling us that they were having problems with the new Corvettes running synthetic oil during break in. It has something to do with the fact that synthetic oils don't break down as much as standard petroleum based oils do, which inhibits the break in process. My engine builder always breaks his engines in with standard oil, then said that we could switch to synthetic after the break in period was over.

 

[C4Tom]

So could you break in the motor if you had a roller cam?

Huh...

Yes, you have to break in motors with rollers too.

 

[Vettefan87]

I have a friend that put synthetic oil in a new engine. Rings didn't seat and and he had an oil burner.

Yup, that is what my engine rebuilder said. He said run it 2000 miles with the so called conventional oil, but I ran mine for 3000 miles. Then he said switch to synthetic preferably Mobil 1, but he said stay with 10w30.

 

[vader86]

The reason LT and LS engines run from the start with synthetic is due to the tighter production tolerances than the Gen I SBC, they dont get started off with dino oil. The LS did initially have oil burn problems due to the ring material, and the Z06 nearly always has, but otherwise that problem is fixed.

The initial start up break-in procedure is different for roller-cammed engines, you dont have to start it and rev it to 2000rpm like the other cam types, but the actual engine break-in is the same.

You just don't need to run synthetic with a brand new motor if you have a Gen I, it doesnt allow the rings to seat properly because its too good at lubrication. Most with new LTs dont need to run it either, aftermarket builders dont use the same tolerances as GM did in most cases.