Originally Posted by 97 SL320

I still say no to dumping oil in the cylinders and cranking it. Sure you can get it to run but in the long term you can do more damage.

If a cylinder bore is rusted and you manage to break it free, the rough bore will damage an otherwise serviceable piston. Sleeving a cylinder bore is inexpensive, sourcing new pistons for an older obscure engine is going to be costly.

There is also a chance that piston rings are stuck on the grooves, the ring will unevenly expand with heat and score the bore.

A valve can be stuck open ( usually exhaust ) and allow a piston to hit the valve. This could result in the valve shutting or bending and breaking a valve guide. And, it is possible for a cam follower / lash adjuster / rocker arm / push rod to come out of place causing damage.

At minimum the plugs need to come out and a bore scope inserted to inspect the cylinders.