My car is currently nearing 187,000 miles. Accelerates slower than it used to, exhaust reeks of oil, and to keep oil in operating range a quart of oil must be added every 200-400 miles. So I’m replacing the piston rings as soon as I have time for the work, and for the vehicle to be down.
Meanwhile, the brakes seem less powerful lately. Now, I recall reading about Jake brakes, that the reason gasoline vehicles didn’t use exhaust brakes was because they had automatic engine braking due to the way the engine functioned: when the throttle is closed all the way, the downstrokes generate a vacuum, which consumes energy as the piston moves down in spite of the vacuum it generates (whereas diesel Jake brakes waste the energy by expelling compressed air that would normally revert back into the engine).
So the question is [preferably experienced mechanics who have done a lot of work of this kind and can give a definitive answer] could a loss in braking power be attributed to bad piston rings (i.e. the vacuum that would normally be created and slow down the engine is not created because air comes in from the crankcase) and replacing the piston rings will solve my braking problem, or a. is the vacuum not that much of a contributor to stopping power or b. (if it is), if there was enough suction loss to noticeably affect braking should the engine be incapable of running - and therefore I must work on the brakes too?