Does anyone know approximately how much it would cost to replace piston rings on a 302? My 68 has been burning an absurd amount of oil (like a quart per week) and stem seals, valve guides, pcv, etc all seem to be fine. I know the whole engine will have to be torn down to replace the rings which is alot of work. Then again, its a 302. Its practically the simplest engine ever made that an experienced mechanic should be able to take apart blindfolded.

Mechanic is looking at it now--hasnt told me what the deal is yet. The engine was rebuilt 3 years ago and has new heads which is why Im confused that its burning so much oil.

Anyone have any guesses as to cost and/or if the problem could be something else?

 

If its 3 years old the rings shouldn't be leaking unless they got damaged or put on wrong.Do a compression test on every cylinder see where its leaking.

 

or they didn't hone the block. I've seen this done with people trying to save a few $$, sometimes they need a light hone in which case you can run the same pistons, sometimes they need more in which case you need to step up to a larger piston.

I'd do a leak down test on it, if the numbers are low then its the rings. Compression test will also be an indicator if you don't have a leak down tester. If the numbers look good then I'd pop the valve covers and make sure all the valve seals are good.

 

Everyone above is right, and to add to it, rings are one possibility, but the last thing touched in a process that might fix the problem that may lie elsewhere. Something as simple as a wrong PCV valve can cause high oil usage. Leaking intake gaskets can be an issue. Does it smoke? If so, when? Cold startup, all the time, accel, decel? 3 years on properly installed rings doesn't sound right. Has it been overheated to the point of turning the rings into spaghetti? What kind of oil? One of my customers changed to a popular high mileage oil and promptly started using 2 qts between changes. I sold him on the bulk I sell and his problem all but went away. It wasn't a bad oil, his 2000 Silverado just didn't like it. Some things to consider...

 

And is it burning or leaking? Don't overlook leaks from the front and rear main seals or oil pan gasket. I know my rear main leaks and my motor was supposedly rebuilt.

 

Any signs of external leaks? Blowing smoke? What pcv valve does it have?

Ring replacement cost varries, the cost of rings alone depends on the piston package. My rings for instance are $100, but it's for a $700 piston package.