How to check for pinched or bad rings.

[BogusSVO]

I had a customer drop off a 1g 6 bolt short block, the timing belt broke and valves hit the pistons.

You must be logged in to view this image or video.

See where the valves hit.


Rotate the engine over so all 4 pistons are about the same level in the block.

You must be logged in to view this image or video.

Now take a screwdriver, stick, paint stirrer and mark it about an inch from the bottom.

You must be logged in to view this image or video.

Now take a cheap quart of oil, or some not so nasty used oil.

You must be logged in to view this image or video.

Now pour the oil on top the piston, in all 4 bores.

You must be logged in to view this image or video.

So it comes up to the mark on your measuring tool.

You must be logged in to view this image or video.

Once this is done, forget about it for several hours, or over night.

This one sat for 20-22 hours.

You must be logged in to view this image or video.

I had a slight drop in #1,#3,#4

You must be logged in to view this image or video.

#2 was almost twice as much

You must be logged in to view this image or video.

You can see it by eye.

You must be logged in to view this image or video.

Now how fast it drops will depend on a couple things, How long the oil sets, what weight oil is used and what the air temp is, along with what ring gaps are used.

All this dose is help decide if you may have a ring issue. If you go back and all the oil is gone off the top of one piston, pull that piston out.

The result of the test on this short block does not help much.

Ring wear, cylinder wear could cause a bit more to pass.

The oil is leaking thu the ring gaps, so even a good running engine will have some oil leak by.

 

[goodhart]

I realize this is an old thread and this is not a super accurate way to tell the condition of the rings with this method because of the many variable you mentioned, but what would you consider a reasonable amount of drop in the oil level?

 

[BogusSVO]

I have never kept a record of how much has passed by the rings.

They should be fairly equal in the drop across the board.