I tested my evo's cylinder pressure and had 125 on cylinders 2, 3 and 4 and 100 on cylinder one. My car still runs fairly well, however I do not imagine its good to keep running the engine like that. I am curious if anyone thinks a drop in re-ring is feasable. I also have cams which is more than likly why the other 3 seem low.

I did look up drop in's but only found info about changing out pistons and rods, just looking to re-ring. Any input is appreciated, especially if someone has experience with it.

 

Drop a little oil in cyl 1 then retest, if compression reading goes up it's the rings. To double check you can do a leak down test on cyl 1

 

What do you mean by drop in re-ring? The head and pan have to come out which leaves the block. You could just leave the block in and pull the pistons and re ring them, but if it were me I would go ahead pull the motor and do new bearings while I was at it.

 

I meant do a wet compression to determine if I could be the piston rings. To truely lockdown the problem perform a leak down test.

For a wet compression test squirt oil inside the spark plug hole into the cylinder that read 100psi, if it significantly improves, it "might" be the piston rings, if it doesn improve the reading it could be a valve not seating.

 

A leakdown test would eliminate many other potential causes.