piston ring changing
- Thread starter murphmaster5
- Start date
bill302
Active Member
have you done a compression test on each cylinder to determine if it needs freshing up. let us know some more info. to determine the best route for you to go using oil, high mileage ect.. and in my experience what you call freshing up your motor only reveals other weaknesses especially if you have high mileage. but others here may have a different opinion.
Black1987Stang
Active Member
Yea i agree with Bill, r u sure its rings? not alot of times u just change the rings, I would also do the bearings etc. while ur down there. For instance in my school, we got a car that came in saying needs rebuild, burning tons of oil, so we change the rings, bearings, gaskets, valve job etc. and we found out the original problem was from the tube from the crackcase to the intake(cavalier) or something like that and the tube was crimped, that was what caused the oil consumption.
I would do a compression (wet and dry) and leakdown test and go from there, they will tell u alot Good Luck
I would do a compression (wet and dry) and leakdown test and go from there, they will tell u alot Good Luck
In response to the question....
Not hard to change rings. Get a ring expander. $6.00 @ napa/autozone...
As far as gapping goes, square the rings in the bore with a piston or tomato
can, and check with a feeler gauge. You would want .018-22" end gap, for nitrous (stock bore). they wont be that large, so you file them to the right size. Then go over them with an extra-fine toothed file and 400 grit sand paper. Use the expander to put them back on, allign the rings, and use a ring compressor to get the pistons back in the bore. Takes no time at all. Good luck.
Not hard to change rings. Get a ring expander. $6.00 @ napa/autozone...
As far as gapping goes, square the rings in the bore with a piston or tomato
can, and check with a feeler gauge. You would want .018-22" end gap, for nitrous (stock bore). they wont be that large, so you file them to the right size. Then go over them with an extra-fine toothed file and 400 grit sand paper. Use the expander to put them back on, allign the rings, and use a ring compressor to get the pistons back in the bore. Takes no time at all. Good luck.
Vipersix
Founding Member
I'll agree with a little bit each of the other guys have said so far but would like to add a couple things.
First off, anyone can change rings with the proper tools and instructions/supervision but it takes a bit of practice to do it correctly and without any errors or accidental damage. While removing/inserting the rod and piston in the cylinder use absolute care not to scratch the sides of the cylinder wall. The rod has a tendency to do a good deal of damage if you don't have the engine on a stand and insert/remove vertically.
Be cautious while inserting the piston into the cylinder after changing rings. Depending on the condition of your block and the type of ring compressor you are using it might take a bit of finesse to get right. Plus you'll need to be cautious of the location of your crank if it is still installed. The rod won't go in straight and will contact the crank, possibly causing damage.
A regular motor oil is sufficient to pre-lube the piston assembly prior to installation.
That said, definitely do a compression test before anything. A leak in compression does not even necessarily mean bad rings though so I would recommend getting a second or third opinion before jumping in over your head. Leaks can also be caused by head gaskets or intake/exhaust valves. (Or if you're unlucky like me, you could have a cracked piston.)
As you are wanting to "freshen up" your engine, I would also change bearings like was mentioned before but would also look into the need for honing your cylinders. Depending on mileage this could be an issue.
Good luck! Take your time!
First off, anyone can change rings with the proper tools and instructions/supervision but it takes a bit of practice to do it correctly and without any errors or accidental damage. While removing/inserting the rod and piston in the cylinder use absolute care not to scratch the sides of the cylinder wall. The rod has a tendency to do a good deal of damage if you don't have the engine on a stand and insert/remove vertically.
Be cautious while inserting the piston into the cylinder after changing rings. Depending on the condition of your block and the type of ring compressor you are using it might take a bit of finesse to get right. Plus you'll need to be cautious of the location of your crank if it is still installed. The rod won't go in straight and will contact the crank, possibly causing damage.
A regular motor oil is sufficient to pre-lube the piston assembly prior to installation.
That said, definitely do a compression test before anything. A leak in compression does not even necessarily mean bad rings though so I would recommend getting a second or third opinion before jumping in over your head. Leaks can also be caused by head gaskets or intake/exhaust valves. (Or if you're unlucky like me, you could have a cracked piston.)
As you are wanting to "freshen up" your engine, I would also change bearings like was mentioned before but would also look into the need for honing your cylinders. Depending on mileage this could be an issue.
Good luck! Take your time!
okay the motor has about 90 i think thats whats on the speedo but you know how that goes any way it runs great but im doing so much to it and i wanted to make sure its up for it, It doesnt matter now cause i went to the garage were my car is and some how moisture got on the motor and now its starting to rust so i think im just going to try to get the money together and have it rebuilt.
88Stangboy
Banned
Nah dude, your going to need to hone the cylinders. And like was said before, you need .18-.22 for the gap. But i would hone the cylinders, just because it's going to help your rings seat a little better if you do. And like everyone else said, usually you run into more than just replacing rings. Go ahead and get you all new bearings while you got the engine apart. When its all back together it'll be like brand new, ready to run with that nitrous. Go with Clevite 77 bearings. And dont be tempted to use harder racing bearings like my friend did, race bearings are for exactly that, racing. Just use some good street bearings just incase your engine does get a mouth full of dirt or something it'll en-bed into the bearing and not your crank. Just a tip, thank god he found out the hard way and not me.
