Help with piston ring gap..
Thread Starter
On The Tree
Joined: Feb 2019
Posts: 123
Likes: 5
Help with piston ring gap.. First time I do this, so I already messed up 1 set. I left the messed up set at .021 for the top and .023 for 2nd..should I still use it for a 3.905 bore..
suggested measurements are (rounded)
.018 for top high perf street
.020 for 2nd..
thinking of doing .019/.021..
anyone have any information on how exact do the piston ring gap needs to be or if there is any wiggle room in between?
thanx
suggested measurements are (rounded)
.018 for top high perf street
.020 for 2nd..
thinking of doing .019/.021..
anyone have any information on how exact do the piston ring gap needs to be or if there is any wiggle room in between?
thanx
TECH Addict
Joined: Dec 2017
Posts: 2,201
Likes: 981
It's fine. There's PLENTY of wiggle room.
Rule of thumb is, .0045" - .005" per inch of bore; so, ideally, .018" - .020". Open up a little bit for nitrous or blower or turbo; maybe add .0015" to the first #s, so, up to around .025".
A sheet of copy paper is about .002" - .003", to put it into perspective.
There is no such thing as "perfect", in the sense that you MUST hit that exact number, or that if you miss it by even a little bit, you're toast. Rather, if you have slightly too much gap - emphasis on "slightly" - the only bad thing that happens is, you get slightly more blowby, especially when cold. BUTT... if you have ANY amount too little - even if it's only .001" too little - INSTANT CATASTROPHIC TOTAL DESTRUCTION will result when the ends butt together when they get hot; which of course will be most likely to happen at max power, max load, and max RPM. They will seize to the cyl walls, break ring lands off of pistons, destroy bores, and other undesirable things will happen.
Run it. They're perfectly OK.
Rule of thumb is, .0045" - .005" per inch of bore; so, ideally, .018" - .020". Open up a little bit for nitrous or blower or turbo; maybe add .0015" to the first #s, so, up to around .025".
A sheet of copy paper is about .002" - .003", to put it into perspective.
There is no such thing as "perfect", in the sense that you MUST hit that exact number, or that if you miss it by even a little bit, you're toast. Rather, if you have slightly too much gap - emphasis on "slightly" - the only bad thing that happens is, you get slightly more blowby, especially when cold. BUTT... if you have ANY amount too little - even if it's only .001" too little - INSTANT CATASTROPHIC TOTAL DESTRUCTION will result when the ends butt together when they get hot; which of course will be most likely to happen at max power, max load, and max RPM. They will seize to the cyl walls, break ring lands off of pistons, destroy bores, and other undesirable things will happen.
Run it. They're perfectly OK.
Thread Starter
On The Tree
Joined: Feb 2019
Posts: 123
Likes: 5
It's fine. There's PLENTY of wiggle room.
Rule of thumb is, .0045" - .005" per inch of bore; so, ideally, .018" - .020". Open up a little bit for nitrous or blower or turbo; maybe add .0015" to the first #s, so, up to around .025".
A sheet of copy paper is about .002" - .003", to put it into perspective.
There is no such thing as "perfect", in the sense that you MUST hit that exact number, or that if you miss it by even a little bit, you're toast. Rather, if you have slightly too much gap - emphasis on "slightly" - the only bad thing that happens is, you get slightly more blowby, especially when cold. BUTT... if you have ANY amount too little - even if it's only .001" too little - INSTANT CATASTROPHIC TOTAL DESTRUCTION will result when the ends butt together when they get hot; which of course will be most likely to happen at max power, max load, and max RPM. They will seize to the cyl walls, break ring lands off of pistons, destroy bores, and other undesirable things will happen.
Run it. They're perfectly OK.
Rule of thumb is, .0045" - .005" per inch of bore; so, ideally, .018" - .020". Open up a little bit for nitrous or blower or turbo; maybe add .0015" to the first #s, so, up to around .025".
A sheet of copy paper is about .002" - .003", to put it into perspective.
There is no such thing as "perfect", in the sense that you MUST hit that exact number, or that if you miss it by even a little bit, you're toast. Rather, if you have slightly too much gap - emphasis on "slightly" - the only bad thing that happens is, you get slightly more blowby, especially when cold. BUTT... if you have ANY amount too little - even if it's only .001" too little - INSTANT CATASTROPHIC TOTAL DESTRUCTION will result when the ends butt together when they get hot; which of course will be most likely to happen at max power, max load, and max RPM. They will seize to the cyl walls, break ring lands off of pistons, destroy bores, and other undesirable things will happen.
Run it. They're perfectly OK.
