File to fit rings: How difficult?

69427

69427

The Artist formerly known as Turbo84
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Mar 30, 2008
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Clinging to my guns and religion in KCMO.
I'm having some (Wiseco) custom pistons made for me, as off-the-shelf standard bore 427 pistons are like hen's teeth anymore. I'm also going to try file fitting the rings. Anybody done that, and how much headache is it?

thanks,
Mike
 
It is not too bad if you can borrow a manual ring grinder. I do it for my engines because it is like bonding! You can do it w/o the ring grinder but it is very hard to keep the edges square. You can do it but it takes twice as long. Then all you need is a fine stone to break the "edge" or burr on the corners when the gap is set. Once you get the "feel" for how much it takes to get close then each cylinder goes faster.

You also need a flat top piston of the same bore to square the ring in the bore to check the gap. If you do not have a piston you can put them in the bore and use a caliper to make sure it is the same depth all the way around.

It is just slow, not complicated.
 
I know what you mean about the 427 pistons being hard to find!! I've never had a set made, but I'm guess'n it isn't cheap. Just curious, boring .030 isn't an option? I found those pistons much easier to find...
 
I did it with a file on my engine. Takes a lot of install, nope, file more, install, nope, file more... I spent several hours doing this. Just make sure to file the edges to get rid of any snags.

Also, every bore is different. So you need to file each ring for its specific bore.

Here's what you do:

File some off of each side,
install in the lubed up cylinder,
push it down about an inch with a piston,
use a feeler guage to see where you're at,
file more... repeat.
 
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Being a std bore, I assume it's a non bored motor where you only used a glaze breaker or bubble hone? If so, the bore will never be perfectly straight and as such you have to gap the ring where it's tightest, that's at the bottom of the bore. Use a flat top to push the ring down perpendicularly. If you gap it at the top the gap will be too narrow at the bottom.
 
Twin_Turbo said:
Being a std bore, I assume it's a non bored motor where you only used a glaze breaker or bubble hone? If so, the bore will never be perfectly straight and as such you have to gap the ring where it's tightest, that's at the bottom of the bore. Use a flat top to push the ring down perpendicularly. If you gap it at the top the gap will be too narrow at the bottom.
Click to expand...

New block. The liners are 4.118, and will be bored to 4.250, so everything should be square.
 
enkeivette said:
I did it with a file on my engine. Takes a lot of install, nope, file more, install, nope, file more... I spent several hours doing this. Just make sure to file the edges to get rid of any snags.

Also, every bore is different. So you need to file each ring for its specific bore.

Here's what you do:

File some off of each side,
install in the lubed up cylinder,
push it down about an inch with a piston,
use a feeler guage to see where you're at,
file more... repeat.[/QUOTE]

I'm a design guy by profession, so my comfort zone is working on coming up with a distinctive item each time. I don't do well in repetitive task environments. I'm hoping a ring grinder setup will speed things up and minimize the tedium factor.
Click to expand...
 
The other thing you need to remember.

PII

Every .0001 you remove from the end of the ring opens the gap .31417.

Take your time and sneak up on it.
 
These last two posts really sum up my experience. It is SO easy to take off too much and you can't put it back on. I do a LOT of ring fitting cuz I race a weirdo that requires the ingenuity. I have one of the rotary ring files but the stone/blade in it is so coarse it's useless. I use a fine file and careful attention to detail. It may take twenty or thirty iterations (Times eight!) but as the good machinists say "There's only ONE zero".. As in, it's right or it's not.

When it gets tedious it's time to set it aside and work on something else. Do it right IMHO:wink:
 
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