File fit or not

[Roger63]

I'm getting ready to order parts for my 440 build. I've never tried file fit rings so I'm looking for a little guidance. What I have, 440 bred .060 over forged aluminum flat tops. I'm not sure yet how far down in the hole they are going to be. 516 heads that have been shaved just enough to clean them up. How much I don't know so I'm guessing compression is going to be around 10to1. Should I use file fit or standard rings? This is my cam.

 

[RemCharger]

You would be fine with standard rings. File fit can quickly get you into trouble, with very very little if nothing gains.
An all out racing engine, sure.

 

[Roger63]

You would be fine with standard rings. File fit can quickly get you into trouble, with very very little if nothing gains.
An all out racing engine, sure.

This was the answer is wanting to see

 

[pnora]

For information sake you could drop them into one bore and see what the gap is. At that point you can decide if you have to do anything.

 

[RemCharger]

Agreed , definitely measure

 

[Roger63]

For information sake you could drop them into one bore and see what the gap is. At that point you can decide if you have to do anything.

Absolutely, I always check the gaps on standard rings anyway. I've have had some in the past that weren't good.

 

[BearDodge67]

I bought file fit once... I have 7 cylinders worth of unfiled rings lying around somewhere..

 

[zyzzyx]

On those heads, If you measure between the bolting face and the head sealing surface on the exhaust
side of the head, you should get at least a 1.000 dimension. Maybe .005 or .010 more if they were never
touched. That'll give you an idea if those heads have ever been messed with and then at that point you
should cc the heads to find out your compression ratio.

 

[33 IMP]

The reason for file fit is to custom tailor the gap to intended use, in case the standard set is too open.
Since any motor I build might get nitrous or boost, standard ring gaps are usually perfect.
My guess is that you won't see a single horsepower difference on a street engine for having "perfect" ring gaps, (and if the gaps are too tight, bad oops can result)
I subscribe to the old axiom. "If you build it too loose, you'll know. If you build it too tight, everybody will know."

 

[Roger63]

The reason for file fit is to custom tailor the gap to intended use, in case the standard set is too open.
Since any motor I build might get nitrous or boost, standard ring gaps are usually perfect.
My guess is that you won't see a single horsepower difference on a street engine for having "perfect" ring gaps, (and if the gaps are too tight, bad oops can result)
I subscribe to the old axiom. "If you build it too loose, you'll know. If you build it too tight, everybody will know."

That's a great analogy.

 

[Kern Dog]

I bought file fit once... I have 7 cylinders worth of unfiled rings lying around somewhere..

I knew that I wasn't the only one that filed and filed...then found that I went too far past the .025 gap !

 

[HawkRod]

I agree that for a standard over engine like a .030 over or .060 over engine just get standard rings and check them.

My 400 stroker is a good example of when you need file to fit rings. I am currently at .042 over with some coatings on the pistons to handle the bore size. But, I need to get the rings right and nothing standard will work. So, I get to file them down (really not hard with the right tool). Plus, then I can tailor them and make the second set of ring gaps slightly larger and as "ideal" as I can make them.

 

[Diodedog]

I knew that I wasn't the only one that filed and filed...then found that I went too far past the .025 gap !

Use the side of a grinding wheel and a small, fine straight cut file to deburr and close the gaps by hand while looking into a light to confirm they're square, then put in cylinder to check, it's tedious but not bad once you've got the hang.

 

[Kern Dog]

Like this?

 

[Diodedog]

Like this?

View attachment 1449081 I use one of these with a 1/2" wheel, bought it new in 74 to do rings.

 

[Kern Dog]

No way.....That takes material off way too fast. I have enough trouble with the hand crank file!

 

[beanhead]

No way.....That takes material off way too fast. I have enough trouble with the hand crank file!

Really? I have no trouble with my hand crank...though wifey seems to have a better feel for the job.

 

[Diodedog]

No way.....That takes material off way too fast. I have enough trouble with the hand crank file!

There are some great tools available now for sure, they weren't available back then and I started working in tool and die shops back in 71 so it was fairly easy for me.

 

[33 IMP]

I made a tool to do my file fit rings. Can't find it at the moment (wanted to take a pic. )
It worked fine, slow and tedious but they got done.
I don't think I'll ever bother with file fit again.

 

[BearDodge67]

Like this?

View attachment 1449081

Yea, that tool don't exist in my tool box.. along with the mag drill for drilling out pilot bushings..