File fit rings.

[adk-roadrunner]

So I was talking to my machinist who is boreing my 440 block about the pistons and rings I'm ordering for my build. I told him the rings that were suggested by summit for the speed pro pistons were speed pro Moly file fit rings and he suggested I stay away from file fit rings as he only uses them on the race engines he builds and I'm better off to just buy rings matched to the 4.350 overbore I'm going with. I'm going to call speed pro and see what they suggest but wanted to see what you guys thought about this thanks.

 

[RustyRatRod]

Nuthin wrong with file fit rings. I like to file fit most anything. Who says your machine shop boy is gonna be perfect? Who says the rings will be perfect? We're talkin about hundred thousandths on an inch here. Machining tolerances on parts ain't what it used to be, specially with the influx of all the chinkesium in the last 20 years. I want my rings to be jam up and jelly tight, so I file fit all my stuff.

 

[adk-roadrunner]

Ya that's how I feel I guess I just wanted to hear someone else say it. The only thing I can think is he doesn't want to file fit the rings. I guess what I want should be important lol and that's what I would like for my build.

 

[64 Post]

File fit.

He's going to charge you by the hour anyway so it's not like he's going to eat the time to file fit.

Oh, and he should know about "breaking" the edges after filing the rings but you might want to ask.

 

[adk-roadrunner]

Right and I have no problem paying someone to do the work they do for me.

 

[benno440]

chinkesium hahhahaha

 

[67 B-body]

It's easy to file fit rings,,, Plus you can set the gaps depending on the application.... Nitrous , turbo, supercharged engines require different ring gaps.
I used Hastings file fit rings in my engine.... I do all my own work, so I don't have to "trust" and "engine builder" with these items....

 

[MikeStahl]

thinking machine shop boy likes out of the box and throw it together rings

 

[bigmanjbmopar]

I used totalseal rings filed them myself bought the ring filer from summit fealer gauge all you need makes quick work of it 16 times over and can be fun ig you have man cave lol escape tje wife and kids for few.

 

[adk-roadrunner]

Ya I've always used them never done it myself but I'm sure I could if he doesn't wanna lol I think he is getting busy and thats the problem he builds race engines all winter and seems to be getting slammed.

 

[rev.ronnie]

Your machinist is right, for the most part..

The biggest benefit of file-fit rings is that they often are the only way to get low tension oil rings without getting a custom set. Running standard tension 3 piece oil rings only gives away horsepower. The OEMs have been using low tension oil rings for years...I have not used a standard tension oil ring in years, other than on blower engines.

I usually order my ring sets from Total Seal in non file fit sizes, but with low tension oil rings. The top two rings are always too tight and need some attention anyway, plus it reduces filing time. File fit rings are good for engines that have had the bores honed a few times for freshening and are a little loose.

This is the case with most rings I see. Look at your piston recommendations...they may want .0045"/bore inch on the top ring and .0055"/bore inch on the second ring. The standard gap rings will most always be tighter than that. don't be afraid to run the gap on the loose side on a street engine. It's cheap insurance and it will not cost you any horsepower.

I recently had a Dyno shop customer with a BBC that was down 40+ hp after freshening. The guy set his gaps at .028" on the top ring. They pulled the pistons on the Dyno and opened them up to .050" and the power came right back up. Some pistons with high ring lands are now over .060" on the gap!

Anyway, I only actually assemble 40-60 engines a year, but this is what I've seen when it comes to ring gaps on standard sets.

 

[bigmanjbmopar]

I recently had a Dyno shop customer with a BBC that was down 40+ hp after freshening.

Ut oh he said the cheby word and used it in a sentence! :busted:

 

[Grabinov911]

Hey Rev,

You mention that a bigger ring gap is "cheap insurance". I'm learning my way with the other guys. Cheap insurance against what?

I assume a bigger gap means a slightly looser seal of the piston in the bore. This means a little more oil and air (little, like tiny, in a good way) get by the rings, meaning slightly lower compression and better lubrication. Yeah? Just an engineer's guess...

Greg

 

[RustyRatRod]

Cheap insurance against the ring ends butting together as they heat up. I stick by whatever the piston manufacturer recommends. Always works good for me.

 

[onephat66]

Ut oh he said the cheby word and used it in a sentence! :busted:

Actually he said "BBC", not cheby!! Just as bad though.

 

[Cranky]

It depends on what I'm doing with the engine and how hard I'm going to push it.......and it really doesn't matter what brand of engine we're dealing with because the ring man's have their tolerances for a certain bore size. The ring has no idea if it's in a Chevy or whatever. I have to laugh when people say they have Chevy bearings in their Mopar with an offset ground 440 crank.

 

[rev.ronnie]

Ut oh he said the cheby word and used it in a sentence! :busted:

I have 5 or 6 big block Chevys, and only 3 Big Block Mopars. I need to work on that.

- - - Updated - - -

Hey Rev,

You mention that a bigger ring gap is "cheap insurance". I'm learning my way with the other guys. Cheap insurance against what?

I assume a bigger gap means a slightly looser seal of the piston in the bore. This means a little more oil and air (little, like tiny, in a good way) get by the rings, meaning slightly lower compression and better lubrication. Yeah? Just an engineer's guess...

Greg

Yes, to keep them from butting in extreme conditions. You won't see a compression loss with a slightly larger ring gap. The grooves stay a bit cleaner though.

- - - Updated - - -

It depends on what I'm doing with the engine and how hard I'm going to push it.......and it really doesn't matter what brand of engine we're dealing with because the ring man's have their tolerances for a certain bore size. The ring has no idea if it's in a Chevy or whatever. I have to laugh when people say they have Chevy bearings in their Mopar with an offset ground 440 crank.

This may freak some of you guys out, but the New Century aluminum block (formerly Arias) for a Big Block Mopar actually uses a Big Block Chevy crank. The deck is just machined for the different head. I have used them for Oldsmobiles too. They all use BBC bearings. The rear main is way stronger.

I only use cranks cut for Chevy type rods in the race Mopars. Most are only offered that way.

A ring only knows what piston it's on, and what the bore material is.

 

[68 HEMI GTS]

yes the file fit moly rings will be fine. set them to piston manufactures specs. alot of times even out of the box "pre-fit" rings need to be filed. i read some of the **** on these forums and it makes me want to bang my head on the floor. this is basic ****. & get a new machinist cause it sounds like yours has his head in his ***... and stay with standard tension oil rings with your application

 

[rev.ronnie]

yes the file fit moly rings will be fine. set them to piston manufactures specs. alot of times even out of the box "pre-fit" rings need to be filed. i read some of the **** on these forums and it makes me want to bang my head on the floor. this is basic ****. & get a new machinist cause it sounds like yours has his head in his ***... and stay with standard tension oil rings with your application

I read that people still use standard tension oil rings and it makes me want to bang my head on the floor.

To each his own I guess. With all due respect, I don't think you have anywhere near enough information to determine that his machinest has his "head in his ***".

In my 25+ years of machining, building engines professionally, and owning my own business,
I have grown to accept that when I offer my opinion on something, based on decades of success, there will always be someone who believes the opposite. I am perfectly fine with that.

- - - Updated - - -

It is also worth elaborating on end-gaps regarding the top ring. There is more at play than some people realize. When you are dealing with a ring that is perhaps .043" or even .028" thick, like in some Super Stock engines, ring gap becomes critical to sealing. This is especially true with back-cut rings with little radial tension.
The ring needs the back pressure that is accumulated through the gap to put pressure behind the land and assist sealing. This is most important on a piston with no gas ports. This is why the engine I referenced that had the tight gaps experienced a HP loss. If there isn't a constant, metered flow of air through the ring package, oil intrusion can lead to build up in the ring land as well, that is caused by combustion gasses "cooking" the oil to the piston.

Don't forget that the top ring of the 3 piece oil ring needs to be a little wider to allow the gas pressure spikes from the second ring to escape through to get to the oil return holes in the third groove.

Food for thought; The outboard motor on my drag boat has .020" gap on the rings and they are in line with each other on a common pin that is installed through the top of the piston into both ring lands. It is a 9000+ rpm two stroke engine that maintains less than 2% leakdown when tested cold.

 

[68 HEMI GTS]

I read that people still use standard tension oil rings and it makes me want to bang my head on the floor.

To each his own I guess. With all due respect, I don't think you have anywhere near enough information to determine that his machinest has his "head in his ***".

In my 25+ years of machining, building engines professionally, and owning my own business,
I have grown to accept that when I offer my opinion on something, based on decades of success, there will always be someone who believes the opposite. I am perfectly fine with that.

- - - Updated - - -

It is also worth elaborating on end-gaps regarding the top ring. There is more at play than some people realize. When you are dealing with a ring that is perhaps .043" or even .028" thick, like in some Super Stock engines, ring gap becomes critical to sealing. This is especially true with back-cut rings with little radial tension.
The ring needs the back pressure that is accumulated through the gap to put pressure behind the land and assist sealing. This is most important on a piston with no gas ports. This is why the engine I referenced that had the tight gaps experienced a HP loss. If there isn't a constant, metered flow of air through the ring package, oil intrusion can lead to build up in the ring land as well, that is caused by combustion gasses "cooking" the oil to the piston.

Don't forget that the top ring of the 3 piece oil ring needs to be a little wider to allow the gas pressure spikes from the second ring to escape through to get to the oil return holes in the third groove.

Food for thought; The outboard motor on my drag boat has .020" gap on the rings and they are in line with each other on a common pin that is installed through the top of the piston into both ring lands. It is a 9000+ rpm two stroke engine that maintains less than 2% leakdown when tested cold.

too each his own, your not the only experienced machinist/engine builder on this board. he asked a simple question, will file fit moly rings work in my 440, i get the impression this is a mild street engine. the answer is yes they will work!!! what do blown big block chevys and 9000rpm boat motors have to do with what he asked???