[jayseasBlue56]

someone explain the use of oversized rings on a standard bore and pistons.Also where to buy?
Thanks jim

[cobalt327]

Originally Posted by jayseasBlue56

someone explain the use of oversized rings on a standard bore and pistons.Also where to buy?
Thanks jim

The ring has to fit both the piston and bore- correctly. There's no "oversize" ring for a standard piston or bore. There are 'file to fit' rings, these are made to have the end gaps hand finished for a more precise control over the end gaps. But the ring diameter would still be standard, or whatever oversize the bore is.

[hcompton]

Originally Posted by jayseasBlue56

someone explain the use of oversized rings on a standard bore and pistons.Also where to buy?
Thanks jim

Myth made up buy people thinking it can be done. it can not. the best you can get is file to fit rings. these are a little long and need to be filed to correct clearnce. 4.030 rings will not fit inside the stock 4.00 inch bore correctly even without the piston. Just use the correct sized rings if the rings dont fit you need to bore the block or buy the right rings. best to have it measured up and see if its correct and what size parts you need to buy.

[painted jester]

A practice from years ago instead of being forgotten pops up in this day and age of technology and people talk like its still done today instead of passing into oblivion!!!!! LOL We used to shim rod cap's years ago as common practice!!! Its still done but on antiques and classics that were built with technology of the time! but someone might say "shim your rod cap to get clearance" (on a new 350 G.M.), "I was told its done on them" Wrong its not!!!

We used to have one crank journal turned to .010, .020, etc without pulling the engine out of the vehicle! I think that's obsolete now tooI don't know The guy that did it was "Georges Portable Crank Grinding" in Detroit.

Years ago:
Hupmobile, Ford, and a few others offered rings not available to the public that were a little over sized for standard pistons up to .005" that's bore could be honed but didn't need boring! It was a quick fix! One cylinder without having to pull the engine!and the practice isn't done any more! I don't think they are available (obsolete)! This is out of an old service manual:

Replacement Rings:—Furnished in standard and
.005", and oversize 010", .020", .030" oversize.

An oversize ring even when file cut on a standard piston in a worn oversize bore is apt to break the ring land because it isn't fully in position (deep enough into the ring land) and creates high stress on the land!!! don't try it!

Jester

[cobalt327]

I'd expect a bore worn bad enough that an oversize ring was being considered to have a pretty big ridge at the top of the cylinder. If new rings are installed, the ring's sharp, unworn leading edge will hit the ridge, often breaking the piston or ring.

Just one more reason not to cut corners. I'd suggest you look into some reading material before going any further. The Vizard book on rebuilding the small block is often recommended even though it's pretty old.

[jayseasBlue56]

[quote=cobalt327;1621842]The ring has to fit both the piston and bore- correctly. There's no "oversize" ring for a standard piston or bore. There are 'file to fit' rings, these are made to have the end gaps hand finished for a more precise control over the end gaps. But the ring diameter would still be standard, or whawr

[jayseasBlue56]

I should haved used different wording on my post. , i have a big block chevy at a repital shop, he's straightening the bores,it has a .002 taper, and hone and said i would use oversized file to fit rings. Forged pistons.
I found this past post on this forum.


QUOTE=Super Streeter;27899]On a blueprinted engine,it is common to use .005" overszed rings and file them to fit.This is done because most ringsets are designed to be used with normal passenger car piston to wall clearances.When blueprinting even an out of the box crate motor to be used for racing,the builder will usually hone the cylinders so that the pistons fit real loose,and then the ring end gaps are too large,so slightly oversize rings are used and filed to get
the correct endgap.As you may notice,most perfromace piston rings will come in oversizes suc as .005,or .035",or .065",this is to allow the engine build to file fit the rings,these rings are to be used in either standard{.005},or .030 or .060" overbored cylinders.Good luck.[/QUOTE]

[cobalt327]

Originally Posted by jayseasBlue56

What about this quote.

The bores for a (let's say) 0.035" ring are still going to need to be 0.035"- after honing- , not 0.030".

[hpete]

Ring sets are available .010" oversize. If you have less than .010" taper in your bores and the ring lands are ok in your pistons you can rering a block with standard bores. This is low budget stock replacement stuff not hiperf at all. Also you have to use a glaze breaker hone on the cyl walls, and measure the end gap at the bottom of the cylinders(because their tapered).

[painted jester]

So you have it bored to .030" over and you hone and get a bore Gage reading larger and the ring gap is over tolerance with the rings you got for your pistons. you need a longer circumference ring to close the gap you then order .035" file gap rings and file fit! That is the reason most performance builders use file fit ring packs. For every .001 increase in bore size you get about .003+ increase in ring gap for Hasting rings!

What ever rings you get, you should ask for tech papers they are free, your Jobber can down load them for you! Different manufacturers have different recommendations for their specific designs!!

Your service books for Ford, G.M., etc. give you their specs, don't set aftermarket rings at Auto manufacturers specs they may differ a lot, and you can screw up your build! these specs I'm giving are for Hastings Only as examples and don't cover all Hasting rings either. The different make up of materials and expansion rates change the specs from ring set to ring set manufacturer to manufacturer

Jester

http://www.hastingsmfg.com/Master_Ca...er_Catalog.pdf

From Hastings Tech papers:
The chart below gives the proper oversize rings to install for various oversize cylinders.
CYLINDER BORE DIAMETER........................ USE RING SIZE
Std. to .010" ................................................ST D
.020" to .029" .............................................. .020"
.030" to .039" .............................................. .030"
.040" to .049" .............................................. .040"
.060" to .069" .............................................. .060"
.080" to .089" .............................................. .080"
.100" to .109" .............................................. .100"
.120" to .129" .............................................. .120"


CHECKING COMPRESSION RING GAPS
RECOMMENDED
AUTOMOTIVE COMPRESSION
RING GAP CLEARANCES
Cylinder .............................Ring Gap
bore Diameter............... Ring Gap Tolerance
1.0000" to 2.3624".......... .006 to .014
2.3625" to 2.9524".......... .008 to .016
2.9525" to 3.5424".......... .010 to .020
3.5425" to 4.3299".......... .012 to .022
4.3300" to 5.1174".......... .014 to .026
5.1175" to 5.9049".......... .016 to .030
5.9050" to 6.8899".......... .020 to .035
6.8900" to 8.9999".......... .024 to .041

An important fact to remember is that these tolerances are rigidly adhered to by the manufacturers and that the ring gaps are inspected in gauges accurate to .0001" at the cylinder diameter the ring is manufactured for. Any
increase in the diameter of the cylinder the ring is being used in, over the designated size, results in an increase of approximately .003" in ring gap for each .001" increase in cylinder diameter.

STANDARD BORE TO .010 TAPER USE STANDARD RINGS.

A common practice in racing applications is file fitting piston ring end gaps. Most Hastings Racing Rings are available in file fit (+.005") oversizes. Professional racers and high performance engine builders understand that the exact setting of the ring end gaps by file fitting is beneficial to obtaining the precise engine efficiency desired.
Today’s performance piston designs are moving the top compression ring higher for optimum performance. This creates even higher operating temperatures, therefore requiring a larger top compression ring end gap. Also, improved thermal efficiency of a hypereutectic piston alloy keeps more usable heat in the combustion chamber with less heat moving down through the piston onto the piston skirt and into the oil.



File fit high performance application:
Formula: bore x ring end gap factor = minimum ring end gap.

FUEL APPLICATION RING END GAP FACTOR:

Street Normally Aspirated .0065"
---------------------------------
Drag Fuel and Alcohol .0075"
---------------------------------
Street Nitrous, Supercharged .0080"
Street Towing; Circle Track .0080"
Unrestricted & Alcohol; Marine .0080"

[jayseasBlue56]

Originally Posted by painted jester

So you have it bored to .030" over and you hone and get a bore Gage reading larger and the ring gap is over tolerance with the rings you got for your pistons. you need a longer circumference ring to close the gap you then order .035" file gap rings and file fit! That is the reason most performance builders use file fit ring packs. For every .001 increase in bore size you get about .003+ increase in ring gap for Hasting rings!

What ever rings you get, you should ask for tech papers they are free, your Jobber can down load them for you! Different manufacturers have different recommendations for their specific designs!!

Your service books for Ford, G.M., etc. give you their specs, don't set aftermarket rings at Auto manufacturers specs they may differ a lot, and you can screw up your build! these specs I'm giving are for Hastings Only as examples and don't cover all Hasting rings either. The different make up of materials and expansion rates change the specs from ring set to ring set manufacturer to manufacturer

Jester

http://www.hastingsmfg.com/Master_Ca...er_Catalog.pdf

From Hastings Tech papers:
The chart below gives the proper oversize rings to install for various oversize cylinders.
CYLINDER BORE DIAMETER........................ USE RING SIZE
Std. to .010" ................................................ST D
.020" to .029" .............................................. .020"
.030" to .039" .............................................. .030"
.040" to .049" .............................................. .040"
.060" to .069" .............................................. .060"
.080" to .089" .............................................. .080"
.100" to .109" .............................................. .100"
.120" to .129" .............................................. .120"


CHECKING COMPRESSION RING GAPS
RECOMMENDED
AUTOMOTIVE COMPRESSION
RING GAP CLEARANCES
Cylinder .............................Ring Gap
bore Diameter............... Ring Gap Tolerance
1.0000" to 2.3624".......... .006 to .014
2.3625" to 2.9524".......... .008 to .016
2.9525" to 3.5424".......... .010 to .020
3.5425" to 4.3299".......... .012 to .022
4.3300" to 5.1174".......... .014 to .026
5.1175" to 5.9049".......... .016 to .030
5.9050" to 6.8899".......... .020 to .035
6.8900" to 8.9999".......... .024 to .041

An important fact to remember is that these tolerances are rigidly adhered to by the manufacturers and that the ring gaps are inspected in gauges accurate to .0001" at the cylinder diameter the ring is manufactured for. Any
increase in the diameter of the cylinder the ring is being used in, over the designated size, results in an increase of approximately .003" in ring gap for each .001" increase in cylinder diameter.

STANDARD BORE TO .010 TAPER USE STANDARD RINGS.

A common practice in racing applications is file fitting piston ring end gaps. Most Hastings Racing Rings are available in file fit (+.005") oversizes. Professional racers and high performance engine builders understand that the exact setting of the ring end gaps by file fitting is beneficial to obtaining the precise engine efficiency desired.
Today’s performance piston designs are moving the top compression ring higher for optimum performance. This creates even higher operating temperatures, therefore requiring a larger top compression ring end gap. Also, improved thermal efficiency of a hypereutectic piston alloy keeps more usable heat in the combustion chamber with less heat moving down through the piston onto the piston skirt and into the oil.



File fit high performance application:
Formula: bore x ring end gap factor = minimum ring end gap.

FUEL APPLICATION RING END GAP FACTOR:

Street Normally Aspirated .0065"
---------------------------------
Drag Fuel and Alcohol .0075"
---------------------------------
Street Nitrous, Supercharged .0080"
Street Towing; Circle Track .0080"
Unrestricted & Alcohol; Marine .0080"

Thanks buddy for that info.
Jim

[1971BB427]

This is going way back to 50's and 60's, and it was a poor practice even then! On cheap rebuilds some shops would save and reuse old pistons and sloppy bores by knurling the skirts. They then fitted oversized rings and filed the end gaps to fit the worn cylinders.
Unfortunately this was a temporary fix, as the knurling on the skirts quickly wore, resulting in piston slop and the newly refreshed engine smoking quickly.