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Discussion Starter #1
I am trying to find out what the proper ring gaps for the 425 Olds are. Any and all information would be greatly appreciated.

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Depends on type of rings and type of piston. What the intended use of the motor is going to be. end gaps for top ring can be from .016-.035"
 

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Discussion Starter #3
info.on ring gaps

They are cast aluminum flat top pistons. Stock for the 425. A stock ring replacement kit. The motor is a 350 block bored to fit the 425 piston. Block has been decked .010 and the heads have been shaved. This motor is being used in a dirt track race car (pure stock division) at the local race track. Max rpm is 4500 to 5000 at any given time on the track.

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Information on Ring Gapp's

Yeah You need a chart . Usuall here is So many thousandth's Per Diameter in. Of Bore .

If Im sayin this Right ? Basically If it is .004 Too .007 Thousandths per inch Diameter of Bore a 4 Inch bore would Be 4 Times 7 >>> .028 Thous . Or .004 Times 4 in >> Would be .016 Thousandths So Then it would be a ring Gap of .016 Too .028 << Theorehtically speakin .

You need a Chart On Acceptable Ring Gap Thousandth's measurement's per Diameter Inches of Bore . Per type of ring used , In what type of Motor !

My book show's 4.126 As the bore in a 1971 455 Olds So 4.126 Times what ever the reccomended ring gap measurement is per inch diameter of cylinder .

Ifn memory serve's me I think it's .003 too .004 thous << Not sure on this ?

But your Ring's should have some instruction's Stateing , how many thousandths per inch diameter of the cylinder it is. If it's .004 ? Then .004 times Cylinder Diameter of >> 4.1 Inches = ???? << Roughly .016 too .017 Thousandths ring Gapp .

Better too Error on too large of a ring gapp . Than too small .
Too small will definately break a ring !

Too file ring gapp's . I use a Fine metal File in a Vise !
Push the ring gapp together on the File and Push or File too the Inside <<, Meaning dont dragg the Ring across the file . << This would be fileing too the out side , Definately De Burr, the Ring Gapp, after fileing ?

Also be aware that piston ring's come in different thicknesses <<, Per, different type's of Piston's . A 71 455Cu in. Might use Different thickness ring's than say a 69 Or 72 Piston.

check your side clearances per spec's on your top ring . << Make sure your usin right Thickness ring . Along with Proper side clearance << Between Ring and ring groove ,, Usually .005 too .006 thous. <, Just slide a feeler gauge in between Ring and top of the Groove . Too get this measurement .

Piston Groove depth's <<, Also need too check them . Best too compare new ring's with old Rings Most Ring depth's are standard in factory application's . But Be aware ring groove depth's can and do Vary Dependin on Application and Aftermarket Application's , usually with aftermarket Piston's .

Question ? Is the use of aftermarket Total seal ring's Considerd Cheating :D ? ??? :D

Anything you dont understand Post again I can break out some more Manual's Etc. Get exact Measurement's or tolerances ? Think I have another Manual covering 455 Old's .

But be aware Different style rings . May need Different Ring Gapp measurement's / Box Ring's Are typically used on new Bore's while a Tapperd or Beveled ring is typically sold as a replacement ring for use in a refurbished Bore .

Typically a Beveled ring is sold as the replacement ring, for a Rebuild . They tend too be more forgiving in Cylinders that have been Honed ?

Re - Ringin is Kinda an art ! Can be Pretty complicated ! But Slow down get it right ! Figure it out ! Your Sett of ring's should have come with Instruction's ? << should have the Spec's for Ring gapp in it ? >> So many Thousandth's of ring Gapp per inch diameter of Cylinder .

Sean
 

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kkc65p said:
They are cast aluminum flat top pistons. Stock for the 425. A stock ring replacement kit. The motor is a 350 block bored to fit the 425 piston. Block has been decked .010 and the heads have been shaved. This motor is being used in a dirt track race car (pure stock division) at the local race track. Max rpm is 4500 to 5000 at any given time on the track.

Thanks
If your finished bore is right for the pistons you have and your rings are not file fit I think you would have no problem with sticking them in the way they are.
 

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.016 for the top and .012 for the second and you'll be fine, some say wider second gaps are better to keep the top ring seated but tests have shown the benifits happen only at higher rpm 7K+. Wide top ring and second gaps tend to pollute your oil much faster than tighter gaps from what I've seen.
 

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Discussion Starter #7
info on ring gap

Thank you all for the information. I will be trying it all as soon as it warms up a bit outside. I have a "tent" (one of them portable garages) that I am using for a shop.
:thumbup:
 
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