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Registered
Join Date: Sep 2002
Location: Spokane, WA
Posts: 22
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reusing rings?
Refurbishing my 3.2L and I'd like to know if I need to have the cylinders honed and can I reuse my rings or should I use new ones. The cylinders and rings seem to be in great shape with the cross hatch pattern still visible in the cylinder walls but after removing the pistons I'm not sure if the rings will seat again without honing the cylinders and if I do have to hone them do I need new rings?
Thanks, Pete |
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up-fixing der car(ma)
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With 3.2 cylinders, don't hone; empirical data says that honing Nikasil cylinders will make them far too rough, and will cause the rings to wear out again prematurely. I wash them very very well with dish soap and water and get them absolutely sparkling.
Get new rings . Check and make sure your parts are w/in specifications, too. Best Scott
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Scott Kinder kindersport @ gmail.com |
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Registered
Join Date: May 2003
Posts: 3,346
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I reused the rings on the last 3 engines I've rebuilt. I almost put new rings in the last engine but the new Goetz rings had a bigger end gap than my old rings!
Measure the end gaps and side clearance on your old rings and put them back on the same pistons the left if they are within spec. I've found my old rings on the last rebuild had end gaps of about .018 inches and the new Goetz rings had end gaps of .020 inches. The wear limit is .030 inches (I think this is right...I don't have my books infront of me). The old rings will work just fine and you don't have to worry about if they will seat or not. Of course if your old rings are worn out replace them. I also wouldn't hone the cylinders. -Andy
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72 Carrera RS replica, Spec 911 racer |
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Warren Hall Student
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I'm with Andy on this one. If the rings are within spec re-use them. Just make sure you don't mix them up. Having to break in new rings would seem to add un-needed wear on the cylinders.
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Bobby _____In memoriam_____ Warren Hall 1950 - 2008 _____"Early_S_Man"_____ |
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Registered
Join Date: Sep 2002
Location: Spokane, WA
Posts: 22
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Thanks Scott, Andy and Bobby. I appreciate your contributions into helping me make the right decisions in what to do with my cylinders and rings. I'm glad I don't have to hone the cylinders. I've about scraped the money pit to bare bones on this thing, and still have plenty more things I need to buy to finish it.
Have a great day Gentlemen. |
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Registered
Join Date: Nov 2000
Location: Dallas
Posts: 3,575
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Sorry to resurrect an old thread but I have to ask...why is it critical to keep the rings with the same piston/cylinder? I guess it's more of an academic question since mine ('88 3.2 160k)are all mixed up now and I'd been told in another thread that reusing rings should not be done. It seems to me if they are in spec they'd work, but maybe there is something that happens to the external part that moves against the cylinder walls that gets changed at a metalurgical (sp?) level which makes reusing them problematic...just guessing here. I'm finding out in this rebuild process that there is a LOT of room for opinion and often no "one best way" to do things....just see the sealant thread! LOL!
BTW...I had my p/c measured and they all came back in spec
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Buck '88 Coupe, '87 Cab, '88 535i sold, '19 GLC 300 DD Warren Hall, gone but not forgotten Last edited by 88911coupe; 08-22-2008 at 09:13 AM.. Reason: clarification |
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Max Sluiter
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I think it is because of the individual wear pattern for each piston/cylinder/ring assembly. If you disturb it, there will be accelerated wear while the new arrangement establishes a new equilibrium.
More oil is burned and some power is lost. More wear on the parts, which if the rings are old, may cause them to wear down below spec, necessitating changing the rings and res-starting the bedding-in process.
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1971 911S, 2.7RS spec MFI engine, suspension mods, lightened Suspension by Rebel Racing, Serviced by TLG Auto, Brakes by PMB Performance |
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