Piston ring end gap
10-22-2015, 03:53 PM
#1
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Thread Starter
Piston ring end gap
I posted a question on ring end gap setting in 1997-2004 F150forum (https://www.f150forum.com/f6/1997-f150-4-2l-engine-rebuild-307595/index2/). As I have not received any response I try here.
The long story short:
- Currently rebuilding my 4.2L V6, NA stock configuration, not a power build.
- The factory manual recommends 0.17-0.33mm (0.006-0.012inch) for top compression ring and 0.3-0.55mm (0.011-0.021inch) for second compression/scraper ring
- Currently measuring ~0.5mm end gap on top compression ring with 0.5mm over ring kit
- Ordered new rings for +0.75mm over bore and plan to file and set ring gap
Sealed power piston (H850CP50MM), sealed power ring (911K).
Questions:
Does anybody has recommendation of what should I target min,max, middle of factory setting?
My initial thought is to target 0.33mm/upper end of the range as blow-by is less of a problem than ring butting and scuffing.
Does anyone have experience targeting the lower end of range(0.17mm – 0.006inch)?
Thanks
The long story short:
- Currently rebuilding my 4.2L V6, NA stock configuration, not a power build.
- The factory manual recommends 0.17-0.33mm (0.006-0.012inch) for top compression ring and 0.3-0.55mm (0.011-0.021inch) for second compression/scraper ring
- Currently measuring ~0.5mm end gap on top compression ring with 0.5mm over ring kit
- Ordered new rings for +0.75mm over bore and plan to file and set ring gap
Sealed power piston (H850CP50MM), sealed power ring (911K).
Questions:
Does anybody has recommendation of what should I target min,max, middle of factory setting?
My initial thought is to target 0.33mm/upper end of the range as blow-by is less of a problem than ring butting and scuffing.
Does anyone have experience targeting the lower end of range(0.17mm – 0.006inch)?
Thanks
Last edited by bzoli; 10-22-2015 at 11:35 PM.
