Piston Ring End Gap & Conrod Positioning

[Alcyone]

Might check the big ends with the dial bore gauge too. Hadn't thought of them being OOR. Will also check the crank for OOR but I'm not sure how to do that now that it's been linished. Is it bad to place a set of outside micrometers on the cranks rod journals or is there another way to do it?

 

[Alcyone]

Still no closer to figuring this out I checked the end gaps with the 2nd compression ring with it right down the bottom of the bore and got pretty much the same results. 0.45mm to 0.48mm. Only bit of info I could gleam from the Hastings site was to use the;
3.8" x 0.0035 = 0.0133" (0.33782cm) ...but... why on earth does the Haynes manual want it in between 0.762mm and 1.016mm? (about double the end gap of the 1st compression ring). I know you said to disregard the specs in the manual when using aftermarket rings but should I widen them at all or just let them be?
Someone out there must have come across this before. These are the standard Hastings rings to suit V6 3.8 Ecotec. There is no information in regards to end gaps which comes in the kit so the only thing I can do is to follow what Immortality and EYY said in regards to the calculation.
I did more research and it is recommended to have the 2nd ring gap slightly larger than the 1st compression ring gap so what Immortality said there is spot on. But how much larger should it be?
Feeling like such a wally right now because I never expected to have to adjust anything with the rings. I thought all the info would have just come in the ring kit and that it would all be within spec right out of the box as the cylinders weren't even bored.

 

[EYY]

Forget the haynes manual. Follow the Hastings instructions and measurements and throw it back together. With years and years of wear, the bores will on the looser side of the tolerances anyway.

Hastings is saying that the MINIMUM ring end gap is .34mm and you have .45mm, so you're good to go. The factory specs are probably something to do with low tension rings to increase economy etc (think back to the problems of the LS1's in the VT/early VX commodores). The second ring doesn't really do much at all anyway. The second ring's there to help stabilise the piston (stops it from rocking in the bore), prevents blowby, helps a little with compression and assists in scraping oil. In some engines, its not uncommon to discard the second ring (think dirtbikes etc).

 

[Alcyone]

Forget the haynes manual. Follow the Hastings instructions and measurements and throw it back together. With years and years of wear, the bores will on the looser side of the tolerances anyway.

Hastings is saying that the MINIMUM ring end gap is .34mm and you have .45mm, so you're good to go. The factory specs are probably something to do with low tension rings to increase economy etc (think back to the problems of the LS1's in the VT/early VX commodores). The second ring doesn't really do much at all anyway. The second ring's there to help stabilise the piston (stops it from rocking in the bore), prevents blowby, helps a little with compression and assists in scraping oil. In some engines, its not uncommon to discard the second ring (think dirtbikes etc).

Cool! Thank you so much EYY. Haynes manual is forgotten I'll go start checking my side clearances and then put the rings on the pistons. My mind is back at ease!