Been in contact with my local s.s and they are uncomfortable selling me a set of rings...apparently they want me to take them to my machinist to have them get rings??? senond i want to replace the rod bolts with arp quality...again my s.s told me i would have to have them reworked again for them...any help is appreciated.

 

Rod bolts are pointless to do on the floating gen 4 rods.

As far as rings, just order some stock replacement rings online somewhere and stop dealing with them.

 

I agree if you aren't turning over 7K. Past that, I think there is a certain area where a stock rod can live but might benefit from stronger bolts. FYI, if you go that route, it's only about $100 to have a shop resize them +.002. Lot of debate on the subject but I decided it was worth the peace of mind.

I got the Mahle replacements for my LS2 of RockAuto for a steal and checked them..gap was nice right out of the box. Perfect for any normal-ish build.

 

Someone just ran 7s on a stock bottom end 5.3 with stock rod bolts, shifting north of 8k.

I think the rod bolt myth needs to die eventually...

 

That's impressive. It occurs to me that the 5.3 is likely the lightest factory piston. The higher bores do increase in weight and stress on the rod bolts. Anything to that? When something fails at 8K RPM plus, is it the rod bolts or something else?

Also is there a thread I can check out on that 5.3? Sounds sweet.

 

https://ls1tech.com/forums/forced-in...ill-going.html

Over 50 passes. Engine teardown pics are in there somewhere. Engine still looks brand new, so he's going to try to go faster.

Shifting at 8100 on stock rod bolts.

 

That's really impressive. I wonder how much of this is a) engine built on a Wednesday and b) lighter weight of the 5.3 pistons paired with the same rod bolts that sling up to 4.065" slugs? I'm by far not a mechanical engineer but I'll do some simple math to at least illustrate the concern:

4" bore(6.0/LQ4) - 3.78" bore(5.3) = .22" difference. So the LQ4 in question here only increases 5.82% in diameter..but all on the outside.

4" piston surface area is about 12.566" and the 3.78" piston about 11.222."

This is about a 1.344" sq increase or about 11.97% increase in piston surface area.

There are probably all kinds of other microfactors I am not aware of like the fact that more of the weight is farther away from the center of the piston/rod and stuff like that.

Now the math is much more complex than I know for the stress on the rod bolts related to RPM and weight but even looking at it very simply-- 8100RPM - 12% = 7128RPM.

I think RPM(well; also stroke but we aren't changing that here) is really the primary player here and power doesn't matter nearly as much. I say that because the power stroke is absorbed by the crank journal and the rod bolts come into play once we are stopping and snatching the piston back down the bore...right?

LS3(4.065 bore) is 1.75" sq increase or 15.649% increase in piston weight.

So perhaps is there a case for stronger rod bolts with larger heavier pistons of a 6.0+ engine and 7K+ RPM?

 

There is a major flaw in your math.
You didn't factor in rod or wrist pin weight.

Lets assume you are correct and the pistons are proportional in weight based on diameter.

Stock 5.3 piston weight: 404 grams.
Stock 5.3/6.0 floating rod weight: 646 grams.
Stock wrist pin weight: 149 grams.
Stock 5.3 total weight: 1199 grams.
-----------------------------------------------------------------------
Stock 6.0 piston weight (based on 12% increase): 452 grams.
Stock 5.3/6.0 floating rod weight: 646 grams.
Stock wrist pin weight: 149 grams.
Stock 6.0 total weight: 1247 grams.

6.0 assembly/5.3 assembly ratio: 1.04%
8100 RPM/1.04 = 7788 RPM.

Rod bolt theory still busted.

 

Ah good point! I will reply in the other thread I see you also found. More convo there.

 

The difference in ring weight might fetch you another .5%.
The larger 6.2 pistons will probably lose another couple hundred RPM, I just don't feel like the math is necessary at this point lol.