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I'm putting together some goodies on an otherwise SBE LS3. The car (C6) will be a DD style street putter car, with the occasional closed course 3rd-4th gear rip on TT's (going to give chinese noisey boys as they call them a shot first, if they don't deliver I'll put some real turbos on it).
ARP rod bolts (I don't think at stock torque specs they will cause a cracked rod to go out of round bad enough to warrant machining), melling oil pump, stage 2 turbo cam 226/230 .6/.59 113+4, some TFS platinum dual springs with ti, some johnson drop in 2110 hydraulics, an ati damper, and pushrods. Planning on re-gapping to .25 and running e85.

I'm thinking on the occasional pull I could run to 7500rpm and not worry about it.

I have all the parts ordered, just waiting to get the rest to bang it out in a couple weekends. If it pops I'm fine with buying a wrecked l92 or putting together a decent iron block, but the engine is low miles and healthy...

Am I missing something obvious? This is the first LS engine I've owned or worked on. Thanks.
 

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.025 gap for upper and not sure on lower. I think I'm most concerned with what gap to actually run.
 

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It will do well. Just don't "tug" on it with a tight converter, be conservative with timing until you're over peak torque. Or the rods won't just be out of round they'll be laying in the oil pan and the ring lands will be bouncing around in the chambers. If the old bearings look ok the rod should be ok, I've always reused the old bolts at factory torque plus angle and never had one fail. On ring gap go + .002 more than the top for the second ring. (.025 top and .027 second)
 

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.025 gap for upper and not sure on lower. I think I'm most concerned with what gap to actually run.
Big gaps don't make power, they make problems. Depending on what ignition and boost level you are going to run I would stay in the .016" - .020" . TF makes 11,000hp with .012" plug gaps. As far as rods, you cannot properly resize a cracked cap rod due to being unable to grind the caps and then hone back to size. I have heard mixed reviews about thread engagement with aftermarket bolts. Guys have turned these SBE engines 8500+ rpm with stock bolts. Best thing to do if you are dead set on ARP bolts is to torque both to spec and have someone check them with a .0001" reading dial bore gauge. Whatever has the least distortion is what I would run.
 

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Big gaps don't make power, they make problems. Depending on what ignition and boost level you are going to run I would stay in the .016" - .020" . TF makes 11,000hp with .012" plug gaps. As far as rods, you cannot properly resize a cracked cap rod due to being unable to grind the caps and then hone back to size. I have heard mixed reviews about thread engagement with aftermarket bolts. Guys have turned these SBE engines 8500+ rpm with stock bolts. Best thing to do if you are dead set on ARP bolts is to torque both to spec and have someone check them with a .0001" reading dial bore gauge. Whatever has the least distortion is what I would run.

He's refering to ring gap not plug gap.
 

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Aggree with nonvtec the cam is whats going to limit your RPM, Unless you want to spin the engine past your peak HP rpm. That cam is going to peak out around 6800 is my guess.
 

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That's a tiny cam and as stated no point in revving the LS3 intake beyond about 7000rpm n/a. Buy some real headers for it that are equal length.... plenty of used ones for sale on corvetteforum.com
 

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He's refering to ring gap not plug gap.
Oops, that's what I get for having too much going on to actually READ what is posted, LOL........ I'm definitely on board with opening up ring gaps. If they ever butt it gets ugly fast. I have seen some big ass ring gaps and never seen them be a problem. Just like my bearing clearance motto, tight works sometimes, loose works everytime.
 

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I think ARP rod bolts on a SBE are a waste of money and time. Has anyone actually seen a LS let go because of the stock bolts?
 

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Discussion Starter #11
Big gaps don't make power, they make problems. Depending on what ignition and boost level you are going to run I would stay in the .016" - .020" . TF makes 11,000hp with .012" plug gaps. As far as rods, you cannot properly resize a cracked cap rod due to being unable to grind the caps and then hone back to size. I have heard mixed reviews about thread engagement with aftermarket bolts. Guys have turned these SBE engines 8500+ rpm with stock bolts. Best thing to do if you are dead set on ARP bolts is to torque both to spec and have someone check them with a .0001" reading dial bore gauge. Whatever has the least distortion is what I would run.
Yeah the oem bolts do seem fine. And thanks for the plug info. I have some of the ngk 3346's and saw a lot of people were running .25-.3 on them and that seemed really high. I'll try out .2 and see how it works.

I actually would have just bought new GM rod bolts, but I couldn't find them on summit. And when I look on google I just get results for all kinds of related stuff. I know btr sells some type of LS rod bolts but no idea about them.

I have no problem returning the ARP's, and I know the rod bolts aren't TTY, but re-using rod bolts just makes me nervous. I bought new GM head bolts (I would be ok with re-using the stockers, I know matt of sloppy has done fine with them), but rod bolts make me a lot more nervous. Especially because I don't know how to check them out (stretch etc).
My idea was that as long as I don't torque the ARP's too far over or under the oem's I shouldn't have issues... I was thinking that the cracked surface should distribute the load of the clamping force better than flat cap. But obviously with different fasteners you have different stretch rates which is tricky and I don't have info about. Matt get's about 50lbs with his angle calculation (and I have a torque wrench that does both angle/lbs etc etc). But at the same time, I obviously don't want to spin a rod bearing because of my own re-assembly choices. And I have no experience with cracked rods, nor doing an ARP rod bolt swap. And I'm certainly not a machinist!

If I measured the stretch of the oem rod bolts (on rod and after), could I use that to look for a final stretch on the ARP? Would that be a good way to install them? I know ARP has their own stretch specs too.

This is why I posted, very helpful info... I appreciate it.
 

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Discussion Starter #12
I think ARP rod bolts on a SBE are a waste of money and time. Has anyone actually seen a LS let go because of the stock bolts?
I don't think they have. And there are plenty of 4.8's SBE un opened running hard rpm and huge power. Both gen 3 and 4. But I also just freak out about re-using the stockers. Do you know of the GM part number for the rod bolts? If I can get those I will.
 

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Oops, that's what I get for having too much going on to actually READ what is posted, LOL........ I'm definitely on board with opening up ring gaps. If they ever butt it gets ugly fast. I have seen some big ass ring gaps and never seen them be a problem. Just like my bearing clearance motto, tight works sometimes, loose works everytime.
Hahahaha exactly. Maybe stock rings will work, but we all know you always want to crank the boost controller... not worth the gamble then!
 

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That's a tiny cam and as stated no point in revving the LS3 intake beyond about 7000rpm n/a. Buy some real headers for it that are equal length.... plenty of used ones for sale on corvetteforum.com
It's going to be a twin billet 7268 turbo car
 

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Discussion Starter #15
Your cam won't be good to 7500. You won't see an advantage about 7200..
I'll probably pick up a china short runner manifold and ramp the boost up at the top end. I want the power curve to help the rods live, so my goal is to mechanically insure I'm safe for the rpm. If I need I'll get a bigger cam down the road with a nice converter. I had an import so the idea of making power with boost only, as late as possible to save the rods, is something I'm used to.
 

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It will do well. Just don't "tug" on it with a tight converter, be conservative with timing until you're over peak torque. Or the rods won't just be out of round they'll be laying in the oil pan and the ring lands will be bouncing around in the chambers. If the old bearings look ok the rod should be ok, I've always reused the old bolts at factory torque plus angle and never had one fail. On ring gap go + .002 more than the top for the second ring. (.025 top and .027 second)
Do you check for a certain stretch after the rod bolts come out? I'm just worried about them. I know they're not TTY but you know how it is. First time on this engine, want to do it correctly.
I will run a stock converter for now, until I pull the trans to build it. Don't have access to a lift for now so... But I'll have to put that at the top of the list.

Perfect, thank you for your recommendations on the rings. I will do just that. .025 and .027
 

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Iv never checked stretch on a stock bolt. Just do the 15 ft lbs + 85 degrees if I remember right. IF your set on the ARP rod bolts you need to have the rods resized. And use a larger OD rod bearing. I’ve ran sbe 5.3s for 5 years in a boosted drag car at 900+hp broke a lot of rods and pistons never has a rod bolt been an issue. Tuning errors and or tugging broke every one.
As mentioned on bearings, rings, and bearings. A little loose you know to tight everybody will know.


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Iv never checked stretch on a stock bolt. Just do the 15 ft lbs + 85 degrees if I remember right. IF your set on the ARP rod bolts you need to have the rods resized. And use a larger OD rod bearing. I’ve ran sbe 5.3s for 5 years in a boosted drag car at 900+hp broke a lot of rods and pistons never has a rod bolt been an issue. Tuning errors and or tugging broke every one.
As mentioned on bearings, rings, and bearings. A little loose you know to tight everybody will know.


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Alright that's it I'm sending the ARP's back and running the stockers! Thanks again, I appreciate the insight.


Do you have any videos of your cars? I love checking out these builds.
 

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The factory torque + angle method doesn't work on used bolts. You will possibly stretch them too far. Reuse the rod bolts and just torque them in 3 stages.... 15..35..52 ft/lbs final.

Specs for reusing oem main bolts:

Start with the inner bolts first.. torque them in 3 stages.. ending up with 65lbft.
Then torque the outers In sequence to 55lb ft.

Inners.. 25..45..65 ft/lbs
Outers.. 15..35..55 ft/lbs
 

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you better open up them ring gaps more..if i was you id be more around 28 top an 30 2nd depending on boost an fuel..rule of thumb i use is .0055 x bore on a n/a car an boosted /nitrous is .007 x bore..

your better off having a little extra gap vs not enough..not enough means butted rings an piston crown removal..not what you want

as for rod bolts i do same as launch for tq specs with a stock bolt,arp i go to the 45#s..ive seen rod bolt failure,seems to happen alot of times to people who pull them apart though vs just untouched,the rod will fail first 90% of the time..as for arp rod bolts an resizing..that debates been going for yrs,plenty run arps with no issue an never resized the rod an some do..its really a matter of opinion..search on google, yellowbullet ls arp rod bolts an thread will come up on it..

a stock ls3 intake tends to fall of around 6600 n/a an when ported an rod modded they go about 200 more rpms..that cam aint going to 7500,prob stop carring power around 7k with boost like has already mentioned..prob peak like 6600.
 
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