How strong are the stock Rods?
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Staging Lane
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How strong are the stock Rods? Connecting rods, I always heard that the stock rods are not good for Forced induction motors, but someone told me here locally that stock ls1 rods are good for up to 1100 hp, and while no one has ever done that he has seen 800hp with absolutely no problems, now I know the cranks are strong but is this true about the rods? FYI I am doing a Twin Turbo setup and I plan on peaking around 6500.
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Re: How strong are the stock Rods? well, i hate to tell ya but you're friend has been lost in never never land. <img border="0" alt="[judgement]" title="" src="graemlins/gr_judge.gif" /> you might let him know that the powdered metal connecting rods in the LSX series motors are pretty much crap. i've seen them break and ventilate the block in completely stock motors. and in numerous six liter blocks too. but then again, some are standing up to h/c cars w/ spray but for how long? the skinny is, if you're planning on boosting it, just buy the right guts first, and only cry once.
<small>[ April 14, 2003, 04:06 PM: Message edited by: VentsWoker ]</small>
<small>[ April 14, 2003, 04:06 PM: Message edited by: VentsWoker ]</small>
Re: How strong are the stock Rods? Nicely put
With a twin turbo set-up, rods are the least of your problems. Also make sure your oiling system is up to the task and fuel system too. Rods can be had for pretty cheap. A good rod that a lot like to run are the eagle rods, the you have the lunati stuff that can take almost anything you can throw at it. and then if you want the best go with a set of oliver rods, but theyre over the 1000 mark while the lunati rods will run about 700 and the eagles around 600 <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />
With a twin turbo set-up, rods are the least of your problems. Also make sure your oiling system is up to the task and fuel system too. Rods can be had for pretty cheap. A good rod that a lot like to run are the eagle rods, the you have the lunati stuff that can take almost anything you can throw at it. and then if you want the best go with a set of oliver rods, but theyre over the 1000 mark while the lunati rods will run about 700 and the eagles around 600 <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />
Re: How strong are the stock Rods? The stock rods are underrated. Their weakness is the rod bolts. Also boost is easy on rods because majority of the added stress is on compressing the rods. All rods are stronger in compression vs. tension. Rods usually fail when the tensile loads are too great, which comes from too much rpms.
Re: How strong are the stock Rods? Ive seen some stupid jets put on the juice in stock rod cars. Seems to survive. RPM on the other hand is what is killing a majority of the rods around here, and thats bolt failures.
My stock rods ventilated my last block...or is that "vacated" <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> Bolt failure from what I could tell. (kinda a mess)
I am having my 387 all-bore built with stock rods, but nice rod bolts. I dont plan to go over 64-6500 though.
chris
My stock rods ventilated my last block...or is that "vacated" <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> Bolt failure from what I could tell. (kinda a mess)
I am having my 387 all-bore built with stock rods, but nice rod bolts. I dont plan to go over 64-6500 though.
chris
Re: How strong are the stock Rods? oh, I also agree that on the boost, turbo motors are pretty soft on rods. Remember the 60 deg. buick rods may be long, but they werent all that, and they were handling 600 hp regularly with mid-80s technology. Then again...those are rather low rpm motors.
chris
chris
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Re: How strong are the stock Rods? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Their weakness is the rod bolts</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">
normally i would tend to agree with you Dug however, the ones i've seen have broken or sheared off just above the big end of the rod. and this was in a completely stock, non nitrous use motor. call me crazy but i just cant see using stock rods again in anything over a planned 450 RWHP application, and that is pushing it. yeah that is pretty good for a street engine and for those power levels, and granted, they are holding up but, for how long? however, planned n2o or boost while using a factory rod is asking for trouble. unless you just like learning the hard way <img border="0" alt="[bang head]" title="" src="graemlins/gr_banghead.gif" /> but thats just my opinion cause i tend to lean towards the reliablity side of the equasion. <img border="0" alt="[burn out]" title="" src="graemlins/gr_burnout.gif" />
normally i would tend to agree with you Dug however, the ones i've seen have broken or sheared off just above the big end of the rod. and this was in a completely stock, non nitrous use motor. call me crazy but i just cant see using stock rods again in anything over a planned 450 RWHP application, and that is pushing it. yeah that is pretty good for a street engine and for those power levels, and granted, they are holding up but, for how long? however, planned n2o or boost while using a factory rod is asking for trouble. unless you just like learning the hard way <img border="0" alt="[bang head]" title="" src="graemlins/gr_banghead.gif" /> but thats just my opinion cause i tend to lean towards the reliablity side of the equasion. <img border="0" alt="[burn out]" title="" src="graemlins/gr_burnout.gif" />
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Re: How strong are the stock Rods? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by VentsWoker:
<strong> </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Their weakness is the rod bolts</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">
normally i would tend to agree with you Dug however, the ones i've seen have broken or sheared off just above the big end of the rod. and this was in a completely stock, non nitrous use motor. call me crazy but i just cant see using stock rods again in anything over a planned 450 RWHP application, and that is pushing it. yeah that is pretty good for a street engine and for those power levels, and granted, they are holding up but, for how long? however, planned n2o or boost while using a factory rod is asking for trouble. unless you just like learning the hard way <img border="0" alt="[bang head]" title="" src="graemlins/gr_banghead.gif" /> but thats just my opinion cause i tend to lean towards the reliablity side of the equasion. <img border="0" alt="[burn out]" title="" src="graemlins/gr_burnout.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Bad oiling system can cause that though....seize that rod bearing at high rpm and see what gives first <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
Majority of the failures I have seen seem to result of a rod bolt failure or oiling failure
<strong> </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Their weakness is the rod bolts</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">
normally i would tend to agree with you Dug however, the ones i've seen have broken or sheared off just above the big end of the rod. and this was in a completely stock, non nitrous use motor. call me crazy but i just cant see using stock rods again in anything over a planned 450 RWHP application, and that is pushing it. yeah that is pretty good for a street engine and for those power levels, and granted, they are holding up but, for how long? however, planned n2o or boost while using a factory rod is asking for trouble. unless you just like learning the hard way <img border="0" alt="[bang head]" title="" src="graemlins/gr_banghead.gif" /> but thats just my opinion cause i tend to lean towards the reliablity side of the equasion. <img border="0" alt="[burn out]" title="" src="graemlins/gr_burnout.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Bad oiling system can cause that though....seize that rod bearing at high rpm and see what gives first <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
Majority of the failures I have seen seem to result of a rod bolt failure or oiling failure
Re: How strong are the stock Rods? Off the topic. Hi Fireball, I remember pulling away from you until the 1/8th at MIR at the 2000 F-body shoot out. I have to savor that moment on tape, as I see from the mods you've added since that I sure couldn't do that now. <img border="0" title="" alt="[Frown]" src="gr_sad.gif" />
My stout little LT1 still pulls away from a lot of LS1's at the begining, but too many of them catch up on the big end.
Are you still in contact with Andy? Navy bandmember with the Red LS1 car. Tell him to drop me a line.
My stout little LT1 still pulls away from a lot of LS1's at the begining, but too many of them catch up on the big end.
Are you still in contact with Andy? Navy bandmember with the Red LS1 car. Tell him to drop me a line.
Re: How strong are the stock Rods? dug and Visceral hit the nail right on the head, IMO... RPM is usually the rod/rod bolt killer LONG before the rods themselves tweak, even on a nitrous/FI motor. Rod bearings, on the other hand... they take a HELL of a beating in high cylinder pressure (read: nitrous/FI) apps.
All of that being said, if I was doing a complete build, I would think that a set of good rods would be (relatively) cheap insurance.
All of that being said, if I was doing a complete build, I would think that a set of good rods would be (relatively) cheap insurance.
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Re: How strong are the stock Rods? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by dug:
<strong> The stock rods are underrated. Their weakness is the rod bolts. Also boost is easy on rods because majority of the added stress is on compressing the rods. All rods are stronger in compression vs. tension. Rods usually fail when the tensile loads are too great, which comes from too much rpms. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Analyzing the rod breakage failures will lead to two causes, rod siezing from lubrication problem and or rod bolt failure, neither of which make LS1 rod a weak choice. Head liftage and coolant squeezing in to cylinders could also break rod if enough passed under severe boost or nitrous temp/ pressure to hydraulic the cylinder and bend the rod. A lot of people use stock head bolts with stock or cometic gaskets, this is throwing dice to me on a higher hp setup. Blaming these types of failures on stock rods is not accurate or fair. They are actually sweet designed rods for stock motor, if stock SBC rods handled 8000rpm in bracket type drag motors with floating pins and ARP bolts than LS1 rod can take even more in my opinion(with good rod bolts and sizing checked).
<strong> The stock rods are underrated. Their weakness is the rod bolts. Also boost is easy on rods because majority of the added stress is on compressing the rods. All rods are stronger in compression vs. tension. Rods usually fail when the tensile loads are too great, which comes from too much rpms. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Analyzing the rod breakage failures will lead to two causes, rod siezing from lubrication problem and or rod bolt failure, neither of which make LS1 rod a weak choice. Head liftage and coolant squeezing in to cylinders could also break rod if enough passed under severe boost or nitrous temp/ pressure to hydraulic the cylinder and bend the rod. A lot of people use stock head bolts with stock or cometic gaskets, this is throwing dice to me on a higher hp setup. Blaming these types of failures on stock rods is not accurate or fair. They are actually sweet designed rods for stock motor, if stock SBC rods handled 8000rpm in bracket type drag motors with floating pins and ARP bolts than LS1 rod can take even more in my opinion(with good rod bolts and sizing checked).
Re: How strong are the stock Rods? FWIW, when I had my motor rebuilt I went forged pistons, new rings, new bearings everywhere, stock rods, new ARP bolts everywhere. I discussed it at length with JPR and he says the same as above. I'm not spraying or FI so I feel I'll be fine.
