Engine Rebuild - ARP vs Stock Rod Bolts and Main Bolts

[jawort0]

I am in the process of rebuilding my LC2 and looking for basically a stock rebuild with the capability of going high 11's, although I will rarely if ever race. I want to build a very reliable engine.

I wanted to get everyone's input on going to ARP rod and main bolts (studs?) vs staying with stock. Were the stock main or rod bolts torque to yield? If not, is there any concern reusing them?

If I decide to go ARP rod and main bolts, do I need to have the rods and mains resized? I was planning on resizing the rods, but not planning on resizing (line boring) the mains. I need to know if I would need to do this if I add the ARP main studs.

Thanks, Joe

 

[BlackBandit]

arp makes better hardware and the stock stuff is definitely old. If you go with arp rod bolts/studs you have to get the rods done as the cap registers on the bolts/studs. tas far as the mains go I would do it because it's not that expensive. Some will swear you need to but You don't really have to get the mains align honed if you switch to main studs because the mains register in the block. On a new build it definitely couldn't hurt though.

 

[jawort0]

Align Hone

If you align hone the mains, doesn't that open up the diameter and thus clearances and decrease oil pressure?

Thanks, Joe

 

[Slow91z]

Unless you see a issue with your stock hardware save your money, with your goals no need for anything other than a totally stock shortblock (assuming it's in good condition, or rebuilt by someone that knows Buick's).

 

[Squid4life]

On both the rods and mains they remove material from the mating surface, then hone them to spec. The clearances should nt change if done right.

 

[Squid4life]

Unless you see a issue with your stock hardware save your money, with your goals no need for anything other than a totally stock shortblock (assuming it's in good condition, or rebuilt by someone that knows Buick's).

Agree mostly with this. I wouldn't do main studs. I would probably do rod bolts though.

 

[Slow91z]

Agree mostly with this. I wouldn't do main studs. I would probably do rod bolts though.

I don't have any proof of this, but I have read on here in other threads that the stock rod bolts are stronger than the stock rods...Whether that's true of not I would personally be more concerned about rod bolts in a high RPM application so I doubt they would be needed here.

Obviously there's no downside to upgrading rod bolts, other than money.

 

[imjoesnuffy]

I would probably do rod bolts though.

How many Buick connecting rod bolts have you ever seen fail?

Not being argumentative, but someone once asked me that same question, and I didn't have an answer.

 

[jawort0]

To confirm, the rod and main bolts are not Torque to Yield??

Are the head bolts on the LC2 Torque to Yield?

Thanks, Joe

 

[BlackBandit]

To confirm, the rod and main bolts are not Torque to Yield??

Are the head bolts on the LC2 Torque to Yield?

Thanks, Joe

Rods and mains should be reusable. Head bolts should be replaced. I think there is a service message about reusing them but they aren't expensive enough for me to reuse. In fact, I would use ARP head bolts probably before I redid the rod bolts. I did have a main bolt stretch once but as long as it feels good going together you're probably ok.

 

[charlief1]

Head bolts for the 86-87 engines are TTY but the rest isn't. You can buy ARP head bolts that aren't TTY to replace the stock one if you want to. I chose studs for the heads and mains because they hold better and reduce stress on the block some, but it's subjective.

 

[Squid4life]

I don't have any proof of this, but I have read on here in other threads that the stock rod bolts are stronger than the stock rods...Whether that's true of not I would personally be more concerned about rod bolts in a high RPM application so I doubt they would be needed here.

Obviously there's no downside to upgrading rod bolts, other than money.

That would be an interesting read. I will look around, if you find it please let me know.

I like the extra insurance of the rod bolts. More to come...

 

[Squid4life]

How many Buick connecting rod bolts have you ever seen fail?

Not being argumentative, but someone once asked me that same question, and I didn't have an answer.

A few, but not many. I worked at engine machine shops for about 4 years, and started out as the bore and hone guy/ rod recon guy. I did more rods than I care to think about. (okay, go ahead and take advantage of that, I left the door swinging wide open... )

I had one or two broken, but many stretched, which surprised me. I always thought they would just *snap*, but saw a dozen or so 3.8's come in with rod bolts that needed replaced because they had stretched. You could see it, regular threads, ////// laid over threads like that <, then reg threads.

I honestly do not know whether they were turbo or NA motors, 109 blocks or what, 2 dot or 3 dot rods. 3.8 was a popular rebuild motor, that is for sure.


I guess in my few years rebuilding engines, seeing them come in broken, rod bolts was the most common of broken hard parts. Hence my inclination to usually replace them. Cheap insurance, even if not needed.

 

[charlief1]

A few, but not many. I worked at shops for about 4 years, and started out as the bore and hone guy/ rod recon guy. I did more rods than I care to think about. (okay, go ahead and take advantage of that, I left the door swinging wide open... )

Well you are a squid after all my friend.:biggrin: Have you spent time in a sub with all those seemen?:biggrin: JK!:smile:

 

[BlackBandit]

Well you are a squid after all my friend.:biggrin: Have you spent time in a sub with all those seemen?:biggrin: JK!:smile:

Just because he's had more rods than he wants to remember in his hands doesn't mean he was on a sub or that seamen were involved..... It could have happened in port!!!!

 

[NCTURBOS]

I guess my first question would be... Why are you rebuilding it to begin with? You don't need a rebuild for your goals, but if you have obvious reasons that my sway one way or the other on bolt/stud replacement as well.


K.

 

[turbofabricator]

I have seen alot of bent rods on a turbo engine, but have NEVER seen a broken rod bolt that wasn't caused by the rod breaking and causing EXTREME carnage. For your power levels, there is NO need to replace rod and main bolts. The factroy rod bolts are in fact SPS rod bolts. Not alot (if any) gain in going to ARP. The main bolts are 1/2" grade 8. (Small Block Chevies are 7/16") Takes ALOT to break one of those. I've seen alot of main cap failure but never a broken main bolt. Unless you are stepping up to steel caps or a girdle, leave the stock main bolts alone unless they have been over-torqued.
I "have" re-used head bolts a few times, too. One engine with re-used factroy head bolts ran a 10.79. Gaskets never failed. I like to use ARP head bolts/studs, though. The 10.79 was a low budget rebuild and the owner "knew" they were being re-used and took the chance. Paid off I guess.