Re-using Rod Bolts

[killa-watt]

I'm sure this has been covered somewhere but I can't find info.

What's the general consensus when it comes to checking bearings, can I simply re-tighten the nuts on the rods or do I need to throw em and start again. Are they a TTY bolt, it's on an RB30 if that's different to the other RBs.

[hardsteppa]

put new ones in; pretty important fastener. I would, and did, use ARP's.

[killa-watt]

Yeah I would use arp's, but then it means resizing the rods, was hoping to have a quick inspection of the bottom end which I'm sure is fine, and then bolt it back up, but if they are single use I don't want to introduce dramas

[GTSBoy]

They're not single use. The workshop manual just gives a simple torque figure to do them up to.

[killa-watt]

That was my thinking I'm sure many people re-use them too and have no drama was just wondering what was the correct way, would an engine builder re-use them etc

[Ben C34]

an engine builder wouldn't be using stock rod bolts

 

Chances of the bearings looking good are slim, the engine is 30 years old mate

[killa-watt]

So your saying once you undo em they are bin jobs

[GTSBoy]

On 9/5/2021 at 8:39 AM, killa-watt said:

So your saying once you undo em they are bin jobs

Yes, but not because they are TTY bolts (which they are not). It is because they are 30 years old, have done a million billion cycles and an engine builder is BUILDING an engine, usually with the intent to push it hard.

[Shoota_77]

I agree to replacing original factory rod bolts but would happily re-use upgraded bolts next time.  Presumably you’re chasing more power than the original bolts were ever designed to handle plus the age factor so replace them now and they will be fine for the next build as well.

[killa-watt]

Yeah just slapping a 25 head on and boosting it, is a low K donk that I was gonna have a quick look at the bearings before putting it in the car etc

[Ben C34]

Don't look them in that case

[hardsteppa]

if it's out of the car and the engine is coming out then, replace the bolts. It's what, $160ish? for arp bolts, and 5 min work on the press. If it's in the car still, then...hope for the best.

[CowsWithGuns]

I'm in a similar situation. I've already assembled the bottom end of my 25Neo and next is installing the head. My engine shop said I'm good to reuse the factory rods and bolts (RB26 rods and matching bolts as it is a NEO bottom end, with forged pistons) for this power goal and application (street). I've also been told that there's not much point getting ARP rod bolts if I'm reusing stock rods.

On 9/5/2021 at 10:26 AM, GTSBoy said:

Yes, but not because they are TTY bolts (which they are not). It is because they are 30 years old, have done a million billion cycles and an engine builder is BUILDING an engine, usually with the intent to push it hard.

This has reinspired the fear of god in me. GTSBoy would it be totally moronic to not pull it apart and bring the rods to a shop to get reworked for ARP bolts? I ask this suspecting you will say yes, but I still want to hear it 😁

Edited September 10, 2021 by CowsWithGuns

[GTSBoy]

6 of one or a half dozen of the other. The expense is not huge and the effort is not huge, so you could say that it is silly to not take the opportunity. It's just sump off, rod caps and pistons off and then put it back together afterwards. It's just annoying given the effort that you've put in goes to waste.

On the other side of the coin - the stock rod bolts have been demonstrated to happily run at streetable ~300rwkW power levels without failing on many engines for many years. So as long as you don't plan to beat on the engine real hard, it will probably be fine.

At this point you choose your poison and you drink it.

[CowsWithGuns]

Thanks. I've had some time to research and clarify my thoughts. 300+ rwkw is already incredible relative to what I had, so I'm going to put it together and and just stay modest with the power. If I really want to go beyond say 350 or get heinous redlines, I'll pull it out when the time comes and upgrade. This is only my first build too, I think I shouldn't overthink part selection lest I make some rookie mistake that causes failure anyway...

If my bolts eat shit, I'll be sure to report back to the community  

Edited September 11, 2021 by CowsWithGuns