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Rb30 Rods


tm_r33
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Hey all about to drop my 25/30det in and having second thoughts on rods. Im running acl bearings and all bolts have been changed to arp studs. Running 9:1 forged pistons and crank and rods and pistons all got ballanced but now im thinking I should of replaced pretty much the only part I didnt. The rods.

Will stock rods that are balanced to each forged piston with arp studs and acl bearings survive 350 rwkw ? ?

Crank has also been dynamicly balnced with flywheel and balancer to try keep things running smoothly and im hoping to set limiter no higher than 7000 ~ 7500 rpm.

Thanks james.

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Hoping to make this power on about 18 ~ 20 psi from gt35 not that this should mean anything.

Rods where inspected and crack tested befor assembly.

My engine shop thought they would be fine but my tuner is telling me hes a bit concerned.

Thoughts

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Go back to some early posts pointing out that rods are the same size as some V8 items. Email Robbie at Rips for his estimate of the limit for stock rods - I suspect he will think they are OK for 350kw. My engine has stock rods but with new rod bolts and bearings but it hasn't been fired up yet. Looking for 300 - 350 awkw.

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is that on 30 bottom end or 25?

i wouldnt hesitate to put this power through 25 rods as they is so short but with the extra length in the 30 rod it means there is more chance of deviation in the rod shaft. (obviously as something gets longer it has more chance of bending in the middle). This wouldnt be a problem if the 30 rods were thicker than the 25 rods but they arnt lol.

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i read the early threads pertaining to the v8 rods next to the rb rods ages ago but just wondering if anyone has a real lifeexample of standard rb30 rods holding in their engine for a decent period of time with about 350 kw at the treads

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lol yer thats why im not goin on what the phisical size of them is compared to others.

rb rods have a farely decent journal size next to plenty or other rods and im not 100% sure on there metal make up but from memory they are pressure cast which is slightly better than standard pour cast.

but yer as i said really id just like to know if some one has been abusing a set with decent power for any length of time??

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the guy that is tuning mine says he has tuned a few to 550rwhp complete standard bottomends. he says the rods start to bend around that power and wouldnt reccomend me do it on mine. hees also made 600rwhp with standard bottomends and run 30psi through them.

i think jpc also reccomend not to go over 400rwkw with them. so it seems around that is the max u wanna go if you want it to last a while.

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yes but now that the engine is complete and back home after costing me 9 grand at the engine workshop, if i decide to throw forged rods at it i have to get it back to the shop, and get them to pull the sump off, pull rods and pistons out. press gudgeon pins out, press pistons onto new rods and assemble again. but they prob wont get a ring compressor in past the crank shaft so yer it is pretty much paying for assembly once again yes??

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yer engine is now complete and on engine stand in my garage with engine mounts, alternator, powersteering pump, rocker covers, thermostat housing, cas and all that shit bolted on. would be costly both time wise and to my wallet to now change rods. im thinking 350 at the treads at 7000 rpm will be safe. only just but im thinking safe.

surely some one on here has a 25/30det rids standard rods at over 300 kw??

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yer engine is now complete and on engine stand in my garage with engine mounts, alternator, powersteering pump, rocker covers, thermostat housing, cas and all that shit bolted on. would be costly both time wise and to my wallet to now change rods. im thinking 350 at the treads at 7000 rpm will be safe. only just but im thinking safe.

surely some one on here has a 25/30det rids standard rods at over 300 kw??

You haven't looked very far. There are heaps in the RB30 dyno results thread. On the first page there are people with stock rods making 450kw, 371kw, and the first of Rips at 447kw. NB I will be limiting mine to 6800rpm and using 6500 as the working maximum.
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never got myne on the dyno but can guess around 280-320rwkw, 7200 limiter. then again i'm having engine troubles after less than a 1000km so not a good example

What sort of engine troubles u having mate?

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ive got a stock bottom end and am tuning it up to whatever it will handle soon.

send me a pm mid january, but ill be putting out <350kws

Let me know what numbers u make when its tuned. Ive also got to consider my other parts thats all. Ifa rod lets go it will no doubt f**k one of my pistons. Maybe destroy my modified block and even send the piston flying into my nice new valve train.

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My mate's old man is an engineer and they used to use the nissan rb30 rods in some v8 applications a while back.

He said the standard ones were good up to about 600hp/447kw at the flywheel before they would start to break.

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What sort of engine troubles u having mate?

took it for a thrash one day without realising the BOV plumback hose had come off, sucked in unmetered air and was running at around 13:1 under full load. loaded it up in 3rd for the first time and it pinged pretty hard 4 or 5 times (not audible but was logging at the time). later that day after another 100km or so it started hesitating real bad under any load higher than cruising, started it the next day and made it 500m down the street before it became undriveable (foot to the just to make it idle). started it again a few days later and it started making a bad knocking noise. still has compression so not sure why its running like shit but yer doesnt sound good.

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