hey guys, my 2.4 long rod with ef3 turbo just blew up yesterday, the rod snapped but it looks like the rod bolts let go, the threaded end is still in the cap so it didn't back out they just snapped. What i found wierd when assembling was that 2 of the rods were torqued up like they were supposed to be and the other two rods had bolts that were finger tight?? I found it strange at the time but didn't look much into it. Anyone have any idea what could have happened? I would have been around the 550whp mark when it happened, no signs of knock on piston, bearings look good. Would have thought i'd have blown the headgasket first if there was knock, I have normal ARP head studs and cometic headgasket.

 

so the rod bolts broke or the rods broke? were they torqued to spec or stretched? there was some info recently on nasioc about some bad arp 2000's in manley h-beams.

 

the rod bolts broke but the rod also broke, they were torqued to spec with 30 weight oil. Next time I will be using a stretch gauge, however manley themselves say it's fine to torque to spec.

 

Um...Why spend all that money on a build and get casted in china h-beam rods...??

 

well when my motor blew I was on a bit of a budget and it seemed people were having good luck with h-beams, maybe being a long rod makes it even more likely to break. lesson learnt, i'm going with map ultimates now. they broke after 10,000kms, you'd think an install error woulda blown long before that?

 

What condition are the bearings in?
Who tuned the car?

 

stretch gauge and Loctite anti seize.. (way more accurate then arp lube) rod bolts are the most critical part of the engine.

 

the bearings are fine and the crank journals show no scoring. i tuned it, 4 degrees peak torque ramping up to 16 redline on e85. afrs around 11.5. loctite anti seize??? how can it be more accurate than arp lube when there are no ratings for it? unless you measured stretch on a few bolts using loctite and tested how much torque then it wouldn't work, using figures meant for arp lube with anti seize I don't think will work well, correct me if i'm wrong. Next time I will be using a stretch gauge but I seriously doubt it was incorrect torque as they didn't back out, the threads are still in there just the bolts are snapped. For all I know the rod could have even snapped first then the rod bolts?

so has anyone seen rods that weren't torqued up from factory?

 

From what I've seen and heard.....stretch gauges are way more accurate than a torque wrench but I don't know about this loctite.....would be good to be able to use loctite accurately tho

 

just because it doesn't back out doesn't mean anything.

The reason you do it by stretch is because there is no other physical way possible to know if its right or wrong without this method.. and in order to do this..

you measure each rod bolt before you install it and write down what it is.. zero out your gauge for one, and record the other where its off 0 on the gauge and adjust accordingly when torque / stretching that specific bolt.

When I was stretching the rod bolts on a engine i just built recently we had rod bolts go from 45tq to 55tq to 50tq to 65tq to 70tq. all were set with 100% the same stretch, yet the tq varied quite a bit..

If you don't have it stretched enough then there wont be enough clamping force and the rod bolt will fail.. if you have it over stretched then you lose clamping force and you weaken the rod bolts ability to function..

the rod bolts are like springs.. you can only stretch them so much before you weaken them and same goes for understretching.. if its understretched it will not function the way its designed to.

Manley includes / recommends the loctite heavy duty antiseize for more accurate torque reading.. the ARP lube is known to not give as accurate readings as the Loctite lube.

The whole reason behind using the lube to begin with is to remove as much friction as possible to accurately get a true torque reading.

 

burnzy have you tried talking to manley yet regarding the failure?

actually the second you tell them you didn't tq by stretch they are gonna blame it on you.. so i wouldn't bother.

the only good h beam rod i know thats worth anything is gsc's.

for all you know you could of gotten a bad rod bolt but since you cant measure them you dont have any way of knowing.


either way.. sorry for your loss. personally i would upgrade to manley i-beam turbo tuff's .. ive put them through hell and back and they are still kicking *** 10k miles later.

 

haven't spoken to manley yet. I know how a stretch gauge works, the reason they use arp lube is to try and make it more repeatable, torque means nothing in terms of rod bolts all that matters is how much stretch but if you can take out all other variables such as different lubes etc using torque can be pretty close if the proper technique is used. I have never seen manley including or recommending anti seize though, they usually recommend 30 weight oil. Trying to use anti seize you'd need a totally new set of torque values, but I agree with you stretch gauge is the best way which is why I said i'm using that next time. understretched should cause the rod bolt to back out, over stretched will take it past it's tensile load limit but i'm positive that didn't happen, what usually happens when using torque wrenches is that they're under torqued due to preload scatter. for instance, 30 weight needs 60ft/lb according to manley to get the right stretch, arp lube only needs 45 and if you're right about anti seize being better then it may only need 30. Won't be relying on torque next time even though I doubt it was the cause. Theres a few instances of failed rod bolts scattered around different forums even when people have used stretch gauges.
I haven't spoken to manley cause I doubt they will do squat for me so I just chalk it up to tough *******. People have actually emailed manley and they're one of the few companies that actually says using torque is ok, as thats what they do at the factory.
I was thinking either turbo tuffs or map ultimates, I'm buying through map so will probably get the ultimates. carillo pro H are also good h beams.

 

ya they wont do anything.. and read what i just said.. the tq varies so much that doing it by tq is pointless. every bolt is different.

also the Loctite anti seize is just like the ARP lube but way more consistent from what ive read / heard. If you do some reading you'll see ARP lube is not so good.. or used to be bad.. im not sure if they revised it or not but its caused lots of engine failures like you just experienced from its inconsistencies.

you said some of them were finger tight? what do you mean by finger tight? you could turn them with your hands? if so.. that's definitely bad.

and no.. the loctite uses the same specs as arp. its just the loctite works more efficient per say.

 

i mean when the rods came, they should be pretorqued from factory to hone the big end etc, but 2 of them werent!

I know what you mean by the inconsistencies, but if the bolts were made properly there shouldn't be that much difference

 

oh ok they came from manley finger tight on 2 of them.. interesting. would of been interesting to have a stretch gauge to see if they even tq'ed down the ones that were loose.

heres a good read on stretching: http://speedtalk.com/forum/viewtopic.php?f=1&t=24843