NITROUS OXIDE ( nos / n2o ) advice forum

Well f*ck me sideways and call me Susan! Its happened again!

First time I stretched 3 bolts and snapped one it was due to my own fault over torquing the bolts. This time I can hands up say it wasnt my fault. I replaced the 4 bolts I stretched / snapped with new ones (at daft cost - thanks Eagle! ) 3 of the new bolts torqued up nice and the forth just went plastic - Pulled it from the rod to find it had just started to stretch. Nowt wrong with the torque wrench as I now have two and they gave the same reading!

A call to a rather un sympathetic Eagle and another £50 spent just for a spare bolt to be forwarded to me for next weekend!

FFS I wish I never bothered rebuilding this engine!

Still with the shafted bolt swapped the bottom end is built and the head is already built waiting for new lairy high lift cam shafts to make the journey from Japan to the UK.

With any luck I may get this chuffing engine built this month!

Cheers

James

p.s Nice forum chaps!

You can't win can you? Sometimes I think the headaches are not worth saving the money on doing things myself, but then when I do spend the money I am usually dissapointed by only okay results or bad results.

Bull,

Sorry to hear of your problems.

It's for reasons like this that I strive for perfection in my products and service. ;-)

That's also why my customers appreciate it so much as both are rare commodities in this day and age.

Regards

hi james

ive heard of this quite a few times now, good luck with it!

As Denny says you cant win some times but then I am so f*cking pig headed I just keep going at it until its either gone to hell in a hand basket or its going the way I want it. This minor draw back hasnt dampened my enthusiasium though. After 2 productive days the engine is ready to be slapped in the car - bar fitting two HKS cams and replacing the duff con rod bolt. Boy I feel tired!



Trev I totally hear you on this one! hence why I am always bigging your products and service up like I am on the pay roll



Well thank f*ck for that! I thought i was just being a spazzer! IIRC this has happend to quite a few people which makes me wonder if they are suppling rod bolts with a suitable shank size for the torque they are reccomending they are set to.

Glad to see the Cally is almost up and running Brian, cant wait to see what times it puts in!

Cheers

James

Thanks James, now you are making me second guess my swap to a centrifugal blower. LOL

I'll have to swap to a NA manifold as I have a roots blower now and then fabricate a blower bracket as I don't have an application specific kit. Doesn't sound to bad as long as the fine details of hoses and lines between my current manifold and NA manifold aren't a big headache.

Maybe I'll just run more nitrous all the time instead.

james have a look on www.max-boost.co.uk under "useless mods", plenty of aftermarket rod bolt failures!

James which bolts are you using?the arp 2000?what size 5/16 or 3/8?and what torque setting?
I havent yet had a problem with them& am intreuged as to what is causing this, cheers richie,uk

Hi Richie,

It is the ARP 2000 bolts with a 3/8th shank and a 7/16 head. The first four that went my fault but this one was done to the correct torque and just went plastic before it had been done up properly. I was torquing them to 58NM whic is the ARP listed 43ft/lbs.

Cheers

James

Its got to be the wierdest thing i've ever heard.
Bolt technology isn't exactly new and misunderstood.
ARP don't even need to be the best to get this right.

Is 58NM in roughly the middle of the range on your torque wrench ?
Are you using any sort of socket extension bar ?

Hi Loopy 58NM is roughly halfway up the scale on the wrench and I have had to use an extension bar but that dosnt seem to have effected the other 3 bolts that did up fine. TBH I have lost confidence in the engine it self, not from my work but from the random failure of the parts.

I have to say the Eagle guy didnt seem to bothered? Now if it was a quality product and if these failures were so un-heard off I would have assumed this guy to make a real fuss? He just said he would send some more?

What can I do as this is weird. I knew the faulty one had gone plastic as I was tightening one rod cap up and alternating between bolts (1/4 turn each) and one just click off at 58nm and the other kept going. I am petrified that the other my fail in use!

How can I check them, last thing I want to do is undo them and then find they all going to mush on me again!

I suppose if all the bolts have hit torque then they are happy and havent stretched?

Cheers

James

What are the high boost Supra guys using? How much can the factory bolts handle?

Bolts are subject to their highest stress during installation, technically if they don't fail now then they never will.
The other 3 were alright, simply because they didn't quite reach their limit, proper torque setting is roughly 75% of yeild point, so it's pretty close to fecking them up.

ARP are pretty used to people overtightening bolts i presume, quite often they specify what seems like a lower rating and people don't understand thread pitch / leverage so they keep going.

Extensions give false readings, they twist very slightly and you overtighten the fastener, use long sockets or bloody strong extensions not typical junk ones.

Do you only hold the wrench by the handle or do you hold the head too ?
Torque wrenches should only be held at the handle, not even supported by the head.

Put it this way, i've got smaller standard bolts in the garage that could take that torque. I'm not sure whats going on but something isn't right here, and I know all the rumours but i honestly don't think its the ARP's at fault. This is a very exact science that goes back to the days of steam, the practice is slightly less accurate but people seem to manage every day.

This isn't just weird, unlucky or dodgy bolts.

>>Bolts are subject to their highest stress during installation, technically if they don't fail now then they never will. The other 3 were alright, simply because they didn't quite reach their limit, proper torque setting is roughly 75% of yeild point, so it's pretty close to fecking them up.<<

That’s good to know, as long as I can replace the damaged one then I am home free – I hope!

>>Extensions give false readings, they twist very slightly and you overtighten the fastener, use long sockets or bloody strong extensions not typical junk ones.<<

I will re check all the bolts main and crank – without an extension bar. The bar I use is a stubby 2/3 inches. I will check them all though to be sure, I am sure all but the one that went are fine and going on what you have said above that confirms they probably are.

>>Do you only hold the wrench by the handle or do you hold the head too Torque wrenches should only be held at the handle, not even supported by the head.?<<

I would simply guide the head so it stays seated on the bolt. I didn’t want the socket slipping off the bolt – I will recheck as you suggest using the method you describe. Can holding the head lightly throw the gauge out that much?

>>Put it this way, i've got smaller standard bolts in the garage that could take that torque. I'm not sure whats going on but something isn't right here, and I know all the rumours but i honestly don't think its the ARP's at fault. This is a very exact science that goes back to the days of steam, the practice is slightly less accurate but people seem to manage every day. <<

I expect the stock Toyota bolts would have done the job no issue but sadly they don’t fit the rods Still its only one failure that is unexplained and 4 that went due to my stupidity – so it could just have been a number of factors that threw everything out and meant the bolt failed. Let’s see what happens when I replaced it fingers crossed it all works out.


Cheers

James

James i have 48ft.lbs listed for those bolts so you should have no issues with them at 43ft/lbs,does seem very weird,I only use the 5/16 arp 2000 in my eagle rods& they torque to 26ft/lbs with no issues,we have even re used them when we were stuck with no problems but they really should be changed everytime you torque them,might be worth getting you torque wrench calibrated,last time I had mine checked it was 5ft/lbs over at 25ft/lbs glad i had it checked cheers richie,uk

James, I was playing with this today, actually trying to break bolts especially conrod bolts of similar design (Honda and kubota use similar to ARP)
*As long as you only guide the head then no problem
*Very short extension shouldn't be a problem
(both of these threw the readings by upto 9ftlb at 45)

I know you said all the threads were free and molygreased.
BUT
Did you tighten them to 30ftlb, back them off and do it again to the correct figure ? (helps seat the threads and bearing area)
Is the hole in the cap tapered enough for the radius on the bolt ?

I'm struggling to think of anything else that could be at fault. I tried a handful of standard 3 line bolts and was averaging 51ftlb before they stretched (reccomended 34ftlb)

Thanks for your troubles Loopy, I am hoping it’s just a freak accident and it won’t happen again. I am more inclined to believe that these bolts don’t like being undone and redone. The only reason I say that is because a know US engine build for the 3SGTE has used the bolts and reported similar after h had checked the clearances however trying to get detailed information out of these people is like getting blood from a stone. I am still waiting on the replacement bolts to arrive and hopefully that will be the end of it. All the others are fine except the one that went.

I will do what you have suggested installation wise and hopefully that will be it.

Cheers

James