All bolts have to be torqued up to a certain point, even if angle torqued from there on ...
Checking for stretch on a bolt is only done if re-using the bolt & is done by measurung the bolt length when removed ..
Hi guys,
Does anyone know what 7AFE rod-bolts are to be stretched to? I don't want to use a torque-wrench, i want to do it the right way, so please dont argue about it haha
I have a fairly basic 7AFE torque guide but it doesn't have the info i'm after
Cheers
All bolts have to be torqued up to a certain point, even if angle torqued from there on ...
Checking for stretch on a bolt is only done if re-using the bolt & is done by measurung the bolt length when removed ..
No not exactly man, a rod-stretch gauge is used when you want to do the rod-bolts up perfectly, a torque gauge doesn't do this (too many factors to take into account), hence why ARP recommend stretching their rod-bolts.
So yeah, not here to argue please, just want to know what they're to be stretched to
Are you replacing the bolts with ARP ones? or putting in the stock bolts? If they are ARP bolts I'm sure the stretch could easily be gotten from there website or even through an email to them. If they are toyota I don't know if the info would even be available?
Glen
Toyota doesn't speficy a stretch length in the 7A manual, if they're ARP bolts then I'd check with ARP what stretch length they recommend. The rod-bolt info from the 7A manual is here:
No unfortunately, not ARP
And as far as i can tell, noone "seems to care" at toyota, just torque them and hope that'll do
Thanks anyway guys
... 'cause Toyota are happy with the torque-to-yield approach that they use for one-time bolts like main caps and head bolts. Even the diesels work this way and head torque is much more critical for them (not to mention much, much, fucking higher).
The above mentioned process is more than just do the bolts up to the torque specs - the 90 degree turn (or 2 turns for other engines) put a specific amount of strain on the bolts making them more efficient at their job than simply doing up to a set torque.
It also allows them to not worry about the length of bolts and focus more on the metalurgy/composition of the bolts so that when they're done to their specs the clamping force is more than adequate for the use of the bolt.
It comes down to how many bolts have failed & or come loose this way to date on standard motors & i think that will give you the answer as to why no one seems to care about doing it any other way at Toyota .........
And as has been previously mentioned unless you are using ARP bolts the stretch to yield that you talk about would be inaccurate due to different metallurgy, you could be actually over stressing the standard bolts ..
It's the weak link of the motor, plenty of rod-bolts have unwound or failed in 7A's.
Yep, i guess i'll just do it the toyota way
You arn't making much sense mate!
If you are aware of rod bolt issues with the toyota items, why on earth wouldn't you be putting in the best bolts money can buy while you have it all apart?? Assuming you have it apart by choice not just looking at a conrod through the block!
Cheers,
Jason
3TC Compound Turbo 1976 TA23 - Members Ride Thread HERE
479RWHP on 50psi and 70psi hasn't broken her at the track!
The person i'm building it for is on a VERY strict budget.
Unfortunately, he can't shell out $550 for forged rods, and it'll cost close to $300 to supply, drill/tap the rods for ARP bolts (nothing off-the-shelf is anywhere near the same spec), and resize the bigends.
So yeah, from what i've been told by many, the *only* real way to do up rod bolts is with a stretch gauge. So yeah ... i just wanted to do the bolts up the right way and hope that new bolts/resized bigends will survive.
follow the manual and treat the bolts as a one-use item - once they've been torque'd-to-yield (as per the TSRM above) a second attempt to do that will stretch them too much and they will fail prematurely
Simply doing them up to XX ft/lb will also be a fail.
Yep, shall do
Cheers guys
Strict budget?
You should of said so!!!
I understand strict budget mate!
Good luck!
3TC Compound Turbo 1976 TA23 - Members Ride Thread HERE
479RWHP on 50psi and 70psi hasn't broken her at the track!
Bookmarks