wtf? 3 cylinders dirty, 1 pristine - help?

[dhen]

DEFINITELY retorque after a few heat cycles. My APR's loosened up and the HG started to leak oil. As soon as I retorqued them the oil leak stopped. I'm lucky I didn't get any coolant/oil mixing going on.

Slightly off topic, but can you torque ARPs with the cams still on?

[aintnobiscuit]

I can, but it's difficult. It might be because of the aftermarket cams. The area you can put a wrench on to turn the cams gets in the way of some of the bolts. You can turn the cams repeatedly to gain access to each bolt, but it's easier to just have them off.

[float_6969]

So run the car until it warms up, then check and re torque the studs a couple times but no need to follow the torque, completely loosen 3 times procedure?

Warm up, then cool down. Then retorque. No need to loosen. That's an ARP thing. It's to polish the threads so that you get the correct force applied to the studs/head.

[aintnobiscuit]

Cool, thanks

[mdb4879]

The torque, loosen, repeat twice, then torque is Nissan's procedure, not ARP's, so it's not necessary (granted it's not really necessary on a stock motor either). But it wouldn't hurt to do it. it's suppose to spread the load more evenly across the head gasket. An even better way to do it is to torque, loosen, then torque in two or three steps (torque in steps every time you torque, btw) while waiting a few hours or even a full day in between stages. The Germans like to do this and it's suppose to make the load really even. But once again, it's not necessary.

As far as I'm concerned, all these bolts/studs are TTY. I know they don't specify the torque to rating then an extra "x" degrees, but they do get torqued about to their yield point and over several uses they do stretch. Ideally you should replace them every time, but as long as they're still holding the torque they're usable. I've reused them in E-series motors and usually they do just fine, but every once in a while you get a weak one and it won't torque down. You can feel it when it happens. The bolt will keep turning without getting any tighter. If you feel this happening then immediately back it out and replace with another one.

ARPs are the same way I do believe. People say they're reusable, but if you look up on ARP's website or even call they're technicians the torque spec they give is the same as their yield torque. ARP's can stretch just like any other bolt and should be checked after each use. The head studs might not be as much of an issue since they are stronger than the ones that typically cause issue, but they still can stretch. I don't know if ARP gives a spec for this, but for rod bolts they ideally should be torqued to a stretch rating (there isn't really a way to measure this on head studs I don't guess) and after each use you measure the permanent stretch and if they stretch more than 0.001" then you trash them. A big racing machine shop I talked to said they usually only use rod bolts twice then chuck them anyways. I can only imagine it's different for head studs, but the same principle applies. Btw, my stepdad actually broke a head stud in Casey's motor at 50ft/lbs.

Yes, the head nuts can be torqued with the cams still in place. I know because my stepdad never removed them from Casey's motor. He had stock cams, though. Anyways, upon first assembly it may not make any difference, but after the motor is all together it'd kinda be a pain to remove the cams, reinstall them, and redo your timing just to check and retorque the head nuts.

[aintnobiscuit]

I agree on all points. You can definitely reach all of them, but I have no timing belt on, so I don't want to rotate the cams too much and push a valve into a piston or something. That would be my only concern... I usually just take them out if I have to do the head... it's kind of like, why not? 24 10mm bolts is pretty easy to take off and you won't risk dirt/scratches on the cams. I like to wrap my cams in towels or something like that so they don't get scratched.