Head Gasket and Bolts

[dreamsOfSkylines]

Ok, well no thanks to my FSM I just learned that the head bolts should be replaced each time the head is put back on. Anyone know where I can get these online, the dealership here in Tucson rips people off. Should main bolts also be replaced? How many miles do I wait before I retorque the head? What should I even retorque it to since I'm supposed to go by angle? Should I use any of that spray of crap for a better seal? Which (if any) bolts do you suggest I use threadlocker on? Sorry for so many questions but I want to make sure I do this right the first time. Thanks.

EDIT: Oh, yeah its a ka24de

[NeedCAforS13]

main bolts? like the ones that hold the crank in? (under the oil pan...) did you pull them out too?

Sean

[extheflow]

he said head bolts, yeah those a re stretch bolts courtesynissan.com is probably your best bet.you get a 240sx.org discount there if you talk to someone special.see site for details.

[karay240]

courtesy nissan, or if you're wanting to go all out, you can get the ARP.

[NeedCAforS13]

Should main bolts also be replaced?

he said main bolts too;)

Sean

[dreamsOfSkylines]

Yeah I'm rebuilding the whole engine. The FSM said nothing about the head bolts so I figured I would ask about the main bolts too since you torque those pretty high as well. Why would the head bolts need to be replaced but not the main bolts? Also if anyone can answer the other questions that would rock. Thanks for the replies.

[karay240]

I'm thinking the stretching has to do w/ the length of the bolts. The longer it is, the more it'll stretch.

[NeedCAforS13]

I used the copper spray on my headgasket and turbo gaskets, and the permatex 'paint on' black gooey stuff on all my other gaskets. RTV on the oil pan and any other misc. seals I didn't have gaskets for:)

not sure which bolts to use threadlocker on I would like to know this too as I am assembling my motor this weekend (after its full rebuild;))

I re-used my stock main bolts, but I got new rod bolts (these strech like head bolts!), rod nuts, head bolts, head bolt washers... I also plan on dropping the oil pan and re-torqueing everything after a few thousand miles:)

Sean

[dreamsOfSkylines]

Thanks for the help but I'm still confused how you can retorque the head if the "final torque" is given in degrees of rotation past a certain torque? (hope that makes sense) If anyone has suggestions on where threadlocker helps/hurts please share.

[DAEDALUS]

I don't understand "stretch bolts", since all bolts stretch under load. BUT if I understand the context correctly, then it sounds like maybe the bolts are actually torqued to the point of yielding. If this is the case, then it makes sense to give the installation requirement as an angle. Because once a bolt begins to yield, the amount of torque you can apply to it will begin to decrease, until finally the bolt breaks. If this is indeed the case, then pay VERY close attention to the FSM instructions, since the load on a bolt is affected by things like lubrication (or roughness) and threadlocker. Don't do anything the manual doesn't say to do. Also, if this is correct, then I don't think it would be prudent to reuse the bolt. That would impart more strain than the initial installation, for which it was designed.

Also, if you use a non-OEM bolt, then these rules probably don't apply, since any non-OEM bolt is probably stronger (maybe weaker?) than OEM. So the initial torquing will not bring it to yielding. But the angle installation should still suffice on these as the preload should be close to as-designed.

EDIT: Does the manual state to retorque the bolts? If not then don't. If the bolts are already yielding, it'll only make them weaker. I think of re-torquing as a technique used with RTV seals back in the dark ages. Current RTV products are much better than before and don't shrink like their predecessors. Thus retorquing after 24 hours is usually not needed for RTV anymore.

[dreamsOfSkylines]

Well I ordered all new bolts/studs/nuts/washers today (head, main, rod) from courtesy nissan. The manual says to install the head bolts lightly lubed so thats what I'll do. The FSM doesn't seem to say anything about retorquing the head, but it also doesn't say anything about replacing the bolts. These are both just things I have heard are a good idea when rebuilding an engine. Felpro even designed a special head gasket (PermaTorque) for the purpose of eliminating the retorque step, but I'm pretty sure they don't make them for the KA. Maybe the angle method is good enough though? I'm still a bit confused.