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kully 560

cylinder head bolts retorque

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heu siteunseen , I read in the z car guide .com that after head install the head need to be retorqued 600-1000 miles ans every 12,000 miles for all s30 cars? I rebuilt my motor back in the late 90s and never check the head bolts after ,I did not think I had to but this guide says different!! just checking with everybody what the deal is. thanks

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Most do not do this. Perhaps dealerships did this back in the day. 

If you remove the head then some re-torques after re-installing would be good to do. Perhaps after 100mi and 1000mi

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never did I retorque head bolt after a valve adjustment. I guess tomorrow when the motor cools down I will check the head , intake and header bolts just because it gives me a piece of mind and also would like to see if anything has change.

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After so many years and miles it's dangerous to mess with the head bolts.  Some are probably rusty and ready to break.

On that topic, has anyone considered the clamping force of a head bolt that's half rusted through?  Might be a cause of blown head gaskets on old engines. Who knows.

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the only thing in my favor after the rebuild in the late 90s that I have not put 3000 miles on the motor . it comes out in nice weather 1-2 times a month for a 30-40 mile drive only. It is  also keep it in a heated garage .so I guess can throw a torque wrench on it and see where it is, if it does not move at 60lbs I will leave it alone. I guess on an old motor and left out side in the weather I would think twice about ,I agree with you on that. I did not know nissan recommends a cylinder head bolt torque after a valve adjustment. this could be a can of worms as I don't think anybody does it .

Edited by kully 560
adding
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Usr anti-seize lube too. It'll help future corrosion and rust when snd if you remove them. They won't snap off at the heads.

 

head_sequence.jpg

 

 

 

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Edited by siteunseen

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hi again siteunseen , I was not thinking about removing the bolts, I was just going retorque them . do you think I should remove them and anti-seize ? [I do not want to brake the seal even 1 bolt at a time] and thanks for the bolt sequence !!!

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Torquing a fastener requires that you have clean threads (male and female) and correct lubrication of the threads and the clamping surface around the bolt head/washers according to the manufacturers (bolts) specifications if you are going to get ANY prayer of getting an accurate torque. You can remove a bolt and clean its threads, and grease it up, but how are going to do prep the head hole with the head on?

Long story short, if you have a leaking head gasket, then sure, what’s the harm in trying a bolt re-torque  first, but without some indication of problems, why in the world would you poke a bear? Ne-touche-pas!

 

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well you make a point , but why would datsun recommended a cylinder head retorque after a valve adjustment.  do you think the dealers back then pulled the head? this is a 2 sided coin ? I guess if I do not remove the bolt and retorque to 60 lbs and nothing happens then nothing gained nothing lost make sense. I would just like to see why they recommended this at  every valve adjustment , were they expecting things to get loose?

Edited by kully 560

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I agree with zKars. If its not broke, don't break it. There are a great many recommendations in the FSM, some I do, some I dont. Our modern head gaskets may not require it, the new headbolts might not require it. I can think of a few reasons it might have been SOP in the 60's but not now. In my might there is no upside to retorquing, only downside...

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Is there a difference here in definition between re-torquing and checking the torque?

 

My engine builder recommended that I “check” the torque on the first couple of valve adjustments in the first 1000 miles or so of my freshly built engine and then put the torque wrench down, take my hands off and back away slowly!!!

 

IMHO there is nothing wrong with setting your torque wrench at 40lbft as suggested and letting it click out (beep if electronic) to give you peace of mind. If the engine is built properly and with a decent head gasket then they shouldn’t be loosening. Some lesser head gaskets, I am told, “bed in” - which is probably the logic behind it. Even with a decent gasket, I am in the paranoid camp ;)

 

I even do this to my load bearing bolts with yellow paint, so yeah, paranoid!

 

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13 hours ago, kully 560 said:

hi again siteunseen , I was not thinking about removing the bolts, I was just going retorque them . do you think I should remove them and anti-seize ? [I do not want to brake the seal even 1 bolt at a time] and thanks for the bolt sequence !!!

Perhaps when the FSM was issued Nissan wasn't thinking about 50 yrs in the future with its recommendation of a retorque.  With an engine that has been sitting for 30 yrs there is the distinct possibility of rust forming on the head bolt threads.

Retorquing  on a realitivly fresh engine wouldn't bother me at all but I sure wouldn't want to do that on an old engine, they are set in their ways so to speak.

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11 hours ago, AK260 said:

.

I decided to leave well enough alone as from reading the consensus from ever body. but I did retorque my header bolts and intake today as is seems some of the header bolts were a little loose. I also decided to remove the heat shield and paint it with vht aluminum 550 degree paint , It needed it and looks a lot better . thanks for the support from every body great forum!!!!!!!

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