okay.. so i'm rebuilding the head on my F23A1


i've heard mixed information of whether or not you have to replace all of the cylinder head bolts.


some say yes for sure, some say SOHC no, DOHC yes, some say no you can re-use them regardless of engine.


soooo... do i need to replace my cylinder head bolts? or can i re-use them ??

 

thanks.. yeah i figured i could..

i posted on the honda-tech forums as well and someone replied that stock honda head bolts are not "torque to yield" AKA stretch bolts.. since i'm not building for boost and it's only a DD i'm gonna save 100 dollars and rebuild with stock bolts.


i rebuilt the top end of a 1986.5 supra DOHC inline 6 and we re-used all but i think 2 head bolts.. torqued to 85 ftlbs (corrected torque that toyota should have used in the beginning) and it's still on the road driving today.

 

Helm shop manual for my 1998 F23A1 described a measurement on the bolts. Using a micrometer you measure the diameter of the straight part of the bolt (between the head & the threads). If a bolt has stretched, there will be a section with reduced diameter. The Helm book has an exact diameter for acceptable/unacceptable. Mine were all good when I changed headgasket.

Of all the people I recall talking about this at all, none had stretched bolts, so they were all able to re-use them.

 

yeah.. i can't imagine my bolts stretched at all.. they appear to be a fairly good grade steel.. and a decent diameter.

i'll get ahold of the diameter spec and check them with a micrometer just to be safe though. i gotta go visit the local Honda dealer tomorrow anyhow.. gotta get torque specs for the head bolts among other things, and get a Honda oil filter for the oil change.

i might pick up some genuine Honda hydraulic clutch fluid too.. that's due for a bleeding.. and i might compare price on Genuine coolant vs prestone crap.. OEM has like 120000 mile life or something like that i think... and frankly.. i just dont trust the prestone stuff.. i'm sure it's perfectly fine.. but it's not a GM or Ford and i actually care about this car.. soo i try to stick with OEM as much as needed/possible. i skimped a tiny bit on the head gasket set.. went with a FelPro set.. but they make good parts and the OEM set is insanely priced.

 

Over in the DIY section there's a thread about on-line manuals. Look for yours (98-02) I think it's the type of file you have to burn to a CD before you can read it.

There's all the head-bolt stuff, including the good/bad measurement along with bolting sequence & torque. And bolting sequence & torque for the camshaft bearing caps too.

I've used non-dealer brake fluid all the time, no worries. ATE Super-blue & gold; or ATE SL.6 too.

 

it's the 98-00 ESM right? i've downloaded it before.. and it only has F22 engines... there's not one single bit of documentation that relates to an F23 in there.. and not a whole lot that really even relates to my 02.. or from what i can tell any 6th gen for that matter... i even got a little froggy and downloaded the russian manual for the 99.. and then i got lost and couldn't figure out what buttons to click haha..


looks like i'll just have to save up for a real FSM

 

Sorry, I thought the right one was in there somewhere. I should go check it out for myself before I steer everyone else wrong.

 

its cool man.. if it's the one by Ab0VE then it's not exactly correct.

not to mention it NEEDS the CD in the drive at all times to run, is hard coded to the D drive for the CD so an emulator wont work.. and there's absolutely no option to uninstall it... haha


EDIT: in case anyone cares.. the right way to do it, if re-using old bolts, torque all head bolts to 22 ft-lbs using the correct sequence(cant think of it right now, it's mapped out on a piece of paper somewhere) then after 22 ft-lbs rotate each bolt 180 degrees from it's position at that point.

if using NEW bolts. it's 22 ft-lbs then 270 degrees. easiest way is to make marks on the bolts/head to get them right.

i didn't really have the patience to make the marks(nor could i find a marking pen that would be visible). and i have a pretty good judgment of angle.. so using the torque wrench i got them all to 22 ft-lbs went over them 3 or 4 times after that still keeping 22 to make SURE they were all fully torqued.. and believe me, they moved some after each complete pass on the head, once the gasket was completely set at 22 on all 10 bolts and they wouldn't budge before the torque wrench kicked in, i did the 180 degree rotation.. after that, i used the good old method of trial and error. and slowly worked up to about 102 ft-lbs on the first bolt in the sequence (i knew i had that bolt at a true 180 because i had room to do it.. the others i had to do 2 sets of 90 on) and after getting to 102 and it moved a HAIR before clicking.. i then checked the other 9.. most were really really close.. a couple moved a little more.. so basically the final torque i ended up with is about 102 ft-lbs. your results may vary. and i am in NO WAY telling you to go torquing your head bolts to 102. that's just what i ended up with.

why Honda doesn't have a 3 or 4 step process and a final torque is beyond me.. but i now know for sure that my cylinder head has the most even amount of pressure possible because all the bolts are at the same torque.

 

In general terms, the reason why bolt-torque is specified like that...

Certain applications the bolts and/or the gasket is yielding, and the torque doesn't rise uniformly with angle. So it's actually more repeatable to torque to a low value so all the bolts are at the same TENSION. (That's different than saying they're all at the same torque.) Then a specific angle produces a specific amount of additional stretch; but calling out a specific torque for the final step is less repeatable.

 

eh... either way.. it isn't going anywhere anytime soon haha.