Threaded headstuds WTF!!

[harryshonda]

Just finishing off swapping a d16z6 into my ej2. Anyway, just been outside to torque down the head, doing it in stages in the right order and one of the middle studs suddenly gives as im tightening it. (About 27NM at this point) i remove the stud and there are coils of aluminium in the thread of the headbolt!!! Why the hell has this happened!! I oiled the headstuds before putting them in and tightened them in the right order! Could the problem be that these headstuds are from a d15b? (Engine setup = d16z6 block and d15b head) Any ideas whats happened here and how i can sort it?!

[gearhead98]

i dont think it is because the studs are from another block. unless you are saying you are reusing old studs, then that would be a problem. from what you are describing it sounds like you just stripped the threads out of the block on that particular bolt. you could try heli-coiling it, but i doubt it would hold up to the abuse a head bolt gets thrown at it. so basically you just ordered a new block for your self, unless you can drill and re-tap the hole with a little larger bolt size.

hmmm now that i think about it i think arp sells custom bolts for situations like this.

[99EJ6T]

i dont think it is because the studs are from another block. unless you are saying you are reusing old studs, then that would be a problem.used bolts/studs would not change thread pitch just cause they are used. hardend bolts vs aluminum block = block losing its threads.

more then likely you used a main bolt, only .5 mm (iirc) difference in thread pitch and will go into the head bolt hole with out issue till you tq past ~10 ft lbs.you could try heli-coiling it, but i doubt it would hold up to the abuse a head bolt gets thrown at it. so basically you just ordered a new block for your selfuse a time-cert. it will hold, if installed correctly. i have seen a b-series make 375 whp with a time-cert in the head bolt hole. but i would not use more then one cert on anything but a stock rebuild. even on a stock rebuild no more then two and they would have to be on opposite sides of the head.

if you jacked the threads on the other ones, best to get a different block at that point.

[s_18]

Helicoil, Re-coil etc are way stronger than the stock aluminum threads...

[shifty35]

Please clarify... are you using OEM head "bolts" or ARP head studs?

[gearhead98]

used bolts/studs would not change thread pitch just cause they are used. hardend bolts vs aluminum block = block losing its threads.



as thinking that since the bolts are the stretch type maybe they had become deformed in some way and screwed up the block threads.

and i forgot about helicoils being stronger then most threads they fix

[mindless]

Did you clean the holes out first? The bolt won't just snap just because. Even if you oiled them priot to installing theyt can still get hung up on dirt, debris, etc.

[99EJ6T]

Did you clean the holes out first? The bolt won't just snap just because. Even if you oiled them priot to installing theyt can still get hung up on dirt, debris, etc.i don't think he snapped anything. just stripped out the hole.

[mindless]

i don't think he snapped anything. just stripped out the hole.

lol...reading owns me.....:mikej:

[harryshonda]

Yeah just stripped out the thread on 2 of the bolts, using oem headstuds that i've re-used a few times :( what exactly are time-certs and helicoils? will this mean i need to get the block out again?

[gearhead98]

here are some helicoils, prob not the correct ones, but will give you an idea of what they are.here (http://www.emhart.com/products/helicoil.asp)

[99EJ6T]

no, you can install a time-cert with the motor in the car, just be very very carefull. you should not have re-used the oem headbolts more then once.

btw: google time-cert, it should come up with some. also there was a thread about a month ago dealing with them and a site that had the correct ones for a d, for sale.