head bolt hole stripped in block

[pauly_adams]

hey guys,

 

after a blown head gasket i thought i would rip th head off and replace it, thats where the pain started. when removing the head one of the head bolts snapped leaving about 12mm below the blocks surface, i tryed everthing to get it out easy outs, heat welding a nut on etc nothing worked so i resorted in drilling through the center of the bolt until it was thin enough to get it out with a tap which actully worked but the drill bit did damage a small section of the thread, so after all that i went through and cleaned out all the head bolt holes in the block all full of crud also then cleaned block and head then went to bolt it back down. i started to torque the bolts and got to the 2nd stage and the previously extracted bolt hole gave way and the block stripped.

 

so what is the "best" method to fix the thread in the head stud hole as it is getting turboed and i dont want it stripping again

 

cheers pauly

[C.A.R.]

Helicoil.

[luvemfast]

Is it ok to use a helicoil in a block?

Not that there are many choices  :-\

[peter mc]

its very OK if there done right , make shore you use the long series

[luvemfast]

Basically, whenever working out threads. Ultimate strength is 1.5 X Diameter of thread.

Helicoils are in lenghths x thread diameter.

Example- M10 x 1.5D

So the thread will be 15mm deep.

In this case, in a block. I'd have to agree with Peter and get a longer Helicoil. So would a 2D be enough or would more be needed?

[pauly_adams]

yeh i was thinking helicoil, i have seen these new ones call "time serts" and am thinking of giving them a try as there a full case hardend bush any one used them before ?

[PZG302]

As Lurch said Helicoil, and as others have said a long one. I've ended up with helicoils in just about every L series engine i've used to keep the h ead on, including one L18 that had a compression ration of around 12:1 and had that much taken off the head the A in the A87 for the head casting was a triangle and it was almost take a link out of the timing chain time.

[Scoota G]

One of these would fix it too.

 

http://www.ebay.com.au/itm/JDM-L20-Turbo-Engine-L20ET-6-Cylinder-Motor-Nissan-Skyline-240z-260z-280ZX-/380483521280?pt=AU_Car_Parts_Accessories&hash=item589695cb00

[d3c0y]

Nah those just slow your car down!! 

[peter mc]

Done right there stronger than the datsun thread , 2d is needed to do it right 

[pauly_adams]

all fixed thanks guys, i managed to sretch 2 bolts and break another so i will be ordering new head bolts thankfully though i had a spare set from my L26 i will post up some picks of the head gasket its a bit of a mess im supprised the thing was still running