block head bolt tread...

does anyone know a way how to pretread the bottom block head bolt holes. When tighteneng the head bolt onto my block somehow the tread on hole all got streak and now the bolt would just turn but won’t tighten. The head bolt is fine but the tread inside the holes on the block got all mess up. I would take it to the machine shop but before doing so is there any other way to fix this problem? thanks.

Heely coil it just drill it out tap the hole and put in a heely coil (they say heely coils are stronger than stock) if you take to a machine shop they will do the same thing

There is something better than helicoil for heads…

permacoil or something? dang i forget the name…

helicoils require a kit and a few special tools…namely a tool that inserts the helicoil in place, a drillbit, a tap, and a popping tool that gets rid of the tang at the end of the coil after insertion. costs a bit but worth it. for fun, realize that volvo marine engines use helicoils from the get-go, as they are a little stronger than straight AL threads. think about it, you have a bigger set of threads in AL outside of the coil, and the coil itself is hardened steel, so you end up with a stronger connection than straight AL. but, it is not so easy until you have fucked up a few and learned. do some practice on a piece of aluminum stock, so you are confident when you do the engine. or, take it to a shop but they will charge out the ass for sure. probably $500 or more, where you could get the kit and what not for $75 or $80 maybe.

ps-a drill press is not a must, but will make it much much easier and the holes will be drilled and tapped straight without a doubt. if you no have this, take it to a shop. but for the price, you may be able to find a block at a salvage yard or something for less than what you’ll be paying. you have options just realize dude…it’ll be fine.

well thanks for all y’all replies… I decided to try the helicoil method but places such as Orchard, autozone, kragen, and pepboys don’t have it. They have another kit similare to helicoil which comes with all supplies needed to drill tap and insert. Well since its my first time I really mess up and found out the tap tread didn’t match the headbolt tread, so went and bought one that matches. When I place the tap in the hole, the tap was a bit small it just went straight through without no grip. I really made a mistake by forcing the insert spring to go inside the hole, broke the tang and now its stuck inside. Now the headbolt won’t even fit in because with the insert spring inside the hole is much smaller. So I was like the heck as long as it hold, ran to a hardware store and purchase a thinner bolt about the lenght of the headbolt to tighten it in. Nothing turn out right, when I started torqueing the headbolt this hole where I helicoil just spin in circle and won’t tight. I guess its time to search for a new block.

Dont search for a new block :hmm: think about that … involves removing engine from car… (unless its already out) … Obviously you want the quick fix and not the correct one… unless you do it right it won’t last. have a machine shop or someone who knows what they are doing with helicoils. You didn’t itstall it right… it has to be drilled bigger threaded, then the helicoil does it… and somehow locks (i dont know how really) … that way its back to its original size.
A: fix it yourself (maybe find someone you know to do it
B: take it to a garage.