anyone ever had this happen? got through all my rounds of torquing and one bolt at 62 pounds just spun free all of a sudden.

dont suppose there is any other type of fix other than pulling it apart and helicoiling?

all others torqued fine and i started all the bolts by hand half way anyways so no stripped starts.

You pulled the threads out of the block (or you snapped the bolt). If you pull the threads the wrench just goes kinda soft if your hands as the threads pull up instead of the bolt pulling down. Had it happen to me with several 400ci small blocks.

No other fix but to yank the head and put a helicoil (or similar thread repair method) in it. Just make sure you get it in STRAIGHT so it lines up through the hole in the head that the bolt has to pass through! Especially critical on the long bolts, obviously.

yeah thats what i thought. i chased all the threads before and all were easy in and out, and didnt over torque, guess it was just its time. and its an 010 block too, figured they were less prone to crap happening.

darknight,,
see it alot with older blocks that have heat cycled alot. you can tell those blocks when you see the really fine almost powder like boring chips it leaves when cutting out the cylinders. alot of heat cycles gets the metal very brittle. or very seasoned,, like "over seasoned". i'd sugguest to make sure and chase all the head bolt threads with a die also,, and don't use any head bolts that have any rust on them at all,, like,, where they were hanging out the bottom of the deck into the water jacket and rusted on the bottom couple of threads....... also,,,,,,,don't be surprised if more do it on the next round of torqueing after heli-coiling this one.

i had a 427 truck block that i pulled the same head 3 times to heli-coil 3 different bolt holes that pulled threads on three subsequent tries in a row,, back to back. after the 3rd one pulled threads,, i heli-coiled every one of the sob's. fine from there.

oh,,,,you can put a bolt in an adjecent bolt hole to "see" your vertical planes for alignment of the tap by using the bolt to "eyeball" it square/parallel to the tap. look at it one direction,, then look from 90* from that position. pretty simple fix though,, if no more pull. more of a pain than anything else. sorry man.

good luck.

f ing sucks...i never reuse head bolts anyways, this bits too, cause i spent all day putting it together.

what helicoil kit do i need? and can i resuse the gasket?

what helicoil kit do i need? and can i resuse the gasket?

dark,, it's sbc right,, or a 7/16"x14 thread if so. the kit will/should come with the coils, the installer, and a special tap that oversizes to the o.d. size of the oddball size of the heli-coil. the tap and packaging should give the proper drill bit size to use to be right for the tap to work. good luck. let me know if you can't find a kit.

I figure it's OK to reuse head-bolts as long as they clean up OK.

And fwiw, GM's 300M head-bolt material is just about the best stuff there is if you ever take the time to find out just what it is...

pdq67

I figure it's OK to reuse head-bolts as long as they clean up OK.

And fwiw, GM's 300M head-bolt material is just about the best stuff there is if you ever take the time to find out just what it is...

pdq67

no doubt,, very good bolts. still using stock in all of mine as well.

dark,, i've never had a problem using the gasket again if it never fired up and made heat. or like where you are,, just r&r-ing for a fix without ever having water in the engine while it's still on the stand for instance. as long as nothing sticks and messes up/tears the gasket,, i'd put it back on and go with it. should be fine.

heck i replaced mine when i had to snatched the heads off, but it is just a personal experience thing. i always said better safe then sorry.

off to the parts house.

Had the same happen to me on a "10" block. Which bolt was it? If it was along the bottom rear, then like Rat said, plan on others failing too. These are the holes that sit in water most of the time.

I ended up helicoiling all of the bottom bolts on drivers side after taking the head off 3 times. No problems with the others on that side or on the passenger side.

Not to worry about helicoiling. It works fine and as some will say, is stronger than stock. Mine has been fine for over 10,000 miles so far. Also, like Rat said, if you haven't fired up the engine, just use the same head gasket.

no it was #5 in the order, helicoil went in dead perfect, great kit, sharp taps.
all took torque to 65# and its good to go.

really a quick fix, seeing that the motor wasnt in a car!

dark,, glad to hear it. nothing like new, quality taps. they don't skimp on the heli-coil brand stuff. some of the other brands don't last as long though.

oh,,,,,, got your cd's made....... sending tomorrow in the mail. might wait on the sway bar though. spring is almost here!!!

I'm worried about this on my 383 build when I get to this stage. I have chased all the holes, They all look good, however there was one along the bottom that looked like it had some rot in the threads. I ran a die in it and now it looks better. I will keep my fingers crossed. Glad it worked out. Russ

Maybe you should just prep it now anyways Russ. Like said above, the ones in the bottom of the head are sitting in water all the time.

The angle is not hard to recreate. I put bolts on either side of my bad one and just started the tap real slow and did it by socket all the way. Dont advise a drill, if it wobbles or slips, you just toasted the block. I was pleasantly surprised....this was an early 010 4 bolt block, so it would have been a real waste.

in my opinion,, all the bolts should all be covered with water if the cooling system is full.
i think it's because of the aireation sp. on the hotter exaust side of the heads when making more heat. i'd think that air bubbles/steam bubbles off that side are separating the air from the water and letting it do it's dirty work. i always though it can't rust/deteriorate without air/oxygen. but that dis-similar metals thing comes into play too. just thoughts.