Head Bolt threads in block pulled out / stripped

[lib87t]

My Dad blew head gaskets in his buick and we are in the process of changing them , but one bolt on pass side during 50ft lb torque sequence let loose. Almost like a socket or bolt broke. That wasnt the case , the threads in the block must have pulled.

Whats the best fix for this?

 

[Phoneguy]

That sucks, TTY bolts? maybe the threads on the bolt let loose

Bryan

 

[KEVINS]

If there is enough threads past that point you could try puting a stud in it.

ks

 

[lib87t]

ARP bolts I was using, It seems its the deep threads that let loose.

 

[RmvBfrFlght]

Can use a Heli-coil to fix it.

RemoveBeforeFlight

 

[Nick Micale]

This is something we have done on more than one block.

We use a jig on the block deck to drill and tap for a helicoil as you must be SURE the insert goes in perpendicular to the deck, especially if you are doing this in the car.

We could not find a long insert, so we actually had to stack 2 of them in the hole.

Best to get a head stud kit so you do not put additional stress on the insert, or the other holes.

 

[dr_frankenstein]

I used a diesel thread-sert.... takes a special too to install and cannot be done in car... but best repair out there I can think of. Ive saved a few cracked 4.1s this way and the repair seems much stronger then the rest of the deck material.

 

[ek02]

Where did you get the diesel thread-sert? Sounds like a good way to fix the deck cracks. Nick, when you use 2 helicoils, is it difficult to get the threads lined up?

 

[dr_frankenstein]

the thread-cert i used i got right out of the Enco Machine catalog. the kit comes with the install tool as well as the inserts. I will get a part number for you asap. I might actually have a few left from my last deck repair if you want to use a few and borrow the tool.

 

[ek02]

My cracked deck 4.1 is junk due to the main web failure, but I was interested in case my new block develops the cracks. I recessed the bolt holes to lessen the possibility. As long as I know Enco Machine has the inserts and tool, I can get what I hope I will not need, when I need it. Thanks. Good info.

 

[dr_frankenstein]

well if you happen to need it, I have it, I will try to post up the part number anyways for future member use.

ive been tempted to try installing them in all deck holes..... but i fear a mistake would ruin a good block, and in my parts... 4.1s have become rather elusive, even broken or cracked.

 

[m233roller]

Iv'e also stacked helicoils before and no the threads will line right up.

 

[daves87gn]

X2 on time-sert, have used them many times to fix others work, work great for striped spark plugs and done it with head still attached, also available in different lengths

http://www.timesert.com/html/inchsert.html

 

[lib87t]

what size would i need?

 

[turbodave231]

7/16-14

 

[turboclam]

I used a Time-sert a few months ago on a stripped head bolt hole. Machine shop charged $50 for parts and labor.

 

[ek02]

Turboclam, that 4.1 block you sold me is machined, girdled, and going together at last.

 

[turboclam]

Great to hear! Hope this one stays crack free for you.

 

[84BuickGNYorkPA]

Old thread but, I stripped a hole in the block today, my engine machinist actually told me about the "Time Cert" fix, he suggested that we just put these inserts in all the holes for the head bolts, what do you guys think? This hole was torqued a few weeks ago and today I was re-checking and discovered it let go sometime over the last several weeks while on the engine stand waiting on push rods. I understand that if we do them all the inserts will be in a fresh thread and it should be stronger than threads in cast iron. But the threads on the outside of the inserts are still in cast iron...
Update, so I discovered that I can get longer inserts than the 1" needed for the ARP studs, think I'll go with 1.5" length to give me 50% more engagement of the base metal (cast iron block).

Chuck

 

[Mike T]

I recently had something similar happen but it was due to using bolts that did not engage enough thread (too short) during the machining process. I pulled the top 3 or 4 threads out of one of the outer most holes.

I spent a lot of time trying to figure out how to make it right again and discovered that the outer holes (exhaust side) have the deepest threads from the factory. I was able to drill out a couple more of the damaged/rough threads (total of 5 threads gone) and installed ARP small journal 327 main cap studs (a little over .300 longer) on the outer holes only. I ended up with full engagement of all twelve threads but you can only get away with this on the outer holes.

Also if you have over 5 threads gone the 327 stud kit will be too short on the nut side......I think there were a couple in the .500 range if needed.