2G Stripped head-bolt threads, and repair possibilities.

[Hollyweezle_]

Hello all. Thank you in advance for your time. I have made a search for this topic, and though there is some info in certain posts, my case has some specifics which I could not find information for.

My 2G is suffering from a significant oil leak coming from between the head and block, at the corner where the oil passage goes through from the block to the head. Since it has been more than 10 years this engine was last re-built, I thought maybe the head bolts could use a re-torquing. I pulled the valve cover off, and proceeded to re-torque each bolt in sequence. When I got the the corner bolt where the oil leak is, it would not torque down. I first loosen it, and went lbs, 90* turn followed by another 90* turn and it felt very loose compared to the others. I believe this is the reason why it started to leak oil from that corner in the first place. I turned it juuuuust a bit more than I already had, and still felt loose so I immediately stopped. I am looking to install inserts to repair the threads and get good enough torque to seal a new head gasket I'm going to install. I found the thread size is M11x1.25, so I looked for the proper TIME-SERT kit and found a nice BIG-CERT kit here. I was about to pull the trigger on the buy when I read in the description that this kit is not meant for a "recessed thread head bolt" repair. I've installed TIME-SERT bushings before on an old Rolls Royce aluminium block without a problem, but this description stumped me. After tapping the hole for the new bushing insert, the hole is supposed to be counter bored so the lip on the insert sits flush with the surface it is on. This much I know, but now I am just not sure if I'm going to have a problem with my 4G63.

My question, is if anyone here has successfully used TIME-SERT on a 4G63 block for the head-bolts before. And if this kit I'm selecting here is the right one. I also found some information on converting to head studs, instead of using head bolts. I've already purchased the new head bolts, but if the head stud option outweighs the repair I have in mind, I am willing to follow that route instead. Also, though I understand what a recessed bolt is, a "recessed head bolt" has me stumped. Can anyone enlighten me on that please? Thank you all again, for your time and help on the matter.

 

[donniekak]

You probably stretched the bolt. I've seen fasteners over 120ft/lbs will moly lube do nothing to the threads. I doubt a stock 7-bolt fastener could rip the threads out. Now, if it was installed improperly it could damage the threads.

 

[Bryan 93]

I believe a recessed thread, is just that, threads that start deeper into the block, and not at the surface.

http://www.therangerstation.com/tech_library/3_0-build.shtml

See this page, scroll down to "HEAD BOLTS", they have a nice picture there. Though I've never done it, I would think the timesert should work just fine for this application.

 

[dexterholland04]

Hello all. Thank you in advance for your time. I have made a search for this topic, and though there is some info in certain posts, my case has some specifics which I could not find information for.

My 2G is suffering from a significant oil leak coming from between the head and block, at the corner where the oil passage goes through from the block to the head. Since it has been more than 10 years this engine was last re-built, I thought maybe the head bolts could use a re-torquing. I pulled the valve cover off, and proceeded to re-torque each bolt in sequence. When I got the the corner bolt where the oil leak is, it would not torque down. I first loosen it, and went lbs, 90* turn followed by another 90* turn and it felt very loose compared to the others. I believe this is the reason why it started to leak oil from that corner in the first place. I turned it juuuuust a bit more than I already had, and still felt loose so I immediately stopped. I am looking to install inserts to repair the threads and get good enough torque to seal a new head gasket I'm going to install. I found the thread size is M11x1.25, so I looked for the proper TIME-SERT kit and found a nice BIG-CERT kit here. I was about to pull the trigger on the buy when I read in the description that this kit is not meant for a "recessed thread head bolt" repair. I've installed TIME-SERT bushings before on an old Rolls Royce aluminium block without a problem, but this description stumped me. After tapping the hole for the new bushing insert, the hole is supposed to be counter bored so the lip on the insert sits flush with the surface it is on. This much I know, but now I am just not sure if I'm going to have a problem with my 4G63.

My question, is if anyone here has successfully used TIME-SERT on a 4G63 block for the head-bolts before. And if this kit I'm selecting here is the right one. I also found some information on converting to head studs, instead of using head bolts. I've already purchased the new head bolts, but if the head stud option outweighs the repair I have in mind, I am willing to follow that route instead. Also, though I understand what a recessed bolt is, a "recessed head bolt" has me stumped. Can anyone enlighten me on that please? Thank you all again, for your time and help on the matter.

I run them on my engine because I use 1/2" studs. They've held just fine at 40+ psi. I will be pushing 50 psi soon, I still do not anticipate anything will go wrong.

 

[Hollyweezle_]

I believe a recessed thread, is just that, threads that start deeper into the block, and not at the surface.

http://www.therangerstation.com/tech_library/3_0-build.shtml

See this page, scroll down to "HEAD BOLTS", they have a nice picture there. Though I've never done it, I would think the timesert should work just fine for this application.

Ok, thank you. That's a clear picture. Tough I'm not sure if our 4G63 are this way. I'm going to do an extensive image search.

 

[Hollyweezle_]

I run them on my engine because I use 1/2" studs. They've held just fine at 40+ psi. I will be pushing 50 psi soon, I still do not anticipate anything will go wrong.

Man, that is very encouraging to read! I wish I could push that many psi, but I'm no where near that. The initial setup we did on this car more than 10 years ago was a budget EvoIII setup. It's seen many miles since then, now I'm very interested in doing an EvoVIII ECU conversion. I did some research on that subject maybe 3-4 years ago and the ECUs were less than $400 on ebay, I'm pretty sure they're a bit more pricey now.

BTW, do you remember off the top of your head if our 4G63 has recessed threads at the head bolts?

 

[Hollyweezle_]

You probably stretched the bolt. I've seen fasteners over 120ft/lbs will moly lube do nothing to the threads. I doubt a stock 7-bolt fastener could rip the threads out. Now, if it was installed improperly it could damage the threads.

It could have been over-torqued but I'm not sure. I'm wondering if I can get away with just replacing the head bolts, one by one, without doing the head gasket work. Hmmmm, veeeery tempting! Maybe I can try and do this first, I already have a new set of bolts, and if it fails I have the perfect excuse to take the head stud route .

 

[donniekak]

It would have to be cross threaded to damage the block. If you just over torque the stock 7-bolt fastener you'll end up breaking the bolt before you damage the block.