Exhaust manifold threads screwed... helicoil time
#1
Exhaust manifold threads screwed... helicoil time
Hello all.
The threads for the exhaust studs on my 89 pu's 3.0L heads were seriously damaged when I was removing the studs. Actually, only two of the threads were damaged, but as I am putting headers on this truck now, a mechanic recommended to me to install hell-coils in ALL of these threads to avoid headaches down the road. I have no experience with these, however, and am just wondering how simple it is to drill out the old threads. The last thing I want to do is screw up my heads after I just got them rebuilt and machined, but I would really like to do this job myself. If anyone has undertaken this project or something similar, I would appreciate any advice or recommendations. thanx yet again...
The threads for the exhaust studs on my 89 pu's 3.0L heads were seriously damaged when I was removing the studs. Actually, only two of the threads were damaged, but as I am putting headers on this truck now, a mechanic recommended to me to install hell-coils in ALL of these threads to avoid headaches down the road. I have no experience with these, however, and am just wondering how simple it is to drill out the old threads. The last thing I want to do is screw up my heads after I just got them rebuilt and machined, but I would really like to do this job myself. If anyone has undertaken this project or something similar, I would appreciate any advice or recommendations. thanx yet again...
#2
Contributing Member
Hello all.
The threads for the exhaust studs on my 89 pu's 3.0L heads were seriously damaged when I was removing the studs. Actually, only two of the threads were damaged, but as I am putting headers on this truck now, a mechanic recommended to me to install hell-coils in ALL of these threads to avoid headaches down the road. I have no experience with these, however, and am just wondering how simple it is to drill out the old threads. The last thing I want to do is screw up my heads after I just got them rebuilt and machined, but I would really like to do this job myself. If anyone has undertaken this project or something similar, I would appreciate any advice or recommendations. thanx yet again...
The threads for the exhaust studs on my 89 pu's 3.0L heads were seriously damaged when I was removing the studs. Actually, only two of the threads were damaged, but as I am putting headers on this truck now, a mechanic recommended to me to install hell-coils in ALL of these threads to avoid headaches down the road. I have no experience with these, however, and am just wondering how simple it is to drill out the old threads. The last thing I want to do is screw up my heads after I just got them rebuilt and machined, but I would really like to do this job myself. If anyone has undertaken this project or something similar, I would appreciate any advice or recommendations. thanx yet again...
#3
thanx dale, yah, i was kind of questioning doing them all too... kinda seems like a little overkill. I was just worried that if i was constantly having to re-tourque these studes to eliminate exhaust leaks at header manifold, i might end up damaging more of these weak threads. Apparently helicoil threads are MUCH stronger and durable. i dunno.. neways, thanx again
#4
Registered User
I certainly would not do them all. If only two are messed up just do them. You can have problems later with the heli coils too just like regular threads and it is a more time consuming and annoying job to fix a helicoil (again) than original threads. IMHO if you do them all now you are removing a quick fix option for the next time there is a problem.
#5
Contributing Member
#6
Hey just remember to knock the tang off when your done, if not you'll unthread your helicoil. I think they'll work just fine, hell I even have one in the block for a headbolt. A drillpress makes life easier but with a steady hand you can do it without one. As for strength it's alot stronger, not only did you retap the aluminum but you put stainless steel threads in it that expand when you put a bolt/stud in it. I did a test out in the shop on a junk head and the helicoil took more torque from the wrench than the stock thread or a retapped thread.
#7
went out and checked all the threads, there are two that seem almost perfect, the rest definitely show signs of wear. So ive decided to just go ahead and do all of them. will update after the grand attempt. Thanks to everyone for replies
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#8
Hey you spent the money on the kit, you should use them. My machineshop kindof family owned wanted more than it cost me to do it, and that's me buying everything. They don't do many yota motors, mainly circle/drag stuff so I was probably a pain in the ass.
#10
#12
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I stripped out a few of the holes in my heads where the camshaft caps go. I used a helicoil to fix it and it worked perfect. They are super easy to use. At the company I work for we always put stainless steel helicoils in if we tap into aluminum. They are way stronger than just the aluminum alone. Also, when you use a helicoil instead of just drilling out the hole bigger and retapping to the next size up, you can still use the same bolts on all of holes and down the road someone isn't going to wonder why one of the bolts is bigger than the rest.
#13
I stripped out a few of the holes in my heads where the camshaft caps go. I used a helicoil to fix it and it worked perfect. They are super easy to use. At the company I work for we always put stainless steel helicoils in if we tap into aluminum. They are way stronger than just the aluminum alone. Also, when you use a helicoil instead of just drilling out the hole bigger and retapping to the next size up, you can still use the same bolts on all of holes and down the road someone isn't going to wonder why one of the bolts is bigger than the rest.
#14
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Wha?
If you mean have I ever done, this? Yep, on a chevy S-10 v6 exhaust manifold bolt holes, my 89 toyota thermostat bolt holes and the distributor adjustment bolt. Several of them are now SAE instead of metric and vice versa in the chevy. Tapping out one size larger in aluminum was easy.
If you mean have I ever done, this? Yep, on a chevy S-10 v6 exhaust manifold bolt holes, my 89 toyota thermostat bolt holes and the distributor adjustment bolt. Several of them are now SAE instead of metric and vice versa in the chevy. Tapping out one size larger in aluminum was easy.
#15
Wha?
If you mean have I ever done, this? Yep, on a chevy S-10 v6 exhaust manifold bolt holes, my 89 toyota thermostat bolt holes and the distributor adjustment bolt. Several of them are now SAE instead of metric and vice versa in the chevy. Tapping out one size larger in aluminum was easy.
If you mean have I ever done, this? Yep, on a chevy S-10 v6 exhaust manifold bolt holes, my 89 toyota thermostat bolt holes and the distributor adjustment bolt. Several of them are now SAE instead of metric and vice versa in the chevy. Tapping out one size larger in aluminum was easy.
Last edited by bodo; 10-25-2006 at 06:49 PM.