When sealing head stud/bolt threads..
11-11-2011, 06:10 PM
#1
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When sealing head stud/bolt threads.. Ofcourse the ARP studs paper work didn't say anything about putting any type of sealant on the threads.. But I knew better , just didn't quite know what to use though... Lloyd Elliott recommended I use a maximum oil/fluid resistance RTV silicone like ultra black.. And I did.. Cleaned the excess off the block deck around the studs , slid on gasket and bolted heads down ...
Mistake? If so should i use something else by pulling one stud at a time , applying X and retorquing ?Engine is on the stand still
Mistake? If so should i use something else by pulling one stud at a time , applying X and retorquing ?Engine is on the stand still
11-11-2011, 06:28 PM
#2
I have done studs on a few dozen motors and have always used ARP thread sealer myself. But, at the same time, my last motor (which was one of my own) I had one of the studs actually leak coolant. I ended up using a couple of the GM sealant tabs and the leak was fixed.
Upon redoing headgaskets on that setup (thought there was an issue that didn't exist) I ended up using teflon tape applied properly (ie, twisted in the proper direction to prevent unwrapping while installing) and applied thickly after I chased all the threads in the block. Using teflon tape it has not leaked either. The negative to teflon tape is that in the future if you need to pull the studs you run the risk of getting tape fragments in the cooling system where you could end up plugging up a little of the radiator or the heater core, but, on a car with head studs, unless you are doing a complete rebuild where stuff in the coolant wouldn't matter, how often are you going to be pulling the studs out of the block even if you have to redo the headgaskets? And, yeah, pulling the top 4 studs is a little different since the bottom of the studs are either blind or with only a small amount open to coolant, not a full open hole like the rest of them on the deck, so again, I consider it a non-issue.
Now on headbolts I would use nothing but ARP thread sealer. Never had a problem there either.
Also, I have gotten in the practice of putting a couple of GM sealing tabs in any of the setups I do from now on. Good insurance and saves headaches.
Upon redoing headgaskets on that setup (thought there was an issue that didn't exist) I ended up using teflon tape applied properly (ie, twisted in the proper direction to prevent unwrapping while installing) and applied thickly after I chased all the threads in the block. Using teflon tape it has not leaked either. The negative to teflon tape is that in the future if you need to pull the studs you run the risk of getting tape fragments in the cooling system where you could end up plugging up a little of the radiator or the heater core, but, on a car with head studs, unless you are doing a complete rebuild where stuff in the coolant wouldn't matter, how often are you going to be pulling the studs out of the block even if you have to redo the headgaskets? And, yeah, pulling the top 4 studs is a little different since the bottom of the studs are either blind or with only a small amount open to coolant, not a full open hole like the rest of them on the deck, so again, I consider it a non-issue.
Now on headbolts I would use nothing but ARP thread sealer. Never had a problem there either.
Also, I have gotten in the practice of putting a couple of GM sealing tabs in any of the setups I do from now on. Good insurance and saves headaches.
11-11-2011, 07:12 PM
#4
I had a few of my arp studs leak with their sealant being used. I took each one out 1 at a time and applied teflon tape to them. Then I re-torqued them down. The tape seems to seal perfect the first time. FWIW I was fairly liberal with the amount of arp sealant that I used. It would ooze out of the block as I inserted each stud, and i'd have to wipe off the excess. I talked with a few people about this at the shootout and they said it was common with the arp studs. If I had to do it again i'd use the tape on all of them.
11-11-2011, 07:20 PM
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TooK the studs out of the heads one at a time taped each and retorqued one at a time straight back to 80 ft lbs? And it didn't cause any issues with head gasket? Is what your saying right? And you used oil resistant Teflon tape? Right?
11-11-2011, 08:02 PM
#7
Yes to all of the questions. No issues to report. 2 were on the driverside head 1 on the passenger side. Head gaskets are a 5 layer MLS.
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11-11-2011, 10:15 PM
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So should I even screw with them, and if i do my head gaskets are felpro 1074's will it bother the gasket to take one stud out at a time ,wrap threads and retorque to 80?
11-12-2011, 08:10 AM
#9
If you used a good RTV, it will be fine. I've done many this times.
Personally I use the Permatex Ultra series.
On studs, I fill the bolt threads & screw them in, then wipe off the excess.
It works fine.
Personally I would not trust teflon tape, it is designed for close tolerance pipe threads. You would have to put a ton of it on to even come close to sealing up regular threads. While it may have worked, I would never recommend this.
Personally I use the Permatex Ultra series.
On studs, I fill the bolt threads & screw them in, then wipe off the excess.
It works fine.
Personally I would not trust teflon tape, it is designed for close tolerance pipe threads. You would have to put a ton of it on to even come close to sealing up regular threads. While it may have worked, I would never recommend this.
11-13-2011, 08:39 PM
#20
Actually, in certain applications, ARP even says you *HAVE* to use teflon tape to take up the extra space in loose fitting stud applications as pastes, even thiers, are more likely to leak. I believe W-body head studs for the 3800 are one such application.
The problem with RTV is if you let it set before you torque down the heads you have teh possibility to cause the RTV to shift in the threads when they are torqued, which can cause a leak as well. I know a few instances personally where that has happened and the builder always torqued the heads after the RTV has already setup for a day or two. The other big issue with RTV is if the threads on the studs/block are not fully clean of dirt and oil then you will not get a seal. Eassy enough to say you made sure it is clean, really hard to be 100% certain.
Paste sealers, like ARPs or Permatex non-hardening stuff, is made to deal with less than ideal situations in regards to cleanliness and such and usually do a good job while sealing. Only if the space between threads is too great does it become a compromised solution. That is when something that fills the gap more "solidly" such as teflon tape wrapped on heavily does the job. You just need to make sure it is wrapped in teh proper direction to make sure it does not unravel when you install the studs into the block.
As I said before, GM actually calls for using it's sealing tabs in ALL applications which have either bolts/studs go into water passages or those applications that have aluminum castings holding back cooling system pressure (such as waterpumps and blocks). They are extremely effective on making sure you don't have leaks/weeping from bolt/stud threads and/or porous aluminum castings.
Northstar blocks are well known for having the possibility of leaking through proous castings to the outside of the block itself. Since the LT1 has both bolts/studs the protrude into the waterjacket as well as aluminum waterpump and heads, it falls into all catagories where using sealing tabs in a requirement.
The problem with RTV is if you let it set before you torque down the heads you have teh possibility to cause the RTV to shift in the threads when they are torqued, which can cause a leak as well. I know a few instances personally where that has happened and the builder always torqued the heads after the RTV has already setup for a day or two. The other big issue with RTV is if the threads on the studs/block are not fully clean of dirt and oil then you will not get a seal. Eassy enough to say you made sure it is clean, really hard to be 100% certain.
Paste sealers, like ARPs or Permatex non-hardening stuff, is made to deal with less than ideal situations in regards to cleanliness and such and usually do a good job while sealing. Only if the space between threads is too great does it become a compromised solution. That is when something that fills the gap more "solidly" such as teflon tape wrapped on heavily does the job. You just need to make sure it is wrapped in teh proper direction to make sure it does not unravel when you install the studs into the block.
As I said before, GM actually calls for using it's sealing tabs in ALL applications which have either bolts/studs go into water passages or those applications that have aluminum castings holding back cooling system pressure (such as waterpumps and blocks). They are extremely effective on making sure you don't have leaks/weeping from bolt/stud threads and/or porous aluminum castings.
Northstar blocks are well known for having the possibility of leaking through proous castings to the outside of the block itself. Since the LT1 has both bolts/studs the protrude into the waterjacket as well as aluminum waterpump and heads, it falls into all catagories where using sealing tabs in a requirement.