Another fn set of leaky cometics
12-18-2006, 06:08 PM
#1
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Another fn set of leaky cometics Started the car today for the first time in two weeks. Let it run up to temp and shut it off. Low and behold I heard a frying drip noise and smelled anti freeze. My drivers side head was leaking like a bitch all over my headers. I even used copper spray what gives? I was wondering, have any of you guys had luck retorquing and getting a leak to stop? I really don't feel like ripping this thing apart again.
12-18-2006, 07:37 PM
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head swap on a 75k motor. Everything was as clean as humanly possible believe me. They were new heads completely clean and deburred. The deck had no scratches or surface impurities. I'm going to try to retorque em and see what happens. It just really pisses off that I have to do all this **** again.
12-18-2006, 08:02 PM
#5
If it's the stock bore, I'd use GM head gaskets. IMO, they are the best out there for a stock bore NA motor. Cometics leak when the deck isn't clean or when it's not 100% flat. I've only used one set of Cometics in my life and they haven't leaked. Also, how many times are you torquing the heads when installing? When I installed my heads, the torqued them to 70 ft-lbs. About an hour later they were down to well under 50 ft-lbs. Took me a day of torquing until the heads and gaskets settled.
12-18-2006, 08:06 PM
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Well, that might explain it. I just torqued and called it a day. I didn't even think about going over them again. I'm using the Cometics for the increased CR.
12-18-2006, 10:28 PM
#7
damn, that sucks. thats also not what I was wanting to see. I thought i had my mind made up and was goin to use the cometics too. you do know mr gasket makes a set of .042" gaskets right? I was goin to use those instead of the cometics, but didnt know if they would put up with the cars next big mod, 150 shot.
good luck with the retorque and let us know how it goes.
oh yeah, and never seen this done on an LSengine, but for old school sbc's eng. builders would hit the head in several places with a dead blow hammer to "seat" the head before torqueing it down. maybe that would help with these engines too.?!@?
<-- perfect
good luck with the retorque and let us know how it goes.
oh yeah, and never seen this done on an LSengine, but for old school sbc's eng. builders would hit the head in several places with a dead blow hammer to "seat" the head before torqueing it down. maybe that would help with these engines too.?!@?
<-- perfect Last edited by Irocss85; 12-18-2006 at 10:38 PM.
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12-18-2006, 10:43 PM
#8
It dosent take much to make a cometic leak. Any little something stuck on a dowel or something in the dowel hole, a minor flaw in the deck or head, anything... You need to make sure your using a quality TQ wrench, and make sure you go over them a couple of times.
12-19-2006, 06:33 AM
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Originally Posted by Ferocity02
If it's the stock bore, I'd use GM head gaskets. IMO, they are the best out there for a stock bore NA motor. Cometics leak when the deck isn't clean or when it's not 100% flat. I've only used one set of Cometics in my life and they haven't leaked. Also, how many times are you torquing the heads when installing? When I installed my heads, the torqued them to 70 ft-lbs. About an hour later they were down to well under 50 ft-lbs. Took me a day of torquing until the heads and gaskets settled.
12-19-2006, 08:23 AM
#10
I had the same problem with my head swap. I started with a set of Dart 225's and felpro 1041 gaskets. Only torqued them once with ARP studs. They started leaking in about two weeks. Replaced them with SCE copper gaskets but didnt have the heads resurfaced, DOH! Started leaking again two months later. Took them off the third time and had them milled .010 and went to SCE Titan ICS'. I torqued, waited 24 hours, re-torqued, heat cycled and re-torqued again. I gained about an extra 1/8 of a turn with each re-torque. Good luck! Btw, the head gaskets I got were probably overkill but I wanted the best possible chance of not doing it again so I was happy to shell out the $180 for the gaskets from jegs.
12-19-2006, 03:16 PM
#11
To clear some things up...
It is absolutely necessary to re-torque the head bolts, whether they are ARP studs, ARP bolts, or even stock GM TTY bolts. The difference in procedures between using ARP bolts/studs and GM bolts is the torquing procedure. GM bolts use a certain sequence and steps of torque and so do the ARP's. However, you still must go back over them again once torqued, and I even wait a day and check them a 3rd time to make absolutely sure. I've had Cometics on two engines and both times I have used a light coat of copper gasket spray and checked the torque 3 times like I said... never had a leak. Torquing down the heads is a bit like detailing a car, the reward doesn't come from only one step, it takes a few passes to reach your goal.
It is absolutely necessary to re-torque the head bolts, whether they are ARP studs, ARP bolts, or even stock GM TTY bolts. The difference in procedures between using ARP bolts/studs and GM bolts is the torquing procedure. GM bolts use a certain sequence and steps of torque and so do the ARP's. However, you still must go back over them again once torqued, and I even wait a day and check them a 3rd time to make absolutely sure. I've had Cometics on two engines and both times I have used a light coat of copper gasket spray and checked the torque 3 times like I said... never had a leak. Torquing down the heads is a bit like detailing a car, the reward doesn't come from only one step, it takes a few passes to reach your goal.
12-19-2006, 04:04 PM
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Originally Posted by ArcticZ28
To clear some things up...
It is absolutely necessary to re-torque the head bolts, whether they are ARP studs, ARP bolts, or even stock GM TTY bolts. The difference in procedures between using ARP bolts/studs and GM bolts is the torquing procedure. GM bolts use a certain sequence and steps of torque and so do the ARP's. However, you still must go back over them again once torqued, and I even wait a day and check them a 3rd time to make absolutely sure. I've had Cometics on two engines and both times I have used a light coat of copper gasket spray and checked the torque 3 times like I said... never had a leak. Torquing down the heads is a bit like detailing a car, the reward doesn't come from only one step, it takes a few passes to reach your goal.
It is absolutely necessary to re-torque the head bolts, whether they are ARP studs, ARP bolts, or even stock GM TTY bolts. The difference in procedures between using ARP bolts/studs and GM bolts is the torquing procedure. GM bolts use a certain sequence and steps of torque and so do the ARP's. However, you still must go back over them again once torqued, and I even wait a day and check them a 3rd time to make absolutely sure. I've had Cometics on two engines and both times I have used a light coat of copper gasket spray and checked the torque 3 times like I said... never had a leak. Torquing down the heads is a bit like detailing a car, the reward doesn't come from only one step, it takes a few passes to reach your goal.
12-19-2006, 04:19 PM
#14
Originally Posted by 02Reaper
How would the whole torque process be using stock TTY head bolts?
http://www.bowlingss.com/Head%20Repl...eplacement.mht
Good luck.
Bill
12-19-2006, 09:28 PM
#15
I hope I don't jinx myself but I used Cometic .040s and new GM headbolts and followed the sequence on LS1howto.com to a T, and I have been 100% satisfied. I have put quite a few miles on the car since then, prolly 5-7k, and had it to the track a few times, prolly 15+ dyno pulls, a few with a 100 shot, and they're fine.
12-19-2006, 09:36 PM
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So I have read the install instructions several times and I dont think I have ever heard anyone mention anything about going back and re-tightening the head bolts with the factory gaskets and bolts...Should I plan to pull the valve covers off after a few miles and check them or am I good to go if I follow the proper procedures?
12-19-2006, 10:00 PM
#17
with the factory bolts you prolly have to do the retorque thing after the initial torque setting. then after doin the retorque, maybe leting it sit for a day, retorque for the 3rd time, then do the additional degree stretch. not sure if retightening the bolts will do anything or not after they have been stretched to GM specs. suppose it couldnt hurt to try tightening them a little bit again. just be careful not to break them or pull the threads out of the block. if that doesnt work, you could replace the bolts one at a time with the arp studs and then see if that works before pulling it all apart to remove the head gaskets. just another idea.
