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Author
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Topic: need advice on Cometic head gaskets!! please read!!
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CometGT1974
Gearhead Posts: 479
From: Asheville, NC USA
Registered: Jan 2002
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posted 08-14-2003 10:29 AM
 
I recenlty purchased a set Cometic's MLS (HP) head gakets. I installed the head gaskets after checking the deck and heads for flatness and making sure that both surfaces were spotless!!! I torqued the heads to ARP recommendations for 7/16" studs ( 65 ft. lbs. on the lower bolts and 70 ft. lbs on the uppers using ARP molylube) and I feel that I installed everything the absolute correct way!! After initial fire up I noticed a little bit of "leakage" coming from the rear of the heads where the main water crossover is. It's not a bad leak by any means, just a little leak, a couple drops here and there. I called cometic and they said to take the gaskets off and inspect them. I don't feel that the leak necessarily would require the long/hard process of re-pulling my motor and pulling the heads back off. I suggested that I run some block sealer through it but cometic said that wouldn't be there first choice!! What does everyone think about this and has anyone ever experienced anything like this before?? What do you think I should do??
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7DMACH1
Gearhead Posts: 2915
From: PHILA. PA.
Registered: Feb 2001
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posted 08-14-2003 10:48 AM
Did you try retorqueing the heads after the head up and cool down? I would try this if you didn't. RAY------------------
RAY, THE WISE A@@ PHILLY
GUY!!!!
FAST UGLY CARS ARE FUN, BUT THEY'RE LIKE FAT CHICKS, FUN TO RIDE, BUT DON'T WANT TO BE SEEN WITH!!!
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CometGT1974
Gearhead Posts: 479
From: Asheville, NC USA
Registered: Jan 2002
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posted 08-14-2003 10:55 AM
Cometic told me NOT to retorque the heads, they said that there head gaskets do not require retorquing. After thinking about it though, the torque specs that ARP gave for there 7/16" studs seems low to me. Every other torque spec I have seen for my application is around 80-85 ft. lbs. Do you think torquing the longer studs to 70 and the shorter ones to 65 could cause problems since this is basically a solid steel head gasket?? I'm considereing just getting some Moroso block sealer and retorquing the heads to about 80 - 85.......
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kid vishus
Gearhead Posts: 7251
From: middle of NC
Registered: Oct 2000
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posted 08-14-2003 11:18 AM
If it were mine, it would be a 3 part process to try and get it to stop. First thing I would do is retorque to ARP's specs. If that didn't work, I would torque them down a little higher (although, the reason ARP's specs are lower is because their moly lube is much slicker than conventional lube and therefore doesn't have to overcome friction), if that doesn't work, then I would add some sealant. I would only do one thing at a time. But I would definately try something before pulling the motor.
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V8 Thumper
Gearhead Posts: 4777
From: Phoenix, Arizona
Registered: Dec 2001
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posted 08-14-2003 11:29 AM
What heads/block?------------------
1965 GT coupe, 333ci aluminum headed/solid cammed stroker, four speed, 3.70:1 9" All Blue Oval, no blue bottle
http://mustangsandmore.50megs.com/V8Thumper.html
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CometGT1974
Gearhead Posts: 479
From: Asheville, NC USA
Registered: Jan 2002
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posted 08-14-2003 11:31 AM
Victor Jr heads and a factory (late model) 302 block. The heads are basically new and the block has been slightly surfaced. I checked both for flatness before re-assembly.
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CometGT1974
Gearhead Posts: 479
From: Asheville, NC USA
Registered: Jan 2002
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posted 08-14-2003 12:07 PM
I spoke with a tech at cometic again today. He said that the small "rivets" that hold the gasket together could be pinched causing the gasket to not receive the proper torque. He also said that the torque recommendations from ARP may not be the best thing for there "style" of gasket. Since this is basically a solid steel head gasket I might need to keep all the studs at the same torque instead of the recommended 70 lbs on the uppers and 65 on the lowers!?!?!?!
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Rustang
Gearhead Posts: 880
From: Clarion PA
Registered: Nov 2000
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posted 08-14-2003 01:44 PM
Hopefully this isn't the case, but since you had the block decked there's a chance the deck surface is not smooth enough to hold a steel gasket. If that were the case, something like Permatex's spray on copper gasket cement would help.------------------
'68 mustang 351 clevor- 10.92@124
'67 Stang, 351W -11.18@118
'69 351C Torino-14.90@100
'78 Pickup 351W-15.56@88
'79 Pickup 460 ET=??
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WARDF
Journeyman Posts: 44
From: Cecilia, Ky. USA
Registered: Mar 2002
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posted 08-15-2003 01:04 AM
Like Kid stated about the friction, I understood that 70lbs. with the molylube on the threads is equivelant to the 85lbs. without that you would normally do. Before I went to torquring them down more I would call Edlebrock and find out what they say about torquing them down and to what amount, I would hate to here about you breaking a head.
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V8 Thumper
Gearhead Posts: 4777
From: Phoenix, Arizona
Registered: Dec 2001
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posted 08-15-2003 09:49 AM
About those rivets... I too run Cometic MLS gaskets, and I did cut the rivets off prior to assembly. I test-fit everything, and found that they 'pinched' by just a hair. That gasket material is spring steel, you'll have a helluva time trying to cut it. I ground one side of the rivet down and pushed the rest out the other side. Hopefully this is not causing your leaking condition, because it'll mean pulling the heads  ------------------
1965 GT coupe, 333ci aluminum headed/solid cammed stroker, four speed, 3.70:1 9" All Blue Oval, no blue bottle
http://mustangsandmore.50megs.com/V8Thumper.html
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V8 Thumper
Gearhead Posts: 4777
From: Phoenix, Arizona
Registered: Dec 2001
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posted 08-15-2003 10:04 AM
On the torque issue, I torqued mine to 70 and 75, ARP bolts and moly lube. I'm not sure what Cometic is saying about the torque, but the longer bolts require a bit more to compensate for torsion due to the length. What KV and Ward said about the moly lube is why they don't require as much torque as 'traditional' fasteners. Less load = less cylinder distortion.I checked the torque of my heads at 1000 miles, and they didn't move or change at all. Still, re-torquing is SOP. I don't care what Cometic says, I'll still check them periodically. Aluminum moves a whole bunch  ------------------
1965 GT coupe, 333ci aluminum headed/solid cammed stroker, four speed, 3.70:1 9" All Blue Oval, no blue bottle
http://mustangsandmore.50megs.com/V8Thumper.html
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CometGT1974
Gearhead Posts: 479
From: Asheville, NC USA
Registered: Jan 2002
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posted 08-15-2003 10:48 AM
I appreciate all the replies to this subject!!! I think I will go back and check the torque on the heads and maybe increase to 70 and 75 ft lbs and see if that will fix it!! I'm also gonna drill the rivets out if I can get a drill down in there!! If all that doesn't work i'm gonna try some moroso block sealer. If it still doesn't work i'll pull the heads off, send the gaskets back to Cometic and kindly ask for some new gaskets!!!
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