Author Topic: Head gaskets  (Read 4131 times)

Offline cudabob496

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Re: Head gaskets
« Reply #15 on: July 06, 2014 - 07:47:55 PM »
is there an ARP head bolt that will work better?
What about lubricating the bolts before torquing.
Sounds like not getting adequate clamping force, unless
surfaces are not flat. Felpro gaskets should have worked
the first time, you would think.

Might run it, then let it cool down and recheck torque on bolts.
If still ok, then must be un-flat surfaces.

did car ever overheat, which could cause some head warpage.

Would a washer under head bolts help? Not sure if that's allowed.

Maybe retap bolt holes to clean them out?
« Last Edit: July 06, 2014 - 07:52:43 PM by cudabob496 »
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000




Offline Dusty1

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Re: Head gaskets
« Reply #16 on: July 06, 2014 - 08:51:32 PM »
They didn't wait for me at start up and overheated it. They didn't know how the Pertronix worked and it was out of time, but I had the machinist check that head since then. It was good.
Garys 1972 BS

Offline cudabob496

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Re: Head gaskets
« Reply #17 on: July 06, 2014 - 10:30:50 PM »
They didn't wait for me at start up and overheated it. They didn't know how the Pertronix worked and it was out of time, but I had the machinist check that head since then. It was good.

Hmmm, maybe time for another opinion?
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000

Offline Dusty1

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Re: Head gaskets
« Reply #18 on: July 07, 2014 - 09:23:22 PM »
Yah I know, something may have to go. I have a hard time giving up on the old boys, I spent a lot of money on these old iron heads just so they could keep hanging around.
Garys 1972 BS

Offline cudabob496

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Re: Head gaskets
« Reply #19 on: July 07, 2014 - 10:26:41 PM »
Yah I know, something may have to go. I have a hard time giving up on the old boys, I spent a lot of money on these old iron heads just so they could keep hanging around.

May not be too big of a problem.  Recheck for flatness, and perhaps doing some resurfacing.

In hotrodding, seems for every 10 things that go right, one or two go wrong. Perseverence
will win out.
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000

Offline Dusty1

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Re: Head gaskets
« Reply #20 on: July 07, 2014 - 11:23:59 PM »
They have been shaved so much I can barely get the intake to bolt back on. Last time I blew a head gasket the machineist said they were good, that he wouldn't do any thing to them.
Garys 1972 BS

Offline Strawdawg

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Re: Head gaskets
« Reply #21 on: July 08, 2014 - 12:08:23 AM »
Pull the head, put a straight edge across it at various angle and see what the "thickest" feeler blade is that you can slide between the straight edge and head surface is.

You can do a search but I think we always looked for 0.004" lengthwise and 0.002" across as maximum numbers.  If worse than that, have it lightly decked.

Also do a couple of checks on the block decks and examine them for any flame erosion between cylinders.


Use a thread chaser and clean all the holes.  Check all the bolt lengths to be sure you don't have any "extra" long ones.  If the bolts have been used several times, replace them.  Studs will provide better clamping but should not be required unless you are making some serious compression and power.

Lubricate the threads or use a sealer/lubricate like the one ARP sells for the threads.  Be sure to lubricate the washers on both sides and some oil on the bottom side of the heads.  Check to see what the torque is for the lubricant that you are using.  Torque numbers are quite a bit higher when using oil as compared to when using the ARP lube.

Torque in several steps.  Warm the engine up, let cool completely and retorque.  None of them should require significantly more movement than the others.

If the intake bolts still line up, it would not seem that the heads have been overly decked.  I would check the pushrod preload as well which is a good indicator in some cases as to how much the heads or decks have been cut.

Offline cudabob496

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Re: Head gaskets
« Reply #22 on: July 08, 2014 - 02:23:37 AM »
They have been shaved so much I can barely get the intake to bolt back on. Last time I blew a head gasket the machineist said they were good, that he wouldn't do any thing to them.

Getting the intake gasket to seal may be another issue to deal with.  I have a pan gasket, and the individual
intake gaskets on each side of it.  Had to open up the size of the holes on the intake a little too.
Or, may need the intake machined a little.  Otherwise, can suck a lot of oil into your intake valves,
among other things.
« Last Edit: July 08, 2014 - 10:22:08 PM by cudabob496 »
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000

Offline Dusty1

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Re: Head gaskets
« Reply #23 on: July 09, 2014 - 01:29:07 PM »
Thanks guys for all the help! I'll try your suggestions as soon as I get time to pull the head.
Garys 1972 BS