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Head Gasket
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kch
Senior Member
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Taken from AH-spares webpage:
To loosen a cylinder head prior to removal , first remove all the head nuts (remembering to loosen in the correct order) and then with the spark plugs still in place but NOT connected , operate the starter briefly a couple of times.
The head should now be easy to remove.
And when you put the top on back, remember to tight the exhaust, and inlet manifolds nuts, before you put on the heat shield between carburettors and inlet manifold.
To loosen a cylinder head prior to removal , first remove all the head nuts (remembering to loosen in the correct order) and then with the spark plugs still in place but NOT connected , operate the starter briefly a couple of times.
The head should now be easy to remove.
And when you put the top on back, remember to tight the exhaust, and inlet manifolds nuts, before you put on the heat shield between carburettors and inlet manifold.
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Hi Dave,
If the previous gasket failed, which I assume, you need to check a few things carefully. I would check them anyway.
First, before removing the head, check that all hold down studs will torque to 75 ft lb. This checks the condition of the studs & threads. Any that won't tighten to this torque should be replaced.
It is a lot of trouble, but I personally would remove all studs, clean them up, & chamfer the top of the stud holes in the block. A large drill bit used by hand will work. There is often a top thread that has been raised above block level which may prevent the head or gasket from fully seating.
Clean the block & head surfaces by lightly running a large flat file across them at various angles. In addition to cleaning the surfaces, this will show any low spots that may prevent a good seal. You can place a straight edge across the surfaces & measure any low spots with a feeler gage. If you find any, .003" would be the maximum that would likely seal for any length of time. If more than this, the block or head should be resurfaced. Especially check the surfaces between cylinders. It really wouldn't hurt anything to do the same with the manifolds & surfaces on the side of the head.
A coat of grease in the cylinder bores will prevent any metal filings from getting where they shouldn't. I would vacuum out all spaces & then wipe out the grease. Also, temporarily plug the rocker oil feed hole.
Replace the studs, use a sealer such as "Permatex Aviation" on any stud holes that may penetrate into water or oil spaces. Just snug the studs lightly in their holes.
Some headgaskets such as the "FelPro PermaTorque" require no sealer as they have their own sealer built in. If you have a gasket with metal on both sides, Especially copper, I would apply a couple coats of "Permatex Copper Spray-A-Gasket" to both sides. I know others will disagree with this but it can't hurt & I have never had a gasket failure with it. (Maybe I wouldn't have without it.)
When you reinstall the head Torque the nuts three times progressively to 40, 60, & 75 ft lb. Use a spiral inside to outside pattern or what ever your book shows.
Before reinstalling the rocker arm assembly, temporarily reinstall the rocker feed banjo bolt so that it's small shoulder lightly seats into it's drilled hole in the shaft. After the rocker assembly is tightened down, remove the bolt & install the banjo. If the assembly is tightened down with the banjo/rocker shaft misaligned, the bolt will strip in the aluminum shaft support when you try to tighten it. If you already know all of this just skip over it.
Good luck,
D
If the previous gasket failed, which I assume, you need to check a few things carefully. I would check them anyway.
First, before removing the head, check that all hold down studs will torque to 75 ft lb. This checks the condition of the studs & threads. Any that won't tighten to this torque should be replaced.
It is a lot of trouble, but I personally would remove all studs, clean them up, & chamfer the top of the stud holes in the block. A large drill bit used by hand will work. There is often a top thread that has been raised above block level which may prevent the head or gasket from fully seating.
Clean the block & head surfaces by lightly running a large flat file across them at various angles. In addition to cleaning the surfaces, this will show any low spots that may prevent a good seal. You can place a straight edge across the surfaces & measure any low spots with a feeler gage. If you find any, .003" would be the maximum that would likely seal for any length of time. If more than this, the block or head should be resurfaced. Especially check the surfaces between cylinders. It really wouldn't hurt anything to do the same with the manifolds & surfaces on the side of the head.
A coat of grease in the cylinder bores will prevent any metal filings from getting where they shouldn't. I would vacuum out all spaces & then wipe out the grease. Also, temporarily plug the rocker oil feed hole.
Replace the studs, use a sealer such as "Permatex Aviation" on any stud holes that may penetrate into water or oil spaces. Just snug the studs lightly in their holes.
Some headgaskets such as the "FelPro PermaTorque" require no sealer as they have their own sealer built in. If you have a gasket with metal on both sides, Especially copper, I would apply a couple coats of "Permatex Copper Spray-A-Gasket" to both sides. I know others will disagree with this but it can't hurt & I have never had a gasket failure with it. (Maybe I wouldn't have without it.)
When you reinstall the head Torque the nuts three times progressively to 40, 60, & 75 ft lb. Use a spiral inside to outside pattern or what ever your book shows.
Before reinstalling the rocker arm assembly, temporarily reinstall the rocker feed banjo bolt so that it's small shoulder lightly seats into it's drilled hole in the shaft. After the rocker assembly is tightened down, remove the bolt & install the banjo. If the assembly is tightened down with the banjo/rocker shaft misaligned, the bolt will strip in the aluminum shaft support when you try to tighten it. If you already know all of this just skip over it.
Good luck,
D
John Loftus
Darth Vader
Offline
[ QUOTE ]
Hi Dave (snip) ...much info... (snip)
Good luck,
D
[/ QUOTE ]
Dave,
Great post ... love it when you give long detailed explanations ... always learn something.
/ubbthreads/images/graemlins/cheers.gif
John
Hi Dave (snip) ...much info... (snip)
Good luck,
D
[/ QUOTE ]
Dave,
Great post ... love it when you give long detailed explanations ... always learn something.
/ubbthreads/images/graemlins/cheers.gif
John