My 63 327/340 was reassembled with a Fel-Pro/Sealed Power gasket set 260-1000/KS 2600. Is it necessary/recommended to re-torque the heads at some point? I was not able to determine which of Fel-Pro's specific head gaskets were included with this set. Thanks.
-
-
Re: re-torque heads?
no. fire it up. good luck. mike -
Re: re-torque heads?
if the heads were torqued in steps till you got to 65# ft you should be OKComment
-
Re: re-torque heads?
Jim-----
If the head gaskets were supplied as part of an engine gasket set AND are composition-type gaskets, they are virtually always of the type that requires re-torque. The only Fel Pro COMPOSITION type gaskets that do not require retorque are the Perma-Torque Blue series. I don't think that these are supplied in any engine gasket KITS; just seperately. The Permatorque Blue gaskets are easily identified by their blue teflon coating on both sides. However, I don't know if other non-Permatorque Fel Pro gaskets might now have the blue coating, too.In Appreciation of John HinckleyComment
-
Re: re-torque heads?
What is the problem with re-torquing them whether required or not is?BobComment
-
Re: re-torque heads?
lots of work as you have to pull the exhaust manifolds. i never retorqued a head no matter what type of gasket BUT i did start at 25#ft and go up 10#ft at a time around the pattern till i reached 65#ft. i bet GM never retorqued them.JMHOComment
-
Re: re-torque heads?
clem-----
I don't know, either, if re-torquing the head bolts is absolutely necessary. However, it's generally specified for most composition-type head gaskets by the gasket manufacturers.
GM never needed to specify re-torque of the head bolts since, generally, they used steel shim type gaskets which do not require any re-torque. There were a few early engines that did use a composition type gasket, though. L-88 and ZL-1 were among them.
C4 era small blocks also use a composition-type gasket. However, I believe that these are a no-retorque type gasket.In Appreciation of John HinckleyComment
-
Re: re-torque heads?
I agree totally with Clem, altho I take them down in 5# increments. Takes more time, but makes me feel better and have never had a problem.Comment
-
Re: re-torque heads?
Just an observation. Head bolts do stretch don't they? Therefore I'd go the safe route and re-torque. How about Compression affecting the need to re-torque? JMHOComment
-
Re: re-torque heads?
Any bolt that is torqued will stretch due to the applied tension load, but usually in the elastic range; however, some head bolts are designed to stretch inelastically (beyond the material yield strength) and these are usually one time use, but this group does not include vintage Corvette engines.
The problem with composition gaskets is that they can "creep", which means they continue to compress with time under compression load, and this will reduce bolt clamping force. This is not an issue with steel shim gaskets.
Since composition gaskets will take up to about .003" surface warp, they are best to use when assembling a rebuilt engine that does not have freshly machined head and block deck mating surfaces, and the "permatorque" type - or whatever name the manufacturer calls them - are the best to use since they resist further compression with time under compressive load and don't require retorquing.
The OE steel shim type will not be as forgiving of warp, but with freshly machined surfaces, they rarely caused problems with factory built engines.
DukeComment
Comment