do you torque Head bolts after heatup?

C

cjc56

Senior Member
The shop manual for my 56 tbird calls for the head bolts to be retorqued after the engine has run for 30 minutes. To do this the exhaust manifolds along with the rocker arms must be removed. Is this step necessary?
 
If you are using a modern "no retorque" gasket such as Fel-Pro's Perma-Torque, then no. If you're using steel shim gaskets the answer is probably yes although some have used them successfully without retorquing by coating them with aluminum spray paint or Permatex Kopper Cote before installing.
 
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I never have retorqued any that I have built. A racer once asked me why, and my reply was the same as above. The racer said if that's what you need to do, then do it. I have run about eleven to one on one engine, and it was fine.
 
I never have and been building engines since the early 70s. Never had a head gasket let go on any of them.
 
I guess if you used Chinese head bolts, you would have to re-torque every 100 miles, and then replace them every thousand miles.
 
thanks everyone. I am sure that Ford did not use Chinese head bolt back in the 50s, so I am just wondering why they put that in the Shop manual. As Y-blockhead said surely they did not start the engine up just to retorque everything.
 
If you were to buy a new engine gasket set for a Ford 223 I-Block 6, you might get one of those old style head gaskets with the sandwich type construction that do require re-torquing, HOWEVER, there is no need to remove anything but the rocker arm cover regardless of whether you are working on a Y-Block or an I-block. Every head bolt on a Y-block is accessible with a socket even with the rocker arms in place. It might be wise to slightly loosen the exhaust manifold bolts prior to re-torquing head bolts. If you must re-torque, it would be very wise to go back through all your valve lash adjustments after re-torquing.
Again, it is about a thousand-to-one odds that you need to re-torque. Engine gasket sets often identify the type of head gaskets enclosed in the set. If the set includes Fel-Pro prema-torque head gaskets, they do not require re-torquing. If the gasket set contains sandwich type with rubber middle in the head gasket, the kit instruction sheet should clearly indicate that the head gaskets require re-torquing.
 
I amof two thoughts in regards to retorquing. It used to be essential when using copper head gaskets and advisable when using steel gaskets. You also had to coat the gaskets with a sealant. This was necessary as the gaskets were annealed when assembled and would compress. Old Don is right that the manufacturers of the new compound gaskets claim you don't have to retorque them once hot. It used to be that you would do 100 miles and then retorque as the engine would have heated up evenly. I have had lots of problems over the years with these new gaskets and especially on yblock engines as they have so few head bolts. For this reason I also retorque. For example the last engine I built which is a 292 with big cam and heavily planed head has a blown head gasket at the moment. These in my experience always blow between the cylinder and a water jacket which pressurises the cooling system, causes the coolant to heavily discolour and dump water out of the radiator. It has always been with this set of heads, but they have been considerably reworked and are nice and flat. I had the block decked when I built this engine. I am probably at about 10-11:1 CR and it has 175 Psi cranking pressure. It has taken about 6 years but it is blown again. I use this car infrequently about once a month and do probably 100 miles when I do.
 
The Ford shop manual is made for service work, so maybe they say re-torque to cover any type of head gasket you may use.
 
If your using a modern day gasket say a fel pro you can also use a product called Hylomar where you coat both surfaces then torque up once to specification, generally though when using the fel pro gaskets I torque to spec's leave it an hour or so back off the bolts then re torque...if you mark the bolts you generally see that you get another 1/8 to a 1/4 of a turn on them...never had a problem.
 
I've used nothing but Fel=pro for years and never re-torque and have never had an issue. If it makes you feel better, do it, no harm done. Also if you are using 60 year old head bolts that have possibly been re-used many times and maybe of questionable metallurgy due to many stretch cycles, it is probably a prudent idea.
 
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