I just recently got my 312 back together after a re-ring and followed the shop manual's instruction to 2-stage the cold head bolt torque at 55 then 65 ft-lbs. This is my first time installing heads on a Y and have never had an engine call for hot final-torquing before. I used the Fel-Pro gasket set that came with the Fel-Pro complete engine kit. I had already warmed and cooled the engine a couple of times before attempting to do the hot 75 ft-lb final torque. Of course I found the outer 4 bolts on each head completely inaccessible; of the 6 inner bolts, only a few rotated at all before my wrench clicked at 75. I didn't like the idea of removing the rocker shafts or the exhaust manifolds while hot to try to get the outer 4 bolts, so I just left them untouched.



I feel pretty uncomfortable about the whole affair, but though it's still quite fresh (I have only driven a few miles and idled), there is no evidence of leakage and the engine runs beautifully. I am considering leaving the bolts alone in their present positions. What would you recommend at this point?

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

I would just re torque them cold.

Head bolt re-torqing was a way of life with the steel shim head gaskets but technically should not be needed with composition gaskets assuming ‘good’ fasteners are being used and the bolts are being brought up to torque in steps and in a consistent torquing sequence.  If you still have the original head bolts, then re-torquing is likely a good idea and will not hurt.

Lorena, Texas (South of Waco)

I have read on here that most folks do their re-torquing around the 500 mile mark, with the engine cold. I have also read something about backing the bolts off and then bringing them up to 75, which seems like risky business to me. I am indeed using the original head bolts.



Since I haven't really brought all the bolts up to 75 to begin with, should I do it now, or wait until about 500 miles and check them all at 75 with the engine cold? Also, if I undo the manifolds at that point will it destroy the manifold gaskets?

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

Try modifying a 3/8" drive short socket. I ground one down on both ends so that the socket just covered the bolt head with no extra.  It was short enough to get under the rocker shafts, and was much easier to get on the lower head bolts as well. The smaller dia 3/8" drive extensions also help access and will take 75 ft lb of torque withouut problems.

Doug T

The Highlands, Louisville, Ky.

If they hold leave them alone, if they do not and you blow a head gasket (which I cannot count how many I have gone through) buy a set of arp head studs (they are not very expensive) and torque them down to 90 lb/ft.  Actually on my engine I torqued them down to 120 lb/ft and then tightened them about 45 degrees farther. They will be set for life.  I know some guys will disagree with me but I have done this several times and I am running 15 lbs of boost with mine for over 1500 miles and not a hint of gasket failure.  I don't ever agree with the retorque.  I also don't agree with the factory torque spec of 65-70 lb/ft.  That was sufficient from the factory when the compression ratio was 7:1 but if the engine has been rebuilt most likely you ratio is slightly higher.  You can do what you want I am just letting you know from expirience and I replaced many of my head gaskets untill I decide to just tighten the damn bolts down.  I am running this engine very hard at these boost levels and the gasket are holding up great.  By the way I am also using the blue felpro gaskets and am very happy with them.  Good luck and let me know if you have any comments or questions. 

Hutz;

I was just wondering which head gaskets you are using? I am using Fel-Pro Permatorque head gaskets with ARP head bolts on the motor I am building which will see 7-9 psi boost. Currently I have the bolts torqued to 65 ft./lbs. I HATE BLOWN HEAD GASKETS

Rono

  Ron Lane,  Meridian, ID

Thanks for the responses guys.



I figure since I'm running the thicker-than-stock felpro gasket and it's just a re-ring of an engine with some cylinder wall pitting that will never be raced and probably rarely pushed hard, that stock bolts at stock tightness should suffice.



I have never had a blown head gasket and don't care to. One thing I'm wondering is, if it's gonna blow due to improper bolt tightening, how soon might I expect that to occur?



Also, just to clarify, most of the responses thus far have referenced "re-torquing", which I take to be the same as checking that all bolts are still at the intended torque some time in the future of the engine's life. Since I never really brought all the bolts up to 75, I'm mostly wondering how important it is that I do so with the engine hot, and whether having already run the engine a fair amount as is will adversely affect head gasket life. I'm looking for peace of mind and trying to figure out what I need to do to get it

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

I am just using the felpro gaskets that are in the engine reseal kit.  My initial head gasket issue was due to the heads not having proper bracing in the coolant chamber inside the head.  Once I took care of that I purchased the arp head studs and torqued the heads to 115 lb/ft then another 45 degrees.  It is easier to torque the heads with that torque when you have the studs.  That way the threads in the head are just being pulled don instead of torquing that coarse thread.  The thread on the top of the studs is a fine thread which has more holding force.  As far as the retorquing the idea of that is to compress the combustion ring a little more.  My personal opinion is that once the ring is torqued you should not loosen the bolts.  You can give them a little more torque but I don't like to loosen them.  I own a mechanic shop and have been a tech for 11 years and I still disagree with loosening head bolts.  Even a lot of new torque procedures want you to do that.  If the head gasket is going to go it will most likely happen at wide open throttle under high low which is when the cylinder pressures are high.  I would leave them alone and if they go out then install new head gaskets with studs and good torque.  The main issue that manufacturers are concerned with overtorquing isn't warping the head but stripping the threads out of the block.  That is the great benefit of head studs so the threads are pulled on and not turned while trying crush a compression ring.