bb high compression head bolt re-torquing

[Chris H.]

My head gaskets are weeping and I'm going to retorque the headbolts and I have a few questions relating to the task.

Is it common for the high compression head gaskets to weep or leak? I've seen more than one that does it.

I need to remove the exhaust manifolds to access the bolts behind the manifold. Will I have any issues like knocking the dip stick out of its mount on the oil pan? Any other land mines I should watch out for?

[Joe L.]

Re: bb high compression head bolt re-torquing

Chris-----

I've not seen very much of this problem. However, I'm sure that it has a lot to do with whatever type gasket was last used on the engine. Generally, steel shim type gaskets do not require retorquing, assuming that they are torqued properly in the first place. Also, the stainless steel wire ring gasket available from Fel Pro (Fel Pro #1017-1 or GM #12363413 for 4-1/4" bore big blocks) should not require retorquing. Incidenatlly, the latter are the only gaskets that I will use. They are VERY expensive (GM LIST about $80/EACH and available from discount Fel Pro sources for about $50/EACH) but they are worth every penny.

If other types of composition head gaskets were last used on your engine, they may very well now require retorquing. And, you may get away with simply retorqing them. However, when a head gasket "loosens up" it can otherwise deteriorate making retorquing a futile effort. It's worth a try, though.

As far as the exhaust manifolds go, you will need to remove them to get at the lower head bolts. If you are careful, there should be no problem with the oil dip stick tube. On big blocks, the oil dipstick tube is a press fit into the special flange on the oil pan and is further retained by an attached bracket. You can remove the tube if you wish without facing the same dilemma that would exist if you were dealing with most small blocks.

[Chris H.]

Re: bb high compression head bolt re-torquing

Thanks Joe. Would you happen to know which bolts are long and which are short as the long ones require 75-80 ft/lbs of torque and the short ones 65-70. Thanks, Chris

[Joe L.]

Re: bb high compression head bolt re-torquing

Chris-----

My recollection is that the "external" bolts (i.e. those "under" the exhaust manifolds) are the "short" bolts and the "internal" bolts (i.e.those under the valve covers) are the "long" bolts.