Re: loose manifold bolts

Posted by Peter Packard On 2013/3/3 3:51:05

Hi all, Brass is good..I would recommend new brass manifold nuts.....My 66 Rolls-Royce wheel nuts are brass and torqued to 45 ft lbs. The principle of the Packard Exhaust manifold is no different....You must have sufficient manifold tension to seal the manifold, but must allow the exhaust manifold to "slip" across the face of the gasket as it expands. I have quite often observed my Packard exhaust manifolds glowing in the dark after a 65 mph run. The brass nuts are designed for this use as they expand more than the stud when heated and grip the steel studs in the block. This discourages their migration during use. I have tried to "second-guess" Packard some times and it usually ends badly. I recommend that you use the brass nuts and the 25-30 ft Lbs torque recommendation. (use 25). DO NOT overtighten as a tight manifold will tear the gasket apart. Be very cautious also of refacing manifolds as this is usually done by milling and the resultant milling marks will grip and kill the gaskets. Best regards Peter Toet .