Dr. Davin diagnoses the “Redline Rebuild” Buick straight-eight - Hagerty Media
Finding engines for the Redline Rebuild series has never been an issue. However, the mechanical diagnosis of those engines is usually more complicated; Davin often discovers the engine to be in pretty rough shape during the tear-down process. The new Redline Rebuild candidate wasn’t the healthiest he’s taken on, but the Buick straight-eight was far from the worst. Of course, we documented the whole process in the second Redline Update so you can dig into all the details.
This engine was running recently—though not perfectly. The 1951 Buick Special this straight-eight was originally in is now undergoing a thorough resto-mod, and a “good-enough” engine was not going to cut it. Davin yanked the long engine from the Buick chassis and hauled it back to the Redline Rebuild garage. Now, he’s breaking down the motor bit by bit to evaluate the tools and the work needed.
“Since this engine was a runner, I had pretty high hopes that it would need minimal work,” says Davin. “Little did I know that the few small things that stood out were indicators that this was not going to be so smooth.”
Among those tell-tale symptoms was the rust forming from the leaking freeze plugs on the side of the engine block. In addition, the pulley on the nose of the crankshaft had a slight movement when it shouldn’t. Once the cylinder head came off, Davin made a more interesting discovery: the pistons were stamped .040, signifying this straight-eight had been to the machine shop at least once in its life, where it received a .040-inch overbore and accompanying larger pistons.
The worst news of the whole adventure, though, is that those already-bored cylinders are in pretty sad shape. With any luck, the team at Thirlby machine shop will tell Davin that it’ll clean up by going to .060-inch overbore; but in that case, Davin is more worried about finding properly sized pistons.
“We probably have enough meat left in the block to go to 60-over, but if I can’t find 60-over pistons to match then it doesn’t really matter. It might shape up to be eight fresh sleeves getting hammered into this block. Not the worst, but not great either.”
The machine shop is the next stop for the block and cylinder head. If you want to be the first to know how it all shakes out, be sure to subscribe to the Hagerty YouTube channel to receive notifications as Redline Updates are posted each Monday.