Why was the Buick nailhead an unusual engine?

Why was the Buick nailhead an unusual engine?

Its unusual head and valve arrangement made it a narrow engine, increasing its appeal to engine swappers, like this one replacing the six in an old Chevy. But it was precisely that narrow head that also presented serious challenges. Here’s a nice cutaway of the Buick nailhead engine.

What makes a nailhead a good spark plug?

After doing a lot of research, here’s what I found: The less timing advance needed in an engine means it has a good combustion camber design; the Nailhead has the least timing advance (30°) that I know of, and the spark plug is right in the middle of the chamber for a short flame travel.

How big is the pushrod hole on a Buick nailhead?

The early 264-322 heads (up to mid-1955) have a very small pushrod hole that should be enlarged if a larger cam is used, explains Martin. All 1959-’66 364, 401 and 425 heads have the same ports and valve size; the 1957-’58 heads are the same with smaller valves.

What was the intake valve on a Buick nailhead?

Perhaps the most obvious thing about the Buick nailhead is that its arrangement demands very small valves, which seems antithetical to the whole concept of the modern V8 in the first place. And small they were, hence the “nail head” moniker. The early engines had a 1.75″ intake and a 1.25″ exhaust valve, puny even for the mid fifties.

What kind of engine was the Oldsmobile nailhead?

It was an OHV pushrod engine like the then-new Oldsmobile “Rocket V8”. It became known as the “nailhead” for the unusual vertical alignment of its small-sized valves, features that were the result of putting both valves on the intake manifold side of the “pent-roof” combustion chamber used in this engine series.

How many nailhead engines does a Buick have?

Buick made four different 401 engines, three of which have different blocks. Plus, there were two different 425s.” the correct year before starting the rebuild. “Certain engines cannot be used crankshaft changes,” Martin explains. “Plus, since all Nailhead engines were to work.” your balance with a the Buick is critical.

Are there cracks in the nailhead cylinder head?

The whole valvetrain is very light so softer valve springs can be used for less engine wear and quicker revs. .Cracks are rare in a Nailhead cylinder head,” he says. “And they rarely leak oil because of the way the valve covers are designed.” The ports are smaller than most HP engines but designed with high velocity.

Can you put exhaust valve seals on nailheads?

Martin says you can add them to all Nailheads but never install exhaust valve seals. “Very little too dry.” warns Martin. “Without the right gaskets, engines can leak oil front and rear of the gasket from the oil passages that feed oil to the rockers.