EngineLabs

One seemingly innocent yet critical dimension is deck height. This term is often used in two different ways. The first defines the actual distance from the cylinder head mounting surface to the crankshaft centerline. As an example, a big-block Chevy’s deck height is 9.800 inches.

The other commonly used measurement is the difference in height from the flat portion of the top of the piston relative to the block’s deck surface. This can be where the piston is either above or below the block’s deck surface and what is referenced when the assembly is said to be “zero decked” — that is, the piston is perfectly even with the deck surface at TDC.

If the block has been align-bored, it can change the distance from crank centerline to the deck, adding to this wandering of specs. Add in the variables of connecting-rod length and changes to the piston’s compression height, and it’s not unusual to find deck height variations of 0.005 inch or more.

The only way to truly know this dimension is to measure it. On an engine already assembled with the heads removed, it is an easy procedure. For a rebuilt engine, it requires pre-assembly for several reasons. First, we want all the pistons to have as close to the same relative deck height as possible.

Piston deck height also has a critical impact on piston-to-head clearance. So you can see how a flat and parallel deck surface affects several engine performance areas, especially when pushing piston-to-head clearance to the minimum in order to maximize compression.

"Free" power, or broad, predictable powerband right off idle?

What are you working on this weekend?

Pop Quiz: What engine is this piston for? Hint, it's from CP Pistons...

Flashback Friday: a home-built TrailBlazer engine that now turns over 10,500 rpm down the strip!

“It sounds like a pi**ed off bumblebee. 560 horsepower at 9,200 rpm is the peak number, and it’s still making good power at 10,600 rpm. I’m pulling the stick at 10,500 rpm,” says the owner and builder of the engine, Ron Bohn.

The 242-cube inline-six made 560 horsepower at 9,200rpm when the article was first published, with Bohn working on more displacement and RPM as the article was written.

Here's an inside look at the world's quickest and fastest naturally aspirated Coyote engine. Carlos Sobrino teamed up with Elan Power Products with the sole purpose of building the baddest N/A Coyote around. Not only did they do it, but they aren't hiding the recipe, which we dive into in our most recent EngineLabs article.

For Weird Engine Wednesday, we're going to talk a little about a current production engine, instead of a failed engineering experiment from fifty or a hundred years ago. We're talking about the inline-7-cylinder engine. The AGCO Power HD 98. A 9.8-liter turbocharged diesel inline-seven engine, that utilizes a a 1, 3, 5, 7, 2, 4, 6 firing order with a maximum engine speed of 2,100 rpm.

Relying upon 598 cubic inches of real estate, this I7 engine makes about 470 horsepower at 2,100 rpm and 1,327 lb-ft of torque at 1,500 rpm thanks in part to its compound turbocharger system. Additionally, each 1.4-liter cylinder in this motor comes with its own personalized cylinder head.

Does higher viscosity oil give you the protection you think it does?

After a LOT of oil samples processed, Lake Speed, Jr. pulls from his data to find that just because a higher viscosity oil is used doesn't inherently make it perform better. It goes way deeper, with additives and even HOW the additional viscosity is achieved, since some oil thickeners can break down when needed the most in a performance engine. We dive into his full premise in our latest article on EngineLabs.