Question about the 8100 engine

[boomer 33]

My 8.1 i(2004) is supposed to be 496 inches, the numeric conversion comes out to actually 494 cubic inches. What is the difference between this engine and what GM markets as the 502 engine?

[Colorado Kid]

Everything.

Bore

Stroke

Firing Order

Heads

Pistons

.

.

.

You get the idea.

 

Let's see here . . .

From GM Powertrain Bore = 107.95mm, Stroke = 111.00mm (5 significant digits )

107.95mm/25.400(mm/inch) = 4.2500 inch bore

111.00mm/25.400(mm/inch) = 4.3701 inch stoke

Area of the bore = Pi x (Bore/2) x (Bore/2) [A=Pi x R squared]

Area = 3.14159 x 2.125 x 2.125 = 14.186 square inches

Area x Stroke = swept volume of cylinder = 14.186 x 4.3701 = 61.995 cubic inches per cylinder

x 8 = 495.96 cubic inches.

 

That's a 496 by my calcs. or 8128cc for the US units impaired.

 

The 502 is 4.446" bore and 4.000 stroke. (a bored 454, as opposed to the 496 which is a stroked 454, sorta.)

[boomer 33]

Wow, I wouldn't have guessed there was that much differnece. Now I want a 502 !

Thanks

[o4yukonxl]

The 502 is a great engine but the 8.1 is a next generation engine. It has two extra head bolts on each head to improve cylinder sealing. The firing order is changed to reduce the stress on the crank, etc. etc. With the new stuff coming from Raylar, you can make as much HP or more than the 502 and get way better mileage and longer engine life. Enjoy.

[boomer 33]

Was wondering about that, and at much reduced cost I would bet. Did not see the cost of the crate 502 on GM Parts site, but I know the Marine 502's are LARGE dollars. You sound like a potential Raylar customer?

[o4yukonxl]

You could say that. I only have 13K on the truck and am waiting until I'm out of warranty. When that day comes, I'll probably pop for the heads first. Nothing like a Big Block for power.