2 Bolt Vs. 6 Bolt Main

[Lextreme II]

My friend's shop (www.sparkracing.com) have few 2JZ motors laying around and I start to study it a bit. From the look of the engine, i was just wondering how its possible for the 3.0 liter making some much power.

On the other hand, i look at my 1UZ block and its massive and wonder why is this potentially potent engine is not currently making huge hp?

 

[turboandrew]

inline 6 motors rarely need more than 2 bolt main because all of the forces are aligned up and down, not 45 degrees off like a V8. You can also get beefier bearing caps for the 2JZ if you feel the need to put out 1500 HP.

 

[Pro]

the 2JZ is a squarebore too.
i read somewhere about engine harmonics (not swinging stress) and squarebore engines - i think it was david vizard again - not requiring as much bracing internally. i would have thought the shorter the stroke the better as far as internal stress goes.

manufacturers seem to be heading this way too - a lot of engines lately are squarebore so maybe there's some truth in it...?

 

[jibbby]

Isn't a V8 motor more balanced during operation then an inline six cylinder? I understand the cylinders are all alligned in a the inline, but I would thing the V8 1uz's would be more evenly balanced at the 45 degree angle with equal weight and force on both sides..no?

 

[XR8tt]

Strength.. 7 main caps against 5. Plus its spread over a longer area..
Bore/ stroke ?? Not too sure?? The Aussie Fords 6 can run up to and over 1000 h.p for a 4.0 with 3 1/2 bore and 4" stroke....

 

[V8Datto]

A straight 6 or V12 engine (two straight sixes beside each other) are the smoothest

Here is some info I dug up,

"There are four different forces and moments of vibration that can occur in an engine design: free forces of the first order, free forces of the second order, free moments of the first order, and free moments of the second order. The straight-6, flat-6, and V12 designs have none of these forces or moments of vibration, and hence are the naturally smoothest engine designs. (See the Bosch Automotive Handbook, Sixth Edition, pages 459-463 for details.)"

Engines with particular balance advantages include:

• Straight-6
• Flat-6
• Flat-12
• V12

Engines with characteristic problems include:

• Flat-4 boxer and straight-4 have no better kinetic energy balance than a single, and require a relatively large flywheel.
• Crossplane V8, which requires a very heavily weighted crankshaft, and has unbalanced firing between the cylinder banks (producing the distinctive and much-loved V8 "burble").
• Flatplane (180° offset crankshaft) V8.