Do all new engines use cylinder offset and cracked rods?

General Discussion
1

The engine in my Nissan has offset cylinders and cracked rods. Is that the norm nowadays or do most modern engine designs still build them the old way?

2

Both are used. Cracked powedered metal rods are common but forged rods are still used.

Offset pistons have been used to reduce noise for 80+ years. I think there are engines built with offset cranks but it is not universal.

Why would this matter to you? Or just curious?

3

Just curious. I haven’t seen either cracked rods or offset cylinders myself but haven’t rebuilt a car engine in many years.

4

Like a vee engine would have? The cyl bores are offset from bank 1 to bank 2?

5

Vee engines more typically have the cylinder centerlines pointing directly to the crank center with no offset. Usually it is only the piston pin that is offset. But the crank can be offset as well to reduce friction in vee or inline engines.

6

I think our esteemed colleague @Cavell is referring that v-engine cylinders are by necessity offset bank vs bank. Opposing cylinders can’t line up, b/c there’s only one crankshaft that both bank’s connecting rods must connect to.

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7

“Offset” here refers to a difference between the center line of the cylinder and the center line of the crankshaft, as mentioned above.

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8

Ok, thanks for the clarification. As I understand now, if a line extended from the center-line of the cylinder intersects with the perpendicular line defined by the center-line of the crankshaft main bearings, then that is defined as “no cylinder offset”.

Hopefully someone will explain the term “cracked rods” … seems like an undesirable thing … lol…

9

Cracked rods are a way of manufacturing connecting rods in one piece then cracking off the rod cap. The advantage is the cap fits the rod more precisely which holds the bearing more precisely for a better fit on the crank journal.

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11

My 1996 Dodge Stratus has fracture-split forged connecting rods. 245,000 miles, seems to be durable but time will tell.

12

I had a friend that raced a1965 Barracuda 2 bbl carb engine in a stock 280 class hydroplane. That engine has offset pistons. He swappedthe offset to reduce friction. When they finally caught on the make him install them in the stock direction. He still won a lot of races.