The GM 54 degree V6

[James McGrath]

So I've been reading allot into V6 engines, the different types, how they work and their advantages and disadvantages.

V6s are essentially a compromise between compactness and smoothness. They are smother and allow for higher displacements than inline-4 cylinder engines yet fit more easily into modern front wheel drive designs than an inline 6 cylinder engine.

There are two main types of V6. The 90 degree and the 60 degree.
(I was going to write a brief explanation of the advantages of each, however I ended up writing two pages worth of information all of which is available on Wikipedia any way.)

Basically, for physical reasons, the 60 degree angle gives the best smoothness as it eliminates primary order vibrations which are present in the 90 degree design.

What I want to know is the mechanical properties of the GM 54 degree design as there appears to be very little information around on the subject.
Does it have an even firing order?
Does it use an offset crank pin like the 60 degree v6?
Does it have primary order vibrations?

[humbucker]

Ack! I was at Ellesmere Port last week, private tour around the body shop, assembly lines etc. Coulda asked all the questions you had if I'd have known!

[James McGrath]

Dam and blast!

[Lowrider Dave]

Firing order is 1-2-3-4-5-6. It is molded onto the rocker cover.

[Lowrider Dave]

https://www.youtube.com/watch?v=pufR5vR5ne0

[James McGrath]

That's a great vid. I think I linked it a few months back but it doesn't really go into much detail about the engine itself.

54 degrees is a vary peculiar angle to have on a V6 and I wanted to know why they chose that particular angle (I know it was to reduce it's size but why not 53 or 55) and what are the effects of that angle in regards to smoothness and vibration compared to a more traditional 60 degree angle.