[DML] Re: "Odd-firing" engine
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[DML] Re: "Odd-firing" engine



It's related to crankshaft rotation. In a vee type engine it's quite common to have two opposing piston rods share the same crankshaft journal. In the case of the DeLorean the vee configuration has the cylinder banks 90 degrees apart. This all works out to the two cylinders sharing the crankshaft journal rotating the crankshaft different degrees of rotation. When the first cylinder fires the crank rotates 120 degrees. The second turns the crank 60 degrees, the third 120, the fourth 60 and so on. When a V-6 is banked at 60 degrees it becomes an even firing engine. When a 90 degree vee becomes a V-8 it becomes an even firing engine. It's just the way the math works out. If youwent to the expense of casting a crankshaft with a separate journal for every cylinder then even the 90 degree V-6 could be made even firing. The most obvious detriment to odd firing is an inherent engine shake. The DeLorean doesn't shake but it's not particularly smooth at idle because of this. Some manufacturers have added a counter rotating balance shaft to overcome this.
 
Bruce Benson
 
The Delorean Shop Manual refers to the PRV engine as an "Odd-firing" engine. 
Can someone shed some light onto this term and what it means compared to an
"Even-firing" engine?

Thanks,
Steve
VIN 2650

Before posting messages or replies, see the posting policy rules at:
www.dmcnews.com/Admin/rules.html

To address comments privately to the moderating team, please address:
moderator@xxxx
eGroups.com Home: http://www.egroups.com/group/dmcnews
www.egroups.com - Simplifying group communications


Home Back to the Home of PROJECT VIXEN 


Copyright ProjectVixen.com. All rights reserved.

Opinions expressed in posts reflect the views of their respective authors.
DMCForum Mailing List Archive  DMCNews Mailing List Archive  DMC-UK Mailing List Archive

This site contains affiliate links for which we may be compensated