What is the reason ??????
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
There are a few reasons.
1. smoother running engine with the power pulses spread out.
2. high engine speed harmonics are better
3. eliminates the often troublesome #7 cyl. failure anomalies by having 5 and 7 not fire right after each other, eliminating a hotspot concentration at the back of the engine in a low air circulation, elevated coolant temperature area
#7 usually suffers from various failures related to heat.
A. ring tension failure
B. coking of the intake valve
C. early head gasket failure
D. early intake manifold gasket coolant leaks at #7
E. head warpage
F. on single plane manifolds, #5 disturbs part of the intake air by drawing air just before the #7 gets it's air.
G. #7 runs lean on carbureted engines, and manifolds need to be designed to prevent this.
1. smoother running engine with the power pulses spread out.
2. high engine speed harmonics are better
3. eliminates the often troublesome #7 cyl. failure anomalies by having 5 and 7 not fire right after each other, eliminating a hotspot concentration at the back of the engine in a low air circulation, elevated coolant temperature area
#7 usually suffers from various failures related to heat.
A. ring tension failure
B. coking of the intake valve
C. early head gasket failure
D. early intake manifold gasket coolant leaks at #7
E. head warpage
F. on single plane manifolds, #5 disturbs part of the intake air by drawing air just before the #7 gets it's air.
G. #7 runs lean on carbureted engines, and manifolds need to be designed to prevent this.
Pro
Joined: Jun 2009
Posts: 628
Likes: 0
From: OR
Some cool info on swap.http://www.speedtalk.com/forum/viewtopic.php?t=130
http://www.hotrodders.com/forum/4-7-...er-134294.html
http://www.hotrodders.com/forum/4-7-...er-134294.html
Last edited by NitroNutt; Jul 31, 2010 at 12:13 PM.
