It might have something to do with the uneven runner lengths that are
mandatory with running a single DCOE on any Spitfire engine that has an
8-port head.
At idle you can have one of two things:
1: the inside two cylinders running rich compared to the outside two
2. The outside two cylinders running lean compared to the inside two
Neither of those options are particularly good.
Two DCOEs will have a much more balanced runner arrangement since you have 4
barrels going into 4 inlets on the head.
Joe C.
-----Original Message-----
From: fot-bounces@autox.team.net [mailto:fot-bounces@autox.team.net] On
Behalf Of f s
Sent: Monday, September 27, 2010 6:36 PM
To: triumph friends
Subject: [Fot] DCOE questions for Spitfire
I have a DCOE 40 on my 79 spitfire. The engine is 9 to 1 compression. Mild
cam, ported and relieved head, balanced, very lite rods, flat top pistons,
Electric fuel pump, electronic ignition and a vacum retard distributor. It
runs ok.... but does not idle well and seems like it has a miss at mid range
rpms. 2500 to 3500 rpms. It also wants to run at 20 degrees before top dead
center, I would think it would run better and idle smooth at 1000 rpms. But
it
does not. I have tried several different jet and air correctors and tried
several timing settings. Does anyone have experience with DCOE 40 on warmed
over Spitfire 1500 engines.
Thanks
Andy
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