| [GMCnet] A tale of two coaches [message #221788] |
Mon, 09 September 2013 15:23 |
glwgmc
Messages: 1014
Registered: June 2004
Karma: 10
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Senior Member |
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Hi Kerry,
I was referring to the CAM timing being 4 degrees advanced. The DISTRIBUTOR or ignition timing is set for 8 degrees initial during break-in and will gradually be advanced to 10 degrees initial (vac hose removed and plugged with engine idle as low as it will go and still run) if I can and not get pinging on our fuel and mountains. Advancing the cam timing four degrees (according to Jim Hupy) will lower the RPMS at which peak torque is achieved in our engines by about 400 RPMs. Some, but not all, cam timing gear and chain sets will allow you to set the cam at zero (the factory setting), advanced four degrees, or retarded four degrees. I used a double roller set with that adjustment option. Since we never see more than 3000 to 3400 RPMs anyway, lowering the torque curve seemed like a good idea to me. So far, I am impressed by the benefits but don't know what the downsides, if any, might be so do your own research before making a change like this.
I am running a Patterson carb and distributor and find a bit of hesitation on acceleration when cold but not when fully warmed up. I think the electric choke is set to release too quickly and plan to set it to stay on a bit longer to see if that helps.
Jerry
Jerry Work
The Dovetail Joint
Fine furniture designed and hand crafted in the 1907 former Masonic Temple building in historic Kerby, OR
Visitors always welcome!
glwork@mac.com
http://jerrywork.com
541-499-1027
541-592-5360
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Message: 3
Date: Mon, 09 Sep 2013 11:34:19 -0500
From: Kerry Pinkerton <Pinkertonk@MCHSI.com>
Subject: Re: [GMCnet] A tale of two coaches
To: gmclist@temp.gmcnet.org
Message-ID: <36243.522df889@gmc.mybirdfeeder.net>
Content-Type: text/plain; charset="ISO-8859-15"
Jerry, you said your new J&S engine has 4 degrees advance. Do you mean 4 MORE degrees, ie 16 BTDC? I assume you are running a carb. What are the specifics of your configuration in carb and distributor?
I recently went to a Paterson Distributor and Carb and am still tuning them in a bit. Have a very slight bog when I put my foot in it. Moved the timing to 14 and it's improved but still a bit of a hesitation.
Also a new rebuild with rings still seating. (403, Manny Tranny, Power Drive and 3.21)
--
Kerry Pinkerton
North Alabama, near Huntsville,
77 Eleganza II, "The Lady", 403CI, also a 76 Eleganza being re-bodied as an Art Deco car hauler
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Jerry & Sharon Work
78 Royale
Kerby, OR
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