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Cam Timing [message #163751]

Wed, 21 March 2012 13:00

hal kading

Messages: 642
Registered: February 2004
Location: Las Cruces NM

Karma: 4

Senior Member

Should the cam be timed different than stock for best mileage with the 455? We have a 3.70 final drive so torque doesn't seem to be lacking. Engine has 120K plus miles so timing chain is past due. What is recommended?

Hal Kading 77 Kingsley 455 Las Cruces NM

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Re: Cam Timing [message #163765 is a reply to message #163751]

Wed, 21 March 2012 17:01

pyolet

Messages: 78
Registered: August 2006
Location: Helena, MT

Karma: 0

Member

Hal, I was told to keep the timing stock when I changed chain/sprockets. Other users may have a different slant from experience.

With a timing chain that old, it's probably got 5 degrees or more of slop, mine did when I changed it at 90K miles, so your valve timing is likely all over the place. A new roller chain and sprockets will make a world of difference in stable performance....and a lot less worry.

Woody

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Re: [GMCnet] Cam Timing [message #163793 is a reply to message #163751]

Wed, 21 March 2012 21:16

USAussie

Messages: 15912
Registered: July 2007
Location: Sydney, Australia

Karma: 6

Senior Member

Hal,

Cloyes makes a double timing chain set that will allow the cam timing to be
advanced or retarded.

If you advance it the power band will shift downwards by about 300-400 rpm.
The rpm shift is a GUESS!

With a 3.70 FD I reckon I'd install it without advancing it.

That's what I did when I replaced the timing chain in Double Trouble; it has
a 3.21 to 1 FD.

Regards,
Rob M.

-----Original Message-----
From: Hal Kading

Should the cam be timed different than stock for best mileage with the 455?
We have a 3.70 final drive so torque doesn't seem to be lacking. Engine has
120K plus miles so timing chain is past due. What is recommended?

Hal

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Regards, Rob M. (USAussie) The Pedantic Mechanic Sydney, Australia '75 Avion - AUS - The Blue Streak TZE365V100428 '75 Avion - USA - Double Trouble TZE365V100426

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Re: [GMCnet] Cam Timing [message #163817 is a reply to message #163751]

Thu, 22 March 2012 06:36

Steven Ferguson

Messages: 3447
Registered: May 2006

Karma: 0

Senior Member

Hal,
The stock setup was designed to be installed straight up. Unless you
really want to screw around a lot with offset bushings and a special timing
chain gear, just leave it and if it needs it, install a good T chain.
Dbble roller is the best but not necessary. An easy way to check for slop
is with a timing light at idle. Watch for flutter on the mark on the
balancer. That's usually a good sign that the chain is getting sloppy.

On Wed, Mar 21, 2012 at 11:00 AM, Hal Kading <halkading@fastwave.biz> wrote:

>
>
> Should the cam be timed different than stock for best mileage with the
> 455? We have a 3.70 final drive so torque doesn't seem to be lacking.
> Engine has 120K plus miles so timing chain is past due. What is recommended?
>
> Hal Kading 77 Kingsley 455 Las Cruces NM
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>

--
Fathom the hypocrisy of a nation where every citizen must prove they have
health insurance......but not everyone has to prove they're a citizen.
Steve Ferguson
Sierra Vista, AZ
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Re: [GMCnet] Cam Timing [message #163911 is a reply to message #163817]

Thu, 22 March 2012 22:42

hal kading

Messages: 642
Registered: February 2004
Location: Las Cruces NM

Karma: 4

Senior Member

Thanks guys. Since straight up was the consensus, that is what we went with. Cloys double roller, new water pump and hopefully ready to go tomorrow. Old chain was really loose, at least an inch play in and out at the midpoint.

Still screwing with torsion bar sag on the Buskirk stretch so old faithful is going to Shawnee, hopefully leaving around noon tomorrow.

Hal Kading 77 Kingsley 455 Las Cruces NM

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