Soon to be new owner asked if timing set had been changed and if not, was the cam sprocket plastic or not and I could not answer.
--
1978 Eleganza II
--
1978 Eleganza II
Cam sprocket - plastic or not?
- Thread starter ken harland
- Start date
I believe (well pretty sure) the OEM cam sprocket was nylon. Get a double roller chain and sprocket to replace it.
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
OE was nylon over aluminum cam gear. Heat and combustion by products attack the nylon over time. I’d be surprised to find a working survivor these
days but possible.
--
John Lebetski
Woodstock, IL
77 Eleganza II
days but possible.
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John Lebetski
Woodstock, IL
77 Eleganza II
> I believe (well pretty sure) the OEM cam sprocket was nylon. Get a double roller chain and sprocket to replace it.
If he does get the double rolled, have him be sure to check that it is installed on time. The double roller are speed parts and so come with keyways
for +&-4°. He needs to know where he wants it to end up.
Matt
--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
If he does get the double rolled, have him be sure to check that it is installed on time. The double roller are speed parts and so come with keyways
for +&-4°. He needs to know where he wants it to end up.
Matt
--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
Not aluminum, It is steel. See below
Cloyes part no. is 9-3113
Summit part no. is MAH-9-3113
https://www.summitracing.com/parts/mah-93113
Jegs part no 220-9-3113
https://www.jegs.com/i/Cloyes/220/9-3113.010/10002/-1
On Ebay
https://tinyurl.com/537nxa84
https://tinyurl.com/w8nm2smh
https://tinyurl.com/94tksdn3
https://tinyurl.com/ybc54xst
https://tinyurl.com/yru97k9v
https://tinyurl.com/yru97k9v
These are all from various Ebay suppliers
J.R. Wright
GMC Great Laker MHC
GMCGL Tech Editor
GMC Eastern States Charter Member
GMCMI
78 GMC Buskirk 29.5’ Stretch
75 GMC Avion (Under Reconstruction)
Michigan
>
> Thanks all, as I suspected, nylon over aluminum. I'll let him know.
>
> --
> 1978 Eleganza II
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
Cloyes part no. is 9-3113
Summit part no. is MAH-9-3113
https://www.summitracing.com/parts/mah-93113
Jegs part no 220-9-3113
https://www.jegs.com/i/Cloyes/220/9-3113.010/10002/-1
On Ebay
https://tinyurl.com/537nxa84
https://tinyurl.com/w8nm2smh
https://tinyurl.com/94tksdn3
https://tinyurl.com/ybc54xst
https://tinyurl.com/yru97k9v
https://tinyurl.com/yru97k9v
These are all from various Ebay suppliers
J.R. Wright
GMC Great Laker MHC
GMCGL Tech Editor
GMC Eastern States Charter Member
GMCMI
78 GMC Buskirk 29.5’ Stretch
75 GMC Avion (Under Reconstruction)
Michigan
>
> Thanks all, as I suspected, nylon over aluminum. I'll let him know.
>
> --
> 1978 Eleganza II
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
The factory timing set has a nylon tipped steel cam gear. At least mine did.
--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles,
Solar battery charging. GMCSJ and GMCMI member
--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles,
Solar battery charging. GMCSJ and GMCMI member
I second the mention using the Cloyes 9-3113 set (steel). We had our OEM nylon gear pulled a few years back by our mechanic, 65K miles on it, and the
nylon gear was pristine believe it or not. However our worry was like others mentioned, not knowing how much lift the nylon gear had left and didn't
want to worry about it.
Chris
--
Chris S. -
77 Kingsley, 3.70 FD, mostly OEM -
S.E. Michigan
nylon gear was pristine believe it or not. However our worry was like others mentioned, not knowing how much lift the nylon gear had left and didn't
want to worry about it.
Chris
--
Chris S. -
77 Kingsley, 3.70 FD, mostly OEM -
S.E. Michigan
At 67,000 miles, my gear looked good but the chain had stretched to the point that half of the crank gear teeth on the bottom were visible above the
chain.
--
Greg Crawford
KM4ZCR
Knoxville, TN
"Ruby Sue"
1977 Royale
Rear Bath
403 Engine
American Eagle Wheels
Early Version Alex Sirum Quad bags
chain.
--
Greg Crawford
KM4ZCR
Knoxville, TN
"Ruby Sue"
1977 Royale
Rear Bath
403 Engine
American Eagle Wheels
Early Version Alex Sirum Quad bags
Stock or plastic makes no difference. It's the combination of wear between
gears, sprockets, and chains that gives you the slack that RETARDS CAM
TIMING, the effect is that the torque curve is moved upwards in RPM'S.
If your 403 won't pull the hat off your head at 2200 rpm, but runs
like a scalded dog at 3600+ RPM'S, you probably have a stretched timing
chain. New double roller chain and sprockets, advanced 4° or so will wake
the lower rpm range up.
Jim Hupy
Salem, Oregon
On Fri, Jul 16, 2021, 3:58 PM Greg Crawford
wrote:
> At 67,000 miles, my gear looked good but the chain had stretched to the
> point that half of the crank gear teeth on the bottom were visible above the
> chain.
> --
> Greg Crawford
> KM4ZCR
> Knoxville, TN
>
> "Ruby Sue"
> 1977 Royale
> Rear Bath
> 403 Engine
> American Eagle Wheels
> Early Version Alex Sirum Quad bags
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
gears, sprockets, and chains that gives you the slack that RETARDS CAM
TIMING, the effect is that the torque curve is moved upwards in RPM'S.
If your 403 won't pull the hat off your head at 2200 rpm, but runs
like a scalded dog at 3600+ RPM'S, you probably have a stretched timing
chain. New double roller chain and sprockets, advanced 4° or so will wake
the lower rpm range up.
Jim Hupy
Salem, Oregon
On Fri, Jul 16, 2021, 3:58 PM Greg Crawford
wrote:
> At 67,000 miles, my gear looked good but the chain had stretched to the
> point that half of the crank gear teeth on the bottom were visible above the
> chain.
> --
> Greg Crawford
> KM4ZCR
> Knoxville, TN
>
> "Ruby Sue"
> 1977 Royale
> Rear Bath
> 403 Engine
> American Eagle Wheels
> Early Version Alex Sirum Quad bags
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
