| Timing Gear [message #350929] |
Wed, 25 December 2019 11:52  |
uprooted
Messages: 72
Registered: December 2019
Location: Hilliard, OH
Karma: 0
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Merry Christmas everyone! Hope everyone is enjoying time with family / friends / whomever this season. Since the GMC is now part of our family, I've been spending plenty of time with it this week too. While the fuel pump is out I tried to get in and see whether the timing gears have been upgraded from the nylon cam gear. The borescope I have does not have the best picture quality so the best I could do is go in with a mirror. Still it's difficult to get enough light and your eye lined up well enough to get a good look. The best way to do it was put my phone camera with flash on up to the hole. The chain appears to be OEM type, but I know there are aftermarket sets with original style chain but with all-metal cam gear. I Got a pretty good shot of the gear teeth, and I THINK they are metal but I guess I've never seen one of the nylon tipped gears in person. I would much appreciate the expert eyes of those of you that have seen these nylon gears before. The video is here: https://youtu.be/Gqvk4Y05R4Q . Thanks!
Corey P /
Hilliard, OH /
1974 Glacier 26' /
3.70 FD /
ION Wheels
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| Re: Timing Gear [message #350930 is a reply to message #350929] |
Wed, 25 December 2019 12:01  |
Melbo
Messages: 144
Registered: August 2018
Location: Albuquerque NM
Karma: 0
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I would agree with you that you have a fully metal cam gear. Mine is orange by the teeth. The nylon is white when it comes off if I remember correctly from 48 years ago when I changed them on pontiac motors. The nylon is easy to identify from the metal.
One less thing to fix is a good thing.
Melbo
Albuquerque NM Bus Conversion 1978 MCI 1973 GMC
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| Re: Timing Gear [message #350933 is a reply to message #350929] |
Wed, 25 December 2019 12:30 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Corey,
I am not at my desk and don't have a keyboard, but were I you,I would inspect the engine front. If the timing cover, front mount and related parts do not appear to have disturbed, I would take that as proof that the timing set is still OE.
The chain set that I put in was still not a roller set, so visual inspection would be difficult, but in my case, the build bok will tell a lot.
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
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| Re: [GMCnet] Timing Gear [message #350938 is a reply to message #350933] |
Wed, 25 December 2019 13:25 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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It is an original equipment style timing chain set. If you look closely at
your picture, you can see the teeth on the camshaft sprocket. They are
metal, not plastic. They may have been there since the coach was new, or
they could have been replaced somewhere along the way. No way to tell from
here. They could be within service limits, or not. You have already been
told how to check it. So, I won't repeat that.
Jim Hupy
Salem, Oregon
On Wed, Dec 25, 2019, 10:31 AM Matt Colie via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Corey,
>
> I am not at my desk and don't have a keyboard, but were I you,I would
> inspect the engine front. If the timing cover, front mount and related
> parts do
> not appear to have disturbed, I would take that as proof that the timing
> set is still OE.
>
> The chain set that I put in was still not a roller set, so visual
> inspection would be difficult, but in my case, the build bok will tell a
> lot.
>
> Matt
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Electronically Controlled Quiet Engine Cooling Fan
> OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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| Re: Timing Gear [message #350947 is a reply to message #350933] |
Wed, 25 December 2019 15:25 |
uprooted
Messages: 72
Registered: December 2019
Location: Hilliard, OH
Karma: 0
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Most of the engine has about 85% of its blue paint left on it. The water pump and timing cover behind it have none. This tells me they've both been off / replaced
Corey P /
Hilliard, OH /
1974 Glacier 26' /
3.70 FD /
ION Wheels
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| Re: Timing Gear [message #350956 is a reply to message #350947] |
Wed, 25 December 2019 19:40 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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uprooted wrote on Wed, 25 December 2019 16:25Most of the engine has about 85% of its blue paint left on it. The water pump and timing cover behind it have none. This tells me they've both been off / replaced
Corey,
That sure looks a lot like the timing gear set I recently installed. It is also about the only reason someone would bother the timing gear cover.
I think you won this one.....
Matt - Back from Christmas dinner with the daughter and family.
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
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