Timing Set question
Thread Starter
Racer
Joined: Sep 2003
Posts: 454
Likes: 1
From: Lompoc CA
Timing Set question
Does anyone know whether or not the 1985 Vette had the covers over the timing set that the chain rode on? This is what caused many problems with running quality on the trucks I saw a while back. Just trying to figure out if I will be able to refresh my engine instead of replacing it.
Thanks
Richard
Thanks
Richard
Team Owner
Joined: Mar 2000
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From: Boston, MA
Re: Timing Set question (nonetooclose)
I don't quite follow you. The timing cover has no itneraction with the chain and sprockets as far as I know. There may be a nose on the cam or something as it isn't a rollercam, but I am not sure.
Race Director
Joined: Sep 2000
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From: The Top of Utah
Re: Timing Set question (nonetooclose)
I agree, that the way it is worded, it makes no sense. Maybe he is talking about the nylon coating on the teeth of the cam sprocket? But no matter what, it wouldn't be a factor in whether the engine could be be rebuilt or have to be replaced. Unless there is a coherent clarification, I would have to recommend you take the car to someone and have, whatever, done for you. GOOD luck, and...
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Burning Brakes
Joined: Aug 2002
Posts: 779
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From: West Point Utah
Re: Timing Set question (CFI-EFI)
I agree, that the way it is worded, it makes no sense. Maybe he is talking about the nylon coating on the teeth of the cam sprocket? But no matter what, it wouldn't be a factor in whether the engine could be be rebuilt or have to be replaced. Unless there is a coherent clarification, I would have to recommend you take the car to someone and have, whatever, done for you. GOOD luck, and...
RACE ON!!!
RACE ON!!!
Thread Starter
Racer
Joined: Sep 2003
Posts: 454
Likes: 1
From: Lompoc CA
Re: Timing Set question (EDMGUY)
Okay okay. I am referring to the nylon coating encasing the outer teeth of both the crank and camshaft sprokcket on these earlier 350s. I have a 77 which had this particular piece and was the sole cause for rough running conditions later in the engine's life.
It actually has a lot of bearing to whether or not I rebuild or replace. I have in mind not a rebuild, but a refresh where I would replace the worn timing set, distributer, and possibly redo the heads. This way I do not have to remove the engine from the car which is very difficult for me to accomplish with space limitations.
I am not sure if the same nylon covering is on the 85's or not.
Thanks
Richard
[Modified by nonetooclose, 6:41 AM 2/10/2004]
It actually has a lot of bearing to whether or not I rebuild or replace. I have in mind not a rebuild, but a refresh where I would replace the worn timing set, distributer, and possibly redo the heads. This way I do not have to remove the engine from the car which is very difficult for me to accomplish with space limitations.
I am not sure if the same nylon covering is on the 85's or not.
Thanks
Richard
[Modified by nonetooclose, 6:41 AM 2/10/2004]
Team Owner
Joined: Mar 2000
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From: Boston, MA
Re: Timing Set question (nonetooclose)
I am not sure if the same nylon covering is on the 85's or not.
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Re: Timing Set question (nonetooclose)
My 85 Corvette (produced in Apr 84) had the factory cam gear with nylon teeth. The gear itself is actually cast aluminum I think, and it has small aluminum teeth, which have a thick nylon coating on em... which builds em up to the normal tooth size. The factory crank gear is steel.
I replaced em with an all steel timing set from Napa. I've seen pics of a guy on here who's nylon cam gear teeth sheared/melted off.
I have my original timing set sitting on my desk (as a decoration!).. and dropped it once by accident, and it actually broke three of the nylon teeth! :rolleyes: Now that's pathetic.
I replaced em with an all steel timing set from Napa. I've seen pics of a guy on here who's nylon cam gear teeth sheared/melted off.
I have my original timing set sitting on my desk (as a decoration!).. and dropped it once by accident, and it actually broke three of the nylon teeth! :rolleyes: Now that's pathetic.
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Team Owner
Joined: Mar 2000
Posts: 83,383
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From: Boston, MA
Re: Timing Set question (CentralCoaster)
I have my original timing set sitting on my desk (as a decoration!).. and dropped it once by accident, and it actually broke three of the nylon teeth! :rolleyes: Now that's pathetic.
Drifting
Joined: Feb 2003
Posts: 1,978
Likes: 2
From: San Antonio Texas
Re: Timing Set question (nonetooclose)
I don't know what years they used them, but I know they used them because they are quieter than bare metal. Not as strong though; I'd use metal.
:chevy
:chevy
Race Director
Joined: Sep 2000
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From: The Top of Utah
Re: Timing Set question (nonetooclose)
Okay okay. I am referring to the nylon coating encasing the outer teeth of both the crank and camshaft sprokcket on these earlier 350s. I have a 77 which had this particular piece and was the sole cause for rough running conditions later in the engine's life.
It actually has a lot of bearing to whether or not I rebuild or replace. I have in mind not a rebuild, but a refresh where I would replace the worn timing set, distributer, and possibly redo the heads.
This way I do not have to remove the engine from the car which is very difficult for me to accomplish with space limitations.
RACE ON!!!
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Re: Timing Set question (CFI-EFI)
I think what he's indicating, is that if a sloppy timing chain is mostly whats causing the car to run poorly, than a new timing chain will help. Otherwise he's going to dig deeper and maybe start rebuilding.
Thread Starter
Racer
Joined: Sep 2003
Posts: 454
Likes: 1
From: Lompoc CA
Re: Timing Set question (CentralCoaster)
It is quite simple really. Chevy in their utmost scrupulous fashion put plastic coated timing sets in the ealier engines just like what was indicated prior to "make them quieter". This is quite ridiculous since I have never even heard a timing set make any noise unless it is a geardrive. As the car ages the plastic gets old and brittle due to chemicals and acids in the oil created during combustion and engine use. This in turn breaks down the plastic and as a couple of people have indicated the gear literally dissolves. This dissolution actually creates a terribly running vehicle since it is gradual as the gear looses integrity.
I reiterate, just as Centralcoaster pointed out, that it is a refresh not a rebuild. Careful of the definitions here. A refresh is just that, a refresh of easily accessible parts without tearing the whole engine down for a complete rebuild.
This is preventative maintanence since I know that these sets are a problem. Is there a confirmation that the 1985's do have these nylon cam gears?
Thanks
Richard
I reiterate, just as Centralcoaster pointed out, that it is a refresh not a rebuild. Careful of the definitions here. A refresh is just that, a refresh of easily accessible parts without tearing the whole engine down for a complete rebuild.
This is preventative maintanence since I know that these sets are a problem. Is there a confirmation that the 1985's do have these nylon cam gears?
Thanks
Richard
Race Director
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From: The Top of Utah
Re: Timing Set question (nonetooclose)
I don't think there is a lot of argument about the desirability of the nylon coated cam sprocket. I cannot state positively, but I am relatively sure that the '85 does have the coated sprocket. I just want to see if I have understood you correctly. If the engine has an all metal cam sprocket, you are going to change the timing set, the distributor, and possibly have a valve job done. Assuming for the moment, the sprocket IS all metal, what criteria will you use to determine if you do the valve job? If the engine does have a nylon coated cam sprocket, you will replace, not rebuild, but replace the engine. Do I read you correctly?
Thread Starter
Racer
Joined: Sep 2003
Posts: 454
Likes: 1
From: Lompoc CA
Re: Timing Set question (CFI-EFI)
I don't think there is a lot of argument about the desirability of the nylon coated cam sprocket. I cannot state positively, but I am relatively sure that the '85 does have the coated sprocket. I just want to see if I have understood you correctly. If the engine has an all metal cam sprocket, you are going to change the timing set, the distributor, and possibly have a valve job done. Assuming for the moment, the sprocket IS all metal, what criteria will you use to determine if you do the valve job? If the engine does have a nylon coated cam sprocket, you will replace, not rebuild, but replace the engine. Do I read you correctly?
The criteria for the valve job would be an inspection of the valve seats looking for wear on the seats and the valve itself. I suspect they are fine, so my most probable scenario is to simply replace the timing set and water pump. Thanks for all the input!
Thanks for the pic Centralcoaster. That is exactly what I am afraid of! It seems pretty conclusive that the 85 does have this nylon coated cam gear. Any recommendations for a good timing set?
Thanks
Richard
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Re: Timing Set question (nonetooclose)
Thanks for the pic Centralcoaster. That is exactly what I am afraid of! It seems pretty conclusive that the 85 does have this nylon coated cam gear.
Any recommendations for a good timing set?
