Stock GN timing chain replacement

[stage1gn]

This has been probably touched upon many times over,did a search for my info needed,but am coming up with many diff opinions.
Going to replace the timing chain in my 87 GN ,82k miles,stock,T/A 49 turbo,etc,never been apart.I don't want to be a victim of it falling apart in there.I have run the car at the track 150 times or so,so I geuss the stock chain has had more abuse than someone who did'nt do that to it.
Looking to just get a new chain/gears to install with no difficulty,what has been the choice of sets that have been readily available?Comp,Cloyes,Napa,etc????If anyone has part number,would be great to.
Oil pan gasket and rear main are leaking to,so a great time to do everything.

 

[stage1gn]

BTW,thanks in advance.

 

[mgmshar]

Ten years ago, when I replaced my timing chain, double rollers were the way to go. I installed one without the chain tensioner, and it's been fine ever since.

If I ever remove the front cover again, however, I'm going to install the TA Performance stock replacement chain with billet gears. This is a single row silent chain (like the stock chain) that can be used with the chain tensioner. Based on everything I've read, this is the best choice for guys running either the stock cam or a "small" cam.

My opinion.

You can order them directly from TA, from Nick at Arizona GN, or possibly other vendors.

Good luck,

 

[earlbrown]

I prefer to pop for the extra money and get one of those junky stock timing sets. The down side is they only last 150,000 miles or 20 years, which ever comes first.

 

[Tom87GNX]

Melling makes a stock replacement type, it's the single row chain with steel gears. You can get them from basically any auto parts store (pep boys, oriellys etc). Think mine was $25-$30, no need for over kill. Stock replacement like earl mentioned is fine too. I'd say they are dependable (150 runs, 25+ years) still hasn't broke, why would you not feel good about using one?


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[Nick Micale]

I would "assume" Earl is referring to the stock timing set, not a stock replacement set made off-shore with a poor quality cast cam gear that will wear down in a few 1000 miles, as it is very unlikely they would perform as well, or a long, as the original factory replacement set.

The $25-30 sets I have installed and seen within a few 1000 miles have lots of slack due to excessive gear wear?

I have also seen some of these cast gears fail even in the higher cost double roller sets.

 

[earlbrown]

I was talking about the stock GM timing set. Based on my personal experience the parts store steel timing chains will make a magnetic oil drain plug grow an afro (they will go 100,000 miles with LT1 springs though) and when they fail they take out the timing cover. The stock sets last for decades and don't grow afros.

 

[stage1gn]

Earl,are you saying a GM timing set,nylon gears and all?????Can you even get them anymore ?????Reuse the tensioner also ????Whats all the hype about T/A's single row silent chain ????My car has stock cam in it,but does have the 100lb. springs on it.

 

[stage1gn]

And also,from what I understand,it's not so much the miles on the car,it's the age of the plastic gears that has broken them down,so getting an NOS set is also 27 years old now to,....????But I do agree with you,it's been in there 27 years now with some drag strip use,why not instll a new orig set,would last another 27 years !!!

 

[turbobitt]

I'm not an expert in this area but Bison was showing me a stock replacement single row chain and tensioner that he claims is stronger than the double row. The crank gear even has multiple positions for advance and retard. Don't know who makes it but Bison can chime in.

Allan G.

 

[Nick Micale]

I'm not an expert in this area but Bison was showing me a stock replacement single row chain and tensioner that he claims is stronger than the double row. The crank gear even has multiple positions for advance and retard. Don't know who makes it but Bison can chime in.
Allan G.

Most likely this is the timing set Bison was showing you as it has billet steel gears.

http://www.taperformance.com/proddetail.asp?prod=TA_V1522B

 

[turbobitt]

Most likely this is the timing set Bison was showing you as it has billet steel gears.

http://www.taperformance.com/proddetail.asp?prod=TA_V1522B[/quote]

Yes that is it. I have the box in my workshop and has TA performance part numbers on it.
Allan G.

 

[bison]

I'm not an expert in this area but Bison was showing me a stock replacement single row chain and tensioner that he claims is stronger than the double row. The crank gear even has multiple positions for advance and retard. Don't know who makes it but Bison can chime in.

Allan G.

It's a TA performance set.

 

[BigTady]

Subscribed

 

[earlbrown]

Earl,are you saying a GM timing set,nylon gears and all?????Can you even get them anymore ?????Reuse the tensioner also ????Whats all the hype about T/A's single row silent chain ????My car has stock cam in it,but does have the 100lb. springs on it.

Yes. Nylon and all. GM installed millions of them over the years and gave a warranty on every car that had them. They have proven to go well over 100,000 miles or 20 years. (hell, there's still GNs out there with the original set. Granted it's a ticking time bomb after 20+ years).
They also run quieter so it's one less thing to potentially show up on the knock sensors radar. The last one I bought wasn't cheap. It was right at $100. I believe the bottom gear is discontinued from GM but the replacement gears are fine for the bottom one.

 

[stage1gn]

Last but not least question,would you trust an NOS nylon gear still in the GM plastic bag,as it is now 20+years old?Was it the age that breaks these down,or the engine heat cycles it has gone thru ????Or both???I have no problem putting back in a NOS one,as my motor is stock,orig cam,and not racing/beating on it anymore per say.

 

[earlbrown]

If it's NOS it'll be fine. I'd run the hell out of it.

 

[turbobitt]

Last but not least question,would you trust an NOS nylon gear still in the GM plastic bag,as it is now 20+years old?Was it the age that breaks these down,or the engine heat cycles it has gone thru ????Or both???I have no problem putting back in a NOS one,as my motor is stock,orig cam,and not racing/beating on it anymore per say.

Just my opinion, nylon gear was fine for bone stock car but start adding higher spring loads why not just run the best single roller you can buy ? I have the correct TA performance one for your stock cam and you can come over and see it for your self since you live close buy.
Allan G.

 

[bison]

240lbs over the nose with a stock gear no problem. 400+ I wouldn't want to find out the nylon toothed aluminum gear wasnt enough. I commonly spec out aggressive hyd cams for street cars that have 500+ over the nose. Everything has it's place.

 

[mgmshar]

Last but not least question,would you trust an NOS nylon gear still in the GM plastic bag,as it is now 20+years old?Was it the age that breaks these down,or the engine heat cycles it has gone thru ????Or both???I have no problem putting back in a NOS one,as my motor is stock,orig cam,and not racing/beating on it anymore per say.

Plastics like Nylon degrade over time. However, the rate at which they degrade is very dependent on the temperature to which they are exposed. See the graph that I've attached below, which is a study done on Nylon 6-6. The left and right graphs are identical - the only difference is that they use a linear X-axis scale on the left graph, and a log X-axis scale on the right graph. Notice that at low temperatures (the lowest studied was 37 Celsius, or 99 Fahrenheit), the tensile strength of the Nylon really doesn't change at all after 1000 days. At 99 Celsius (210 Fahrenheit), the Nylon starts to lose its tensile strength after about 800 days or so. At 138 Celsius (280 Fahrenheit), the Nylon starts to lose its tensile strength after only 10 days.

I do not know what grade of plastic is used for the stock timing gears (Nylon 6-6 or something else), so the graphs for the timing chain plastic might be different. However, if you are sure that the gears have been sitting at room temperature for the last 20 years and not getting cooked in a hot attic or something, I would suspect that they are fine. When I say "fine", I mean that they should be OK to drive the stock cam with stock valve springs, like the factory intended.

Reference: Nylon 6.6 accelerated aging studies: thermal–oxidative degradation and its interaction with hydrolysis, Robert Bernstein, Dora K. Derzon, & Kenneth T. Gillen, Polymer Degradation and Stabilty, Volume 88, Issue 3, June 2005.

Does this answer the question?