I am going to be doing my cam swap next weekend and was wondering if i would need to change the whole set or just the chain. My cam is the gm847 with stock heads i will be spraying 125 shot also. Thanks

 

Whenever I read about timing chains, I have read to replace the whole timing set and NOT just the chain, as just replacing the chain will cause premature wear on the gears and/or chain.

 

very true, i would just use a stock replacement set

 

Ideally, with a 125 shot and that cam, I'd strongly recommend a double roller. However, you then need an electric water pump. With that being said, I did run the 847 on a stock replacement chain, and sprayed a 150 shot with no issues. Motor is still running great, but doesn't have the gas on it, and it's been a few years, spinning it to 6700, daily driver.

 

why? when is the last time you heard of a stock one breaking.

 

Most people here with heads/cam and making good power have already gone to a double roller chain, or at least the LT4 extreme duty. It's cheap insurance I guess. Why become the thread starter for the My motors shot cause the timing chain broke. A stock head 847 with a 125 shot should make over 500 ft. lbs of torque. Why take a chance if you have the cash to do it right?

 

The timing set is driving the cam and the water pump. How much do those loads increase with HP/torque?

 

ha ha. none. but go ahead and try to explain that to one of these internet cowboys. best to just let em waste there money if they want.



stock chain, stock sprokets here, if i ever have a problem i will be sure to let you know, but i would be sure that you will have a problem before i do.

 

I have a stock replacement timing set in my 847 car.

 

I would think that increased seat pressure pushing down on the more aggresive cam lobes would affect it, but I'm just an internet cowboy.

My stock 110k mile chain had less slack in it than my 10k stock replacement one did on my cc306.

 

e-WP helps... but I went with a LT4-XD chain set just to be sure.

you can try a slightly larger sprocket to tighten up the chain as well... but opinions are mixed on that as well.

 

Point is, the 500 lb-ft of torque is not what affects the load on the timing set, particularly when most of that comes from nitrous. High RPM solid roller, with huge seat pressures is an issue.... I run the LT4 ED, but basing the selction of the timing set on how much torque the engine makes is questionable, at best.