Ballenxj wrote:
Griff in Fairbanks wrote:
IIRC, OEM sprockets were a composite material and OEM chain was an 'economy' version. Replaced with metal sprockets and premium chain. Lasted at least 150,000 miles that I know of.
GM did the same thing. That composite around the timing chain gear was meant dampen it and make it run quieter. Problem was, once you had some miles on (as you noted) the stuff could fail at any time with no warning. I've seen big chunks of it break off, leaving so much slop in the chain that it was useless. My fix was to buy a high performance all steel double roller timing set. TRW, I think it was. Yeah, it was a small bit noisier, but the timing chain never failed again. It was like a permanent fix. :)
In my case, sprocket didn't fail. They just wore quickly until they were so loose the timing jumped around plus or minus 5-7 degrees. The fact I tend to advance timing a few degrees for fuel economy made the wear more problematic.
Yes, I think it was a TRW double roller set that I used as a replacement. Additional noise wasn't noticeable because I always run winter M&S tires with an aggressive tread.
The few times people mentioned the noise, I'd tell them, "This is a truck that spends a lot of time off the pavement. If you want quiet, find someone else for a ride."
