So one day, I went to turn my car on, and I heard a loud knocking noise, I reved a little, and noticed the noise got louder and faster with the RPMs. I went out for a listen and it sounded like it was coming from the timing chain. I took the valve cover off, and noticed there was a little bit of sludge on the cover, but the head looked alright. I took of the upper chain guide to see if the chain had any slack, and there was a very minimal play, maybe 1/4 inch or less. I put the guide back on, cleaned out the valve cover and drained the oil, and put some fresh synthetic in, and it sounded much better after I put everything back together. I let the car warm up, and right after warm up the noise starting to come back. I reved to about 2k RPM, and let my foot off the throttle, and now the RPM won't go down fast. It usually will go down until about 1k RPM, and stay there. So I'm wondering, could this be a timing issue, and is the slack in the chain, about 1/4 inch, too excessive? Oh ya, and I just hit 100k the other week. I'm thinking about switching the chain over anyway, but I don't want to switch it, and still have an issue. Thanks for any replies.
Thanks, but would that cause the RPM to drop very slowly, or is that another problem.
Hi Brian,
I would start by reading the OBD codes. It should report if anything is amiss. This could give some explanation why the RPM returning slowly to idle.
The Ecotec is an interference engine, if the timing chain jumped, you would have major mechanical problems.
Despite of this, you could check the timing of the chain. There are colored links in the chain, they can be seen from the front of the engine, it should line up with the intake and exhaust markings on the camshaft sprockets. (Both camshaft sprockets are identical, they have both markings. The front is the intake, the back is the exhaust camshaft.)
There is also a colored link for the crankshaft sprocket, on that sprocket there is a "0" marking that should line up with the colored link. I guess you would need to take off the front cover plate of the engine, looks like quite a bit of work.
You might need to turn the engine over a couple of times (by hand) before you see the links matching up.
The timing chain tensioner works on oil pressure, so when the engine is stationary there is no chain tensioning. I guess that is when you checked the timing chain slack.
Peter
Peter Orban wrote:Hi Brian,
...
The timing chain tensioner works on oil pressure, so when the engine is stationary there is no chain tensioning. I guess that is when you checked the timing chain slack.
Peter
Sorry, the above is not correct. You should not have slack in the chain, the tensioner is also spring loaded.
Did you change tensioner? Before installation the tensioner needs to be compressed, and after installation it needs to be engaged, the compression released.
Peter
Peter Orban wrote:Peter Orban wrote:Hi Brian,
...
The timing chain tensioner works on oil pressure, so when the engine is stationary there is no chain tensioning. I guess that is when you checked the timing chain slack.
Peter
Sorry, the above is not correct. You should not have slack in the chain, the tensioner is also spring loaded.
Did you change tensioner? Before installation the tensioner needs to be compressed, and after installation it needs to be engaged, the compression released.
Peter
I should never have any slack in the chain? Well...if that's so, I might as well get that timing chain kit. Should I also replace the balance shaft chain? And...I should make sure you buy the expensive oiler instead of the OEM one right?
Also I was thinking about getting this kit:
Your text to link here...
I'm not sure if that has the newer oiler or if its the old design. I'm not sure on the kit either, its that, or I go straight to the dealership and pay hell of a lot more.
Hi Brian,
I read a description of the Ecotec engine in an engineering magazine quite a while back. It mentioned that the timing chain is good for the life of the engine. As I got a '05 Cav with the above engine, I was dismayed to read on the net about the timing chain problems that I can expect. (I only have about 90,000Km on my car.)
What I gather, the balance shaft chains are a lot more robust.
Check out the following forum (maintenance) as well:
http://www.ecotecpower.com
If I am correct, you automatically have the same username/password as here on the J-body forum (you have to have cookies enabled for that site to be able to log in).
Peter
Peter Orban wrote:Hi Brian,
Check out the following forum (maintenance) as well:
http://www.ecotecpower.com
If I am correct, you automatically have the same username/password as here on the J-body forum (you have to have cookies enabled for that site to be able to log in).
Peter
I actually use ecotecforum.com
I think its run by the same guy who did ecotecpower.
It's been awhile since I drove it, and after I did another oil change, and throw some seafoam in it, its pretty quiet now. I wonder if the chain slap, or what I thought of as a chainslap was just thick oil. Maybe it caused the oiler to not perform as good as it should have? I don't know. I have the timing chain kit and it claims it has the new updated oiler so I might just swap out the chain now anyway. I have a spare car now so I don't have to worry about getting my j done now. Thanks for who commented.
