Question for those who have replaced timing chain
01-02-2023, 10:30 AM
#12
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Join Date: 12-05-2014
Location: Northern Ohio
Posts: 2,627
Are you using at least 91 octane? It's recommended for 2.4, and if knock is detected, the spark advance will be rolled back, reducing fuel economy.
Also, the fuel economy on the dic has limitations.
In 2008, the 2.4 had VVT and potentially offers better efficiency than the 2.2 which did not. But the 2.4 has a lower ratio transaxle. The focus was more skewed toward performance.
Roller chains get rough at high speed. A light foot will preserve the timing chain guides. Their life is highly variable. I wouldn't do a chain job before there was some sign it was needed. And it won't help fuel economy unless something has already failed, and then fuel is the least concern.
Also, the fuel economy on the dic has limitations.
In 2008, the 2.4 had VVT and potentially offers better efficiency than the 2.2 which did not. But the 2.4 has a lower ratio transaxle. The focus was more skewed toward performance.
Roller chains get rough at high speed. A light foot will preserve the timing chain guides. Their life is highly variable. I wouldn't do a chain job before there was some sign it was needed. And it won't help fuel economy unless something has already failed, and then fuel is the least concern.
01-03-2023, 07:23 AM
#13
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Thread Starter
Join Date: 06-21-2008
Location: SE Michigan
Posts: 1,457
Are you using at least 91 octane? It's recommended for 2.4, and if knock is detected, the spark advance will be rolled back, reducing fuel economy.
Also, the fuel economy on the dic has limitations.
In 2008, the 2.4 had VVT and potentially offers better efficiency than the 2.2 which did not. But the 2.4 has a lower ratio transaxle. The focus was more skewed toward performance.
Roller chains get rough at high speed. A light foot will preserve the timing chain guides. Their life is highly variable. I wouldn't do a chain job before there was some sign it was needed. And it won't help fuel economy unless something has already failed, and then fuel is the least concern.
Also, the fuel economy on the dic has limitations.
In 2008, the 2.4 had VVT and potentially offers better efficiency than the 2.2 which did not. But the 2.4 has a lower ratio transaxle. The focus was more skewed toward performance.
Roller chains get rough at high speed. A light foot will preserve the timing chain guides. Their life is highly variable. I wouldn't do a chain job before there was some sign it was needed. And it won't help fuel economy unless something has already failed, and then fuel is the least concern.
I'm not looking to do the timing chain for fuel mileage, I'm doing it because I'm planning a 3000 mile trip this summer and I'd rather not worry about the chain breaking during the trip. But, if there is a measurable difference as the chain ages, it may be a valuable metric for determining end of life before it breaks and does more damage. Say, for instance, your fuel mileage starts decreasing with all other factors being the same, it may be time to at least remove the valve cover and check the chain.
01-03-2023, 07:53 AM
#14
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Join Date: 03-29-2022
Location: Davison MI
Posts: 1,083
91 or 93 octane, depending on price.
I'm not looking to do the timing chain for fuel mileage, I'm doing it because I'm planning a 3000 mile trip this summer and I'd rather not worry about the chain breaking during the trip. But, if there is a measurable difference as the chain ages, it may be a valuable metric for determining end of life before it breaks and does more damage. Say, for instance, your fuel mileage starts decreasing with all other factors being the same, it may be time to at least remove the valve cover and check the chain.
I'm not looking to do the timing chain for fuel mileage, I'm doing it because I'm planning a 3000 mile trip this summer and I'd rather not worry about the chain breaking during the trip. But, if there is a measurable difference as the chain ages, it may be a valuable metric for determining end of life before it breaks and does more damage. Say, for instance, your fuel mileage starts decreasing with all other factors being the same, it may be time to at least remove the valve cover and check the chain.
Your reasoning seems overly cautious.
01-03-2023, 11:16 AM
#15
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Join Date: 01-23-2009
Location: Fredericksburg,VA
Posts: 25,326
You can remove the cam cover and look at the chain. If you can see or feel any slack between the sprockets or the plastic part of the upper guide is damaged or gone you need to worry about the chain. Usually the slack shows up long before the CEL, and it is surprising how many don't care about that strange light on the dash and don't have a chain fly off.
Otherwise, blissful ignorance seems to work.
Otherwise, blissful ignorance seems to work.
01-03-2023, 09:47 PM
#18
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Join Date: 03-29-2022
Location: Davison MI
Posts: 1,083
You do not know what you are talking about. You don't make the cam turn only the crank and you measure how many degrees it moves from stop to stop. They sell a degree wheel for just this test.
01-04-2023, 06:42 AM
#19
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Thread Starter
Join Date: 06-21-2008
Location: SE Michigan
Posts: 1,457
You can remove the cam cover and look at the chain. If you can see or feel any slack between the sprockets or the plastic part of the upper guide is damaged or gone you need to worry about the chain. Usually the slack shows up long before the CEL, and it is surprising how many don't care about that strange light on the dash and don't have a chain fly off.
Otherwise, blissful ignorance seems to work.
Otherwise, blissful ignorance seems to work.
01-04-2023, 06:43 AM
#20
Administrator
Join Date: 10-13-2011
Location: Welland,Ont Canada
Posts: 37,619
I have experienced turning the crankshaft CCW and watched the tensioner move and the chain skips tooth .
I’ve replaced and repaired it over 30 timing chains , I do know about the use of a degree wheel, in the Ecotec engines, one is not required as the crankshaft and camshafts have timing marks to align during assembly then the crankshaft and camshaft sprockets align with those marks to align the timing chain for correct timing.
If not positioned correctly the sensors will do there job and throw a code, or if out of time enough the pistons will kiss the valves and bent the valve stems.
read and learn Greg, watch the videos and learn
https://www.chevyhhr.net/forums/how-...in-kits-60394/
http://www.ddmworks.com/assets/image...uild%20Kit.pdf
I’ve replaced and repaired it over 30 timing chains , I do know about the use of a degree wheel, in the Ecotec engines, one is not required as the crankshaft and camshafts have timing marks to align during assembly then the crankshaft and camshaft sprockets align with those marks to align the timing chain for correct timing.
If not positioned correctly the sensors will do there job and throw a code, or if out of time enough the pistons will kiss the valves and bent the valve stems.
read and learn Greg, watch the videos and learn
https://www.chevyhhr.net/forums/how-...in-kits-60394/
http://www.ddmworks.com/assets/image...uild%20Kit.pdf