timing chain life

[mjoekingz28]

You're right worm, but they generally allow you a couple hundred rpm before the limiter kicks in. Pretty sure holding the engine at 100rpm below the limiter can not be so good.

Once asked a buddy how fast his automatic Prelude would do in third (didn't know he'd do this) so he shifts to third and floors it. It spent a considerable amount of time above redline since it was so slow picking up revs. never found the answer but his engine ended up knocking and got written a ticket for attempting to find out.

 

[Donald]

Originally Posted By: MetalSlug
Originally Posted By: Donald
Originally Posted By: 440Magnum
Originally Posted By: Donald
What wears with respect to the timing chain on a GM 5.7L engine. I have one in a boat and one in a Suburban. Or do they just keep on going?


Depends on the year. If it came from a year where "silent" (that means "nylon") cam gears were in vogue, then the nylon wears down until the teeth break off the cam gear and the timing chain slides around the gear.

Years with all-metal chains are just like any other cam-in-block V8 with no tensioner- the chain gradually stretches and gets noiser and noisier. On the SBC in particular more than Ford and Mopars (although all will eventually do it), the floppy chain will begin to rub the timing cover until it grinds a hole in it and makes a nice big oil leak.

As the manufacturers have introduced more and more efficient engines that depend on very precise timing, variable valve timing, etc., even cam-in-block engines now usually have a slack-side chain tensioner and IT tends to become the early failure point. I've been told that the first couple of years of the new Hemi had some tensioner issues that would tend to show up around 100k miles. The Jeep 4.0 has a chain snubber, but it seems to last forever just like the rest of the engine.


Don't be quite so sure about the Jeep 4.0 engine lasting forever. Your year (2001) and a few other years has definite problems with piston skirt cracking and then possible total engine failure. In mine the wrist pin was not even attached to the piston when the oil pan was pulled. But yes, they are mostly bullet proof. My reman engine has almost 4K on it, wow!!


those having problem is the one that over rev the engine, over rev while off road, driving like having a v8, its 4.0l. its slow, drive it easy. I seen many wj on the road around here, every where I go, I seen at lest 5 wj.


Given that I had to replace the manual transmission in my 1965 Mustang (in 1970) because of fast starts I decided to drive more conservatively like there is an egg between my foot and the gas pedal. So I definitively do not drive fast or off road. Yet my 4.0 engine failed with a piston skirt problem. Just because you see Jeeps with 4.0 engines where you go does not mean they have not had a piston skirt problem and had the engine repaired or replaced. And my Jeep also got the best mechanical care with synthetic oil and Amsoil oil filters. Certainly I am not suggesting all 4.0 engines will fail. Just that they are not as bullet proof as I once thought. Contact me when you hear a tapping sound in your engine.

 

[artificialist]

Originally Posted By: MetalSlug
Originally Posted By: Donald
Originally Posted By: 440Magnum
Originally Posted By: Donald
What wears with respect to the timing chain on a GM 5.7L engine. I have one in a boat and one in a Suburban. Or do they just keep on going?


Depends on the year. If it came from a year where "silent" (that means "nylon") cam gears were in vogue, then the nylon wears down until the teeth break off the cam gear and the timing chain slides around the gear.

Years with all-metal chains are just like any other cam-in-block V8 with no tensioner- the chain gradually stretches and gets noiser and noisier. On the SBC in particular more than Ford and Mopars (although all will eventually do it), the floppy chain will begin to rub the timing cover until it grinds a hole in it and makes a nice big oil leak.

As the manufacturers have introduced more and more efficient engines that depend on very precise timing, variable valve timing, etc., even cam-in-block engines now usually have a slack-side chain tensioner and IT tends to become the early failure point. I've been told that the first couple of years of the new Hemi had some tensioner issues that would tend to show up around 100k miles. The Jeep 4.0 has a chain snubber, but it seems to last forever just like the rest of the engine.


Don't be quite so sure about the Jeep 4.0 engine lasting forever. Your year (2001) and a few other years has definite problems with piston skirt cracking and then possible total engine failure. In mine the wrist pin was not even attached to the piston when the oil pan was pulled. But yes, they are mostly bullet proof. My reman engine has almost 4K on it, wow!!


those having problem is the one that over rev the engine, over rev while off road, driving like having a v8, its 4.0l. its slow, drive it easy. I seen many wj on the road around here, every where I go, I seen at lest 5 wj.

That is true, however, there is another major weakness in some 4.0L Jeep engines:

Some cylinder heads are prone to cracking.