I just bought my XJ knowing that there were motor issues ...it would hardly idle and backfire all the time. I finally had some time to do a compression check on it today. I had 130 lbs in all cylinders except for # 3. So I figured it must be a burned valve ... I removed the valve cover and saw that #3 intake valve spring was broken , I pulled the head and disassembled the retainer, the valve and seat are both fine but the spring not so much ...




Is this a common problem with these motors ? I have never seen a broken valve spring in a motor before ... I'm going to order 12 new spring and some gaskets tomorrow ....

 

good sleuthing

 

I have seen many that have collapsed. But never seen one snap like that. I'm not saying that it can't happen as you proved that but I never seen it.

 

I know old but you know what I've replaced one in my sister jeep about 5/6 years ago, and how she just broke another one tonight. Last time was exhaust 6 , this time intake 1 all just do all of them and don't deal with it again.

 

Also get and replace the valve stem seals.

 

I'm not doing that mess again unless I know the motor has never.been touched before. Learned that.with the gf Jeep.

 

Not necessarily.


My personal experience has been with Chevrolet, not jeep, either AMC or Chrysler.
But springs like anything else wear out.


I have seen that in several 350's and even a big block 393 that were all over revved.


Olds. was a real common problem back in the day, but again pointing out AMC or Chrysler, typically they will do that only after being VERY old.