Broken rocker arms an failed lifters

Happened to 2 different cylinders now. Starts as a miss when cold that goes away then eventually breaks a rocker arm. Any ideas? Are lifter issues common? This is a rebuilt engine that I had installed a couple of years ago.

Broken valve spring?
Bent valve?
Floating valve guide or seat?

What engine?

turblediesel said:

Broken valve spring?
Bent valve?
Floating valve guide or seat?

What engine?

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03 with a 3.7. Valves springs are ok. Have not pulled the heads. Have been able to fix it both time pulling the valve cover.

What do you mean by broken rockers? Did they actually snap or just fall off? If they just fell off it's not that uncommon and probably weak hydraulic lash adjusters.

One broke and one fell off. Looks like the lifters are failing. Going to replace all of them. I love my Liberty but that love does not extend to the 3.7. I can't believe no one has ever come up with an engine swap that would not break the bank.

ktmrider said:

One broke and one fell off. Looks like the lifters are failing. Going to replace all of them. I love my Liberty but that love does not extend to the 3.7. I can't believe no one has ever come up with an engine swap that would not break the bank.

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I love all of my 3.7s, no issues at all really
04 has over 232,000 ( bought new ) , 03 at 132,000 and 05 at 120,000
have enough power, easy to work on, easy to maintain properly
I can play all day with those new JKs etc with supposedly better motors and they won't keep up

Mine had a broken lifter well when I bought the Liberty. I put a new head on and got another year out of the engine before it dropped a cylinder. Put a reman in a couple years ago and now lifters are failing. Fuel mileage and power are ok until you try to tow even small trailers then both suffer significantly. I've lost count of how many coils I've put on the original and reman chasing what seems to be constant misfire codes. They are thankfully easy to work on.

tommudd said:

I love all of my 3.7s, no issues at all really
04 has over 232,000 ( bought new ) , 03 at 132,000 and 05 at 120,000
have enough power, easy to work on, easy to maintain properly
I can play all day with those new JKs etc with supposedly better motors and they won't keep up

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One thing the 3.7 does not have is a lot of power. hahaha

Its adequate at best but the I guess there is a saying "you cant miss what you never had".

I had a 5.0 explorer before, the 3.7 is damn good for its size but a 4.7 would have been ideal in these.

I really need 4.10 gears but it will likely never happen.

Getting a #3 cylinder missfire code again. Running ok actually but I can clear it and it will come back after a couple of days..usually right after a cold startup.

Juggar said:

One thing the 3.7 does not have is a lot of power. hahaha

Its adequate at best but the I guess there is a saying "you cant miss what you never had".

I had a 5.0 explorer before, the 3.7 is damn good for its size but a 4.7 would have been ideal in these.

I really need 4.10 gears but it will likely never happen.

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Has plenty of power for the vehicle, wouldn't have a 4.7 in it.
More than adequate unless you want a quarter miler
As far as never had........LMAO, had more muscle cars back in the 70s than you could dream of.
I know what power is, but you do not need anymore in the KJ is what I am saying. I run 4.10s in two of mine, ( with lifts and larger tires ) and they do fine on and off road, pulling trailers or just running around .
As far as 5.0 Exploders go..........well I loved Fords but not them
Yes you do need 4.10s but of course I build mine to drive, no matter 5 miles or a 500 mile trip !

I'm not familiar with this valve train, could they have been over tightened in the adjustment?

Hope all goes well