Collapsed lifter valve? --with sound--

[romanella]

I have a really annoying knocking sound coming from my engine. Not sure what it is.... Sounds like a collapsed lifter valve. Any ideas?

Click here to hear the knocking - .WAV file (http://cmcgems.com/etc/jeep/jeep_knocking.wav)

[ademster]

that sucks, take the valve cover off and check the push rods. if one is loose then it is a collapsed lifter.

if non of them are loose, well then it had a bad rod bearing somewhere.

[AbsoluteOffroad]

There are a few ways to diagnose more accuratly where the knock is coming from. While the engine is running, first remove 1 spark plug wire at a time, untill the noise stops. When it does you have found the cylinder where its happening at. After you have found the cylinder, first run a compression test on it, then the other cylinders. This will determine a colapsed lifter (doubtful) by the change in compression. Remember that the 2.5 engine is VERY famous for cracking pistons. Thats what my "un-educated" guess is. (Guess made by not ACTUALLY having the vehicle in FRONT of me) If you have not found anything at that point, start by LOOKING at EVERYTHING that spins. I.E. Harmonic Balancer, torque converter to flexplate mounting bolts, bad bearing in a pulley...there could be so many things causing that noise, just dont condemn the engine right off the bat. If you cant figure it out, take it to a reputable mechanic to figure it out.



Joe
Absolute Offroad
602.248.8949

[TanTJJim]

Hey Chris, a collapsed lifter will usually make more of a ticking noise. That is definitely a knock. I know you had to do something to your harmonic balancer, I would take a REALLY close look at that. Possibly even remove it and run the engine for just a couple seconds to see if the noise went away. Otherwise it will probably be something internal. Just out of curiosity, how did you get that piston installed that you had to swap. Did you use a ring compressor?

[ademster]

ohh now that truth comes out

[romanella]

I'll have to take a look @ the harmonic balancer tomorrow after work. I did take the engine apart a lot today, replaced the cylinder gasket, cleaned & conditioned all the lifters, so I'm thinking it might not be that anymore.

What exactly is a ring compressor? I used a tool from Autozone to squeeze the rings around the piston while we dropped it in. Installed it and it slid in fine. Was the same size as the old one.

I'm seriously considering taking it to a mechanic to look at. Any recommendations? Jim, if I take it to your place, do they offer a VJC discount?

Thanks for the help guys. I just drove it to Tempe and back. Had all the power of the old 2.5L, performed like normal even under heavy load while passing someone. Oil pressure around 15-40 PSI (it was a little low on oil, put 3/4 quart in, will check tomorrow)

Chris

[My Green Jeep]

I recommend:

Joe
Absolute Offroad
602-248-8949

I will be stopping by there tomorrow to pick up parts for
My Green Jeep... she is eating parts again :banghead:

Good luck :)

[My Green Jeep]

bump... it double posted... hmmm... weird

[TanTJJim]

The tool you used from Autozone is a ring compressor. Unfortunately the shop I work at doesn't give vjc discounts. I don't want to discourage you from taking it to a shop if it comes down to that but be forewarned it will probably not be cheap. If it isn't a problem with the harmonic balancer look at the tips that Joe said. That will help narrow it down if it's an internal engine problem. Let us know what you find.

[ademster]

You can bring it to me if you want... pm me for details.

[romanella]

I was thinking long & hard about the Jeep this morning while driving it to work & I remembered that the noise existed even when I had the old harmonic balancer on. It was the stock one and had never been removed. What else should I check now that the harmonic balancer being a problem is eliminated?