need help, knocking noise

[Rugbyfan]

I will attempt to make this as clear and as thorough as possible. The problem I have: a knocking noise coming from the head when the motor is running. shit.

The background:
Some of you may have seen the thread I made where I replaced the starter. Once the starter was on, the car was started up running just with the headers. It started up and seem to run fine. After about 20 seconds, We shut the car down, and left it there on the lift.

The next day, We replaced my whiny fuel pump. I double checked the connections, and ensured the flow path was correct. I then went to start the car and a horrible noise came once it was running. It ran rough, and there was a loud metallic knock. I have a video of the noise here:




I can't wrap my head around it. It seems unrelated to the starter, and the fuel pump can be heard (both new and old were tried). The noise is definitely coming from the head. Did I just get extremely shit luck and happen to drop a valve or spin a bearing?

[Rugbyfan]

video is now embedded

[scottinAZ]

pull valve cover, check for collapsed lifter

[Ceeker]

sounds like a valve dropped to me...or has ^ said..collapsed lifter

[Rugbyfan]

So just extremely shit luck? I pulled all of the plugs and peered into the cylinders. On cylinder #4 I found this[IMG][/IMG]

That plug was put in less than 1500 miles ago. They were all gapped to 0.034. When I pulled this plug, as you can see the electrode is touching. I feel that the plug just got too hot, and was perhaps gapped to close, as there is nothing that seemed like it had made contact. Furthermore I replaced the sparkplug, started the car, then shut it off and re-pulled the plug. The electrode was fine.

[Rugbyfan]

On a sidenote, if there is anyone in the Savannah, GA that wants to make money by helping me diagnose this, Let me know. I have access to lifts, airtools, etc etc.

[Mr.SWISS]

On a sidenote, if there is anyone in the Savannah, GA that wants to make money by helping me diagnose this, Let me know. I have access to lifts, airtools, etc etc.

MarkerMW is in ATL. I bought this E30 in Sav,GA last year and drove it back to Tulsa.







Threw a set of 14" weaves and it sold for $5.5K

I paid $450 at the auction for it and spent $600 going to get it lolz.

[Philo]

Pull the valve cover. It only takes a couple minutes, and the gasket can be re-used. Did you have the head apart or removed from the block? Did the engine run properly before the swap?

[Rugbyfan]

I'm at the shop now on my Phone and I'm pulling the valve cover (it's stuck, all 15 bolts are out). I have not removed the head before and for the last few thousand miles it ran fine.

[nrubenstein]

Pry it up. Use a screwdriver. They like to stick after they've been on for a while.

[Rugbyfan]

Used a wooden dowel and rubber mallet, came right off. The top end looks extremely clean. So to check for valve play/collapsed lifter what specifically would I be looking for. Should I rotate the crank by hand to TDC?

[Rugbyfan]

With all the plugs out the motor will not turn by hand a full 360 degrees, in either direction. On cylinder #4's compression stroke is where the crank will stop. I need to find one of those cameras that I can put down in there and see.

[Rugbyfan]

Ok here's what I believe is happening. Something is preventing the exhaust valves from opening on cylinder #4. This would be consistent with the fact that the top of piston #4 was wet (possible unburnt fuel). I'm thinking that. Lifter on the exhaust side of cylinder #4 is stuck. How do I check for a stuck lifter?

[Mr.SWISS]

Ok here's what I believe is happening. Something is preventing the exhaust valves from opening on cylinder #4. This would be consistent with the fact that the top of piston #4 was wet (possible unburnt fuel). I'm thinking that. Lifter on the exhaust side of cylinder #4 is stuck. How do I check for a stuck lifter?

Remove cam tray. somewhat scary although haven't broke a set yet.

[Ceeker]

if your crank isn't rotating a full 360 degrees then it's not a exhaust valve that is stuck shut but open since it would only make sense it is making contact with the piston. if the valve was closed on both the intake and exhaust then you wouldn't have any contact. A dropped valve would indicate the piston making contact with the valve. that means while car is running the piston is just slamming the valve up and down without spring load. valve is just floating. hence a "dropped valve." Since it sits slightly below the seat contact, the piston will touch it just enough to slap it -giving you that tapping or ticking noise. So on intake the fuel goes in and piston goes down. then the intake valve closes -piston comes up. Then spark (both valves closed for compression) sends the piston down for the power stroke. as the piston comes back up the exhaust should be open. and it is...but...I think your exhaust stays open all the time. reason for the binding when you try to crank it. Manually it may bind but under engine load it may push past that resistance. so you get fuel, spark but no ignition or partial with no compression.

connect a compression tester gauge in spark plug #4 cylinder and crank engine slowly if you get low or no reading then it is obvious that the chamber isn't getting compressed on the compression cycle.

but since you stated the motor gets stuck either way you crank it. This isn't advisable since you may bend the valve. sometimes you can cheat the job buy sending compressed air into the cylinder to pump the valve up; then change the valve spring/lifter and seal and the try it again.

last resort will be to remove the head entirely and inspect and repair accordingly.