Engine knocked for 60 seconds then went away.

[Wyant472]

So I pulled my 4.0 replaced the timing chains, oil pump, water pump & the passenger side head. I had to replace the head because it developed a crack and started sucking coolant. The truck has 215k miles on it so I decided to pull the engine and replace the head & timing chains.. It's a good thing I did because the timing chain guides were pretty much gone. This is where it gets weird. I get everything back together, I primed the oil through the engine by turning the ignition without the spark plug wires hooked up. I did this 20 times for about 5 seconds each time.. I then hooked up the spark plug wires and started the truck. The truck started right up but had a knock for about 60 to 90 seconds to be exact.. It knocked just long enough for me to walk around the truck then long enough to put my head under the front pumper to see where the noise was coming from. I wanted to see if the noise was in the top or bottom. To be honest I'm not sure, I kinda thought bottom end at first. It didn't do it long enough for me to really pin point it because as soon as I stood up it stopped. I've put about 100 miles on the truck since it stopped and everything seems to be normal. Nothing odd or out of the ordinary. No check engine lights or anything. My question is, is this something I should be concerned with? What would everyone else do if this happened to them? Any feedback would be greatly appreciated. Also, thanks for taking the time to read my story.

 

[shucker1]

When you were doing your engine oil pump priming cycle did you notice if the oil pressure came up?

 

[Wyant472]

Yes, the oil pressure jumped up to around the middle of the gauge. It did this each time I primed it. Not once have I ever heard of a kick that goes away and doesn't come back. That's why I have some concerns.

 

[shucker1]

If you didn't disable the fuel pump during the process you were dumping fuel in the cylinders while you were cranking.

What you may have been hearing is detonation as the engine tried to burn off the excess fuel?

Was it localized to one side or all over?

 

[Wyant472]

It seemed to be localized in the driverside. I guess you're right I should have disabled the fuel pump. I didn't think about it . I had the battery unhooked for some time, so my initial thought was the computer needed to relearn everything and maybe this was the cause. I thought about it more and came to the conclusion that this scenario was likely not the cause of the noise. Only other thing I can think is I didn't get all the timing chain material out of the engine. I haven't ever seen anything like it. My timing chain guides (metal included) littered the engine. Not in small pieces or shavings but big chunks. I have no idea how it didn't jump time. When I put the new oil pump on I looked over everything. I didn't wanna do all this work to just skip something so major. I also pulled the valve cover on the driverside to check things out and it looked normal. The truck is also in time. I am 100% sure without a shadow of a doubt that it's in time. I went out and bought the special tools to do it. My goal is to get 3 more years out of the truck and then get the new 4 door Ford ranger. At the moment I think i should just keep driving it. If the engine pops then I'll just replace it.

 

[koda2000]

Did it make the noise, stop making the noise and hasn't made it again since? If this is the case I don't know what the noise was, but if it doesn't repeat and it's now running well I'd just monitor the engine and keep my finger's crossed. Maybe it just took a minute for the chain tensioners to fill up with oil.

BTW: If you want to crank your engine w/out allowing it to start, just press the accelerator to the floor and hold it down. This turns off the fuel injectors, w/o which the engine will not start.

 

[Tech By Trade]

I second the tensioners, especially if they aren't OEM.