'03, 3.0L with knock piston slap rod or fuel pump drive? how to test fuel pump drive?

[schiker]

My 3.0L is knocking. Just cranked it up for first time in 2 years. I had fogged it and let it turn over a handful of times before letting it crank but could have easily scored a cylinder. But it runs pretty good sitting in the yard even with the knock.

I read through a few threads and someone mentioned the cam driven fuel pump could sound like a knock. How can I test the fuel pump drive to see if that is it?

I took the sparkplug wire off each cylinder and the knock was still there for each test. Do I need to take the sparkplug out of each cylinder to see if knock quits to shade tree check if rod/piston slap?

 

[Bt Doctur]

Re: '03, 3.0L with knock piston slap rod or fuel pump drive? how to test fuel pump dr

just remove the fuel pump, there should be enough gas in the carb to do a quick test.
for the knock that may be a bearing or rod, remove the spark plugs, bring #1 to just past TDC, insert a suitable prying tool in the spark plug hole and try to move the piston down, do the same for the rest of the cylinders, dosent matter if compression or exaust srtoke, just make sure its on the way down just past tdc. only proves downward motion that can be a wrist pin or rod bearing.

 

[JWebber]

Re: '03, 3.0L with knock piston slap rod or fuel pump drive? how to test fuel pump dr

Look at rockers under valve cover too!

 

[schiker]

Re: '03, 3.0L with knock piston slap rod or fuel pump drive? how to test fuel pump dr

Oh well, it wasn't the fuel pump knocking. I loosened the fuel line and unbolted the pump from the block and pulled it out then cranked the boat. The knock was still there same noise.

I guess it could be a collapsed lifter but I am afraid its worse than that. I thought a lifter was more of a tap or ticking noise this is a knock.

 

[schiker]

Re: '03, 3.0L with knock piston slap rod or fuel pump drive? how to test fuel pump dr

Look at rockers under valve cover too!

Please forgive the long inbetween posts I am working on it in my spare time. I had 2 friends with car service provider experience listen to it. One said don't know but did not sound like lifter to him. Wasn't sure if rod knock or piston slap was his guess. The other said he still bets lifter due to side placement of lifter and engine has ran for while now and still sounds good and same. Cranks up and idles smooth sound doesn't change cold to warm etc. Knock hasn't changed with 1/2 qt marvel mystery oil then run til warm shut down recrank today same knock.

Ok, I have the valve cover off. I have cranked it up and watched the rocker arms and don't see anything real obvious. Same knocking sound. I took a cut off wooden broom handle and pushed down on the end of the rocker end at the pushrod fairly hard. The second or third rocker arm back from front changed a bit started a bit of ticking sound. But knock is still there. Should it be real obvious such that a shade tree guy could tell. And the rocker should have a lot of backlash. And with downward pressure of broom handle should I pickup up a lot of ticking from rocker backlash. This was just some ticking but it did change sound. The knock was still there though same sound just an additional slight ticking. Maybe the one next to it also did this but not as strong of tick/tapping.

Does this sound like something to further investigate? Or is that normal. How do I now rule out this as a stuck lifter?

Does this engine have 100 percent valve / piston clearance such that I can crank down on the rocker fulcrum nut a 1/4 -1/2 turn to see if kock goes away???. Or should I loosen til I hear a slapping/ticking/tapping sound of the rocker on the valve stem then tighten until it just disappears and a final 1/4 turn more. This after its ran a while so the lifters are pumped up good.

IF the lifter is just real weak/sticking what's the danger in cranking rocker arm down too much then the lifter all of a sudden starting to work and cause too much lift and cause the valve to hit the piston ???? Or would I tell a big miss and or poping sound from valve being open out of sequence????

What should I test next and how?

TIA

 

[JWebber]

Re: '03, 3.0L with knock piston slap rod or fuel pump drive? how to test fuel pump dr

Are any of them loose more than any others, you might have to slowly turn engine per each cylinder to see if one or more is loose than the others. Does it seem the sound is coming from this area? A quick give away is the thread height on the rocker threaded nut.

watch this video

http://www.youtube.com/watch?v=QAlCVA5cCQM

 

[krisnowicki]

Re: '03, 3.0L with knock piston slap rod or fuel pump drive? how to test fuel pump dr

could be spark knock, if the the boat sat for a while and the fuel system leaned out

 

[singlesupra]

Re: '03, 3.0L with knock piston slap rod or fuel pump drive? how to test fuel pump dr

What did the test of pushing down on the pistons yield? Please tell me you tried that before pulling the covers, pump, etc... as the other guy suggested?
And something tells me its not spark knock at idle...
and I didn't see it mentioned, but it does increase with rpm correct? Its not the shutters you are hearing is it?

 

[schiker]

Re: '03, 3.0L with knock piston slap rod or fuel pump drive? how to test fuel pump dr

watch this video

http://www.youtube.com/watch?v=QAlCVA5cCQM

Thanks, I found that video this afternoon and readjusted all rocker arms. It yielded same knock and no valve rocker arms are rattling or floating etc. My friend said you could bleed out a lifter pushing on it hard like I was doing at idle.

I had siphoned out the tank then added 2 or 3 gallons of new gas with the startron? additive and some SeaFoam. I shook the boat on the trailer then let it sit for a while then siphoned the "rinse" gas out. I took fuel line off fuel pump and stuck it out the hull drain as low as possible. I used compressed air in the fill port to start siphon and let it go unitl it dribbled to a stop - this took quite a while each time so I guess the tank should be ok clean. I then put in a gallon or 3 of new gas with marine stabil and startron? I could tell when carb purged the old gas and it picked up fresh gas it evened right out.

I had my 2 friends listen with me again earlier this evening and its probably piston slap or rod. The knock frequency varies with engine rpm like a rod/piston.

I did not try the piston at top dead center test as I don't think I am good enough to feel a few extra thousands wrist pin or rod movement unless it was gross play. I am not sure I would have much confidence in my feel contorted and feeling blind in the sparkplug holes. Plus the 3.0 is not that friendly to rotate as you can't get to the crank nut. I have to tighten the alt belt then rotate the alternator pulley nut and the belt slips some so its press belt and turn a bit at the time takes 2 hands. Might could do this test with helper and mark up some timing marks on the crank pulley for TDC of each cylinder.

I feel like its a take the engine out problem now.

Now to investigate rebuild or new long block. Ebay has new long blocks for $2000. Any other good sources of inexpensive new engines. Not sure I want to spend time on a used engine.

 

[schiker]

Re: '03, 3.0L with knock piston slap rod or fuel pump drive? how to test fuel pump dr

Its not the shutters you are hearing is it?

I doubt it cause sounds like internal to engine but hey I could be wrong what are you referring to as the shutters? I am not familar with that term.

 

[schiker]

Re: '03, 3.0L with knock piston slap rod or fuel pump drive? how to test fuel pump dr

In that video he has a rocker arm "floating" in my opinion and was ticking and tapping my sound is more a knock. I thought maybe with the placement of lifters on side of engine it might knock or slap the lifter and make a knocking sound maybe. And I did not want to take engine out for a bad lifter.

Anyone think it could still be a lifter if I can't feel any rattling or floating of the rocker arms while its running. Can't pinch them with your fingers and quiet or change the knock sound etc.

 

[Jas0n]

Re: '03, 3.0L with knock piston slap rod or fuel pump drive? how to test fuel pump dr

Have you tried pulling plug wires one at a time while it is running (use insulated pliers) ? If it is piston slap or a rod bearing when the load is taken off the suspect cylinder the noise will change.

 

[schiker]

Re: '03, 3.0L with knock piston slap rod or fuel pump drive? how to test fuel pump dr

Have you tried pulling plug wires one at a time while it is running (use insulated pliers) ? If it is piston slap or a rod bearing when the load is taken off the suspect cylinder the noise will change.

I did take each sparkplug wire off one at a time and cranked it up (cut it off to disconnect individual wires). After getting it warm enough so it would run on 3 cylinders smooth. It did not change that I could tell. I guess I can try with insulated pliers while running continuously and see if there was a subtle change I did not catch.

How much change in noise should I hear?

 

[schiker]

Re: '03, 3.0L with knock piston slap rod or fuel pump drive? how to test fuel pump dr

OK clipped from another thread....

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The shutters can start making a "clakity" noise.
The sound is often diagnosed as a bad lifter, connecting rod, gimbal bearing or a bad drive.
Bad shutters will only make noise at or just above idle.
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I doubt its my shutters as its frequency changes with rpm on up to 2000 rpm but the sound doesn't really change tone. And it sounds more like a knock that a tap or ticking.