Help Diagnose Engine Knock

if you have the time and the determination to pull it you might as well.
if you pull it and the valves did just need adjustment at least then you'll have new head gaskets and you'll know for sure what the issue is.
i say do it! pull it and do a good inspection measuring tolerance on the parts put new valve seals in wile you are at it.

if it was just adjustment at least youll have the comfort of knowing that!
 
Ekimrm said:
Badbob. Other than the ticking noise how is your 4runner running?
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Well, since we did the SEAFOAM treatment (Fuel, Vacuum, and Crankcase), put new plugs in, change the oil (after the 30 miles SEAFOAM treament) Mobil 10w-30 plus a quart of Lucas Oil Treatment, I'd say she runs very strong (I've owned an 88, 91, and 04)

The knock goes away as she warms up. But there are still lots of little **** that needs to be fixed: oil pan leaks, PS pump leaks, Idle arm and gear box leak, shot vacuum hoses, needs tires, windshield washer pumps, and so on.

Ok, I'll pull the heads this weekend and give a report Sat night. Maybe with some pics too.

What brand head gaskets do you recommend? Is NAPA good?

Badbob
 
Update

This afternoon we pulled off the intake manifold and valve covers and measured the valve clearance. Everything spec out. 2-3 valves where .001" over but nothing glaring out of place.

So, next step, as we bore down into this diagnosis is to pull the head and have look.

All in all, everything looks clean. inside the valve covers is was pretty dark brown, but no built up sludge.

We broke 3 of the 6 injector wire connectors--ARRG! So brittle, they just snapped. One more thing to fix.

Badbob
 
Update2

We got the driver side head off. Look at the values. Nothing looked glaringly wrong. the camshaft measures, at #2 cyclinder, about .002 thinner than the min. spec.

Cylinder #2 has wear left and right, perpendicular to the crankshaft. When the piston is up it touches the inner side of the wall, when it is down, it touches the outer side of the wall. I tried to upload an image but no go.

I take it this is what you guys thought was possible 'piston slap' and the reason for the knock. No scoring in the cylinder walls of #2, #4 and#6.

We still need to remove passenger side head and take a look.

So, if i were cheap and wanted a quick easy fix, could i just replace the piston if the cylinder is still within spec?

Is a rebuilt a cheaper better option than doing a rebuild yourself?

Thanks,

Badbob
 
yes you can just do a master rebuild kit with no machining on the engine!!!
as long as the cylinder walls are not scored this is a viable cheap option. keep in mind doing this without machining the engine block could reduce the life span.
i have done 3 rebuilds without having machine work done 1 engine went another 140k before i had to rebuild it with machine work(threw a rod bearing)
1 i did now has 567k on it and still 146compression the last one blew up because i was cheap and didnt replace the oil pump.
 
because the piston knuckle would be broken or beyond tolerance leaving a gap and thats the slap
 
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Ekimrm said:
Ok but what is causing the slap? Why is the piston doing this?
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What I've read is that it is probably do to a overheating problem. Not enough oil, oil pump problem, failed headgasket, and so on. the piston warped. It could have happened when the original headgasket failed or was recalled.

I'm pricing out rebuild kits and local machine shops. Since the oil pan leaks and this is going to need a new oil pump I'm think'n just pull the entire bloody motor. Then we can fix the leaky PS pump and hoses.

Badbob
 
Ok bob here is another question for you. When your engine made the knocking noise did it do it all the time or just on acceleration? My noise tends to be only on acceleration and only when the oil has warmed up. I know the only way for me to see what is actually broke is to take it apart but would like to have an idea so I can make sure I have access to the parts to fix it. I haven't had this truck very long and took it to the woods last weekend and am very impressed with the way it handled. I have found a new love for this truck. Lol. I took it through stuff my old truck had issues with and I never had to put it in 4wd.
 
Ekimrm said:
Ok bob here is another question for you. When your engine made the knocking noise did it do it all the time or just on acceleration? My noise tends to be only on acceleration and only when the oil has warmed up. I know the only way for me to see what is actually broke is to take it apart but would like to have an idea so I can make sure I have access to the parts to fix it. I haven't had this truck very long and took it to the woods last weekend and am very impressed with the way it handled. I have found a new love for this truck. Lol. I took it through stuff my old truck had issues with and I never had to put it in 4wd.
Click to expand...


Mostly when it was cold and I was accelerating. it would quiet down when i would let off the gas. Why? Less compression in the #2 cylinder

Ekimrm, start out doing the simple diagnosis stuff. Oil change, new plugs, seafoam treatment, compression test, and then while idling the truck unplug each spark plug wire, one at a time, and see if the knock goes away. Mine disappeared when we unplugged #2. So I knew it was either a bad valve, or piston, or rod specific to #2.

When all the above fails, then u need to tear into it. I have 172k miles so this type of crap is normal.

Badbob
 
quick update

I haven't really moved forward this week. I'm pricing local machine shops and still assessing what caused the #2 piston to slap.

The good news is that we've done some exhaustive cylinder bore measurements and found that #2, #4, and #6 are well within specs. So one option is to do a light honing on the cylinder and put in new pistons and rings.

Today, we'll pull the passenger side head off, oil pan, oil pump and see if we can get to the #2 cylinder rod, disconnect it and examine the piston, rod, wrist bearing, etc. to see if we can find the culprit for the piston slap.

Stay tuned. Badbob
 
Quick Question

Quick update--took of passenger side head and everything looks ok. All cylinders measure well within specs, including the bad #2.

So here is my course of action:

1) send heads in to local machine shop for rebuilding. One shop does them for $140 a head.

2) get master rebuild kit and hone cylinders and put new pistons/rings. I'm assuming I got a bad rod, write pin, or piston that is causing the #2 slap. but thankfully the cylinders are not worn.

One quick question: Can I replace the oil pump and all six pistons without removing the lower end? Can I drop the frt. differential and work from below or do I need to pull the whole frick'in block out?

Thx bigbob
 
you will need to pull the lower end off totally to do anything with pistons or piston rods.
as for the engine i say pull it out and make life easier on yourself monkeying around with a block not on a engine stand is a bad idea.
 
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