Head gasket replacement and now knocking (1 Viewer)

[BILT4ME]

There was the guy recently that dropped.a head guide dowel down the intake and into the cylinder........

That was ugly.

Yes, you could pull the upper and lower pans to get to the rod. It will be VERY difficult to determine exactly which one it is unless you decide to pull the rod cap and bearing from each..


Lotta damn work.

 

[ajax1]

Did you leave the screw in the cam gear tensioner ? Have seen that before

 

[baldilocks]

On the exhaust leak theory; you might check the short rubber hose that connects exhaust pressure from the egr pipe to the bottom of the vacuum modulator.

I had an exhaust leak there after doing my HG three years ago. It created a larger exhaust leak and had me thinking something major was wrong for a few minutes until I tracked it down.

 

[ZRotheohv]

I doubt it's an exhaust leak because it sounds like a metal hammer banging against a metal table. Plus I desmogged, so there's no EGR, PAIR, or EVAP system. I hope that didn't ruin something... I have a sneaking suspicion that it's something directly related to the lack of oil pressure. But why would it start with good oil pressure and within about 10 minutes drop to zero?

 

[ZRotheohv]

Do you think this might help diagnose?

 

[Jgrauman]

Do you think this might help diagnose?

Lost a rod bearing on my 3rd gen 4runner last year. Sounded just like yours. Oil had shiney flakes from the disintegrated bearing. Happened all of the sudden. 200k on the engine.

 

[ZackR]

I doubt it's an exhaust leak because it sounds like a metal hammer banging against a metal table. Plus I desmogged, so there's no EGR, PAIR, or EVAP system. I hope that didn't ruin something... I have a sneaking suspicion that it's something directly related to the lack of oil pressure. But why would it start with good oil pressure and within about 10 minutes drop to zero?

Others can provide more detail on what could happen in this particular engine to result in oil pressure loss but I agree its related to the noise. Unfortunately none of the potential outcomes are sounding good but in the end its all repairable/replaceable.

To minimize damage I'd avoid running the engine again until you open things up and figure out whats going on, especially since you have a fresh head that could be reused. Drain the oil and take a look to confirm what our suspicions are, then reach out to @slow95z for a short block and go from there.

 

[Cass007]

Drain the oil and run it through a strainer or coffee filter. If it looks like you've been panning for gold, you lost a rod bearing. I will find a pic of one of the motors I toasted in my tuner car. It's usually not had to find.

 

[flintknapper]

The oil pressure issue is certainly concerning. At 2200 rpm my engine is making 60+ psi and it has over 300K miles on it.

 

[Cass007]

Bearing material in the pan

 

[Cass007]

Normal pressure at idle was ~30psi. This is what mine was right before this motor peaced out ... just noticed my 80 in the backround rocking thew original chrome rims.

 

[BILT4ME]

Drain the oil and send it off to Blackstone for analysis. This will be fairly definitive if it's bearings.

 

[Tools R Us]

Did you leave the screw in the cam gear tensioner ? Have seen that before

This, the scissor gear is to prevent noises, gear knock. If the service bolt is left in, the gear will be noisy and the bolt can bang on the head causing noise and aluminum debris.

 

[ccslider]

Check the crank bolt torque.. 303 ft lbs

 

[ZRotheohv]

So I did a few more tests, and after taking multiple samples of oil out of the pan (filling up a small plastic folger's can) and running a magnet through it, I found absolutely no metal shavings. There were also none on the drain plug magnet. I also did the screwdriver test in the video I posted, and none of the pistons budged or made a noise whatsoever. I also took off the valve cover and everything under there looked normal. No timing chain issues or camshaft issues.

I'm leaning more and more away from the rod knock theory and I think I might tackle the crank bolt torque theory. I'll do some research on how to do it and post up what I find out.

What screw can be left in the cam gear tensioner? To install, I thought you just hooked the plunger in, installed it on the studs, then turned the crank backward to release the hook. I see no screw to leave in...

 

[flintknapper]

You didn't happen to jack up the engine for any reason underneath the oil pan?

 

[ZRotheohv]

Do you mean jack up as in ruin, or jack up as in raise with a hydraulic jack? Ha ha...

The answer to both is... not that I know of!

 

[ppc]

So I did a few more tests, and after taking multiple samples of oil out of the pan (filling up a small plastic folger's can) and running a magnet through it, I found absolutely no metal shavings. There were also none on the drain plug magnet. I also did the screwdriver test in the video I posted, and none of the pistons budged or made a noise whatsoever. I also took off the valve cover and everything under there looked normal. No timing chain issues or camshaft issues.

The bearing material is not going to be magnetic. Send off the oil to get properly analyzed

 

[ZRotheohv]

Is the bearing material not steel? Or is it a non-magnetic alloy?

The fact that none of the pistons have ANY kind of play in them and the the knocking noise seems to be in the front of the engine (measured by using a stethoscope) plus the fact that there is no metal in the oil leads me to believe it's something outside the crankcase. Of course I'll have to find out for sure eventually, so I may get it analyzed after I spend some more hours poking around...

 

[NorCalFJ100]

Hope this gets worked out easily!!!