Head gasket replacement and now knocking

[flintknapper]

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!

Should have known that was coming. We Old Folks sometimes forget the younger generation(s) have their own lingo.

'Jack Up': To raise an object.

The reason I ask...is you might want to look at your lower oil pan and inspect of any dents...especially at the front part of it. Whether or not it was 'jacked up'. Just be sure it has not been dented.

We had a member here last year chasing down a knock that sounded very similar to yours and we finally found that to be the problem. (crank contacting dented oil pan).

 

[BILT4ME]

Rod and Main bearings are made of non-magnetic alloy (Babbit, lead, other alloys) and may only be visible in an engine oil analysis.

Contact Blackstone Labs and collect and send off an oil sample (pull plug, let it run for a second, then pull sample, then install plug) then refill with oil unless going to drain and change.

It's about $25 for the sample, then you need to ADD the extra for $10 to get the extra test done and they can give you a complete review on what they see. It will take about 2 weeks to get the results. It's worth the wait.

I have done mine right after I got it, then I do it every other oil change so I build a history and can track wear. Trucking companies do this on most of their trucks to monitor lifespan of certain rigs.

 

[ZRotheohv]

Ah interesting about the metal... I would have thought they were some kind of carbon steel to resist the wear, but it looks like the babbitt metal wears in to make little spaces for the oil to hang out. I learn something new every day! Speaking of that...

While I wait for the lab results, I did some more testing:

I bought a big torque wrench and made sure the crank bolt was torqued using the chain method. It was, and the problem remains.
There was no evidence that my pan had ever been used to jack up the truck.
I also got a leak down tester, and every cylinder was about a 75% loss... Which is terrible, but the truck has 365,000 miles! That tester is pretty subjective though. I could test it again and it would be way different. But any way you slice it, it's a leaky motor.
Lastly, I did a compression test, and found these numbers:

1 30
2 150
3 140
4 140
5 150
6 145

So the number 1 cylinder isn't doing squat! I also tried doing the spark plug removal test again, and noticed now that pulling the #1 wire prevented the knock from getting very noticeable when I accelerate the engine.

So now I can safely say that it's the #1 cylinder, and it's probably bad... Before I plan to pull the engine, are there any other tests I can do?

 

[Michael Hanson]

Hi, Glad you finally tested compression. Could just be a bad exhaust valve. Look for that first. Mike

 

[Starlord]

i would get a borescope to take a look at the valvetrain on #1

 

[NorCalFJ100]

***edited, for whatever reason didn't see you already did a leak down!!!*** DOH!

 

[Tools R Us]

...
I also got a leak down tester, and every cylinder was about a 75% loss...
Lastly, I did a compression test, and found these numbers:

1 30
2 150
3 140
4 140
5 150
6 145
...

These two do not add, on the leak down #1 should have been significantly different.

The next test I would do: With #1 at TDC, inject compressed air into the spark plug hole and see where it comes out. Does it mainly blow out the intake, exhaust or breather? My favorite method is to remove the valve from a compression tester hose, screw it into the plug hole and plug the air hose in where the tester would normally go.

 

[ZRotheohv]

Yea the leak down didn't make sense to me either. I think the harbor freight leak down tester might be a little... testy...

I did use the compression test hose to attach my air compressor to the spark plug hole and it turns out one of the #1 intake valves is stuck open. Air pours out of the throttle body. And yes, I made sure it was on the compression stroke ha ha. None of the other cylinders poured air out of the exhaust or intake like the #1.

I'd think right after a valve job it would be squeaky clean in there, but maybe something happened. I'll be pulling the valve cover again later to get more details. I'm not sure if it has anything to do with the knock and low oil pressure or not! The game continues...

 

[Tools R Us]

A possibility: There are alignment dowels over the studs between the upper and lower intake, they have been knocked off and are the perfect size to hold an intake valve open.

 

[BILT4ME]

A possibility: There are alignment dowels over the studs between the upper and lower intake, they have been knocked off and are the perfect size to hold an intake valve open.

And to pound around inside a cylinder between the piston and the head........

 

[Tools R Us]

And to pound around inside a cylinder between the piston and the head........

The ones so far have not. The right size to fowl the valve but too big to fit through into the cylinder. Have been picked out and the problem is resolved.

 

[Tools R Us]

And to pound around inside a cylinder between the piston and the head........

It looks like this.

Should be here, note the missing one between 4&5 runner. The threaded stud likes to snatch it out, then as removed drop it into a handy runner.

If so, can get stuck behind the valve like this, holding it partly open.

 

[baldilocks]

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...

Oil analysis is only $25 at Black Stone. I send in a sample from each car I own yearly. It’s a cheap way of using your oil to see what’s going on with every part that motor oil lubricates.

In a case like yours, oil analysis will save you lots of time in chasing down the source of the knock.

Sample collection kits a provided free of charge from Black Stone Labs.

 

[ZRotheohv]

Until then I'll probably just go crazy and start tearing things down...

So I borescoped my valves, and it didn't have the glaring resolution I was hoping for. Here are my #1 intake valves:

They're definitely not wide open, but I can feel a good bit of air coming out of there at about 40PSI at TDC. I measured the clearances and I can still fit the feeler between the cam and bucket. I think my next steps are to take the exhaust manifold off to check things, and then drop the pan. But by now it seems like I'll have to take the head back off to really get any kind of closure on this...

 

[ZRotheohv]

Oh, and when I separated the intake manifold, all of the alignment dowels were still there. Thanks for the idea though!

 

[ppc]

The fact that #1 is still giving you a 30 psi in my opinion indicates a relatively small leak or a leak that may not be totally obvious from the pictures you posted. I don't like the looks of what appears to be rust on one valve.

 

[Tools R Us]

Well, that would have been too easy! When dealing with low compression, I prefer to have as much info as possible before taking it apart. Putting a rebuilt head on, only to find out the rings are the problem isn't fun.

 

[ZRotheohv]

Well the search is over for the knock I guess... The engine's coming out! Would the crap in the oil pickup be responsible for the low oil pressure? It's a lot of stuff in there but I'd think the pressure wouldn't fall to zero. Unless as it's running it keeps pulling more and more stuff up to it and then lets it go after the engine stops.

 

[slow95z]

Hard to tell on my phone but is it metal chunks in the tube?

 

[ZRotheohv]

Yes there are quite a few of them in there