Yes, the jets were all fine when the engine went in, and when it came back out. Honestly, if I didn't know better I'd think the engine had been recently rebuilt just based on looking at the part of the cylinder walls I can see from the bottom. I'm sure it hasn't been though; I believe I found a Navistar part number on the bearing.

 

The wear pattern on the rod bearing doesn't indicate a twist in the rod.

on edit. Now after thinking that through, I'm not sure if a twist would show on a bearing.

 

If all the other bearing are good, mains and rods, I'd pull that piston, check very close, check oil passages there, fix that and go on my way. That's if your not looking for some big power.

 

Subscribing... May have to pull my motor to chase an ongoing oil leak that keeps getting worse between the pan and block.

 

Well, only one picture for today. The Mitutoyo-ish clone items in this picture will lead to more pictures very soon <br><br><br>

 

Carbide faced, ratchet thimble? SPI?

 

Carbide faced, ratchet thimble. Not sure who the actual manufacturer is, but most likely Chinese in origin. They're surprisingly smooth. I really didn't expect it for the price ($89.00). I would like to check the included standards against a known good standard, just to be sure they're correct. Not that I have any specific reason to think they're off; just for peace of mind.

 

Quick update for Saturday . . .

I think I've found the most likely source of the knock. The #5 main bearing (farthest one back), or the bearing journal, is probably the culprit. Plastigage shows the clearance to be .005", tapering to .004". The clearance spec is .0018" - .0046", so it's not too far out, but it's out nonetheless. The taper wear spec for the mains is only .00015", so I'm really hoping all that taper is in the bearing, not the crank journal.

So it looks like the crank is going to come out tomorrow or Monday and get fully checked before I decide which road to take. I still might re-ring the low compression cylinder in the other engine and drop it back in and take my time rebuilding this one.

Only one pic today because I spent most of the time working one handed so I wouldn't have to set bearing caps down on anything that would possibly contaminate them. The #7-#8 rod bearing journal seems to be in spec, so that's good news.

 

Personally, I don't think that little bit would cause much knock. But that's me. Take your time, check pins, etc., if it wasn't fuel you will find it.

 

I "feel checked" the pins in #7 and #8 with the pistons in the bores, and I don't feel any movement at all, but all that will get checked too as it comes apart. Man, it's been years since I've had to get this deep into an engine.

 

Before you removed the rod caps, did you check the side clearance with a feeler gauge?
What was the crankshaft end play and how does the thrust bearing look?
Did you cut open the oil filter and spread out the pleats?
I hate to be a broken record but what type of knock did you hear? Fast or slow. deep in the bottom, loud near the top. Was it soft thud or a loud crack?

 

Side clearance was well within spec on all 4 journals, as was crank end play. The thrust faces on #5 main looked to be in good shape. I didn't cut open the filter, but oil analysis showed elevated iron and lead. The problem was there as soon as the engine went in several months ago, but it sounded like a bad injector to me at first. It got progressively worse over the short time I drove it, and changing the injector in #8 made no difference, but shutting it off via breakout box pretty much eliminated the knock.

It was at camshaft speed, sounded low in the engine, and was starting to sound more and more like metal striking metal. I started thinking it may have been a wrist pin, but that doesn't seem to be the case. I posted a video of the noise here, where I cut off and turned on #8 injector a few times. It was hard to kind of fully get the sound on audio; it was worse sounding in person.

 

Here are today's pics of the teardown.



Popped both heads off of it.




A few of the pistons with carbon deposits, probably from poor spray patterns from the injector nozzles. Injectors have been an ongoing problem with this engine. That's the next thing on the list after it goes back in.


Finally, a piston with a decent looking face. The injection timing is slightly advanced, but that I already knew about




Several cylinders on even side have some evidence that there was surface rust present when I installed the engine. I had the other head off before install to have exhaust manifold bolts machined out, but this one stayed in place. This could be the make or break factor, depending whether they can be honed out and still have the cylinder remain in spec. I didn't see any evidence of any rust under the odd side head.


Ridge reamed the cylinders and popped the pistons out.


Loosened all the main caps and popped them free. #2 and #5 bearings are the worst looking of the five of them. I was too dirty to take pick of them; I'll take some tomorrow.


All the pistons, snuggled together and ready for bed. The only one with any real evidence of blowby is out of cylinder #7, and it isn't anything major at all.


That's it for today!

 

Nice write up and thanks for sharing this project

 

On an average, how much ledge (or ridge) was there?

Any evidence of scuffed skirts?

How do the pins feel?

How do the rings look close-up?

Anything further on cam wear?

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