Life is like a box of chocolates....L9h engine

[ckeister]

Ok screw it this thing is going to the machine shop. I just hate to tear this down cuz everything is literally perfect minus these bearings. I was almost doing cartwheels when I pulled the lifters, looked at the cam, and then big letdown when I saw the factory style bearings.

The deciding factor is I’m not doing the R&R for multiple reasons so I’m paying a shop to do it. I would probably loose my cookies if I didn’t do it and then had a problem bearing a year or two from now

 

[rdezs]

There's a lot to be said for peace of mind.....

 

[ckeister]

There's a lot to be said for peace of mind.....

Yeah this truck has been a real sore spot for me. I bought for my wife as an X-mas present. Only vehicle I have ever been burned on in my entire life. Right after that, I broke my ankle, surgery, down for 6 months and she has hardly even driven it. Tried the whole pick up tube, oil pump and that’s when I figured out it was the cam bearings.

Thank for the input. Appreciate the help

 

[ckeister]

Well the mystery deepens…….WTF?

Someone suggested the paint marks were from the factory. These one’s most definately are not. The bright yellow is my markings as they came out of the holes.

 

[strutaeng]

Bearings look typical. They look pretty similar to my 06 LQ4 with around 265k. I replaced the cam bearings with Durabond CH-25, new main/rod bearings, cylinders dingle berry ball hone, new piston rings, and I "sent it." Kept the original oil pump because it was pristine. Truck runs good.

I originally was going to replace the lifters (intermittent lifter tick), but wound up doing a diy rebuild. I didn't have to do any machine shop work though.

 

[ckeister]

Cylinder walls…..#1 definately the worst of the bunch

 

[ckeister]

Don’t like the scoring on the skirts but I understand this is common. Again #1 is the worst

 

[ckeister]

Camshaft looks ok far as I can tell. The lifters were beautiful but not attached to the trays very well. Matter of fact I had to pull all of them out with a magnet. Pushrods rockers look good

 

[ckeister]

Oil pump looks like it’s newer than everything else. VVT phaser looks good, very minimal wear on tentione. This is what the pan and valley looked like. Almost too clean huh?

 

[ckeister]

Bearings look typical. They look pretty similar to my 06 LQ4 with around 265k. I replaced the cam bearings with Durabond CH-25, new main/rod bearings, cylinders dingle berry ball hone, new piston rings, and I "sent it." Kept the original oil pump because it was pristine. Truck runs good.

I originally was going to replace the lifters (intermittent lifter tick), but wound up doing a diy rebuild. I didn't have to do any machine shop work though.

What do you think about the non sensibility paint marks on the rods?? How many miles on your truck since you did it?

 

[strutaeng]

What do you think about the non sensibility paint marks on the rods?? How many miles on your truck since you did it?

The numbers are definitely not factory, I don't think(?) Edit: looks like the rods are factory with the little "dimple", but they were just numbered by someone for reassembly?

I've got close to 10k on my truck since the rebuild. It was done about 1 year ago. I'm a Gen III, so I little different, but general concepts are the same. This may help some: https://www.tahoeyukonforum.com/threads/tty-head-bolts-with-engine-in-vehicle.147231/

The cylinder walls are kinda hard to tell on the photos, maybe try some close-ups of the actual wall. Do the vertical scoring get caught on your fingernail when you drag it across? Same for piston skirts. That first one does look pretty rough on the photo.

 

[rdezs]

That is a real head scratcher. Are you thinking maybe someone just did the rods and mains, and new oil pump?

But that oil pan gasket speaks volumes, covered in RTV. That leads me to ponder a shade tree mechanic trying to address low oil pressure and swapped out the oil pump..... Didn't want to spend the $45 on an oil pan gasket. But that doesn't makes sense with the cleanliness inside the block. (Unless they were using Valvoline restore and protect for 10,000 miles perhaps?) The camshaft looking good with bad cam bearings is not unusual. I've removed a lot of AFM camshafts and they've all looked pretty good, except for one that had a lifter issue and chewed a lobe.

When you drop it at the machine shop, make sure and leave the camshaft with them along with a new camshaft retainer plate. (In case the bearings need to be reamed a little bit, and they can verify camshaft end play.)

Just curious, how much did you pay for the engine? Hopefully it was a decent deal.

 

[ckeister]

Are you thinking maybe someone just did the rods and mains, and new oil pump?

Bingo. Possibly the lifters cuz they look great too. And something let go in the lower half of this engine or it got ran low on oil. Crank seem like a polish will suffice but I havn't broke the mains loose yet. What is crazy is the way those rods are marked makes absolutly no sense. How are you going to have 5 rods marked 1 or 2 with a single 3 and the number 8 cylinder marked with a 4? I'll post my theory on what happened after I get it all apart.

No I paid $2700 for this plus a $500 core so im not happy about it but I cant blame the wrecking yard they didn't do it. I heard it run, it was in a collision so more than likely it was driving down the road. I did get everything so I wont have to buy another P/s pump alt, coil, etc probably for as long as we own this thing. Fortunately, or depending how you look at it, I have more money than time right now.

I've never been so baffled in my life with a vehicle. Did everything I knew to do when buying the truck. Did everything I knew to do and felt totally confident with this motor but when i see something, I have to go after it. Just the way Im built. In hindsight, wish now I would have done a compression test before I opened it up. This thing very well could have ran 4-5 years but now it is what it is.

 

[ckeister]

The numbers are definitely not factory, I don't think(?) Edit: looks like the rods are factory with the little "dimple", but they were just numbered by someone for reassembly?

I've got close to 10k on my truck since the rebuild. It was done about 1 year ago. I'm a Gen III, so I little different, but general concepts are the same. This may help some: https://www.tahoeyukonforum.com/threads/tty-head-bolts-with-engine-in-vehicle.147231/

The cylinder walls are kinda hard to tell on the photos, maybe try some close-ups of the actual wall. Do the vertical scoring get caught on your fingernail when you drag it across? Same for piston skirts. That first one does look pretty rough on the photo.

Yes you catch a nail on the scoring on #1 piston and one other. The cylinders themselves are definately not the worst ine ever seen all have visible cross hatching but #1 is the worst. Don't think they need to be bored.

 

[rdezs]

A light hone will probably be all it needs in the cylinders.

Any plus or minus signs on the connecting rods? I'm just picturing one of the high volume rebuilders, with a big box of good connecting rods.... Writing down some reference to the weight. Like how much each rod needed added or subtracted from it. Difficult to say.

Quite possible it was a short block and they did not prime the oil pump?

It is basically a roll of the dice when getting an engine from a salvage yard. While a lot of people simply install them and drive on budget reasons, I look at a salvage engine has a core to be rebuilt. And do exactly what you're doing.

The L92 is an extremely desirable engine these days, and unfortunately that has pushed the prices up. It makes the alternative.... Building an iron block 6.0 with the same horsepower.... A very viable option.

 

[ckeister]

A light hone will probably be all it needs in the cylinders.

Any plus or minus signs on the connecting rods? I'm just picturing one of the high volume rebuilders, with a big box of good connecting rods.... Writing down some reference to the weight. Like how much each rod needed added or subtracted from it. Difficult to say.

Quite possible it was a short block and they did not prime the oil pump?

It is basically a roll of the dice when getting an engine from a salvage yard. While a lot of people simply install them and drive on budget reasons, I look at a salvage engine has a core to be rebuilt. And do exactly what you're doing.

The L92 is an extremely desirable engine these days, and unfortunately that has pushed the prices up. It makes the alternative.... Building an iron block 6.0 with the same horsepower.... A very viable option.

Yeah I could not find a rebuildable core for sale anywhere. I ran several wrecking yards in the mid-90's (yeah i'm old) so i've seen all the good bad and ugly. Most of the time, if you know what to look for and your dealing with a good yard, you can get good used engines that will last for years. This one im sure would have been fine for awhile and if I was doing the install I would have just dropped it in. But I'm not paying someone to install a motor in this condition. My other concern is the possibility the bearing in my original motor spun enough to make my original block junk. Not sure if the cam jounals on the aluminum blocks can be sleeved or line bored.

As far as the rods go, there are 3 of them that appear newer/cleaner than the others.

Get this....I started doing research on the cylinder heads and the 821 castings are evidently LS3!!!!!

 

[rdezs]

The 821s and 823s are OEM on the L94 AFM/DOD engine, and the only difference from the LS3 heads is they have solid valve stems. Very nice cylinder heads.

 

[Charlie207]

Get this....I started doing research on the cylinder heads and the 821 castings are evidently LS3!!!!!

Yep. Good stuff.

 

[rdezs]

The L9h usually came with the 5364 or the 823 heads.

I prefer the 821 and the 823s....

If they appear recently rebuilt or an excellent condition, that helps offset a huge chunk of what you paid for the motor

 

[SpareParts]

I got a wrecking yard engine L92 for my Yukon. 6mos warranty, Compression is 220-230 and 45 PSI hot oil pressure for $2500. And i do trust the place i got it from. They do run them for 1/2 hour on a stand once removed.
I have not needed it yet but considering the compression it is not in need of rings but i decided to change cam bearings as long as it was on a stand and easy to do.
Glad i did as the #2 was shot. I'm sure they all are on L92's. The rest were normal LS wear. Replaced them with CH25 bearings.