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Discussion Starter · #1 ·
This post is about rod knock and what I have done to temporarily fix it and what I plan as a permanent fix.
Vehicle 2000 Buick LeSabre 200k Miles l36 N/A
Recently replaced all gaskets on top end (valve cover, upper & lower intake, head gaskets) installed zzp front power log. The knocking started very soon afterwards.
  • Used Shadetree Stethoscope (long flat head) to pinpoint noise coming from bottom end.
  • Dropped the oil pan and screw that stupid motor mount attached to the oil pan. (Make sure to have good sockets that can remove rounded bolts. I found this type to be the best
Personal protective equipment Auto part Metal Font Fashion accessory

  • Dropped oil pan and noticed metal slivers but after cleaning oil pan it looked like the pan itself could be flaking. Also the metal slivers kind of felt like something that was one step above tinfoil. Here are some pics.​
Gas Font Asphalt Road surface Carmine

Automotive lighting Automotive tire Automotive exterior Font Asphalt

There were also several other smaller slivers.
Here is the oil pan before and after cleaned.
Brown Water Water resources Liquid Fluid

Automotive tire Wood Road surface Automotive lighting Grey

Fun Gas Plastic Electric blue Wood

Here is the pan after cleaning
Water Liquid Automotive tire Flash photography Grey

Inspecting The Rods and Bearings
  • Checked Side to Side Play and any up and down play and all passed except cylinder 4 on up and down play.
  • Cylinder 4 bearings were still in their caps so I don't think they spun however, both bearings had lost there locking tabs.
  • Measured the journal for cylinder 4 and it is within specs however, even with new bearings it still had decent up and down play.
  • Using Gageing Plastic I seemed to be getting around 32 about 6 outside of the top end spec of 25.
  • I ended up using 400, 800, 1000, 1500 wet sandpaper soaked in tranny fluid to polish each journal and then polished each journal as all of the old bearings looked horrible. Pics of the old bearings at end of thread.
  • Rechecked mmeasurements and it seemed I was still of by .04.
  • Using a soda can I carefully cut to size a shim to install on the cap side and this brought me within spec. I plan on adding Lucas as an additional support for this temp fix.
  • I have ordered new bolts for cylinder 4. all other journals, bearing clearance, and con rod caps measure within oem specs.
I'm hoping to remove the shim and the new bolts will fix the issue permantly, until I get the funds to beef up the bottom end.
she runs good at the moment I'm just worried about the shim coming loose..

Here are some of the pics of the old bearings with 200k miles on em.
Material property Gas Auto part Metal Fashion accessory

P.s I also cleaned up the caps.
 

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Dang...I am all for keeping stuff going as long as possible.My pickup will be rolling over 500k miles any day now.But for the cost of even gaskets anymore,you might consider finding another engine.I know Cleveland well,gotta be a rusted donor somewhere.With all the bearing material thats been thru it,I am assuming cam bearings and such are probably showing it as well.I just found a Grand Prix GT that is hit in the nose with a nice clean 3800 for $450.I know the car well,and want the motor for a top swap and lower gear set.They are still out there to be found.
 

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Ya, Upull yards are where to get an engine (and dirty) for a decent price. 97-03 GP's and a couple others have normal odometer you can read, too, unlike many 3800 cars that went digital pretty early on & need a battery to check miles.
 

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Discussion Starter · #5 ·
I only really need this as a Band-Aid fix right now to get me by until I set up an engine hoist.
Yeah I can go by a used engine at my local junkyard for around 4 to 500 bucks but I don't want to go that route.
I can rebuild the bottom end for under that amount and I'm sure it would last a lot longer than a used engine coupled with the fact of pretty much rebuilt the top end.
Not to mention the skills and knowledge gained from working on the engine will be handy.
 

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Discussion Starter · #7 ·
I will agree with you yal on it probably being the sane decision of just dropping in a junker motor.
I plan on doing a lot for this car in the long run and I'm going to need a strong foundation to build upon 😃
 

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Discussion Starter · #8 ·
I forgot to mention the oil filter was clean nothing metallic or shavings at all. I cut it open to check. Those metal slivers almost remind me of what would be on the outside rim of a foil cap and they were only in the oil pan and to be honest I think the last time that oil pan was dropped was probably 15 years ago if ever.
 

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Discussion Starter · #9 ·
Well my Band-Aid it's not holding up as well as planned. The knock is back (I knew this wasn't a permanent fix) however, it is barely audible and if you weren't listening for it you probably wouldn't hear it.
She's parked for now and I will be starting my tear down after Easter.
Going to end up replacing at a minimum in this teardown
  • Timing chain with a double chain
  • Oil pump and pressure relief valve
  • Water pump
  • Crank position sensor
  • Cam position sensor
  • Have crankshaft machined
  • Inspect connecting rods and pistons
  • piston rings
I'll be updating this on my main build page.
Tldr. If you spin a bearing you're going to need your crank machined or a new crank.
 

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You may have to check the connecting rod you shimmed very closely for roundness.At least platigauge in more than ! spot in the circumference of the bearing journal.
 

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Discussion Starter · #11 ·
I did this and it turned out the problem was the bolts and the metal slivers were from the oil pump.
I ended up taking the front cover off to get ready for a tear down and notice my oil pump rotor was cracked. Everything else look like in tip top shape and the timing chain was tight.
So I thought let me try this replace the oil pump and spring and instead of using a shim order a couple OEM bolts for the cap and use just a standard size bearings.
Bam the knock was gone and the engine is running great.
 
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