[Gary H]

Originally Posted by wbnapier

Does anyone know why Clevite no longer grinds the teardrop-shaped relief in the thrust bearing? Does FM or King do this?

I don't use many Clevite bearings, mostly FM, but I don't ever remember Clevite having the reliefs on the thrust surface of the thrust bearing.

[steve25]

I have seen that kind Crank breakage with a non beat on SBC 350 2 bbl automatic no less!

[tom s]

Here are pics of the Clevite and FM bearings in the block.The crank has been cut 10 which cut some of the radius.The Clevite sits a little farther back in the block.FWIW,Tom

[ponjohn]

Originally Posted by tom s

Here are pics of the Clevite and FM bearings in the block.The crank has been cut 10 which cut some of the radius.The Clevite sits a little farther back in the block.FWIW,Tom

Would the first photo present a problem?

[tom s]

Depending on the radius!By the look of the seized bearing the machinest thinks so.Hard to tell now that the crank has been turned.He just think it’s another thing that needs to be checked close on all builds.Tom

[wbnapier]

From Butler:

"We have seen this with every brand of bearing and it seems to be more a difference in the blocks to us (most likely core shift over time possibly?)

We just recently had the same issue with a 389 but this is something we always check and sometimes have to slightly narrow and/or re-chamfer the bearing.

This is just part of the blueprinting process and a step we always check."

I wonder what else is always checked that I don't know about.

[MarkS57]

Originally Posted by wbnapier

From Butler:

"We have seen this with every brand of bearing and it seems to be more a difference in the blocks to us (most likely core shift over time possibly?)

Core shift? I can believe that of the rear main seal area but the main bearing saddles, thrust location and the bearing tangs- aren't they machined operations? As well, why no warning in the kit instructions? Hmmm..

[NeighborsComplaint]

Originally Posted by wbnapier

From Butler:

"We have seen this with every brand of bearing and it seems to be more a difference in the blocks to us (most likely core shift over time possibly?)(

quite possibly the stupidest excuse I've ever heard. Core shift occurs during casting and results in the off-specification location of a casting feature where there are voids needed in the casting. The core forms the void. When the core shifts, the void is formed off the intended location. Core shifts do not occur over time, the core is long gone from the casting process and the void is where the core formed it. Cast iron doesn't bend to allow a cast-in void to change position over time.

Basically Butler sold you a crankshaft kit of mismatched components and wants to pass the buck on the failure off on the "machinist/installer" knowing you are a novice. That's like them saying "We will rebuild your heads but you need to check all our work as additional machining may be required before you install." Jeezus, if you go to Autozone and buy any crappy re-ground crankshaft kit, the bearings fit the crank without machining.

The other thing I find unbelievable is that you were unable to discern an 8 cylinder engine was running on 5 cylinders. I can easily discern a single fouled plug on startup. When driven, the loss or power is much greater 12.5% (7 of 8 firing). With 3 cylinders down, you would have barely made it down the driveway much less drove it down the highway. Seriously? [B]Nobody[/B} drops 3 plugs in a row, lands them square on their electrodes so as to perfectly close their gaps, then installs them not noticing the gaps are closed. I have been wrenching on cars and snowmobiles for over 60 years and have never once seen a sparkplug come out of the box with the gap closed either.

I still say there's lots more to the story you are unwilling to share and I'll leave it at that.

[wbnapier]

NeighborsComplaint -

1) I am not satisfied with Butler's answer in the least. I have 19 years experience with casting in an unrelated field, and I found their answer patronizing and have not responded.

2) Based on the spark plug thing, it is understandable you are skeptical and think I am leaving some info out. I have absolutely no logical answer to explain the 3 closed gaps. I absolutely did not drop them. I gapped them all at .045 and double checked each. It is ALSO TRUE that there is no sign of mechanical interference, debris, nor combustion. It is ALSO TRUE that they don't come out of the box closed. So WTF happened??? I have no idea. My machinist thinks that I HAD TO HAVE dropped them. I cannot argue with his logic either. I have to move on.

I have been playing with cars since 2016 when I bought the GTO. I am a novice, but I immediately knew there was improper combustion at part throttle. I didn't think I was missing 3 cylinders. I assumed timing or AFR. This was the first time in my life I had ever fired a new engine. I chose to drive it a couple miles before addressing the misfire. On was only misfiring on partial throttle under load. The rest is history.

You may wonder why a novice would take on such a big project. I am mechanically inclined, have good friends with lots of knowledge, and have successfully done all sorts of work on the car. I thought it would be fun to try. Guys have been rebuilding these engines in their garages for 50+ years, so why not me?

[MarkS57]

Originally Posted by wbnapier

NeighborsComplaint -

1) I am not satisfied with Butler's answer in the least. I have 19 years experience with casting in an unrelated field, and I found their answer patronizing and have not responded.

Good!

You may wonder why a novice would take on such a big project. I am mechanically inclined, have good friends with lots of knowledge, and have successfully done all sorts of work on the car. I thought it would be fun to try. Guys have been rebuilding these engines in their garages for 50+ years, so why not me?

Yep, fall 2023 will be the 50th anniversary of my 1st engine rebuild, a 62 389. It was a ton of fun, absolutely. I have not rebuilt near as many engines as some have on this site though. I've never used an aftermarket crankshaft in any project to date. My next build will be a 428 w/ a stock crankshaft.

[Dragncar]

Originally Posted by NeighborsComplaint

quite possibly the stupidest excuse I've ever heard. Core shift occurs during casting and results in the off-specification location of a casting feature where there are voids needed in the casting. The core forms the void. When the core shifts, the void is formed off the intended location. Core shifts do not occur over time, the core is long gone from the casting process and the void is where the core formed it. Cast iron doesn't bend to allow a cast-in void to change position over time.

Basically Butler sold you a crankshaft kit of mismatched components and wants to pass the buck on the failure off on the "machinist/installer" knowing you are a novice. That's like them saying "We will rebuild your heads but you need to check all our work as additional machining may be required before you install." Jeezus, if you go to Autozone and buy any crappy re-ground crankshaft kit, the bearings fit the crank without machining.

The other thing I find unbelievable is that you were unable to discern an 8 cylinder engine was running on 5 cylinders. I can easily discern a single fouled plug on startup. When driven, the loss or power is much greater 12.5% (7 of 8 firing). With 3 cylinders down, you would have barely made it down the driveway much less drove it down the highway. Seriously? [B]Nobody[/B} drops 3 plugs in a row, lands them square on their electrodes so as to perfectly close their gaps, then installs them not noticing the gaps are closed. I have been wrenching on cars and snowmobiles for over 60 years and have never once seen a sparkplug come out of the box with the gap closed either.

I still say there's lots more to the story you are unwilling to share and I'll leave it at that.

Core shift can not cause this issue. Its crazy to try and blame it on core shift.
Did the OP not spin his crank when torqued down ? There is a lot missing from this story. Plugs with closed gaps ???? When there is nothing about the bearing/crank fit that can cause the gaps to close.
If there was 3 plugs with closed gaps, what it tells me is there is more wrong with this story.
Right now I have a Scat 4340 crank in a block with FM performance bearings. Crank has the large radius's. Spins perfect in the block.
It just goes to show you that every little thing needs checked with these engines. Once you change a part like a crankshaft from OEM to aftermarket, take nothing for granted.

[KEN CROCIE]

The user has become the mfgs quality control dept.

[HWYSTR455]

Amen.


.

[charlie66]

When setting up a new set of bearing one should check the endplay with out the caps . If its good then go forward with the caps starting with the thrust. If good go to the next one and so on.. As you go the problem will reveal itself if there is one..

[darbikrash]

King does put the oil relief on Pontiac thrust bearings.

The thrust bearing on top came out of my 400, not sure of the brand, the bearings below still in the package are King.

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[chiphead]

The FM4040 (3" main) do have the reliefs in the thrust shoulders. They also have an oiling slot and not just a round hole to line up with the block oil passage.

Ditto to what Charlie66 says about checking each half of the thrust bearing. Sometimes the upper and lower halves of a thrust bearing are slightly different thicknesses at the thrust shoulders.

If you have .007" endplay with the upper insert only and .005" with the cap installed, there is a .002" misalignment somewhere. Usually requires feeler gauges between the thrust faces and the crank to find it. Then glass plate sand the thrust face of the tightest insert to get back to .007" with the cap installed. This prevents all the thrust load of the crank shoulder from being loaded on only the upper or lower half of the thrust bearing.

[ponjohn]

Originally Posted by chiphead

The FM4040 (3" main) do have the reliefs in the thrust shoulders. They also have an oiling slot and not just a round hole to line up with the block oil passage.

Ditto to what Charlie66 says about checking each half of the thrust bearing. Sometimes the upper and lower halves of a thrust bearing are slightly different thicknesses at the thrust shoulders.

If you have .007" endplay with the upper insert only and .005" with the cap installed, there is a .002" misalignment somewhere. Usually requires feeler gauges between the thrust faces and the crank to find it. Then glass plate sand the thrust face of the tightest insert to get back to .007" with the cap installed. This prevents all the thrust load of the crank shoulder from being loaded on only the upper or lower half of the thrust bearing.

Interesting.

[charlie66]

Also,as you tighten each cap down rotate the crankshaft to see if it locks up or gets tighter. After all checks out try rotating it while holding pressure to the thrust just like you would for checking end play.. If theres a radius problem it will show signs of wanting to get tight .

[61-63]

As someone above said we the end users must perform the quality control on products. It behooves all of us to buy some quality measuring instruments and learn how to use them. This thread has been an eye opener for me beyond what I already knew to be true.

[mgarblik]

You do get an appreciation for how well the original engines and all the internal components fit together and worked flawlessly for millions and millions of miles when weird stacked-up tolerance problems like this happen. I have built probably just under 100 Pontiac V-8 engines and I have never seen this problem crop up. But there it is and apparently Butler has seen it. Another little thing I will certainly check moving forward. I am glad the OP won't have a huge expense getting this fixed. A tough lesson for sure. My personal thank you for sticking with the Pontiac engine and getting it repaired so you can enjoy the car. It will be worth it.