[wbnapier]

Originally Posted by tekuhn

You drove the car a fair distance before the seize, and surely you would have known if the engine was running on 5 cylinders. I tend to agree the spark plugs are a real mystery, but can't believe you wouldn't have detected that severe of a misfire if the gaps were closed from the first fire-up. Especially with a manual transmission and clutch where everything is transmitted to the driveline.

I did detect the misfire. I thought it was A/F or timing. I didn't think it was a no fire in the plugs. My plan was to cruise for a few minutes then return home and figure out the misfire.

And, I used the temp gun on each exhaust port and all were + or - 10 degrees. So, I assumed all cylinders were firing.

Remember, this is my first rodeo... Not an expert.

[tekuhn]

Originally Posted by wbnapier

Remember, this is my first rodeo... Not an expert.

Ah, OK. I didn't realize it was missing from the beginning. Not being critical at all. Has me rethinking whether I need to pull an engine I've had sitting installed in the chassis and never fired yet. I'm pretty sure I used Clevite 77's. This bearing thing could have been easily missed. I think I do understand what the machinist is saying. When you measured your thrust end-play, the crank was stopping short of reaching the rear-facing thrust face on #4 and instead stopping because the crank journal radius was hitting the rear edge of the #5 bearing shell. That would explain the weird noise that you heard when you pushed in the clutch in the final moments before seizure. The number 5 bearing edge and crank journal radius was under extreme contact from the pressure plate pushing the crank forward until it failed.

[wbnapier]

Originally Posted by tekuhn

Ah, OK. I didn't realize it was missing from the beginning. Not being critical at all. Has me rethinking whether I need to pull an engine I've had sitting installed in the chassis and never fired yet. I'm pretty sure I used Clevite 77's. This bearing thing could have been easily missed. I think I do understand what the machinist is saying. When you measured your thrust end-play, the crank was stopping short of reaching the rear-facing thrust face on #4 and instead stopping because the crank journal radius was hitting the rear edge of the #5 bearing shell. That would explain the weird noise that you heard when you pushed in the clutch in the final moments before seizure. The number 5 bearing edge and crank journal radius was under extreme contact from the pressure plate pushing the crank forward until it failed.

Exactly. He said that with aftermarket crankshafts, specifically my Scat and an Eagle he measured, they are longer compared to the stock Pontiacs he measured. Either overall or in a specific area, I don't know.

So, when one measures end play, you get a good mesurement. This is a false measurement though. Had I used a stock crank, I would have had too little endplay with these bearings and known there was a problem.

I don't know what to suggest to you. Of course, based on my experience, I would tear it down. Remember, my machinist bought a 10 under set of Clevites, and same problem as mine. So, this wasn't a one off error.

I emailed Butler tonight. I want them to test the Clevites vs. FM.