Dodged a bullet

[PolaraFury]

I built a 500 stroker B Block over the summer. I made some mistakes and had to yank the motor out to fix the rear main seal because it leaked.

Found out the #7 rod bearing was toast and my mains were wearing odd. I should have purchased the chamfered bearings. (I received bad advice) ((Lesson learned))

Took the block to get it lined honed and crank polished. I explained to the shop my #4 main cap fit loose.

When I went in to pick up my block I found out the #4 cap was cracked, but the machinist is a perfectionist, so he dug around his shop and found a b block #4 bearing and machined it to fit. You couldn’t see the crack with the naked eye, he machined a couple thou off and you can see it plain as day.

I think the crack explains the #7 rod bearing going bad. That rod marries up the cap and the crack would have given up enough wiggle room to wear.

Now that I have a new set of bearings (rod and mains)

 

[MoparLeo]

Machine shop 101. Always Magna flux everything before you use it or machine it. Drop off the rotating assembly so the machine shop can bore and hone each cylinder to fit each piston. Crank polished to proper bearing clearances.
Building something is not the same as assembling something...
Surprised someone assembled it with a loose main cap.
The line hone should have been done the first time around.
The current situation would have been avoided.
You never save money trying to save money.

 

[F4R/T]

You got lucky! Thank God!

 

[padam]

Good job for your machinist finding the crack.
I'm not sure how that would cause a bearing failure on #7 rod though, unless it was letting oil out.

 

[MoparLeo]

Great information for the novice/experienced engine "builder"