Hi guys,
I’m currently rebuilding an H headed 455 442 W 30.
It came to me originally because of excessive oil consumption, about a qt. every 500 miles, even though it was recently rebuilt. After tearing it apart, I found numerous mistakes and careless assembly practices as well as now, questionable machining operations as well.
The last statement is the reason for this post. I typically run into mistakes and such other shops do on Oldsmobile engines in general. But what I found yesterday is unacceptable. This engine had very good oil pressure, but when I pulled it apart and saw the Crank, etc., in this condition, I was confused as to how it would have such good oil pressure with the crank and bearings in less than optimum condition.
In addition, all the main saddles were .0015-.002 OVER the high spec. So how did it still have real decent oil pressure?
I found they “adjusted” the bearing clearances by grinding the crank only .008 under, not the full .010. That tightened up the bearing clearance, even with the larger main saddles. This was a blatant machining practice to circumvent doing it the correct way(ie align honing correctly and adjusting clearances from there). Stuff like this is unacceptable to me, and should be to everyone as well. The cost of this rebuild when done in 2021 was over 7k, and it was basically just a hone, re-ring, with a new flat tappet cam.


I’ll finish by saying the shop that did this is in Greeley CO.

 

Geez.. what a mess!

 

Is it the place that does the YouTube videos by chance?

 

Looks like a ton of crap went through it too. Did you find what was causing the oil consumption ?

 

Yes, loose guides, worn valves, questionable seals.
Rings looked OK, but the cyls were a bit barrel shaped as well.

 

Dunno, what place is that?

 

Yikes. I'd understand a bare-budget "git 'er done" rebuild going that direction but a $7k rebuild bill? Wow.

 

Jim's Automotive

 

No, not it. But if someone guesses it, I will say it, or if someone wants to PM me, I will tell them as well.

 

not uncommon to see GM factory bearings +plus on the bearing OD to compensate for out of spec main saddles back in the 60’s and 70’s. I’ve seen it many times.

but today that’s a no go when doing a build not coming down an assembly line.

 

how’s the valve sticking open issue coming along with that 400G block?

that’s twice now…hopefully someone doesn’t tag you online for that problem like you are trying to do with this bearing problem..because, that would suck.

 

All fixed, defective guide, kept swelling.
And that’s why I run them extensively, not just a pull or two.
They don’t leave until they’re right, unlike the one in this post.