How to inspect case for use? Measurements, plastigauge?

[Martin S.]

I need to build up an engine. I have an almost-new Brazil AS41 block that I bought after the shop that had it used another block because they said there was a problem with this Brazil case and something about it seizing up a bearing. It was assembled, ran briefly, then torn down, and then I bought it.

When I look at the block, it looks perfect to me. The bearing saddles are not marked up, no scratches even. I have a set of new standard bearings and the thrust is nice and snug when I slide it in one half. I was told to bolt the case together with only the six big bolts and look down the tunnel with a light and see if it looks straight. Are there any other checks I can make before assembly?

[Tufty65]

You cannot check a block accurately just by looking at it unfortunately, you need to measure it with dial bore gauges and the like.
I'd want to know what was wrong with the case ? To cause a bearing to seize up too.

[Martin S.]

I don't have the exact info to know what went wrong. I figure that when assembled with new bearings it should rotate smoothly without a hard spot than it should be good. Of course there could be zero clearance on one of the bearings which would suck.

[baz]

Some good reading here

https://www.thesamba.com/vw/archives/manuals/Jim_Martin_Engine_Build/Jim_Martin_Engine_Build.pdf

[Martin S.]

That's an excellent write up, thanks! 

[Martin S.]

My like new AS41 case.

[baz]

As mentioned above you need to measure all bores for size and roundness before anything else. If it specs out OK you need to fit the bearings and measure again, then compare measurements to your crank.

Whoever discarded the case did so for a reason, they ain't cheap to replace.

I've learned the hard way that unless you are experienced in this area its best to have a reputable shop check it out and make it right before you do anything else. Have the crank centreline checked out too and have the case decked to it rather than the case split.

If the motor seized when running you'll need to open all the gallery plugs to clean it out properly, then have the galleries tapped for removable plugs.

[Martin S.]

That sounds reasonable. I'm hoping the previous problem was with the crank and bearings. The shop could have wanted to sell the customer another case but who knows?
This is a stock motor application. My all original 71 bus is leaking at the main seal so a shop is swapping the case for me. It's a family minivan so I want it period stock perfect like it deserves.
Look what I found in my stash. It likely came from the same 1929 model German dude that I got the case from. Would it work for cases or just for barrels?

[Jim Ratto]

Check out the Bill Fisher HP book, there are several good chapters on checking and preparing a good case.
FYI I had a brand new, fresh from the box Brazil case that was "way off"- just something to keep in mind.

[Martin S.]

How did you find out it was way off?
Would a problem be apparent when assembling the engine and then turning it over by hand?
Or does it have to be run at operating temp before know something isn't right?

[Brian Rogers]

When I've looked at used cases I've had my straight edge with me and a flash light. Look at the #2 main saddle and bore. Any light is grounds for scrap. The bore may show light but the saddle surface is still parallel, you might get away with an aligne bore. This doesn't cover #4 main but look at the saddle web.  Look at all of the above. Just my 2 cents.

[Jim Ratto]

How did you find out it was way off?
Would a problem be apparent when assembling the engine and then turning it over by hand?
Or does it have to be run at operating temp before know something isn't right?

Once I went to 20 lb ft on M12 studs, the crank would not turn. This was after "measuring case", and then checking to make sure I didn't pin a bearing, buy wrong size, mis-box, etc.
Upon disassembly, there were weird witness marks on diagonal edges of bearing # 2
I thought crank was grounds weird, as "it couldn't be the case, it's brand new"- so tried a different, known-good crank. Same thing. Tried different bearings. Same thing.
Case had to be align honed. Center journal had a slight taper to it, on each half, but one side on rear edge, and one side on leading edge.
I might have pictures buried somewhere.
Only time it's happened to me in 29 years, with a new case build. Really frustrating.

[Martin S.]

Now there is some super useful info, thanks Jim!
I will drop a crank in with bearings and tighten up the six nuts and see if it turns smoothly before starting this project. Awesome idea thanks again!! 

[Martin S.]

The crank got tight when I tried that, even before tightening the six nuts. I pulled out the thrust bearing and it turned ok. So I sent it out for line boring and got this msg back today from Joe:
"Your motor is ready I had to line bore it.020 on the mains the rear bearing was out of round like a egg."
Thanks for the quick and easy way to check my case Jim!

[andy198712]

The crank got tight when I tried that, even before tightening the six nuts. I pulled out the thrust bearing and it turned ok. So I sent it out for line boring and got this msg back today from Joe:
"Your motor is ready I had to line bore it.020 on the mains the rear bearing was out of round like a egg."
Thanks for the quick and easy way to check my case Jim!

atleast you know its good to go now!

[Martin S.]

And like my buddy says, "thicker bearings are always good" !