Machined block, ok or not?

[John@RED]

Hello, just received back from machining shop an old block I'm trying to save and restore
but I found those little dents where cross-hatch pattern is not present and that sit over the first ring, what would you do?
Thanks

[BillK]

John,

Those are rust pits that did not clean up at whatever size the block was bored to. What you do next just depends on the block and what size it is now. If there is enough room you could bore it to the next size larger and see if it removes them. Or you could put a sleeve in that cylinder. If I had been doing it I would have called you and asked which way you wanted to go with it.

Like I said, just depends on what it is and what you plan on doing with it.

Some guys would say run it as is and I have seen worse but that would not be my advice.

[mag2555]

The motor will not have the greatest ring seal and some level of blowby will be taking place.

If the Bores have enough meat I would overbore it enough to fully clean up the Bores and then get custom Pistons made if need be as they are not that much more costly then off the self ones these days. , but it may be a 2 month long wait on these.

If your wallet is big then you could sleeve all the cylinders and start off fresh.

What is this motor and what / how will this motor be used?

[houser45]

Run it. Very minor

[Dave Koehler]

Block was rusty going into the shop. Hence the "save and restore" sentence.
Castings are essentially a block of air with some metal thrown in willy nilly.
So there are plenty of voids where corrosion can sit after cleaning.

What you see here is what I call Ghost rust.
You can't measure it, you cant feel it. You can only see it.

Run it.

[MotionMachine]

Totally insignificant IMO. I've seen much worse put together and run with no issues.

[steve316]

I would run it. I have ran worse.

[John@RED]

Thanks All for the replies

Another better photo. Yes, almost all of them are ghost rust nicks, but the bigger and lower one I can feel it with my nail, so I'm still confused on what to do, even because customer already has the pistons, so no overbore




Bigger image clicking here:
https://i.postimg.cc/j2w2hM35/old2.jpg

[racear2865]

Ive machined 100's of blocks just like that in my 50+ years. Built many of those and run on dyno. Never seen any problem with any of them. Per all those suggestion above for resurrection/restoration---run it or send it to me and Ill run it. All kidding aside, will not be a problem.
reed

[swampbuggy]

If that's your biggest problem, you will be in good shape Mark H

[BillK]

I'm still confused on what to do, even because customer already has the pistons, so no overbore

Show it to your customer and ask him what he wants to do. Tell him the right way to fix it and then let him decide. That way when there is a problem it wont be all on you.

Then again if you are building the engine and you will be responsible for it, I think you know the answer.

[Dave Koehler]

Show him this thread also before a decision is made.

FWIW, you can bore that out as far as you dare, pat yourself on the back, wait a few days and that ghost will show up again, guaranteed.

I'm with Reed, send it to me, especially if it is a numbers matching block.

[bentvalves]

pay those stains ZERO attention and get to assembling.

[rebelrouser]

I agree minor stains, I rebuild a lot of old rusty junk and since it is getting pretty hard to come by an old block that is not rusty, I had to lower my standards a little. 20 years ago I might have looked for another block. But my experience is that it will not cause a problem, no oil consumption or blow by increase.

[Baprace]

John@RED , I have seen that type of rust many times on engines with no problems running, I would just put it together, if you wanted to show the customer this site he would at least be better informed. That little ghost rust is no problem and will not affect performance. I'm self employed and started building engines in 1965, I'm still going strong today.