We bought a 350 vortec to build and tore it down today. One of the cylinders had pitting from water and my dad scratched another measuring it with a micrometer. Its going to the machine shop Monday, but is there a way to tell if boring wont fix the problems?

 

I doubt a micrometer scratch would be deep enough to be considered damage. Pitting from rust may just need a honing but could also just need an overbore. If it needs an overbore, purchase the pistons first so they can match the pistons to the bore.

 

I dont mind having it overbored,I just want to make sure it is a correctable problem.

 

That's typically why a block is overbored. It corrects problems to make a new surface on the cylinder wall.

 

I know this too lol, I just wanted to know If it was possible for them to be to deep for the overbore to fix it.

 

You will have difficulty finding rings for over .060. At .030 over you will have a 355ci, 357ci with .040, and 360ci with .060 over. the greater the bore is increased, the greater the problem with over heating. I wouldnt reccomend over .040 overbore.

 

I wouldnt recommend going .060 over either. I had a .060 over block.

My buddy had it in his car and had issues with his engine, assumed it was the block (he didnt want to go .060 over either) and the problem ended up being his cylinder heads but he had so much wrapped up into the second build he couldnt just switch back over, so I got a 350 block with fresh machinework for cheap. Well I guess the rehone for my pistons was too much for it. It survived a once over at the machine shop and a cam break in and turns out I had junk cylinder heads too, so I had to pull the heads and save money for a new set. And I saw the bore and it looked fine then.

Got my new heads on, took it round the block, heard a weird (nothing I thought was serious) noise and parked it til the next weekend. I went to check the oil the next weekend and found water in my oil, and oil in my coolant.



You just never know how thin those cylinder walls are getting, and unless you get it sonic tested, there's no way to find out. Better safe than sorry. I'd stay .030 over or less for all of my engines in the future. If I was attached to the block I might go .040 but thats it.


My current block had excellent condition bores but one bore had some pitting from rust on it, they had to take it .030 over. Basically they just have to open it up til it's gone. If its too bad the block is trash. But there's no way to really tell by looking at it. A machinist might be able to make a good guess as to how deep it is from experience, though.

 

Depending on how much you have invested in the block, if a cylinder is too far gone to be repaired, the cylinder can be sleeved. For a typical production block, sleeving a cylinder or 2 may not be an economical option. If you have a hard to find or numbers matching or aftermarket block, sleeving all 8 cylinders is cheaper than replacing the block.

My Dart big M block is a fantastic casting. I can bore the cylinders out 0.120" over and still have 0.250" thick walls. My block has 2 sleeves to repair damage from a thrown rod.