C2- Buying A Used Block

[brumbach]

I need your advise. I'm considering buying a used block for my 65/327 vette. The block requires boring to clean up and is currently at +30 (over standard, I assume). Does this mean it has been previously bored to its current state? I've been advised that +60 is the maximum that a block can be bored. Are borings usually performed at increments of 10, whereas the next boring would likely be at +40 providing that would do the trick in reconditioning the cylinder walls? When is sleeving required? Sorry for so many questions but I know little on the subject and don't want to make a bad decision. Thanks in advance. Bill

 

[IH2LOSE]

The block your considering is it a correct block for your car? the reason I ask is that I am finding the crate motors that are available seem to go less then what you can build a motor for these days,

Sorry I could not answer your question directly

 

[brumbach]

The block your considering is it a correct block for your car? the reason I ask is that I am finding the crate motors that are available seem to go less then what you can build a motor for these days,

Sorry I could not answer your question directly

Yes, it's correct. And your right, by the time I finish with the rebuild, I could have bought a crate for considerbly less.

 

[JohnZ]

I need your advise. I'm considering buying a used block for my 65/327 vette. The block requires boring to clean up and is currently at +30 (over standard, I assume). Does this mean it has been previously bored to its current state? I've been advised that +60 is the maximum that a block can be bored. Are borings usually performed at increments of 10, whereas the next boring would likely be at +40 providing that would do the trick in reconditioning the cylinder walls? When is sleeving required? Sorry for so many questions but I know little on the subject and don't want to make a bad decision. Thanks in advance. Bill

.030"-over is the usual first rebuild re-bore, although some blocks with little wear will clean up at .010" or .020". Only your machinist (after measuring each bore diameter and taper) can tell you how much it needs to clean it up from its current state; if it needs more than another .030" (total of .060" over standard bore), sleeves are in order, and they're usually around $100 per hole.

 

[Jack]

I need your advise. I'm considering buying a used block for my 65/327 vette. The block requires boring to clean up and is currently at +30 (over standard, I assume). Does this mean it has been previously bored to its current state? I've been advised that +60 is the maximum that a block can be bored. Are borings usually performed at increments of 10, whereas the next boring would likely be at +40 providing that would do the trick in reconditioning the cylinder walls? When is sleeving required? Sorry for so many questions but I know little on the subject and don't want to make a bad decision. Thanks in advance. Bill

As you said, +60 is the typical sbc's limit without sleeving and boring is usually in +10 thousandths increments and the +30 block means it's been bored +30 (to 4.030") over the STD (4.000").

BUT "off-the-shelf" Pistons are Not typically available in sizes for every +10 step ... it varies amongst piston makers and application. I don't think I've ever seen an OTS piston for sbc in +50. The most popular OTS sbc sizes are STD, +30 & +60. Limited OTS availability in +20 & +40. Never seen sbc OTS larger than +60. Piston makers such as Ross & JE will "custom" machine em for you in about any size you'd like ... but it'll cost you dearly. So ... before commiting to a worn +30 block .... have a pro-machinist inspect & measure the block and advise you of where the bores are & where they'll need to go ... make sure the specific OTS piston type you'll need is available in +40 (or whatever size the machinist suggests). You should also have machinist measure deck height and alignment of the bores (caps) in which the crank lays ... there's a lot more to it than simply the piston bores. Don't make a bad decision Bill, do make an informed one.
JACK:gap

 

[brumbach]

Thanks, John & Jack. Great advise! I'm buying "long distance" but believe the supplier is honest and dependable. You've given me some additional questions to ask before finalizing the purchase. Bill

 

[brumbach]

As you said, +60 is the typical sbc's limit without sleeving and boring is usually in +10 thousandths increments and the +30 block means it's been bored +30 (to 4.030") over the STD (4.000").

BUT "off-the-shelf" Pistons are Not typically available in sizes for every +10 step ... it varies amongst piston makers and application. I don't think I've ever seen an OTS piston for sbc in +50. The most popular OTS sbc sizes are STD, +30 & +60. Limited OTS availability in +20 & +40. Never seen sbc OTS larger than +60. Piston makers such as Ross & JE will "custom" machine em for you in about any size you'd like ... but it'll cost you dearly. So ... before commiting to a worn +30 block .... have a pro-machinist inspect & measure the block and advise you of where the bores are & where they'll need to go ... make sure the specific OTS piston type you'll need is available in +40 (or whatever size the machinist suggests). You should also have machinist measure deck height and alignment of the bores (caps) in which the crank lays ... there's a lot more to it than simply the piston bores. Don't make a bad decision Bill, do make an informed one.
JACK:gap

Jack:

What's your opinion on sleeving? I've been trying to avoid purchasing a block that'll need sleeves but the two different suppliers that I've been working with don't consider it a big deal, other than added cost in rebuild. The cost isn't as that concerning to me but the prospect that the engine will be somewhat inferior w/ sleeves is. Does sleeving degrade the reliability or durability of the engine?

Bill

 

[studiog]

Never mind... I'm sleep walking