Max over bore for 400CI 509 casting
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Max over bore for 400CI 509 casting
OK, my current bore is 4.155",,,,, I would image that 4.165",,,is the max I can go on a stock block 400CI
Got a scratch @ .005 deep and @ maybe .010" wide. I am hoping that I could bore this out, I honed it to clean it up and this is what is left over.
Gonna call the engine shop on Monday. What is the max bore?
Got a scratch @ .005 deep and @ maybe .010" wide. I am hoping that I could bore this out, I honed it to clean it up and this is what is left over.
Gonna call the engine shop on Monday. What is the max bore?
Last edited by LD85; Jun 10, 2006 at 08:38 PM.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Ultrasonic testing.
Whatch'a scratch it for?
Ok, seriously u need to get it sonic tested to see how far that block can be bored. Core shift while casting can be different in any block.
Usually .030" overbore is fine and there are plenty of .040" over pistons availible if your block can handle .040" bore. Also .060" possible but u would be very lucky to find that good a block.
BTW had a block sonic tested once. Nothing to it. Guy plugged in his little box and ran the probe up & down each bore watching the display - 15 minutes.
Don't sweat it though as sleeving is availible for 'bout $200 a hole. Some owners sleeve all the holes but that makes for an expensive block when u can still find cheap cores in the boneyards.
Good luck and let us know how it turns out.
cardo0
Ok, seriously u need to get it sonic tested to see how far that block can be bored. Core shift while casting can be different in any block.
Usually .030" overbore is fine and there are plenty of .040" over pistons availible if your block can handle .040" bore. Also .060" possible but u would be very lucky to find that good a block.
BTW had a block sonic tested once. Nothing to it. Guy plugged in his little box and ran the probe up & down each bore watching the display - 15 minutes.
Don't sweat it though as sleeving is availible for 'bout $200 a hole. Some owners sleeve all the holes but that makes for an expensive block when u can still find cheap cores in the boneyards.
Good luck and let us know how it turns out.
cardo0
Le Mans Master
Joined: Oct 2001
Posts: 5,943
Likes: 3
From: Wildwood IL
Your 509 casting should be the high nickel content block. 4.185 (60 over) is the max, but getting it sonic tested before you go 60 over is the smartest thing to do. Might want to consider plugging those steam holes and inserting 1/8" drilled plugs in the water ports also (for added cylinder strength) if you do go 60 over.
Eddie
Eddie
Melting Slicks
Joined: Jun 2002
Posts: 2,844
Likes: 99
From: Orrtanna Pa.
To be honest with you,if it were mine I'd hone it and run .030 pistons in it as is. This gotta be absolutely perfect BS is what keeps machine shops in business.I've run junkyard blocks to 6500 rpms with nothing more than a set of new rings and bearings.......and of course a can of Chevy Orange paint,with not a problem at all.
By the time the new rings seat,there won't even be a scratch if it's only .005 deep.
By the time the new rings seat,there won't even be a scratch if it's only .005 deep.
Advanced
Joined: Jun 2003
Posts: 81
Likes: 0
From: Alpharetta GA
Originally Posted by The Money Pit
To be honest with you,if it were mine I'd hone it and run .030 pistons in it as is. This gotta be absolutely perfect BS is what keeps machine shops in business.I've run junkyard blocks to 6500 rpms with nothing more than a set of new rings and bearings.......and of course a can of Chevy Orange paint,with not a problem at all.
By the time the new rings seat,there won't even be a scratch if it's only .005 deep.
By the time the new rings seat,there won't even be a scratch if it's only .005 deep.
Drifting
Joined: Dec 2005
Posts: 1,360
Likes: 3
From: NORTHEAST
We have seen worse scratches then that and not had any issues as your ring gap is wider then that and you don't have any problems right.
We sonic test every block that comes in the shop and on the 400 blocks we have 2 in the shop that was sent to us with less then .140 on the thrust side and they are standard bore blocks
At our shop the only block that we won't sleeve is a 400 blocks do to the distortion on the clylinders next to the sleeve and there is a good chance of a crack between the bolt hole and theh sleeve and we have seen where the step is left at the bottom of the cylinder where the sleeve sets that in the it will crack from the step down into the webbing of the mains as ther is no much material there to begin with on the 400 block as the decks and cylinder are thin as well.
We sonic test every block that comes in the shop and on the 400 blocks we have 2 in the shop that was sent to us with less then .140 on the thrust side and they are standard bore blocks
At our shop the only block that we won't sleeve is a 400 blocks do to the distortion on the clylinders next to the sleeve and there is a good chance of a crack between the bolt hole and theh sleeve and we have seen where the step is left at the bottom of the cylinder where the sleeve sets that in the it will crack from the step down into the webbing of the mains as ther is no much material there to begin with on the 400 block as the decks and cylinder are thin as well.
