mike1157":20q33t3m said:
But......will they be able to bore the block .230 w/o turning it into garbage?
Yes. I know for a fact that in a production block 250 with a liner, that will work fine. The Australian Geelong plants made there own versions of the US Cleveland engines, AND THEY categorically used to have liners attached from the factory at greater wall thickness than that. GM England's Vauxhall division used to have a recommendation with the four bearing L6 3.25" 2651 cc and 3.625" bore 3294 cc engine that a standard sized bore be used with a 3.375 or 3.875" overbore. This was a 125 thou wall thickness liner. That's 250 thou over.
You can certainly re-bore some of the older non siamese cast iron Ford and GM engines 230 thou
without a cylinder liner, and get an engine to survive. The standard Detroit thinwall non linered rules have always been 60 thou over is the most, with 20 to 30 thou the suggested maximum if its a Cleveland 351, Windsor 5.0, or iron block Chevy 305/350. With a liner, Ford and Chev generally said take it back to stock bore, with a 125 thou thick liner the suggested minimum. Factory Cleveland 302 and 351 Aussie engines were partly linered from the factory from 1972 to 1979; the whole of those short deck 335 engines had way to much core shift in there production processes and failure in service ment Ford Australia had to recoup the scrapage rate, and so until a landmark case in 1979 which ruled the process unacceptable from a consumer perspective after Ford Australia got taken to court by a 1978 XC Fairmont V8 owner, you'll constantly find many reports of production RPO blocks reworked with liners in them.
A thin wall iron block Chevy V8 under a high load drag or circuit racing situation certainly won't cope with as much overbore as an iron blocked i4 or I6. Strongest thin wall engine ever made was the 180 thick cylinder walls of the early 3.875" 283 and then the better low core shift 350 Chev cylinder blocks. The early 283 ones could take a 125 thou over bore and survive in a hardfill drag race engine, but the later 350 blocks would break with just 60 thou over, but they were in 12:1 compression engines under extreme duty.
Eg 1. X Flow Ford Kent 4 cylinder found in early Pintos, Cortinas, rear drive Escorts and Fiestas could be taken out to +153.5 with 80% reliability in stock 711M blocks to +212 thou with 80 % reliability in an South African AX blocks from a stock 1500 or 1600 cc 3.19" bore size. They used to furnace braze old Ford production iron blocks for BDA racing engines before the HART blocks.
Eg 2. The 3 liter 60 degree Ford Dagenham 'Essex' engines could be taken out to 330 thou to 4" from a stock 3.672" bore size with 80% of blocks so bored becoming scrap. They used those in 450 hp quad cam GAA racing engines.
Eg 3. The thick wall 1948 to 1958 and Holden 132.5 cubic inch I6 Grey Motors . +187.5 thou from an un-rusted early 3.00" bore block without bore distortion, and +247.5 with quite a lot of distortion.
Eg 4. Linered iron Nissan 1985 to 1996 RB24, 26, and 30 blocks converted to Skyline GTR spec can make 900 to 1000 hp turbo charged, and can cope with 103 thick liners from a stock 85 mm bore with perfect reliability.
As soon as you add a liner with a bare minimum of interference fit, you get a great deal of strength back.
