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1966 327 Rebuild - I have many questions.
What's the maximum safe overbore for a 1966 327? Where does cylinder wall thickness / casting core shift become important? If I recall, wall thickness can be checked sonically??? Any suggestions where to find someone with this capability? Are any new technologies available for refurbishing cylinder walls other than simply boring larger?
It has slightly less than 24,000 miles since a rebuild done for the owner prior to the individual I bought the car from. Documentation shows the block was bored .030" over and pistons, rings, bearings, oil pump, cam bearings, lifters, valves, guides, etc, etc were all replaced, but the cam was not replaced. I recall my previous owner related he had subsequent problems with several valve guides that he had taken care of. Obviously, I lament not studying the rebuild documentation more thoroughly before buying!
After owning it for 2 years and only changing the oil twice (I've driven it just 2000 miles total), I finally got around to dropping the oil pan to fix a leaking rear main seal. That's when I made a very disappointing discovery: judging from what can be seen looking at the lower half of the rear main bearing, oil pump gears and cylinder walls, there's significant debris related damage.....felt with a fingernail. Two cam lobes out of maybe 7 or 8 that I
can see are starting to show wear. Also noted is some crankshaft wear, again felt with a fingernail, on the land for the rear seal.
Since the car is matching numbers (with a 1997 Top Flight award), I'm exploring the option of an immediate rebuild. (This will be my first time going beyond installing a cam in building an engine.....but I feel confident I can do much better than the last guys!)
My goal is a rebuild that will last another 100,000+ miles if it's properly driven and maintained. I don't care about increased power, although I would like to do anything possible to enhance reliability / durabilty as long as it is internal and doesn't affect NCRS judging. I plan to focus on these areas:
needs slightest possible overbore (i.e. new rings and pistons)
new cam and lifters
main / rod bearings
valve guides / valves? (will inspect these carefully because previous owner related problems with some guides.)
cam bearings?? (will inspect due to possible debris damage)
Should I plan to replace the connecting rods and bolts? piston pins? Should I use hypereutectic pistons for more compatible expansion rate / more stable running clearances? What about the use of a deck plate during cylinder machinging? Is this a standard practice, or something not all machine shops do?
Does anyone in North Carolina have first hand experience with an machine shop they can recommend who'd be sympathetic to a fanatic antique Corvette owner? My utmost priority is to complete a high quality rebuild while preserving the numbers matching engine. I plan to do most dissassembly / reassembly myself; relying on the shop primarily for machinging.
After seeing horror stories of machine shops mistakenly removing stamp pad markings during block decking, I plan to insist on a written agreement placing a significant $$$ penalty in case of any screwups rendering the block unusable.
Thanks in advance for any and all help / suggestions / comments!!
Best Regards,
Bob S.
What's the maximum safe overbore for a 1966 327? Where does cylinder wall thickness / casting core shift become important? If I recall, wall thickness can be checked sonically??? Any suggestions where to find someone with this capability? Are any new technologies available for refurbishing cylinder walls other than simply boring larger?
It has slightly less than 24,000 miles since a rebuild done for the owner prior to the individual I bought the car from. Documentation shows the block was bored .030" over and pistons, rings, bearings, oil pump, cam bearings, lifters, valves, guides, etc, etc were all replaced, but the cam was not replaced. I recall my previous owner related he had subsequent problems with several valve guides that he had taken care of. Obviously, I lament not studying the rebuild documentation more thoroughly before buying!
After owning it for 2 years and only changing the oil twice (I've driven it just 2000 miles total), I finally got around to dropping the oil pan to fix a leaking rear main seal. That's when I made a very disappointing discovery: judging from what can be seen looking at the lower half of the rear main bearing, oil pump gears and cylinder walls, there's significant debris related damage.....felt with a fingernail. Two cam lobes out of maybe 7 or 8 that I
can see are starting to show wear. Also noted is some crankshaft wear, again felt with a fingernail, on the land for the rear seal.
Since the car is matching numbers (with a 1997 Top Flight award), I'm exploring the option of an immediate rebuild. (This will be my first time going beyond installing a cam in building an engine.....but I feel confident I can do much better than the last guys!)
My goal is a rebuild that will last another 100,000+ miles if it's properly driven and maintained. I don't care about increased power, although I would like to do anything possible to enhance reliability / durabilty as long as it is internal and doesn't affect NCRS judging. I plan to focus on these areas:
needs slightest possible overbore (i.e. new rings and pistons)
new cam and lifters
main / rod bearings
valve guides / valves? (will inspect these carefully because previous owner related problems with some guides.)
cam bearings?? (will inspect due to possible debris damage)
Should I plan to replace the connecting rods and bolts? piston pins? Should I use hypereutectic pistons for more compatible expansion rate / more stable running clearances? What about the use of a deck plate during cylinder machinging? Is this a standard practice, or something not all machine shops do?
Does anyone in North Carolina have first hand experience with an machine shop they can recommend who'd be sympathetic to a fanatic antique Corvette owner? My utmost priority is to complete a high quality rebuild while preserving the numbers matching engine. I plan to do most dissassembly / reassembly myself; relying on the shop primarily for machinging.
After seeing horror stories of machine shops mistakenly removing stamp pad markings during block decking, I plan to insist on a written agreement placing a significant $$$ penalty in case of any screwups rendering the block unusable.
Thanks in advance for any and all help / suggestions / comments!!
Best Regards,
Bob S.
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