TulsaFred
Jedi Warrior
Offline
OK, so this will be anathema to Hap and the other high quality engine builders out there, but here goes.
My goal, for a number of reasons, is to do my own 1275 rebuild (no real experience) on a shoestring budget. It will be a mild street engine for my bugeye. The engine came from a guy who was selling a 74 midget and had this motor as a spare sitting in his shed since the mid-1980s. It appears to have relatively modest wear.
I took it to a machine shop and they recommeded turning the crank .010, boring the cylinders .030 (I think, maybe .020), putting in hardened seats, etc. This came to an estimate in the thousands.
I inspected and measured the engine as best I could with a digital caliper. These somewhat imprecise measurements were all within .005 in from spec. The crank journals all look perfect. There is a minimal ridge on the cylinders but I couldn't really catch it with a fingernail.
So I thought about it and decided to hot tank and magnaflux the block/head/rods, new cam bearings, and put in new valve guides. About $275 as I recall.
I took it home and honed the cylinders with a 3-stone hone on a drill and tried to get a reasonable cross hatch. I decarbonized the pistons, combustion chamber, and valves using a wire wheel and bead blaster. I lapped the valves and put on new valve springs. New rings (STD), bearings (STD), oil pump, lifters, timing chain, oil pressure relief valve and valve seals. A few hundred dollars all told.
I'm bolting it back up like this. I'll need to rebuild the carbs.
My plan is to put it in and see how it runs. If it sounds funny, runs bad, smokes etc. I'll pull it back out and have a pro redo it right. I'll only be out less than a grand and have gained a lot of experience and knowledge in the process.
I am able to find all kinds of advice on precise and specific detailed tolerances, necessary machine work, etc for a "proper" engine rebuild. However, I also know that there are a lot of engines with lots of miles that still run pretty good despite getting out of spec over 50-100K miles. It's hard to find information on a shade tree mechanics budget rebuild without a lot of machine work.
So what do you guys think? Will the motor be crap, or will it surprise us with how cheaply a rebuild can be done for street purposes?
Fred
My goal, for a number of reasons, is to do my own 1275 rebuild (no real experience) on a shoestring budget. It will be a mild street engine for my bugeye. The engine came from a guy who was selling a 74 midget and had this motor as a spare sitting in his shed since the mid-1980s. It appears to have relatively modest wear.
I took it to a machine shop and they recommeded turning the crank .010, boring the cylinders .030 (I think, maybe .020), putting in hardened seats, etc. This came to an estimate in the thousands.
I inspected and measured the engine as best I could with a digital caliper. These somewhat imprecise measurements were all within .005 in from spec. The crank journals all look perfect. There is a minimal ridge on the cylinders but I couldn't really catch it with a fingernail.
So I thought about it and decided to hot tank and magnaflux the block/head/rods, new cam bearings, and put in new valve guides. About $275 as I recall.
I took it home and honed the cylinders with a 3-stone hone on a drill and tried to get a reasonable cross hatch. I decarbonized the pistons, combustion chamber, and valves using a wire wheel and bead blaster. I lapped the valves and put on new valve springs. New rings (STD), bearings (STD), oil pump, lifters, timing chain, oil pressure relief valve and valve seals. A few hundred dollars all told.
I'm bolting it back up like this. I'll need to rebuild the carbs.
My plan is to put it in and see how it runs. If it sounds funny, runs bad, smokes etc. I'll pull it back out and have a pro redo it right. I'll only be out less than a grand and have gained a lot of experience and knowledge in the process.
I am able to find all kinds of advice on precise and specific detailed tolerances, necessary machine work, etc for a "proper" engine rebuild. However, I also know that there are a lot of engines with lots of miles that still run pretty good despite getting out of spec over 50-100K miles. It's hard to find information on a shade tree mechanics budget rebuild without a lot of machine work.
So what do you guys think? Will the motor be crap, or will it surprise us with how cheaply a rebuild can be done for street purposes?
Fred