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Questions and Answers

All About Engine Rebuilding

Q. I am doing a Ford 390 engine rebuild for my senior project and I would like to interview you if possible with some questions about rebuilding an engine. What kind of problems do you/can you run into?

All About Engine Rebuilding

A. Here you go Dale!

Q. What tools are necessary to complete it?

A. Besides the basic hand tools, you'll need an engine stand, cylinder hone, ridge reamer, piston pin compressor, piston pin press, micrometers and torque wrenches. If you are going to do the valves you'll need a valve grinding machine and valve lapper. This is just for the rebuilding. There are many other tools and machines needed to machine certain parts.

Q. What are the common parts replaced in a rebuild?

A. The most common parts that get replaced are the main crankshaft bearings, connecting rod bearings, piston rings and, naturally, all the gaskets and seals. Depending on how much wear there is in the cylinders, it may be necessary to bore them oversize and install oversized pistons. Other parts are replaced as required.

Q. How long can it take to do a basic rebuild?

A. Depending on the engine, and not including R&R, and to disassemble & clean engine, ridge ream & hone cylinders. Inspect all necessary components, grind valves and tune-up, anywhere up to 40 hours, depending on the engine.

Q. How do you know which parts can be reused and what needs replaced?

A. Mostly, experience. Visual inspection will tell you what is obviously bad. In addition, measurements with micrometers and gauges will tell you what is good or bad.

Q. Do you find it easier to use a manual to guide you or are they misleading?

A. If you do a wide variety of engine rebuilds, you need to use the book. It will tell you what special tools are needed, what special procedures are done and give you specifications. I always use the book when I do a rebuild

Q. Is it possible to do a rebuild at home?

A. Do a basic rebuild, yes. To do one right, you need a decently equipped shop.

Q. If so, what tools are needed?

A. Besides the basic hand tools, you'll need an engine stand, cylinder hone, ridge reamer, piston pin compressor, piston pin press, micrometers and torque wrenches. If you are going to do the valves you'll need a valve grinding machine and valve lapper. This is just for the rebuilding. There are many other tools and machines needed to machine certain parts.

Q. Is it usually worth rebuilding or replacing?

A. For the time and work involved it is very often more cost effective to replace the engine with a remanufactured engine. The workmanship is of a higher quality because remanufacturers are setup to do the work. They can get parts as clean as they were when new and they have all the equipment to do the honing, grinding and polishing. In addition most remanufacturers give you a three year/36,000 mile warranty with it. If I did it in my shop, the best warranty I can give is one year/12,000 miles.

Q. What's the best way to go about it if I've never done it before?

A. Slow and carefully. Make sure you have the right tools before you start and read the whole procedure in the manual several times until you are familiar with the whole procedure. Measure every thing twice so there are no mistakes. When you install main bearings, use plenty of assembly lube and rotate the crankshaft after each and every torquing. The crankshaft should spin free and easy. If not, you did something wrong on the last bearing you did. Make sure you have correct orientations. Main bearing caps go in a certain order and a certain position. Mix them up and you're in very deep doo-doo. And don't be afraid to ask questions. The machine shop that is doing your machine work will be glad to answer questions and offer advice.

Q. Are there any good sources I may be able to use that you know of? ie (books, movies)

A. The library has many books in the reference section on general engine rebuilding. That would be the best place to start.

As for who I am:

Vince Ciulla
Auto Repair Guide - About.com
Auto Repair - About.com
autorepair.guide@about.com

Additional Information provided courtesy of ALLDATA

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