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Discussion Starter #1
I've been reading some information on upgrading an engine. I'm a real newbie at all this. One of the instructions says to machine carnk, rods and balance, flycut pistons.

What exactly does all of that mean? What exactly do I (or a machine shop) need to do to machine my crank? Also what is involved in balancing an engine? I've heard of internal and external balancing. What do I need to do while rebuilding my engine?

1967 coupe with vinyl top. 351W engine with C-4. Work in progress.
 
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Discussion Starter #2
Okay,

Flycutting Pistons-this is a method of cutting valve reliefs in the tops of pistons, to allow for bigger valves and/or a higher lift cam. If you're doing a rebuild, you'll likely just get pistons that are already cut to work for your application.

Machining the Crank- If the crank journals have wear beyond the factory specs, you can have your crank machined. The journals are cut down as necessary (probably no more than .010-.020), and thicker bearings are used. If you look in catalogs, you'll probably see bearings that say -.010, or -.020. That's why.

Balancing-Crank is spun to check for balance, weight is added where necessary via weld or mallory metal, taken away where necessary as well. Rods are all weighed, and all are matched to the lightest one. The balance will also be checked between the weights of the big and small ends of the rods. Balancing is not super accurate in a stock engine, and not necessary for a stock rebuild. If you're looking to build a higher performance engine however, it might be something you should look into.

Hope all of that helps!


-Brian

66restomod's Home Page
 
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Discussion Starter #3
You dont always have to flycut the pistons. Only if you have a high lift cam, or maybe with domed pistons. You just have to check clearence!!

65 coupe 302
(rebuilding a 351W)
 
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Discussion Starter #4
Interesting point....since you can't see in the cylinder, how do you check clearance?

http://members.tripod.com/tangdar/
'67 Coupe project car (Did I say project car? I meant pile of rust)
http://www.americainter.net/~fevans/tangdar_flintstone.jpg
 
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Discussion Starter #5
Clay seems to work best for most people.

[color:blue]'68 Coupe
250/C4, 221 Argentine Head
Breakaway Converter, 9", 3.50's/T-lock</font color=blue>
 
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Discussion Starter #6
Ya, you stick clay in, and rotate the motor 1 rotation, and check the indentation!!

65 coupe 302
(rebuilding a 351W)
 
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