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Original Message
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| Actually, CJ and SCJ pistons are identical. |
| By Dave Shoe - 03/27/2002 2:50:23 AM; IP 63.233.224.78 |
The CJ and SCJ drew their pistons from the same pile on the assembly line. They are the same casting and also the same finished part.
The only difference came when it was time to fit the piston to the bore. The SCJ piston was selected to fit a bit more loosely.
I'd like to learn whether the SCJ piston was one grade (.0004") or two grades (.0008") looser than a CJ, but that'll have to wait for another time.
Note that the 427 was listed as the top engine at the start of the 1969 model year. The CJ was second fiddle, and the SCJ idea had not yet been hatched.
The emissions-laden 427 was too expensive and too smothered to put into live production, so some inspired genius decided to make an affordable king motor by converting the CJ into a high-revving monster using a stock crank, LeMans rods, and reinforced cast pistons. Thus was born the SCJ, allowing the 427 to exit the production-engine category with some measure of dignity remaining.
Note that prior to the incarnation of the SCJ, the CJ had pistons designed like other 428 pistons - though it had a dish taylored in volume for the CJ head only. When the SCJ "Super 428" piston was incorporated in Nov 1968, the CJ instantly inherited it, too (obsoleting the original CJ piston). This "Super 428" piston had extra aluminum at the pin bosses for greater revving potential. As soon as these pistons became available, Ford started running tests on them to determine whether they could be improved further. They determined the pistons could benefit even more from further reinforcements and the new "Super 428" tooling was revised. The final CJ/SCJ piston became available in Dec 1968.
I'm pretty much making all of this up as I go along, but then I'm pretty much right on the money, too.
Shoe. |
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