A flat spot on the bearings is a true indicator of detonation. Nearly all the bearings in our project car's bullet had flat spots and were replaced with another set.
Two connecting rods were obliterated. The pin bushing was moved on one rod, and we found piston material imbedded in the side of another. "I've never seen that happen before," Nathan says. He's been working at Big Terry's for the past eight years.
Here, our coupe's engine block is now ready for the long, but hopefully fast, road to recovery.
A fresh rack of eight new SRP-forged, dished pistons highlights the rotating assembly again. Damage was severe enough to warrant a 0.020-inch overbore of the block, so we once again installed SRP's finest (PN 231574) in a slightly bigger diameter. Each piston features a -15cc inverted dome and will make a 9.6:1 compression ratio with our AFR 205s.
All the parts, including the Comp valvetrain, Aussie Muscle Parts beltdrive, and Scat 3.250-inch crankshaft (PN 4-302-3250-5400-2123) were thoroughly cleaned and laid out for engine assembly.
We lucked out, as the crank wasn't damaged to the point of requiring any undersizing.
Rocco pressed a Darton sleeve into the No. 3 cylinder of our damaged Ford Racing Performance Parts R302 engine block. We initially thought the block's original 0.125 overbore could be retained with a simple hone, but the damage proved to be too severe.
The unfinished sleeve and seven other cylinders were bored 0.020 inches beyond the engine's original 4.125 bore size. The additional cylinder diameter increases the cubic-inch displacement of our stroker to 350.
After decking (milling 0.003 inches from each cylinder bank) the block to ensure it's square, the cylinders were honed with a torque plate in place to simulate the weight of a cylinder head on the block. The technique, better known as torque-plate honing, facilitates optimum ring seal, which will maximize the performance potential of the new bullet.
Big Terry's Engine Shop had our T-top coupe's "bigger-bore" engine block fresh and ready for reassembly in less than a week. This kind of service is awesome and appreciated, especially considering they also had to have another customer's complete 'Stang ready to participate in the same event that we're thrashing to attend.
We mentioned earlier that only two of our Scat H-beam rods (PN 2-302-5400-2123A) sustained damage rendering them unusable. We replaced the pair of 5.400-inch rods with the same part number, and Rocco added new pin bushings to the reused original rods.
Cylinder-head repair was limited to welding on one head, then milling 0.004 inches from the surface of both heads to ensure they're straight. Rocco gave each head a five-angle valve job before installing them on the short-block. Now they're better than new-and we intend to keep them that way.