My dad stopped by again this morning and we wrapped up the engine assembly. We ran the oil pump for about three minutes with a drill and spun the motor over a few times with the starter (without plugs) to make sure oil was nicely distributed throughout the engine.

The moment of truth arrived and we fired up the motor. Success!!! The motor sounds fantastic. Nice and smooth, and no knocking!

We kept the exhaust pipes outside of the garage to limit the exhaust inside. We pushed the RPM up to about 2,500 and let it run for about 30 minutes to help seat the rings.

After shutting down, we pulled the car back into the garage and put the car back on the dolly. Since we’re still in the middle of our remodel, we likely won’t make much progress on the car over the next few months, but I’m incredibly pleased that this is behind us!

My dad and I stopped by Dino’s shop this morning to have him balance our new piston and rod. While our piston was lighter than the old one, we lucked out and the new rod was slightly heavier on the small end. There’s still a small imbalance, but Dino said that it’s more important that the rotating mases are balanced than the reciprocating masses. He also loaned us his tapering ring compressor which makes piston installation far easier than with the traditional ring compressor

We got back to the house and made quick work of getting the piston into the block and installing the bearing cap. We turned the motor over a couple of times to make sure everything was moving smoothly.

We installed the newly painted oil pan, then installed and torqued the heads. I hadn’t yet adjusted the guide plates on the new cylinder head, so we spent a bit of time ensuring that all of the rocker rollers were nicely centered over the valve stems. Finally, we installed the intake manifold and cleaned up the sealant. We can’t run the motor until that sets, so that was a good time to stop for the day.

I cleaned the oil pan and painted four coats of the same Eastwood high-temperature ceramic engine paint that I’ve used on the rest of the engine. I put on some extra coats here because this is likely to take more abuse from road debris than the block or heads.

I received the new piston from Ford Racing (on the right). Unfortunately, it’s 9 grams lighter than the piston it’s replacing. We’ve been told that we need to get the rod/piston assembly within 2 grams, but we’ve also heard that it’s important to get each component as close as possible as well. We’ll check with Dino about whether this will work or we need to order a replacement.

We put the Cobra on the lift and dropped the oil pan. After removing the connecting rod bolts, we removed the bottom of the connecting rod and pushed the piston out of the top of the cylinder.

It’s pretty clear that the piston was more damaged that it appeared from the top. This is the bottom edge and it’s pretty well worn above the compression ring. It’s also pretty scored on the skirt. Worse though, both compression rings were pinched in the groooves.

This is the top edge of the piston. You can see wear above the compression rings and scoring on the skirt. The compression rings are also pinched on this side.

In the area the pistons are worn, there is some polishing of the cylinder wall. You can’t feel this with your fingers, so it’s just some microscopic surface polishing. We’ll need to add the cross-hatching back, but that should be pretty straightforward.

It’s pretty hard to see in this picture, but the lower side of the cylinder has similar polishing, but you can slightly feel the polished area on this side. There are no grooves and I think what you can feel is well less that 0.001″.

We dropped by Dino’s shop to have him examine the piston and connecting rod. He showed us how to remove the piston and checked the connecting rod for damage. He suggested we use some 400-600 grit sandpapaer to add the crosshatching pattern back to the cylinder wall. I protected the lower end of the engine as well as I could with aluminum foil and masking tape, then used some 400 grit sandpaper soaked in solvent to add the crosshatch pattern back. I made some good progress on the lower side, but I can still feel the polishing area slightly.

After thoroughly cleaning the engravings with some solvent and a toothbrush, I put some of the of the engine paint over the engravings until I couldn’t see them. After letting it set up for a couple of hours, I used a solvent-soaked q-tip to remove most of the excess paint. I didn’t want do too much at this point since the paint is still soft.

After letting the paint cure overnight, I used more solvent-soaked q-tips to remove the rest of the excess paint. This technique works wonderfully and the engraving really pops.

Even though we’re essentially certain the heads are fine, we still had one head with known damage from the nut going through the engine. It just turned out not to be on the side where he was adjusting the lifter. Since we had already ordered a replacement head, I could either return that or replace the damaged head. I decided to replace it.

I spent a couple of hours tearing down the right side of the motor tonight until it was at the same place as the left side.

I cleaned and masked the new head, then sprayed several coats of Eastwood’s high-temperature ceramic engine paint in gloss black.