Ford 390 Block Surgery

In the last installment of this continuing saga, we ended our dynosession at Roush Racing when the crank decided it'd had enough, just aswe were getting warmed up. The crank destroyed the rod bearing, whichmelted to the rod and crank. The end result was two ruined rods. Onethrew its cap through the side of the block and subsequently broke inhalf.

After a thorough inspection of the block, we found the following:

1. Block skirt "windowed;"

2. Small crack and pair of brinelled spots in opposite side of blockskirt;

3. Two cylinders damaged at the bottom--one with crack and dimple inwall;

4. One lifter bore damaged at bottom;

5. Camshaft retainer bolts broken off flush with the front block face.

All of the important parts of the block were intact and without damage.We decided to repair the mentioned trouble spots and build anotherengine. Let's look at what it took for the guys in Jack Roush's RaceEngine Shop to save our damaged block.

Two of the processes we've had to go through can induce some degree ofdistortion to the cast-iron structure. By far, the greatest degree ofstress would come from the welding. In order to successfully weld iron,it's necessary to preheat the work piece. Then, when the whole block (inthis case) was heated, the actual welding could progress.

Chris Razor of Hi-Tech Welding Inc. was chosen to do the work. Hisreputation includes some very sensitive work for Ford in past projects.It's also really handy that his shop is less than a mile from the Roushfacility. After a discussion with Chris, I went back to my shop and tooka "whizzer wheel" to one of the block pieces left from the research intoimproving the oil passages in the ordinary FE block. I cut out asufficiency of the block skirt and took it back to Chris.

Further discussion centered on the advisability of using the Meta-Laxstress-relieving process as an adjunct to producing the finest possiblerepair. After listening to Chris, we reached this conclusion in thismanner.

In the metro Detroit area, there are a number of steel-manufacturingconcerns. The giant crucibles that hold the molten metal during thesteel-making process require repair on a regular basis. It's not unusualto have to cut a 6x6-foot section out of one and weld in a patch. Thewall of the crucible is 5 inches thick. Such a repair was generally goodfor as much as two or three months. The repair would then fail and haveto be redone. The addition of the Meta-Lax process to the rebuildingeffort was so successful that repairs would last as much as three years.

It's beyond the scope of this article to explore the metallurgic reasonsfor this improvement. In simple fashion, the improvement in grainstructure, not only the weld, but also the entirety of parent metal,brings about the amelioration. I had to have it. Luckily, Chris has thenecessary equipment.

Another benefit was discovered at Hi-Tech. The grinding and welding madeit clear that this block has a high nickel content. Almost all blocksfrom Ford during the early '60s were ordinary gray iron. My sources allagree it would be unusual to have the nickel. The grinding sparks andwelding ease made it clear that, at least in this case, nickel ispresent.