COAL Update: 1953 Buick Special – Snitches Get Stitches, A Whimsical Tale Of Drilling And Tapping

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– Posted on January 5, 2022

The efforts of Julius Caesar and Pope Gregory notwithstanding, our system of keeping track of our place in history is utilitarian but still somewhat arbitrary.  Regardless, 2021 was a rough year in my garage, with almost every member of the fleet earning its merit badge for pissing me off at one point or another.  It was therefore no surprise when my surprisingly reliable 1953 Buick managed to drive home what it’s been hinting at for about a decade: It has a cracked engine block.  Learning how to repair it has been a journey.

In hindsight, the symptoms were there all along.  About 10 years ago, I noticed that the breather was snotty at oil change time, but I chalked it up to the 160* thermostat I usually run in this car, and changing to a 180* thermostat eliminated the problem.  There was no discoloration of the oil, although the water level seemed to be a touch lower than I left it whenever I flushed the cooling system, and the car often left a drip of condensation from the draft tube.  The only reason I found the crack itself, however, was that I was chasing an oil leak originating from somewhere in the pushrod cover area.

*Note for people wondering why I run a 160* thermostat: This car “heat creeps” at cruising speeds, and the carburetor is positioned directly over a long, long exhaust manifold, exacerbating an already tenuous situation regarding carburetor heat soak and the modern equivalent of gasoline.  My thousands of miles of driving have revealed that the engine runs up to 20 degrees cooler on longer trips with a 160 degree thermostat than it does with a 180 degree thermostat.

After cleaning up the crack and highlighting it, this is what I found, although the crack actually extended past my line on each side (as evidenced by the picture of the crack before cleaning).  I posted about my quandary on a couple of my favorite car forums, asking for experience with block repairs. Being open to everything from JB Weld to a new block, I got every answer in between, from marine epoxy to water glass to brazing to cast iron welding.  A few members, however, brought up a system I had heard of before, and that is the avenue I followed.

I contacted a company called Lock-N-Stitch in California, which directed me to drill a hole in the block and measure the thickness of the water jacket wall.  In my case, it was fairly thin, under a hundred thousandths of an inch (which I later found to be worth five or six threads when tapped).  They then assembled a kit including pins, drills, taps, anaerobic sealer, cutting fluid, and instructions for a “one pin at a time” repair.  Additionally, their customer service was excellent – my questions were answered promptly by a guy named Mark who was extremely helpful.

The premise is actually fairly simple: You drill a hole, tap it, thread in a sealed pin until the head breaks (it’s designed to break at a low torque value), grind down the pin until it’s almost flush, and then drill a hole on the edge of the previous pin so the next pin overlaps it.

It’s a tedious process, but once I got rolling, it only took a few hours.

Here I am, hard at work (hardly working?).  Luckily, the crack was easily accessible with the block in the car.  A Buick Straight Eight is a huge engine and my garage is tight in the winter months when I am loath to leave one of the oldies in the driveway.  I did remove the head to get the valves touched up at the machine shop.

Once the pins are installed, you peen the pins with a hammer and do a pressure test.  Since I’m not equipped to pressure test a bare block, I reinstalled the head using the old head gasket and bypassed the Dynaflow cooler and defroster core, and then I used my radiator pressure tester to pressurize the system to about 19 pounds (the Buick uses a 7 psi radiator cap, so this is nearly three times the operating pressure).  Unfortunately, that’s when I discovered that the crack extended about an inch past the visible section on each side, as I mentioned above.

(As a side note, reinstalling the head for testing is certainly advantageous: since the crack is only a few inches below the deck and directly underneath a head bolt boss, torquing the cylinder head down more closely approximates the strain placed on the repaired area.)

In response to the leak, I simply added more pins to each side of the crack, which took less than an hour.  Lock-N-Stitch recommended using a needle scaler to rough up the repair and make it invisible, but this is already a spot nobody sees; additionally, I hope to never sell this car and I wouldn’t try to hide anything if I did.

I am no metallurgist or engineer, but I’ve made an educated guess about the reason for the crack.  First, the crack seems to follow a parting line of some sort that is visible in the picture above; therefore, it’s entirely possible that there was a slight flaw in the casting that finally exposed itself after 60+ years and over 100,000 miles.  Second, the car spent the first 25 years of its life in Florida, where straight water was likely used in the cooling system.  Third, the block was hot tanked only a few years before this crack anecdotally appeared.  Finally, the cylinder head was removed and retorqued twice in my ownership before the crack appeared.  It’s likely that some combination of those four contributed to the problem, perhaps in addition to an overheating problem that had been overlooked for quite some time when I bought the car back in 2005.

In total, I probably used 30-35 pins to repair the crack, which was about four inches long.

After adding the extra pins, I pressurized the system again and it held 19 psi for two and a half hours without any leaks.  Of course, there are still plenty of opportunities for heartbreak here.  I haven’t run the engine yet (I need a new head gasket and other assorted goodies to reassemble everything), so heating and cooling cycles could still affect my repair, as could the rigors of a running engine.  Other cracks could also form around the original crack.  On the other hand, I’ve heard excellent reports of this stitching process, and the threads lock the pins and the block together for a really nice repair; my machinist also mentioned that he’s successfully pinned blocks and saw no reason why I couldn’t save mine.  At any rate, I’ll drop a few GM sealing pellets in the radiator for good measure and say a quick prayer to the gods of internal combustion.  I’ll probably also run the engine for a while with the pushrod cover off to see if everything holds up.

Even if it doesn’t, this was a method worth trying.  Buick 263 blocks are almost 70 years old and not sitting in every garage or barn in America, and there is no guarantee that another block would be any better in a variety of ways.  Second, the whole stitching kit cost me $200, which is inexpensive enough that even if it fails, it is worth the attempt, and if it lasts, it is an even better deal.  Only time, in any of its myriad formats, will tell.