Live and learn. We've been saying that to ourselves a lot lately. It's essentially just a nice way of saying you've just screwed up, but don't plan on doing it again. Because we did a lot of livin' and learnin', Project Mudslinger was delayed so much that the car was completed about the same time the season came to a close.

Once the racing season closed, work on the car went from steady (if slow) to sporadic. We live in the southern reaches of North Carolina, where it never stays very cold for very long, so our preparations for winter were basically limited to putting the car up on jack stands and closing the garage door. Unfortunately, it wasn't enough. One afternoon, Scott Helms walked into the shop and immediately noticed a puddle of water underneath the car. It didn't take too long to discover the source: a big, horseshoe-shaped crack in the block. It was between the number two and three cylinders on the intake side, and looked as if a chunk of metal had been pushed straight out.

139 0310 Mud 01 Z
Here's what not paying attention to details can do for you. We left the engine full of water and it froze during a cold snap last winter, cracking the block.
Here's what not paying attention to details can do for you. We left the engine full of wat

So, I did the only thing I knew how to do in this situation: I made a panicked call for help. I called our engine builder, Johnson's Machine Shop in Kinards, South Carolina, to see if the block could be repaired.

"Sorry," was owner Richard Johnson's reply. "You can weld it up, but in two races it will just be leaking again. The only good solution is to machine up a new block and move all of your pieces into it."

Johnson continues with what I hope is a comment meant to make me feel slightly less embarrassed about the problem: "If I had a nickel every time somebody called me with a cracked block, I'd be a rich man."

Not that that made me feel better, but it did make me realize that this is a far more common problem with racers of every stripe than I had at first thought. Johnson recommends draining the majority of the water from the cooling system--simply unhook the lower water hose on the radiator--and even add a little anti-freeze. One or the other should work, but taking both precautions is good insurance. If your car stays outside or in a trailer, it's also a good idea to pull your engine at the end of the race season and bring it inside your shop for the winter. Just remember to tape up the intake and exhaust ports in the head, and any other access points moisture may have to the interior of the engine.

Project Mudslinger's 2.3-based engine had not been raced--only taken out on shakedown runs on a 1/4-mile private drive once the car was nearing completion. There hadn't been major wear and tear on any of the components. Regardless, Johnson's wanted to check everything out before moving all of our internals over to a new block. There was a fair amount of carbon buildup, which signals that the carburetor was running too rich. We suspect it was from a burst power valve in the carburetor. We had already found and fixed it, but the engine likely hadn't been run enough afterward to burn the carbon out.

Overall, there was a lot more involved to the engine repair than simply pulling all the parts out of our busted block and bolting them up to a new one. Johnson's Machine was very careful to recheck and refit every piece to its specified tolerances. Machining up a new four-cylinder block isn't too expensive, but a careless mistake on reassembly could be. The moral of the story here is that a little precautionary effort in the fall can save you from a lot of heartache in the spring.

  • 139 0310 Mud 02 Z
    Here's our new block. It's a Ford 2.3-liter four-cylinder and has already been bored and honed to 0.030 over. The deck is being cut down so that at TDC the top of the piston will be even with the deck of the block to maximize compression.
    Here's our new block. It's a Ford 2.3-liter four-cylinder and has already been bored and h
  • 139 0310 Mud 03 Z
    Johnson's Machine Shop's lead engine builder Tim Yates spends as much time hand-prepping the block as he does on any other stage in the process. Every oil gallery, water passage, and threaded hole must be chased to make sure no stray particles or casting slag is left to do damage later on. Also, all the passages are chamfered at the deck to make sure they do not interfere with the gasket's ability to seal between the block and head.
    Johnson's Machine Shop's lead engine builder Tim Yates spends as much time hand-prepping t
  • 139 0310 Mud 04 Z
    Yates also took a sanding roll to the dish where the oil filter connects to the block. Yates says it is a small difference, but it does help improve oil flow through the engine.
    Yates also took a sanding roll to the dish where the oil filter connects to the block. Yat
  • 139 0310 Mud 05 Z
    Yates disassembles the damaged engine slowly, inspecting every piece as it came off the engine to spot any signs of trouble.
    Yates disassembles the damaged engine slowly, inspecting every piece as it came off the en
  • 139 0310 Mud 06 Z
    One rod bearing had a small scuff. Yates suspected it was a dry spot when the engine was cranked the first time. Other than generous amounts of assembly lube and making sure you bring the oil pressure up with a hand drill before cranking the engine for the first time, there isn't too much else you can do.
    One rod bearing had a small scuff. Yates suspected it was a dry spot when the engine was c
  • 139 0310 Mud 07 Z
    Larry Teal inspected and rebuilt the head for us. Here, he is using a twisted wire wheel on an air-powered grinder to clean the carbon deposits from the combustion chambers.
    Larry Teal inspected and rebuilt the head for us. Here, he is using a twisted wire wheel o
  • 139 0310 Mud 08 Z
    After cleaning the head, Teal touched all the seats with a grinder and relapped the valves to make sure all the valves were still seating correctly. This is an important step because it is almost impossible not to inadvertently scratch the seats with the brush. Teal also touched up the deck with a horizontal belt sander.
    After cleaning the head, Teal touched all the seats with a grinder and relapped the valves
  • 139 0310 Mud 09 Z
    Before grinding the seats, Teal had already measured all the stem heights. After the head had been thoroughly cleaned, he checked the heights again. The intakes were fine, but the exhaust valves were now too tall. Because this is an overhead-valve engine, stem height is critical. Teal ground the exhaust stems slightly to bring them back within tolerance. The extra height also put too little pressure on the springs. This was corrected by using valve locks that held the retainers 0.050-inch lower than the stock locks did.
    Before grinding the seats, Teal had already measured all the stem heights. After the head
  • 139 0310 Mud 10 Z
    Johnson's Machine has its own pulley set CNC machined to its specifications, and it's pretty trick. This is the lower pulley (black) with the cam belt pulley sitting on top. The standard setup (this image) requires that the stock belt retainer be used to hold the cog belt on the pulley, and they are often difficult to find. Johnson's (next image) pulley incorporates the retainer, making it impossible to lose. Also, you will notice Johnson's pulley is made for a grooved belt rather than a V-belt. Richard Johnson says dyno tests have proven that the reduction in parasitic friction from switching belts is worth two horsepower on these little motors.
    Johnson's Machine has its own pulley set CNC machined to its specifications, and it's pret
  • (See Previous Image's Caption)
  • Here's another view of the pulley set. The top pulley connects to the water pump.
  • A new block means all new main bearings must be purchased and installed.
  • 139 0310 Mud 14 Z
    Because we scuffed a rod bearing, Yates decided the best thing to do was replace all of them. This, of course, means rechecking all the tolerances against the crank just like it is a brand new assembly.
    Because we scuffed a rod bearing, Yates decided the best thing to do was replace all of th
  • (See Previous Image's Caption)
  • 139 0310 Mud 16 Z
    We probably could have gotten away with reinstalling the rings, but it's much simpler to replace them now, rather than later. Yates uses a standard tension set in ours because we are more concerned with engine longevity than squeezing every last drop of power out of it.
    We probably could have gotten away with reinstalling the rings, but it's much simpler to r
  • 139 0310 Mud 17 Z
    Before bolting on the head and degreeing in the crank, Yates confirms the number one cylinder is at TDC.
    Before bolting on the head and degreeing in the crank, Yates confirms the number one cylin
  • 139 0310 Mud 18 Z
    A single overhead cam engine is fairly easy to set the advance. After confirming the deck of the head is dead level, set an angle finder across the lobes (intake and exhaust angled up). Zero degrees of advance is when the angle finder is level. To advance the cam two degrees, simply rotate the cam until the angle finder reads two degrees.
    A single overhead cam engine is fairly easy to set the advance. After confirming the deck
  • 139 0310 Mud 19 Z
    Here's our new engine, all belted up and just about ready to go. Johnson's new pulleys are quite a bit smaller than our previous set, reducing a little more weight.
    Here's our new engine, all belted up and just about ready to go. Johnson's new pulleys are
SOURCE
Johnson's Machine Shop
8-64/-697-6067
www.johnsonsmachine.com
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