EFI & Supercharger Project (Phase II)
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What happened to Phase I ???
As you may have noticed the picture gallery for Phase I of this project does not show the car all put back together and ready to run. The reason for this is that we began experiencing some difficulties at that point in the project and it required so much concentration and effort from me that I forgot to keep taking pictures. As a result, I don't have pictures of the final stages of Phase I where we got the air tubing for the supercharger all finshed, the engine all back together, and the car ready to run. Don't worry, I have pictures of the finished product that you can see here in Phase II, but there is a lot of explaining to do before you see those.
The EFI Problems...
Once we got the 440 all ready to run with the EFI and supercharger all set up, we went ahead and fired the engine to do the cam break-in. The engine fired right up and began breaking in the cam, but we noticed that it seemed to be running extremely rich. I was monitoring the EFI system with the CalMap software on my laptop computer as the engine ran and it was reading way too rich. I kept leaning out the mixture but to no avail. We noticed a lot of white/grey smoke coming from the passenger side tailpipe and you could tell it was fuel. Suddenly we had more to worry about as a small fire broke out under the hood on the passenger side. Turns out the passenger header got so hot it lit fire to one of the spark plug wires. We shut off the engine and put out the fire. We decided to pull some passenger-side spark plugs to see what was going on. When I pulled the number 6 plug, out shot a solid stream of liquid gasoline! We tested the plug and wire for that cylinder and it was definitely firing. As we were scratching our heads over this, I just happened to touch the number 6 fuel injector with my bare hand and it liked to burned the crap out of me! I called up Rance Baxter and after telling him what happened we agreed that there must be something wrong with the injector driver hardware in the ECU (computer) that was causing it to hang number 6 injector wide open (100% duty cycle in efi terms). In other words, the computer was telling number 6 injector to stay wide open and spray a constant stream of fuel at the intake valve. There's no way the cylinder could burn that much fuel running at only 2,000 rpm; it would have had to be running wide open throttle to burn that much fuel. This explained why the computer thought the mixture was way too rich also... because the O2 sensor is mounted in the passenger-side header collector! The hung injector was resulting in the O2 sensor seeing extremely rich exhaust gas, even though the other seven cylinders were running normally.We had a hell of a time fixing this because we had to send the ECU back to Accel and Rance wheeled and dealed with them to send us a "loaner" ECU so I could get my car running. Once we got the loaner box and put it in, everything was fine. I was eventually able to tune the fuel mixture on the laptop good enough to get me on the road. The initial break-in run of the car (from Lincoln, Missouri to Chicago Illinois) went very smoothly. I did not push the car into the power range since I did not have the fuel map tuned yet for power under boost.
The 440 Blows Up...
After returning to Chicago the following weekend, I decided to take the car to Burlington Iowa to visit my Dad. The trip there was uneventful and the car ran fine. I was using this trip to get the fuel map tuned in better and I used every opportunity to drive the car and tune it. I always had the laptop hooked up and running while I drove. So while I was in Burlington one day I went out to run some errands and while I was out I decided to try and do some power tuning for the first time. This is the first time I would hit the engine with boost from the supercharger. The very second I put my foot down THE ENGINE BLEW APART! It happened so fast I didn't have time to see or hear anything. One second it was running fine, the next it was a smoldering pile of rubble. There was a huge crack in the drivers side of the block and a big chunk of the block had been blown out. I pulled a valve cover and could see that four pushrods on the drivers side were missing along with the lifters! After pulling the intake manifold I found that an entire section of the camshaft was missing, and this is why the lifters had fallen into the crankcase along with the pushrods. The pushrods and lifters on the passenger side were also in the crankcase. Needless to say this messed things up in the bottom end pretty good. The number 6 connecting rod was broken and the bottom edges of it's cylinder were beat to hell at the bottom, and the rod had kicked a giant chunk out of the side of the block.We took the engine entirely apart and performed a very thorough post-mortem examination. Here is what we think happened. Remember when we broke in the cam the number 6 injector was hanging wide open filling the cylinder with gas. When I took the plug out a steam of gas shot out under pressure. This tells me that when running that cylinder was very close to hydro-lock, putting an extreme amount of stress on that connecting rod. I think that number 6 rod sustained a stress fracture during that incident. The fracture was not severe enough for the rod to break until the first time it was hit with a shock load. Of course, I had been babying the engine for the first week just trying to get the fuel map dialed in before going into the power range. The first time I hit the engine with load from the supercharger... wham! that stress fracture in the number 6 rod snapped. When we examined the rod there was a chunk of it missing in the middle. I think that chunk of connecting rod got whipped straight up into the camshaft and took out that section of cam. Once that section of cam broke and fell into the crankcase there was nothing to keep the lifters from falling through the bottom of their bores and into the crankcase with the pushrods following closely thereafter. The bottom part of that connecting rod was still attached to the crankshaft and it spun around on it's bearing until it was sticking out at an un-natural angle which caused the crank to slam it into the side of the block on the driver's side and that's what knocked the big chunk out of the side of the block. Well, I guess if you live long enough you will eventually see everything.
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| In the photo above you can see the chunk of block that got blown out. In the two photos that follow, you can see the broken connecting rods. |
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The Replacement Bullet...
When life gives you lemons you have to make lemonade. So, with my 440 in ruins I had to come up with a plan for a replacement bullet. Thankfully, nothing in the top end of the engine got hurt and my investment in the aluminum heads, the EFI system, the supercharger, and the new exhaust system were ok. I decided that if I had to build a new short block anyway I might as well go ahead and step up the cubic inches while I was at it. I called up the guys at Muscle Motors in Lansing, Michigan and ordered up one of their custom 493 stroker short blocks. I was going to try to have the car back on the road in time to make the Mopar Nationals on August 2. The new short block was ready on July 26, and I drove up to Michigan to get the new engine.
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