- Official Post
This is a fairly long story, but worth the read, so a comfortable chair and an appropriate beverage would be a plus.
This does not involve a Hipo 289 but rather a 55 Chevy back in the mid 60's. I personally had a 57 Chevy with a 270 horse 283 which is a factory dual quad solid lifter engine. These engines were known at the time as high RPM engines. I was replacing my clutch at one time and noticed a lot of heat cracks in the flywheel so I chose to replace it. Moving on with this story, a friend of mine had a 55 Chevy with a 283 bored .125 over making it what we called at the time a 301. When Chevy created the same .125 over 283 engine, they called it a 302 as in the 67-69 Camaro Z28. My friend also put a Mickey Thompson patent pending cross ram with two AFB's on the engine. This setup normally did not work well at lower RPM but this one worked well throughout the range. He also put a close ratio T10 aluminum 4 speed in the car. 55-57 Chevys only have engine mounts at the very front of the engine and on the bell housing. The transmission bolts to the bellhousing with the bellhousing being the only support as Chevy did not use a transmission mount until 1958 when they went to engine side mounts. When he was building the car, he did not have a flywheel and he asked to borrow my old one temporarily. All of this information is important as it all ties in very soon.
I was riding with him in my neighborhood where some of the streets were fairly long and on a slight downgrade. He wanted to show me how fast his car was now with all of his upgrades. He was in first gear and jumped on it as I was trying to tell him this was not a good idea with my flywheel. He either did not hear me or ignored me and power shifted to second gear. With the 3.55 rear end gears and a 2.20 first gear, 60 miles per hour is easily attained. So, at this speed and RPM, the flywheel did explode. I pulled my feet back when I heard and felt the explosion but if the flywheel had come through, I do not believe that my reaction time would have been good enough to keep my legs intact. The floor was pushed up on my side. My friend had a large hole on his side and about ¼ chunk of flywheel hit him in the leg. Miraculously, he did not get physically hurt. He did have a mental panic when he realized what had just taken place though. He started opening his door so that he could jump out. I was hanging onto him to keep that from happening. He realized that the service brakes were no longer functional, so he tried the parking brake. Remember that there is no transmission mount, and the parking brake is below the transmission. With the transmission laying on the parking brake, the mechanism would not function. Downshifting was of no use as the transmission was no longer attached to the engine. So here we are at around 60 MPH on a slight downgrade with no brakes, somehow, I made the decision to grab the steering wheel from the passenger side and keep steering the car against the sidewalk curbs. About a 3/8 mile after the explosion, we came upon a cross street where we had the stop sign and the cross traffic did not. Luckily there were no vehicles there when we went through and also had to navigate a double dip in the road for drainage. We continued on another ½ mile with me steering into curbs attempting to stop us and came to a main street that is well traveled. I managed to steer us into a sharp right turn and successfully stop us at the curb of the main street without any issues.
Now we had time to survey the actual damages. This explosion made a perfectly good 55 Chevy into a total loss at the time. The obvious damage without even getting out of the car was that the whole dash board was ballooned up against the windshield. Looking beneath the car was a reality check and a half!! The right side frame rail was cleanly cut through. The upsetting part is that the fuel and brake lines were also cut which explains the lack of service brakes. The fuel line was a much larger concern while we were still rolling as it was dripping fuel. The scary part was that the starter had been dragging the ground making sparks right next to the fuel line while we were still in motion. Had I known this, I might have wanted to jump out myself!! The rear of the block was torn away where the bell housing attaches and a significant hole in the oil pan happened as well.
The next day we observed the damage at the point where the explosion happened. There was a significant hole in the street and a small picket fence next to the street where this happened was torn down by the chunks of flywheel.
A flywheel explosion is enough of an issue without being on public streets trying to bring a car to a stop without any brakes. From this point forward, I used billet flywheels and Lakewood hydroformed scatter shields with block plate on my own cars, although, Lakewood had to start their business before that could happen. At that time, the Wedge was about the only scatter shield available.
Being able to walk away from this carnage was really a bonus!!
-Fred-
