Blown Motor

[kevinl1058]

Well,
Got on it pretty good last night good shifts at 5,000 rpm then bang.. Yep less than 2800 miles on the built 6 and number #1 rod shot through the side of the block and ripped though the front half of the oil pan. I will be calling my engine builder on Monday since they did all the assembly and final torque settings to see what the hell caused this to happen. Man the motor was strong too. Odd thing is that I've pushed it hard before so as to why now it went? All pressure numbers were good? I just got my 8" with 3:80 gears together also.

 

[powerband]

... good shifts at 5,000 rpm then bang


'Guess the RPM limit was @ 4900 RPM... Stretching performance far beyond OEM design parameters is an ongoing learning experience.

I've asked in the forum a number of times if anyone has a Rev Limiter working on their six. The performance built 250 in my '61 (with 3.80 rear gears) revs to redline so fast I'm seriously concerned about catastrophic failure . It is hard to ease up on the throttle when it's still pulling. THe "'Stroked" 200 design - 250 is reportedly even more susceptible to RPM related failures.


Youz payz youz money and youz take youz chanzes...

Have Fun

 

[kevinl1058]

Power band on the cam grind is 1500- 5500 rpm? Well luckily it let go a 1/4 mile from my house so had a neighbor tow me home. Went back to the scene to see if any parts were on the ground to help diagnose what went wrong. Well I found some casting parts that look like the cam gear broke and blew threw the block and pan. Will know more as I tear into it. Just looking through the hole the rid looks still in tack, but it will be a complete tear down.

 

[drag-200stang]

Kevin,

Sometimes defective parts just happen. Maybe something wasn't put together right, maybe not. Don't worry about it. Do you know if they were the C3 forged rods or the late model cast rods? I have no experience with the cast rods. I've always used the C3 forged rods. Replacing the stock bolts with quality after market bolts. The rods were polished and shot pinned at home by myself. With rods done like this, I have revved this thing high enough numerous times to explode 2 clutch pressure plates. I'm not talking about where the disk throws some material off, I'm talking about the pressure plate completely comes apart disintigrating the bellhousing and the front of the transmission dragging on the ground. Rods were fine. This engine was shifted at 7500 and missed shifts would go to 8000, no rod problems. On my turbo motor due to ignition problems and over boost conditions, bent 2 rods 1/4" down the bore due to the excessive cylinder pressure of severe detenation. In other words, when you crank the engine to top dead center, the rods were compressed sideways so it was 1/4" shy of coming to top dead center. Not knowing it had happened at the time, still ran an 11 sec. pass like that. Rod still did not break. What I'm saying is, I don't feel you're over revving or over stressing the rod. Something probably was defective. It happens!!!!

 

[drag-200stang]

I read over the part about the cam gear. Please let us know what caused this. Cam spacer missing maybe? Old cam bolt being used over again without locktite?

 

[fordconvert]

I have heard of crank gears coming apart lately. Its a combination of poor quality metal and the tolerances in the hole as it fits on the crank.