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That point of RPM stability lke all dynamic situations has its own limit and the number of times we exceed the limit reduces the life of the components. I'm not running my stuff anything like you guys to do, but a few late shifts and the datalog showed the engine seeing 8000 and a lttle bit despite the 7800 rev limiter. Further inspection of my busted parts showed this spring locater which was cut by the damper we think much like a hole saw might do to a washer. The other part is the valve tip which pulled away from the end of the valve stem and then worked its way to the pan where I found it.
This tells us the spring broke and the engine continued to run which I suspect meant that it likely broke at the end of my second Pomona timed run. We then went for the 30 mile drive all on freeways and then parked in staging for two hours before we made our first lap. On that run it slowed to 10.24 compared to the 9.90/9.89 it ran in time trials and the MPH was off 4 at the eigth and 10 at the quarter. We're going to test the rest of the springs just to be sure about fatigue and if there is a difference between the intake and exhuast springs numbers on average.
It looks like I'll be replacing all the intake valves due to the tips coming off issue, and with having to bore it 4.6", all new pistons, not to mention a small cut on the heads which will require a look at the piston dish volume. It was at 11.86 CR on this last build and I think we are close to the limit given the Cali 91 pump gas it has to run on which now has at least 10% ethanol. We may go to a 2.45" intake as that calculates out a bit better and the heads can easily accomodate that size. Might add some lift too. This would be all fun except for the $$$$ part.
This tells us the spring broke and the engine continued to run which I suspect meant that it likely broke at the end of my second Pomona timed run. We then went for the 30 mile drive all on freeways and then parked in staging for two hours before we made our first lap. On that run it slowed to 10.24 compared to the 9.90/9.89 it ran in time trials and the MPH was off 4 at the eigth and 10 at the quarter. We're going to test the rest of the springs just to be sure about fatigue and if there is a difference between the intake and exhuast springs numbers on average.
It looks like I'll be replacing all the intake valves due to the tips coming off issue, and with having to bore it 4.6", all new pistons, not to mention a small cut on the heads which will require a look at the piston dish volume. It was at 11.86 CR on this last build and I think we are close to the limit given the Cali 91 pump gas it has to run on which now has at least 10% ethanol. We may go to a 2.45" intake as that calculates out a bit better and the heads can easily accomodate that size. Might add some lift too. This would be all fun except for the $$$$ part.
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