Different props for Alpha vs. Bravo????
10-25-2013, 07:56 PM
#11
Well, figure I should update this thread. Went out with my 2 boys and took the timing light with us a couple weeks back. Turns out the engines were too far advanced! I was afraid I had toasted the engines due to detonation as on startup while setting the timing, the port motor had a little "rattle" too it until it fired. I set the timing on both at 10 degrees base and ran it again. Still would not pull above 4100 rpm with the 4 blade -21p Solas aluminum props. But I did get a gps speed of 47 mph max which is 14% slip. Idling back in, the port motor again seemed to have a noise in it.
Well, we pulled both engiens out this week and this is what we found. Both had loose rocker arms. This has happened before, so all the rocker arm nuts are junk. No wonder it wouldn't make power, it was running on 4 or 5 cylinders on each engine. The cylinders and plugs all look good if a bit heavy on carbon for 11 hours of running. But being rich and running the 93 octane in an engine designed for 87 is probably what saved it with the excess timing I was running. Well, that and almost all my time was at 3100 rpms or less with no real long runs on it. Got lucky and will not make that mistake again.
Oh, minimum planning speed turned out to be about 16mph. 1/3 fuel, 3 people. Bennet tabs down and drives tucked in, handled real nice at that speed. Any slower and around 14 mph it would want to fall off plane if you turned. 16mph is pretty dang slow for tubing, most want to be in the 22 to 28 range for my kids.
Next summer I will be running 23p mirage props, counter rotating. Putting a CR lower on it and with the motors out, will be increasing the cam a bit and doing some head work to the vortecs (valves, springs, roller lifters).
Motor detail will be in my thread in the formula section soon.
Well, we pulled both engiens out this week and this is what we found. Both had loose rocker arms. This has happened before, so all the rocker arm nuts are junk. No wonder it wouldn't make power, it was running on 4 or 5 cylinders on each engine. The cylinders and plugs all look good if a bit heavy on carbon for 11 hours of running. But being rich and running the 93 octane in an engine designed for 87 is probably what saved it with the excess timing I was running. Well, that and almost all my time was at 3100 rpms or less with no real long runs on it. Got lucky and will not make that mistake again.
Oh, minimum planning speed turned out to be about 16mph. 1/3 fuel, 3 people. Bennet tabs down and drives tucked in, handled real nice at that speed. Any slower and around 14 mph it would want to fall off plane if you turned. 16mph is pretty dang slow for tubing, most want to be in the 22 to 28 range for my kids.
Next summer I will be running 23p mirage props, counter rotating. Putting a CR lower on it and with the motors out, will be increasing the cam a bit and doing some head work to the vortecs (valves, springs, roller lifters).
Motor detail will be in my thread in the formula section soon.
Last edited by befu; 10-25-2013 at 07:59 PM.
10-27-2013, 11:21 AM
#15
Basic L31 vortec engine with a XM-270-HR cam through 1.5 roller rockers. Aluminum intake and stock quadrajet carbs. CR alpha drives. Should push the 23p mirage props and lift the bow is my hope. Speed? I just hope the dang thing runs all summer and will hit 60. I suspect mid 60's, but will take anything under it's own power and over 50 at this point.
10-27-2013, 12:51 PM
#16
Registered
prev owner who did motors said he saw 63 gps. the nova 3 has a step and a small pad, but i don't think they helped top speed any. so 60-ish should be in the ballpark. i don't run it that hard. spousal unit starts complaining at 40, and by the time i am over 55, she is making more noise than the engines...
10-27-2013, 01:10 PM
#17
Registered
iTrader: (3)
Sometimes spousal units get out of calibration. This can happen if to much lube is applied. It allows them to spin up without the needed friction coefficient. When this happens it allows them to easily over rev and the calibration goes out of whack. When this happens plugging the rear exhaust port with a thrusting tool fixes the problem. If it doesn't, you may have to either smack the unit with a deadblow hammer or simply replace the unit all together,
If you opt to replace the unit, several reviews have stated the it can be confusing telling the difference between the spousal unit and the new improved boathoe units as the part numbers are very similar. The differences are usually well apparent if you are not distracted by packaging "bling" . While both units can look nearly identical, upon activation the spousal unit will make low grumbling noises such as "STOP: "NO" and "SLOWDOWN" while the boat how unit will make louder higher pitched squeals such as "HARDER" "FASTER" and "YESSS!!!"
If you opt to replace the unit, several reviews have stated the it can be confusing telling the difference between the spousal unit and the new improved boathoe units as the part numbers are very similar. The differences are usually well apparent if you are not distracted by packaging "bling" . While both units can look nearly identical, upon activation the spousal unit will make low grumbling noises such as "STOP: "NO" and "SLOWDOWN" while the boat how unit will make louder higher pitched squeals such as "HARDER" "FASTER" and "YESSS!!!"
Last edited by phragle; 10-27-2013 at 01:19 PM.
02-27-2014, 11:59 AM
#18
Registered
sometimes spousal units get out of calibration. This can happen if to much lube is applied. It allows them to spin up without the needed friction coefficient. When this happens it allows them to easily over rev and the calibration goes out of whack. When this happens plugging the rear exhaust port with a thrusting tool fixes the problem. If it doesn't, you may have to either smack the unit with a deadblow hammer or simply replace the unit all together,
if you opt to replace the unit, several reviews have stated the it can be confusing telling the difference between the spousal unit and the new improved boathoe units as the part numbers are very similar. The differences are usually well apparent if you are not distracted by packaging "bling" . While both units can look nearly identical, upon activation the spousal unit will make low grumbling noises such as "stop: "no" and "slowdown" while the boat how unit will make louder higher pitched squeals such as "harder" "faster" and "yesss!!!"
if you opt to replace the unit, several reviews have stated the it can be confusing telling the difference between the spousal unit and the new improved boathoe units as the part numbers are very similar. The differences are usually well apparent if you are not distracted by packaging "bling" . While both units can look nearly identical, upon activation the spousal unit will make low grumbling noises such as "stop: "no" and "slowdown" while the boat how unit will make louder higher pitched squeals such as "harder" "faster" and "yesss!!!"
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