SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: 82 baja 460 on October 09, 2019, 03:46:57 PM
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I'm new to this forum and i have an unstoppable passion for my Jet boat... Currently i have a nasty vibration which i think is coming from the drive shaft which is only 6.5" long (hopefully not the motor). It doesn't have a PTO on the 460, it's mounted directly to the flywheel/crank shaft. I've replaced the u joints multiple times and i still have a slight mechanical bind of some sort. I think the yoke is messed up somehow. I've replaced the thrust bearing and impeller/sleeve already which didn't help. I've even removed the bowl and impeller to help trouble shoot and eliminate that part of the drive line. I have the splicer kit 1310 on order with the adapter plate for the 460 bolt pattern, but that makes the drive shaft 2" longer at 8.5" total. How can i support the rear part of the motor now? it was mounted on the bearing block assembly before. Also I've had a hard time trying to get the motor mounted at the correct angle. My understanding is that the engine should be about 1 to 2 degrees off not straight on. With that said, the oil pan drain plug area hits the bottom of the boat. I've had this boat for about 1.5 years now and I've replaced the stringers, floor and interior last winter. It ran great for the first month then i noticed a slight vibration which turned really bad really quick. Any guidance would be appreciated thanks. (Ford 460 big block with a Berkeley 12JE)
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I'm new to this forum and i have an unstoppable passion for my Jet boat... Currently i have a nasty vibration which i think is coming from the drive shaft which is only 6.5" long (hopefully not the motor). It doesn't have a PTO on the 460, it's mounted directly to the flywheel/crank shaft. I've replaced the u joints multiple times and i still have a slight mechanical bind of some sort. I think the yoke is messed up somehow. I've replaced the thrust bearing and impeller/sleeve already which didn't help. I've even removed the bowl and impeller to help trouble shoot and eliminate that part of the drive line. I have the splicer kit 1310 on order with the adapter plate for the 460 bolt pattern, but that makes the drive shaft 2" longer at 8.5" total. How can i support the rear part of the motor now? it was mounted on the bearing block assembly before. Also I've had a hard time trying to get the motor mounted at the correct angle. My understanding is that the engine should be about 1 to 2 degrees off not straight on. With that said, the oil pan drain plug area hits the bottom of the boat. I've had this boat for about 1.5 years now and I've replaced the stringers, floor and interior last winter. It ran great for the first month then i noticed a slight vibration which turned really bad really quick. Any guidance would be appreciated thanks. (Ford 460 big block with a Berkeley 12JE)
Your information is flawed?
The engine should be nearly dead nuts with only a slight parallel offset. ANY difference in final angle will play havoc with harmonics and driveline vibration.
The parallel offset should not net more that a degree of joint deflection, but not less than 1/2 a degree for joint bearing lubrication and dynamic tightening.
Sent from my LG-H872 using SoCal Jet Boats mobile app (http://r.tapatalk.com/byo?rid=201)
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thanks for the info. I'll have to remove the oil pan and get it modified so I can get that .5 - .9 degree angle so it's not crashing into the bottom of the boat. Hopefully next few weeks I'll be able to finish it up and test it out.
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You shouldn't have to modify the oil pan, unless it is deeper than 8 inches.
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Yes for whatever reason it's at 8.66" and it looks like a Dorman oil pan part# 264-07. What should the original pan height be?
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Post up some pictures of your setup so we can help.
I've got an F460 with 12JE setup, Milodon 8" 10qt pan, 4 point mounting system and everything lines up nice (except my exhaust to transom ports).
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First pic is after I put new stringers and new floor in. Next 2 are before I pulled the motor out again. With the motor out, I was able to remount the original drive shaft and put new u-joints in. When I was taking the old races out, I made matters worse for myself. I pounded them out crooked, and created burrs. So then I had to re-ream the yoke so the u-joint would operate smoothly. Everything seems smooth, but didn't actually get to take it on the water, lakes froze early this season, so now I have all winter to get the motor remounted correctly. I have to make some brackets to mount motor to stringers and get it perfectly aligned. Any feedback would be greatly appreciated. Thanks.
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