SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: motorhome6 on October 24, 2008, 01:59:06 AM
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I'm new to the jet boat seen and I am trying to put one together that is in pcs and missing parts. Can someone tell me do I need to put a flywheel on my motor to connect a driveline to or starter ring ,also how do u go about lining up the motor with the pump so everything is in line. Any info from you guys would really be helpfull. I have a Weridt hull that has a Berkley pump on it and I just purchased a 454 marine motor mark IV to install in it soon as I find more parts like oil pan and motor mounts (4 point mounts) maybe some alumn side fuel tanks looking for GOOD used parts. thanks anyone that can help with my questions.......gary
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You don't have to run a heavy clutch style flywheel. You do need a flexplate for the starter ring, and with the 454 being externally balanced you need to make sure to use the correct flexplate.
I sure someone else will chime in with info on engine angles ;D
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Need to have a PTO on the flywheel/crankshaft, there are two different ones, one for flexplates, (which frees up some rotational force) and one for flywheels, which are proven to be more reliable as far as the starters are concerned, you could use an aluminum flywheel too, best of both worlds, from the PTO you need a driveline, typically a double U-joint "H" and a flange on one end and a splined yoke on the other, all these parts can be had by calling Tom at Jetboat Performance...
Good luck.
GT
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the guy I got the motor from had a V-Drive and he took off the flexplate for his other motor . I didn't know if the flexplate was just for the V-Drive application but I guess it can be used on a jet also from what your telling me . The strange thing is he gave me another flexplate that he forgot that he had. I haven't figured it out yet why he kept the one that was on the motor. All the teeth look good and the teeth matched up with the other one. Is there a way to find out if the one he gave me is for an externally balanced motor. thanks for your help. There's lots I need to learn about putting one of these together and this web site seems to be full of guy's that know there shit. This has become my favorite site now, can't wait to see what's up for sale next and just read what everyone has to say about different projects. thanks again ,I can't wait to get my boat on the water. This is a father and son project to get me and my son closer and so far it's working out. he's really getting into it now............gary
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The externally balanced flywheel/flexplate is very obvious, there will be a counter weight on the outer diameter, there is almost always a part number on it for identification (not neccisarily a GM number) on a 454 the harmonic balancer is also counter weighted.
I like the father son thing, I'm not there yet...almost.
GT
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Thank's GT Jets for the help..........gary
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Thank's CrewChief 22 for your help also...........gary
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well I found out why the guy I got the motor from kept the flexplate and gave me another one he had , because it's an internal bal. flexplate. Since I have to buy a flexplate or flywheel is aluminum the way to go ? do they make an alumn. flexplate or just flywheel. What is the advantage of an alumn. one over a steel one ? Will the motor be more responsive as in rev quicker. What are the advantages? What would you recommend. flexplate or flywheel steel or aluminum. thanks for your comments.....gary....also I've read about a short drive shaft and one that is alittle longer. I don't understand the different is except for one being longer. why 2 different sizes?....there's lots I need to learn
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The length of the driveshaft will be determined by the mounting location of the engine. Engine mounting location will be determined by what you plan on using the boat for. In some types of racing it helps to push the engine forward, but if its a river/lake pleasure boat that needs a back seat you may be limited how far forward you can go.
I would suggest getting all your mounts together before you purchase a flexplate/flywheel because some of the rear mounts will not clear the thickness of a flywheel (requiring a flexplate).
As far as the flywheel goes, for a mild pleasure boat it isn't going to make much difference between an aluminum or steel flywheel. Just make sure that the engine is a 454 and use the correct flywheel.
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The length of the driveshaft will be determined by the mounting location of the engine. Engine mounting location will be determined by what you plan on using the boat for. In some types of racing it helps to push the engine forward, but if its a river/lake pleasure boat that needs a back seat you may be limited how far forward you can go.
I would suggest getting all your mounts together before you purchase a flexplate/flywheel because some of the rear mounts will not clear the thickness of a flywheel (requiring a flexplate).
As far as the flywheel goes, for a mild pleasure boat it isn't going to make much difference between an aluminum or steel flywheel. Just make sure that the engine is a 454 and use the correct flywheel.
X2 on that Crewchief, also just to confuse you some more ;D the crankshaft determins the 454 thing, so you might consider pulling the pan if you have not already done so and get the crank number....
A new aluminum flywheel is super pricey, I got mine from a Good Guys get together swap meet and it was not useable in a car anymore because the face had been damged and was over cut, but since I was not using it for a clutch, it's perfect, I only paid $40 for it. On the other hand if you run a flexplate I recommend getting an SFI rated one because they are much stronger than a Kragen special, this may prevent you from having starter drive issues due to the flexing, flexplates are designed to have a torque converter mounted to them which stiffens them up a whole bunch..
Just a side note, inspect your harmonic balancer real close too and make sure there are no problems with the isolator (the rubber insulator between the metal parts) they tend to slip when they get older.
Just trying to keep you from having to do it twice (which is the way I normally do it) :banghead:
GT
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i have 4 point mounts or a rail kit for bbchevy, also steel flywheel if you decide to use one, used drive line, also can help with small new parts you might need, i would go with a sfi flex plate tho, i also rent a jig to set up the bbc in a jet boat, check out PB jet section under bigamist post, thanks Jim
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........... i also rent a jig to set up the bbc in a jet boat, check out PB jet section under bigamist post, thanks Jim
Jim, thats a neat fixture and cool of you to rent it out. Just wish I'd known that a year ago.......... :)
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fwww.performanceboats.com%2Fhtml%2FyouBoat%2Fdata%2F500%2FIMG_3164.JPG&hash=805f9876da48bd7add82d209cba32b95b46a03f1)
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After reading your suggestions I think I will go with a flex plate (sfi). This is just going to be a family ski boat, but I don't want to be left to far behind when everyone takes off for a beer run.
GT I'm not sure what you mean by the crankshaft determines the 454 thing. ( your right that confused me more ) :banghead: (lol) Jim, I will be getting a hold of you to check on the mounts you have ,drive line and small stuff I still need,thanks also I'm sure I will want to rent the jig from you to set my motor up. I do only want to do the major set up only once, I can only AFFORD to do it once. I don't like dealing with last minute problems when I think I can just launch the boat and just go have fun. Thank's again for all your comments and advice, without them I would be dead in the water putting this boat together.Plus who are you going to believe when they try to give you there advice. I feel real confident that the advice I get from here is the best I can get because you guys are really into your boats and really go into depth on your motors and everything else you do to your boats. Jim I'll get a hold of you soon ....gary Just saw the jig thats awesome !!! can you put some pics of the rail kit and 4 point mounts on here for me to see?
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After reading your suggestions I think I will go with a flex plate (sfi). This is just going to be a family ski boat, but I don't want to be left to far behind when everyone takes off for a beer run.
GT I'm not sure what you mean by the crankshaft determines the 454 thing. ( your right that confused me more ) :banghead: (lol) Jim, I will be getting a hold of you to check on the mounts you have ,drive line and small stuff I still need,thanks also I'm sure I will want to rent the jig from you to set my motor up. I do only want to do the major set up only once, I can only AFFORD to do it once. I don't like dealing with last minute problems when I think I can just launch the boat and just go have fun. Thank's again for all your comments and advice, without them I would be dead in the water putting this boat together.Plus who are you going to believe when they try to give you there advice. I feel real confident that the advice I get from here is the best I can get because you guys are really into your boats and really go into depth on your motors and everything else you do to your boats. Jim I'll get a hold of you soon ....gary Just saw the jig thats awesome !!! can you put some pics of the rail kit and 4 point mounts on here for me to see?
Pretty simple, you can put a 427 Crank in a 454 block, so if you were to check the block numbers and came up with a 454, it could be a 427, that's bitten me in the ass more than once. (craigslist experts ;D) :banghead:
Trying to keep the jetboat alive ;D
GT
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Very good point GT ,I have to change the pan anyway so I will check the numbers to be sure and avoid any headaches by buying parts for something I am not 100% positive of. thank's for bringing that to my attention ........gary, this is what I mean you guy's are a big help about things I don't even think of. I'll catch on eventually.
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mh6, the 454 is externally balanced requiring the harmonic balancer and flexplate to be counterweighted to keep the engine from vibrating. The 396 and 427 are internally balanced, making it difficult for the novice to identify whats what. If you look at the back side of the 454 harmonic balancer it will have additional material "weight" that the 396 and 427 balancers don't have.
If you're going to pull the pan anyway, it is best to go by the numbers.
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Thank's crewchief22 , that's what I'm going to do, pull the pan and check and I will check the H balancer also, thank's for your help!.......gary