SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: AQUAHOLIC on April 07, 2010, 07:33:08 PM
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ok so as you guys know i have been cursed with motors in my boat. I was wondering if my boat could be doing this. what if my motor and pump are not lined up correctly. would that cause the motors to gernade?
or is iti just suck with boats. or maybe my engine guy can not build a boat motor to last.
also i have a friend in town that has a vortec 454 with the roller stock cam that he will give me a killer deal on. it is a late model engine though. will my oil pan fit on it. will it work in a jet boat?
anyway lets here some ideas on what the hell is going on. i cant keep buying motors every season.
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ok so as you guys know i have been cursed with motors in my boat. I was wondering if my boat could be doing this. what if my motor and pump are not lined up correctly. would that cause the motors to gernade?
or is iti just suck with boats. or maybe my engine guy can not build a boat motor to last.
also i have a friend in town that has a vortec 454 with the roller stock cam that he will give me a killer deal on. it is a late model engine though. will my oil pan fit on it. will it work in a jet boat?
anyway lets here some ideas on what the hell is going on. i cant keep buying motors every season.
1 If ya haven't done anything major to the boat, don't see how that would be causing your motors to keep going south. 2 How is your Maintenence ??? 3 Your engine guy? How well do ya know him, and how long has he been in biz ??? Seems to me if you only get ONE season out of a motor, sumthin aint right :sly: 4 your last questions I don't have a clue, I am sure someone else will chime in
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i did the stringers the motor mounts the alignment all that stuff myself. so that is why i was wondering
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I dont see a misalignment taking out a motor. ( a driveshaft yes ) Did your engine guy build your motor with bigger tollerances on the bearings and cylinders? Jet boat motors have ALOT more load on them CONSTANTLY than a typical car motor.
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I'd think you would be getting a knarley vibration if it was the alingment causing the blow-ups. are you sure motor guy is giving the motor proper clearances for a boat motor? If he's building the same as he would for a car I could see a motor a season or less.
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he said he knew all the clearances for a jet boat. i dont know what everything is set at exactly. i just dont know
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Poorly built with cheap parts maybe ???
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The only thing I can think of is if there was not adequate endplay for the driveline, causing the rear main bearing to fail, and debris circulating through the engine. If you call me we can discuss what was common between the 3 engine failures. Phone number was sent by PM on the other site.
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ya i got your phone number. i will double check end play. but i can still see some of the spline on the shaft when the engine is installed. i will also have the engine guycheck the rear bearing for abnormal wear and tear.
thanks for all your help guys. i am just trying to get to the bottom of this
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Man that sucks. I had to switch my builder on my last motor. aka speedomotive. They screwed so many things up. when I called them about no oil pressure after a rebuild because of their stupidity on the motor before that one. They didn't have a clue. so I yanked the motor and pulled the pan and the oil pump fell off and landed on my foot. They forgot to bolt it on :screwy:. I had it with them at that point. How does a high rep engine builder forget to bolt down the oil pump. :banghead:. Later I found out they use china parts, rods cranks cams ext even when the customer pays and asks for top of the line parts. To be safe I would advise having someone else look at your damaged motor to see if it was builder errors.
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we found that the number three exhaust valve came apart. and blew up the piston then knocked a hole in the cylinder. a couple more exhaust valves are cracked. so far we are thinking that under high rpm the valves are floating or bouncing. this might be making the valves impact the seats too hard and causing them to fallapart. does that sound right to you guys.
there is no evidence of water being introduced into the motor via theheaders. the block had a good amount of sand in it and that could have created a hot spot.
anyway i am heading back to the machine shop after work to see what else i can find out.
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Sounds like your heads were not set up correctly to your cam. What are your cam specs. what kind of lifters, rocker arms, push rods, springs, spring rate? What style keepers? If you throw a nasty cam in your motor with stock heads and assy you will have major problems.
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stock everything. motor is .30 over. and a marine cam. i think it is with the valve train thoug. we are taking a good hard look at that.
my engine guy says he should be able to get it back together for under 600. so i am going to give him another shot
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You run that thing HARD too though Tony, I'd probably spend a little more and get some better hardware in that top end. Just my .02
Sounds awfully cheap, but might be cutting you a lot of slack since he's built it before.......and before......and........ ;D
Ray
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ya that and he is the prior owner of my house. so i already gave hime 180k. lol
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Marine cam and stock everything may be your problem. If its a big cam. you may need better lifters and a different spring rate valve springs. I would run some roller rockers as well. Try and find out the cam specs =the lift at 50 thousandths
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Is this the motor that you Had built and the builder was going to do the break in for you at you place. I cant find the old post but wasn't, there some question on that motor at that time. Is why he was going do the break in for you?/ cant find the old post
:banghead:
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no that was in my friends hallet. we put a 383 in it and flattend the cam during the break in cause the water pump failed. same builder though