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jwbbuck
05-07-2002, 07:38 AM
I have a cast aluminum oil pan that I would like to use, but it doesn't clear the part of the jet that sticks up through the bottom of my hull - the sump is too deep. I'm using what I thought was a jetboat specific oil pan with a 7.75" deep sump. If I shim the motor mounts up a little, it will help, but it will change the angles of the driveshaft. What is the maximum difference in angle allowed between the crankshaft and the input shaft on the jet?

froggystyle
05-07-2002, 08:07 AM
I'm not sure what the exact number of degrees is, but I do know that the important part is that the pump shaft and the crank stay parallel. If the driveshaft has an equal deflection at the beginning and the end, the vibration will cancel itself out, and you will have no problems. If it is not equal, for example the motor is tilted going into the pump... you will have major vibration occur, and the drive will shake itself apart.
.02

RiverDave2
05-07-2002, 08:31 AM
Froggy, don't they use a Universal Joint similar to those in Automotive applications? If so where's all this vibration coming from?
RD

jwbbuck
05-07-2002, 09:12 AM
RiverDave2,
My setup uses 2 U-joints connected with a rigid tube. I think it should be able to handle some angle between the crank and pump, just like an automotive driveshaft. But, I didn't know how much.
Buck

1tricky1
05-07-2002, 10:09 AM
I believe that you are suppose to have approx. 3 degree angle in a "u-joint" application to allow the u-joint to work properly. I don't know what the max. degree is though. But I would say if it doesn't look right, it probably isn't....my .02
BTW - I don't know any of you guys or girls out there, but feel like I do, and I get alot of enjoyment and good info on these boards, so whenever I think I can help out I do.......Lance

AGGRESSOR JETS
05-07-2002, 10:21 AM
Originally posted by jwbbuck:
RiverDave2,
My setup uses 2 U-joints connected with a rigid tube. I think it should be able to handle some angle between the crank and pump, just like an automotive driveshaft. But, I didn't know how much.
Buck
standard universal joint like 3 point is 2-3 degrees offset- Never in line will burn out-universal- no angle pressure on the caps and they don't work= failure.

Aluminum Squirt
05-07-2002, 11:16 AM
An unrelated but good source of information for driveline angles are your 4X4 buddies or 4 wheel drive magazines. They frequently deal with a lot of driveline angle issues and there are usually some good articles about angles, cancellation, CV joints (changes the entire set up), going to more durable U-joints etc. The application is far different but most of the principals are the same-Aluminum Squirt

froggystyle
05-07-2002, 12:30 PM
Actually, I am pulling my info from my experience with 4WD vehicles... specifically the 1967 Scout I built with a total of 18" of lift with a hand fabricated 1 1/2 ton suspension...
Dave is right... you need some angle, and with the two U-joints they have to be set up not only with complimentary 2-3 degree offsets, but the joints have to be installed at 90 degrees from each other to avoid having "power-strokes" where it gets hard, then easy to turn. A properly set up driveshaft (I have welded many of them) is set up in this manner. Some Chevy lifted trucks use a small angle in the rear with a single U-joint in line with the yoke, and a "CV-style" U-joint in the front. This eliminates the need for identical angles, but you will go through this joint rapidly with extreme lifts.
The bottom line is, if you do not have complimentary angles, the driveline will always be trying to force itself apart, and will vibrate. The torque will be pushing outwards from the angle, and you will eventually grenade the joint. By having the crank and the pump parallel (not in line, parallel) then you will increase the lifespan of the unit, decrease bearing-killing vibration and increase the ability of the unit to handle power.
Kindly note the 1150 RTI we pulled on the 30 degree ramp!
http://www.highperformancecars.com/froggystyle/collage_scout.jpg
Squirts up!
[This message has been edited by froggystyle (edited May 07, 2002).]

HOSS
05-07-2002, 07:32 PM
Agressorjets, you are the only person other than myself that will agree that a U-joint is designed to run on an angle. No angle meens failure. I set all but 2 motors in the MKV`s. The MARK as it is commonly known. That is the Navy Seal boats,,,,jet driven. There were 2 prototypes, 1 was glass, the other aluminum, rumorred of a 3rd composite. One was triple screwed the other twin. Jets were the way to go. Alot of technology was put into jets over the last 10 years. That is why wave piercing ferries all use them. But anyway, U HAVE TO HAVE SOME DEGREE OF ANGLE FOR U-JOINTS. PERIOD. If you think not then go ahead.

HOSS
05-07-2002, 07:34 PM
Oh, by the way, we covered this in the now juvi forum. Everyone thought I was full of it. Well guess what, elimentary my dear.

Aluminum Squirt
05-08-2002, 02:05 AM
Very nice Scout Froggy! What's in it?-Aluminum Squirt

froggystyle
05-08-2002, 07:42 AM
Well, as you may know it came stock with an IH 304 3 speed. Dana 35 front and 44 rear. After two years in my garage though (More of a mad scientists laboratory) it came out after several intermediate iterations as a 427 BBC with Muncie Rockcrusher tranny, Atlas Transfer case, cement truck driveshafts and a Dana 60 front/70 rear with ARB and Detroit loaded on 4:56 gears. Full cage, all the goodies. This was my first full scale build, and some mistakes were made, but all in all, there was a completely hand-built suspension (16" total), 2" body lift, 35" Super Swampers, and a really trick articulation device in the rear for allowing over 48" of articulation at the front tire before lifting a rear up. This is especially impressive as it is a 98" wheelbase!
Squirts up!
Froggy "Knowinsomethingaboutdriveangles"style http://free.***boat.net/ubb/wink.gif