alpha 1 gen 2 driveshaft problem

[RickyD]

I replaced the seals in the upper dive and took the boat for a test. Well, about 10 mins in, the drive shaft broke. After inspecting I found that the nut on the pinion gear was suppose to be torqued at 6 to 10 inch pounds , I just tightened it and well it broke. My question is how do you set rolling torque? I read one thread on here but I am still confused. I need baby steps. Will someone please help me! I havent a clue about rolling torque.

[Tech Support]

Rolling tourqe is the amount of torque required to keep spinning the bearings. The proper way to reassemble the gear and bearings is to first loosen the bearing pack.

The manual says to remove both bearing and then reinstall. You install the first bearing all the way and the second bearing you leave just slightly loose. Then you pull the bearing in with the nut until you get the proper amount of rolling torque.

A used bearing set should run between 3-5 inch lbs of torque. Do do it properly you need a dial torque wrench.

Tech Support

[RickyD]

I only have one bearing.

[Bt Doctur]

RickyD, not trying to give a short answer but you need a factory manual to
properly set rolling torque not by reading a post somplace.There are in fact 2 bearings for the input shaft. 6-10 in.lbs of torque on the nut IS NOT rolling torque.You tighten the nut ,compressing the bearing package untill the rolling torque is obtained.
go to www.iboats.com and in the adults section you can download the factory manual for your drive.
Follow the new download instructions

[RickyD]

Okay guys im slow and appoligize there are two bearings, sorry about that. i ordered a manual but it has not came in yet. also i ws just wondering what all is involved in the process since i have never heard of rolling torque. but thanks for the info. i'll check out the iboats. Thanks for your help.

[Bt Doctur]

The manuals are free, just follow the new download instructions.
The way to do it is:
assemble the input shaft assembly, the following is from the manual.You support the assembly and hold the bearings with your hand while turning the nut on theyoke untill the proper reading is obtained on the "inch pound torque wrench"

While holding the bearings, rotate the pinion nut
at least two full revolutions. Check preload by rotating
the pinion nut very slowly a third time and,
while rotating, take a reading of the preload. If the
preload is under the specification of 6-10 lb. in.
(0.7-1.1 N·m), torque the pinion nut slightly more
(as instructed in the previous step) and recheck
preload as outlined above. Continue this sequence
until the proper preload is achieved.

[RickyD]

Okay im thinking of replacing the upper unit. a friend has one that has a gear ratio of 1.67 mine is a 1.50 what differences wiil this have and can i run this ratio i have a 98 305.

[Bt Doctur]

It`s a give or take type question
Most V-6`s use that ratio and are aroound 200 hp.
A 305 should be in that vicinity ,but you may have to increase the propeller pitch to compensate and not exceed the recommended wide open throttle limit of your particular engine.

[belectronics]

ALPHA ONE Gen 2 - PRELOAD and ROLLING TORQUE

.
Kindly explain the difference between the two.
I have a 1998 Sea Ray with ALPHA ONE Gen 2, I replace the yoke seal and upon assembly, I missed up the TORQUE. I got no choice but sent the gear and yoke assembly to the local shop. They replaced two bearings and the seal. Upon checking the rolling torque it is 8 in.lbs , but after turning three to four times it went up to 12 in.lbs.
Need an advise if this setting of rolling torque is acceptable that will not damage the drive or the engine coupler.
Also I get confused about PRELOAD and ROLLING TORQUE.
For this alpha I got what are values of PRELOAD and ROLLING torque?
Thanks in advance for any help you can extend.

[admin]

Preload and rolling torque are essentially the same thing. If you mechanic put it together for you, it should be fine. The spec for new bearings is 6-10 inch lbs of torque, but you have to be using a dial torque wrench. Ifyou are using a torque wrench that clicks, it will not give you the actual rolling torque, it gives you breakaway torque which is slightly higher.

Tech support